Also see:

setDefaultWriteLockTimeout

Also see:

LogMergePolicy#DEFAULT_MERGE_FACTOR

Also see:

LogDocMergePolicy#DEFAULT_MAX_MERGE_DOCS

 public IndexWriter(String path,
    Analyzer a) throws IOException, CorruptIndexException, LockObtainFailedException 
{
    init(FSDirectory.getDirectory(path), a, true, null, true, DEFAULT_MAX_FIELD_LENGTH);
}

Constructs an IndexWriter for the index in path, first creating it if it does not already exist. Text will be analyzed with a.

Parameters:

path - the path to the index directory

a - the analyzer to use

Throws:

CorruptIndexException - if the index is corrupt

LockObtainFailedException - if another writer has this index open (write.lock could not be obtained)

IOException - if the directory cannot be read/written to or if there is any other low-level IO error

 public IndexWriter(File path,
    Analyzer a) throws IOException, CorruptIndexException, LockObtainFailedException 
{
    init(FSDirectory.getDirectory(path), a, true, null, true, DEFAULT_MAX_FIELD_LENGTH);
}

Constructs an IndexWriter for the index in path, first creating it if it does not already exist. Text will be analyzed with a.

Parameters:

path - the path to the index directory

a - the analyzer to use

Throws:

CorruptIndexException - if the index is corrupt

LockObtainFailedException - if another writer has this index open (write.lock could not be obtained)

IOException - if the directory cannot be read/written to or if there is any other low-level IO error

 public IndexWriter(Directory d,
    Analyzer a) throws IOException, CorruptIndexException, LockObtainFailedException 
{
    init(d, a, false, null, true, DEFAULT_MAX_FIELD_LENGTH);
}

Constructs an IndexWriter for the index in d, first creating it if it does not already exist. Text will be analyzed with a.

Parameters:

d - the index directory

a - the analyzer to use

Throws:

CorruptIndexException - if the index is corrupt

LockObtainFailedException - if another writer has this index open (write.lock could not be obtained)

IOException - if the directory cannot be read/written to or if there is any other low-level IO error

 public IndexWriter(String path,
    Analyzer a,
    boolean create) throws IOException, CorruptIndexException, LockObtainFailedException 
{
    init(FSDirectory.getDirectory(path), a, create, true, null, true, DEFAULT_MAX_FIELD_LENGTH);
}

Constructs an IndexWriter for the index in path. Text will be analyzed with a. If create is true, then a new, empty index will be created in path, replacing the index already there, if any.

Parameters:

path - the path to the index directory

a - the analyzer to use

create - true to create the index or overwrite the existing one; false to append to the existing index

Throws:

CorruptIndexException - if the index is corrupt

LockObtainFailedException - if another writer has this index open (write.lock could not be obtained)

IOException - if the directory cannot be read/written to, or if it does not exist and create is false or if there is any other low-level IO error

 public IndexWriter(File path,
    Analyzer a,
    boolean create) throws IOException, CorruptIndexException, LockObtainFailedException 
{
    init(FSDirectory.getDirectory(path), a, create, true, null, true, DEFAULT_MAX_FIELD_LENGTH);
}

Constructs an IndexWriter for the index in path. Text will be analyzed with a. If create is true, then a new, empty index will be created in path, replacing the index already there, if any.

Parameters:

path - the path to the index directory

a - the analyzer to use

create - true to create the index or overwrite the existing one; false to append to the existing index

Throws:

CorruptIndexException - if the index is corrupt

LockObtainFailedException - if another writer has this index open (write.lock could not be obtained)

IOException - if the directory cannot be read/written to, or if it does not exist and create is false or if there is any other low-level IO error

 public IndexWriter(Directory d,
    Analyzer a,
    boolean create) throws IOException, CorruptIndexException, LockObtainFailedException 
{
    init(d, a, create, false, null, true, DEFAULT_MAX_FIELD_LENGTH);
}

Constructs an IndexWriter for the index in d. Text will be analyzed with a. If create is true, then a new, empty index will be created in d, replacing the index already there, if any.

Parameters:

d - the index directory

a - the analyzer to use

create - true to create the index or overwrite the existing one; false to append to the existing index

Throws:

CorruptIndexException - if the index is corrupt

LockObtainFailedException - if another writer has this index open (write.lock could not be obtained)

IOException - if the directory cannot be read/written to, or if it does not exist and create is false or if there is any other low-level IO error

 public IndexWriter(String path,
    Analyzer a,
    IndexWriter.MaxFieldLength mfl) throws IOException, CorruptIndexException, LockObtainFailedException 
{
    init(FSDirectory.getDirectory(path), a, true, null, false, mfl.getLimit());
}

Constructs an IndexWriter for the index in path, first creating it if it does not already exist. Text will be analyzed with a.

NOTE: autoCommit (see above) is set to false with this constructor.

Parameters:

path - the path to the index directory

a - the analyzer to use

mfl - Maximum field length: LIMITED, UNLIMITED, or user-specified via the MaxFieldLength constructor.

Throws:

CorruptIndexException - if the index is corrupt

LockObtainFailedException - if another writer has this index open (write.lock could not be obtained)

IOException - if the directory cannot be read/written to or if there is any other low-level IO error

 public IndexWriter(File path,
    Analyzer a,
    IndexWriter.MaxFieldLength mfl) throws IOException, CorruptIndexException, LockObtainFailedException 
{
    init(FSDirectory.getDirectory(path), a, true, null, false, mfl.getLimit());
}

Constructs an IndexWriter for the index in path, first creating it if it does not already exist. Text will be analyzed with a.

NOTE: autoCommit (see above) is set to false with this constructor.

Parameters:

path - the path to the index directory

a - the analyzer to use

mfl - Maximum field length: LIMITED, UNLIMITED, or user-specified via the MaxFieldLength constructor.

Throws:

CorruptIndexException - if the index is corrupt

LockObtainFailedException - if another writer has this index open (write.lock could not be obtained)

IOException - if the directory cannot be read/written to or if there is any other low-level IO error

 public IndexWriter(Directory d,
    Analyzer a,
    IndexWriter.MaxFieldLength mfl) throws IOException, CorruptIndexException, LockObtainFailedException 
{
    init(d, a, false, null, false, mfl.getLimit());
}

Constructs an IndexWriter for the index in d, first creating it if it does not already exist. Text will be analyzed with a.

NOTE: autoCommit (see above) is set to false with this constructor.

Parameters:

d - the index directory

a - the analyzer to use

mfl - Maximum field length: LIMITED, UNLIMITED, or user-specified via the MaxFieldLength constructor.

Throws:

CorruptIndexException - if the index is corrupt

LockObtainFailedException - if another writer has this index open (write.lock could not be obtained)

IOException - if the directory cannot be read/written to or if there is any other low-level IO error

 public IndexWriter(Directory d,
    boolean autoCommit,
    Analyzer a) throws IOException, CorruptIndexException, LockObtainFailedException 
{
    init(d, a, false, null, autoCommit, DEFAULT_MAX_FIELD_LENGTH);
}

Constructs an IndexWriter for the index in d, first creating it if it does not already exist. Text will be analyzed with a.

Parameters:

d - the index directory

autoCommit - see above

a - the analyzer to use

Throws:

CorruptIndexException - if the index is corrupt

LockObtainFailedException - if another writer has this index open (write.lock could not be obtained)

IOException - if the directory cannot be read/written to or if there is any other low-level IO error

 public IndexWriter(String path,
    Analyzer a,
    boolean create,
    IndexWriter.MaxFieldLength mfl) throws IOException, CorruptIndexException, LockObtainFailedException 
{
    init(FSDirectory.getDirectory(path), a, create, true, null, false, mfl.getLimit());
}

Constructs an IndexWriter for the index in path. Text will be analyzed with a. If create is true, then a new, empty index will be created in path, replacing the index already there, if any.

NOTE: autoCommit (see above) is set to false with this constructor.

Parameters:

path - the path to the index directory

a - the analyzer to use

create - true to create the index or overwrite the existing one; false to append to the existing index

mfl - Maximum field length: LIMITED, UNLIMITED, or user-specified via the MaxFieldLength constructor.

Throws:

CorruptIndexException - if the index is corrupt

LockObtainFailedException - if another writer has this index open (write.lock could not be obtained)

IOException - if the directory cannot be read/written to, or if it does not exist and create is false or if there is any other low-level IO error

 public IndexWriter(File path,
    Analyzer a,
    boolean create,
    IndexWriter.MaxFieldLength mfl) throws IOException, CorruptIndexException, LockObtainFailedException 
{
    init(FSDirectory.getDirectory(path), a, create, true, null, false, mfl.getLimit());
}

Constructs an IndexWriter for the index in path. Text will be analyzed with a. If create is true, then a new, empty index will be created in path, replacing the index already there, if any.

NOTE: autoCommit (see above) is set to false with this constructor.

Parameters:

path - the path to the index directory

a - the analyzer to use

create - true to create the index or overwrite the existing one; false to append to the existing index

mfl - Maximum field length: LIMITED, UNLIMITED, or user-specified via the MaxFieldLength constructor.

Throws:

CorruptIndexException - if the index is corrupt

LockObtainFailedException - if another writer has this index open (write.lock could not be obtained)

IOException - if the directory cannot be read/written to, or if it does not exist and create is false or if there is any other low-level IO error

 public IndexWriter(Directory d,
    Analyzer a,
    boolean create,
    IndexWriter.MaxFieldLength mfl) throws IOException, CorruptIndexException, LockObtainFailedException 
{
    init(d, a, create, false, null, false, mfl.getLimit());
}

Constructs an IndexWriter for the index in d. Text will be analyzed with a. If create is true, then a new, empty index will be created in d, replacing the index already there, if any.

NOTE: autoCommit (see above) is set to false with this constructor.

Parameters:

d - the index directory

a - the analyzer to use

create - true to create the index or overwrite the existing one; false to append to the existing index

mfl - Maximum field length: LIMITED, UNLIMITED, or user-specified via the MaxFieldLength constructor.

Throws:

CorruptIndexException - if the index is corrupt

LockObtainFailedException - if another writer has this index open (write.lock could not be obtained)

IOException - if the directory cannot be read/written to, or if it does not exist and create is false or if there is any other low-level IO error

 public IndexWriter(Directory d,
    boolean autoCommit,
    Analyzer a,
    boolean create) throws IOException, CorruptIndexException, LockObtainFailedException 
{
    init(d, a, create, false, null, autoCommit, DEFAULT_MAX_FIELD_LENGTH);
}

Constructs an IndexWriter for the index in d. Text will be analyzed with a. If create is true, then a new, empty index will be created in d, replacing the index already there, if any.

Parameters:

d - the index directory

autoCommit - see above

a - the analyzer to use

create - true to create the index or overwrite the existing one; false to append to the existing index

Throws:

CorruptIndexException - if the index is corrupt

LockObtainFailedException - if another writer has this index open (write.lock could not be obtained)

IOException - if the directory cannot be read/written to, or if it does not exist and create is false or if there is any other low-level IO error

 public IndexWriter(Directory d,
    Analyzer a,
    IndexDeletionPolicy deletionPolicy,
    IndexWriter.MaxFieldLength mfl) throws IOException, CorruptIndexException, LockObtainFailedException 
{
    init(d, a, false, deletionPolicy, false, mfl.getLimit());
}

Expert: constructs an IndexWriter with a custom IndexDeletionPolicy , for the index in d, first creating it if it does not already exist. Text will be analyzed with a.

NOTE: autoCommit (see above) is set to false with this constructor.

Parameters:

d - the index directory

a - the analyzer to use

deletionPolicy - see above

mfl - whether or not to limit field lengths

Throws:

CorruptIndexException - if the index is corrupt

LockObtainFailedException - if another writer has this index open (write.lock could not be obtained)

IOException - if the directory cannot be read/written to or if there is any other low-level IO error

 public IndexWriter(Directory d,
    boolean autoCommit,
    Analyzer a,
    IndexDeletionPolicy deletionPolicy) throws IOException, CorruptIndexException, LockObtainFailedException 
{
    init(d, a, false, deletionPolicy, autoCommit, DEFAULT_MAX_FIELD_LENGTH);
}

Expert: constructs an IndexWriter with a custom IndexDeletionPolicy , for the index in d, first creating it if it does not already exist. Text will be analyzed with a.

Parameters:

d - the index directory

autoCommit - see above

a - the analyzer to use

deletionPolicy - see above

Throws:

CorruptIndexException - if the index is corrupt

LockObtainFailedException - if another writer has this index open (write.lock could not be obtained)

IOException - if the directory cannot be read/written to or if there is any other low-level IO error

 public IndexWriter(Directory d,
    Analyzer a,
    boolean create,
    IndexDeletionPolicy deletionPolicy,
    IndexWriter.MaxFieldLength mfl) throws IOException, CorruptIndexException, LockObtainFailedException 
{
    init(d, a, create, false, deletionPolicy, false, mfl.getLimit());
}

Expert: constructs an IndexWriter with a custom IndexDeletionPolicy , for the index in d. Text will be analyzed with a. If create is true, then a new, empty index will be created in d, replacing the index already there, if any.

NOTE: autoCommit (see above) is set to false with this constructor.

Parameters:

d - the index directory

a - the analyzer to use

create - true to create the index or overwrite the existing one; false to append to the existing index

deletionPolicy - see above

mfl - whether or not to limit field lengths

Throws:

CorruptIndexException - if the index is corrupt

LockObtainFailedException - if another writer has this index open (write.lock could not be obtained)

IOException - if the directory cannot be read/written to, or if it does not exist and create is false or if there is any other low-level IO error

 public IndexWriter(Directory d,
    boolean autoCommit,
    Analyzer a,
    boolean create,
    IndexDeletionPolicy deletionPolicy) throws IOException, CorruptIndexException, LockObtainFailedException 
{
    init(d, a, create, false, deletionPolicy, autoCommit, DEFAULT_MAX_FIELD_LENGTH);
}

Expert: constructs an IndexWriter with a custom IndexDeletionPolicy , for the index in d. Text will be analyzed with a. If create is true, then a new, empty index will be created in d, replacing the index already there, if any.

Parameters:

d - the index directory

autoCommit - see above

a - the analyzer to use

create - true to create the index or overwrite the existing one; false to append to the existing index

deletionPolicy - see above

Throws:

CorruptIndexException - if the index is corrupt

LockObtainFailedException - if another writer has this index open (write.lock could not be obtained)

IOException - if the directory cannot be read/written to, or if it does not exist and create is false or if there is any other low-level IO error

 public  void abort() throws IOException 
{
    rollback();
}

 synchronized  void acquireRead() 
{
    final Thread current = Thread.currentThread();
    while(writeThread != null && writeThread != current)
      doWait();
    readCount++;
}

 synchronized  void acquireWrite() 
{
     
    assert writeThread != Thread.currentThread();
    while(writeThread != null || readCount  > 0)
      doWait();
    // We could have been closed while we were waiting:
    ensureOpen();
    writeThread = Thread.currentThread();
}

 public  void addDocument(Document doc) throws IOException, CorruptIndexException 
{
    addDocument(doc, analyzer);
}

Adds a document to this index. If the document contains more than #setMaxFieldLength(int) terms for a given field, the remainder are discarded.

Note that if an Exception is hit (for example disk full) then the index will be consistent, but this document may not have been added. Furthermore, it's possible the index will have one segment in non-compound format even when using compound files (when a merge has partially succeeded).

This method periodically flushes pending documents to the Directory (see above), and also periodically triggers segment merges in the index according to the MergePolicy in use.

Merges temporarily consume space in the directory. The amount of space required is up to 1X the size of all segments being merged, when no readers/searchers are open against the index, and up to 2X the size of all segments being merged when readers/searchers are open against the index (see #optimize() for details). The sequence of primitive merge operations performed is governed by the merge policy.

Note that each term in the document can be no longer than 16383 characters, otherwise an IllegalArgumentException will be thrown.

Note that it's possible to create an invalid Unicode string in java if a UTF16 surrogate pair is malformed. In this case, the invalid characters are silently replaced with the Unicode replacement character U+FFFD.

 public  void addDocument(Document doc,
    Analyzer analyzer) throws IOException, CorruptIndexException 
{
    ensureOpen();
    boolean doFlush = false;
    boolean success = false;
    try {
      try {
        doFlush = docWriter.addDocument(doc, analyzer);
        success = true;
      } finally {
        if (!success) {
          if (infoStream != null)
            message("hit exception adding document");
          synchronized (this) {
            // If docWriter has some aborted files that were
            // never incref'd, then we clean them up here
            if (docWriter != null) {
              final Collection files = docWriter.abortedFiles();
              if (files != null)
                deleter.deleteNewFiles(files);
            }
          }
        }
      }
      if (doFlush)
        flush(true, false, false);
    } catch (OutOfMemoryError oom) {
      hitOOM = true;
      throw oom;
    }
}

Adds a document to this index, using the provided analyzer instead of the value of #getAnalyzer() . If the document contains more than #setMaxFieldLength(int) terms for a given field, the remainder are discarded.

See #addDocument(Document) for details on index and IndexWriter state after an Exception, and flushing/merging temporary free space requirements.

 public  void addIndexes(Directory[] dirs) throws IOException, CorruptIndexException 
{
    ensureOpen();
    noDupDirs(dirs);
    // Do not allow add docs or deletes while we are running:
    docWriter.pauseAllThreads();
    try {
      if (infoStream != null)
        message("flush at addIndexes");
      flush(true, false, true);
      boolean success = false;
      startTransaction(false);
      try {
        int docCount = 0;
        synchronized(this) {
          ensureOpen();
          for (int i = 0; i <  dirs.length; i++) {
            SegmentInfos sis = new SegmentInfos();	  // read infos from dir
            sis.read(dirs[i]);
            for (int j = 0; j <  sis.size(); j++) {
              final SegmentInfo info = sis.info(j);
              docCount += info.docCount;
              assert !segmentInfos.contains(info);
              segmentInfos.add(info);	  // add each info
            }
          }
        }
        // Notify DocumentsWriter that the flushed count just increased
        docWriter.updateFlushedDocCount(docCount);
        optimize();
        success = true;
      } finally {
        if (success) {
          commitTransaction();
        } else {
          rollbackTransaction();
        }
      }
    } catch (OutOfMemoryError oom) {
      hitOOM = true;
      throw oom;
    } finally {
      docWriter.resumeAllThreads();
    }
}

Merges all segments from an array of indexes into this index.

 public  void addIndexes(IndexReader[] readers) throws IOException, CorruptIndexException 
{
    ensureOpen();
    // Do not allow add docs or deletes while we are running:
    docWriter.pauseAllThreads();
    // We must pre-acquire a read lock here (and upgrade to
    // write lock in startTransaction below) so that no
    // other addIndexes is allowed to start up after we have
    // flushed & optimized but before we then start our
    // transaction.  This is because the merging below
    // requires that only one segment is present in the
    // index:
    acquireRead();
    try {
      SegmentInfo info = null;
      String mergedName = null;
      SegmentMerger merger = null;
      boolean success = false;
      try {
        flush(true, false, true);
        optimize();					  // start with zero or 1 seg
        success = true;
      } finally {
        // Take care to release the read lock if we hit an
        // exception before starting the transaction
        if (!success)
          releaseRead();
      }
      // true means we already have a read lock; if this
      // call hits an exception it will release the write
      // lock:
      startTransaction(true);
      try {
        mergedName = newSegmentName();
        merger = new SegmentMerger(this, mergedName, null);
        IndexReader sReader = null;
        synchronized(this) {
          if (segmentInfos.size() == 1) { // add existing index, if any
            sReader = SegmentReader.get(true, segmentInfos.info(0));
          }
        }
        success = false;
        try {
          if (sReader != null)
            merger.add(sReader);
          for (int i = 0; i <  readers.length; i++)      // add new indexes
            merger.add(readers[i]);
          int docCount = merger.merge();                // merge 'em
          if(sReader != null) {
            sReader.close();
            sReader = null;
          }
          synchronized(this) {
            segmentInfos.clear();                      // pop old infos & add new
            info = new SegmentInfo(mergedName, docCount, directory, false, true,
                                   -1, null, false, merger.hasProx());
            segmentInfos.add(info);
          }
          // Notify DocumentsWriter that the flushed count just increased
          docWriter.updateFlushedDocCount(docCount);
          success = true;
        } finally {
          if (sReader != null) {
            sReader.close();
          }
        }
      } finally {
        if (!success) {
          if (infoStream != null)
            message("hit exception in addIndexes during merge");
          rollbackTransaction();
        } else {
          commitTransaction();
        }
      }
      if (mergePolicy instanceof LogMergePolicy && getUseCompoundFile()) {
        List files = null;
        synchronized(this) {
          // Must incRef our files so that if another thread
          // is running merge/optimize, it doesn't delete our
          // segment's files before we have a change to
          // finish making the compound file.
          if (segmentInfos.contains(info)) {
            files = info.files();
            deleter.incRef(files);
          }
        }
        if (files != null) {
          success = false;
          startTransaction(false);
          try {
            merger.createCompoundFile(mergedName + ".cfs");
            synchronized(this) {
              info.setUseCompoundFile(true);
            }
            success = true;
          } finally {
            deleter.decRef(files);
            if (!success) {
              if (infoStream != null)
                message("hit exception building compound file in addIndexes during merge");
              rollbackTransaction();
            } else {
              commitTransaction();
            }
          }
        }
      }
    } catch (OutOfMemoryError oom) {
      hitOOM = true;
      throw oom;
    } finally {
      docWriter.resumeAllThreads();
    }
}

Merges the provided indexes into this index.

After this completes, the index is optimized.

The provided IndexReaders are not closed.

NOTE: the index in each Directory must not be changed (opened by a writer) while this method is running. This method does not acquire a write lock in each input Directory, so it is up to the caller to enforce this.

NOTE: while this is running, any attempts to add or delete documents (with another thread) will be paused until this method completes.

See #addIndexesNoOptimize(Directory[]) for details on transactional semantics, temporary free space required in the Directory, and non-CFS segments on an Exception.

 public  void addIndexesNoOptimize(Directory[] dirs) throws IOException, CorruptIndexException 
{
    ensureOpen();
    noDupDirs(dirs);
    // Do not allow add docs or deletes while we are running:
    docWriter.pauseAllThreads();
    try {
      if (infoStream != null)
        message("flush at addIndexesNoOptimize");
      flush(true, false, true);
      boolean success = false;
      startTransaction(false);
      try {
        int docCount = 0;
        synchronized(this) {
          ensureOpen();
          for (int i = 0; i <  dirs.length; i++) {
            if (directory == dirs[i]) {
              // cannot add this index: segments may be deleted in merge before added
              throw new IllegalArgumentException("Cannot add this index to itself");
            }
            SegmentInfos sis = new SegmentInfos(); // read infos from dir
            sis.read(dirs[i]);
            for (int j = 0; j <  sis.size(); j++) {
              SegmentInfo info = sis.info(j);
              assert !segmentInfos.contains(info): "dup info dir=" + info.dir + " name=" + info.name;
              docCount += info.docCount;
              segmentInfos.add(info); // add each info
            }
          }
        }
        // Notify DocumentsWriter that the flushed count just increased
        docWriter.updateFlushedDocCount(docCount);
        maybeMerge();
        ensureOpen();
        // If after merging there remain segments in the index
        // that are in a different directory, just copy these
        // over into our index.  This is necessary (before
        // finishing the transaction) to avoid leaving the
        // index in an unusable (inconsistent) state.
        resolveExternalSegments();
        ensureOpen();
        success = true;
      } finally {
        if (success) {
          commitTransaction();
        } else {
          rollbackTransaction();
        }
      }
    } catch (OutOfMemoryError oom) {
      hitOOM = true;
      throw oom;
    } finally {
      docWriter.resumeAllThreads();
    }
}

Merges all segments from an array of indexes into this index.

This may be used to parallelize batch indexing. A large document collection can be broken into sub-collections. Each sub-collection can be indexed in parallel, on a different thread, process or machine. The complete index can then be created by merging sub-collection indexes with this method.

NOTE: the index in each Directory must not be changed (opened by a writer) while this method is running. This method does not acquire a write lock in each input Directory, so it is up to the caller to enforce this.

NOTE: while this is running, any attempts to add or delete documents (with another thread) will be paused until this method completes.

This method is transactional in how Exceptions are handled: it does not commit a new segments_N file until all indexes are added. This means if an Exception occurs (for example disk full), then either no indexes will have been added or they all will have been.

Note that this requires temporary free space in the Directory up to 2X the sum of all input indexes (including the starting index). If readers/searchers are open against the starting index, then temporary free space required will be higher by the size of the starting index (see #optimize() for details).

Once this completes, the final size of the index will be less than the sum of all input index sizes (including the starting index). It could be quite a bit smaller (if there were many pending deletes) or just slightly smaller.

This requires this index not be among those to be added.

 synchronized  void addMergeException(MergePolicy.OneMerge merge) 
{
    assert merge.getException() != null;
    if (!mergeExceptions.contains(merge) && mergeGen == merge.mergeGen)
      mergeExceptions.add(merge);
}

 public  void close() throws IOException, CorruptIndexException 
{
    close(true);
}

Commits all changes to an index and closes all associated files. Note that this may be a costly operation, so, try to re-use a single writer instead of closing and opening a new one. See #commit() for caveats about write caching done by some IO devices.

If an Exception is hit during close, eg due to disk full or some other reason, then both the on-disk index and the internal state of the IndexWriter instance will be consistent. However, the close will not be complete even though part of it (flushing buffered documents) may have succeeded, so the write lock will still be held.

If you can correct the underlying cause (eg free up some disk space) then you can call close() again. Failing that, if you want to force the write lock to be released (dangerous, because you may then lose buffered docs in the IndexWriter instance) then you can do something like this:

try {
writer.close();
} finally {
if (IndexWriter.isLocked(directory)) {
IndexWriter.unlock(directory);
}
}

after which, you must be certain not to use the writer instance anymore.

 public  void close(boolean waitForMerges) throws IOException, CorruptIndexException 
{
    // Ensure that only one thread actually gets to do the closing:
    if (shouldClose()) {
      // If any methods have hit OutOfMemoryError, then abort
      // on close, in case the internal state of IndexWriter
      // or DocumentsWriter is corrupt
      if (hitOOM)
        rollbackInternal();
      else
        closeInternal(waitForMerges);
    }
}

Closes the index with or without waiting for currently running merges to finish. This is only meaningful when using a MergeScheduler that runs merges in background threads.

 public final  void commit() throws IOException, CorruptIndexException 
{
    ensureOpen();
    if (infoStream != null)
      message("commit: start");
    if (autoCommit || pendingCommit == null) {
      if (infoStream != null)
        message("commit: now prepare");
      prepareCommit(true);
    } else if (infoStream != null)
      message("commit: already prepared");
    finishCommit();
}

Commits all pending updates (added & deleted documents) to the index, and syncs all referenced index files, such that a reader will see the changes and the index updates will survive an OS or machine crash or power loss. Note that this does not wait for any running background merges to finish. This may be a costly operation, so you should test the cost in your application and do it only when really necessary.

Note that this operation calls Directory.sync on the index files. That call should not return until the file contents & metadata are on stable storage. For FSDirectory, this calls the OS's fsync. But, beware: some hardware devices may in fact cache writes even during fsync, and return before the bits are actually on stable storage, to give the appearance of faster performance. If you have such a device, and it does not have a battery backup (for example) then on power loss it may still lose data. Lucene cannot guarantee consistency on such devices.

 public  void deleteDocuments(Term term) throws IOException, CorruptIndexException 
{
    ensureOpen();
    try {
      boolean doFlush = docWriter.bufferDeleteTerm(term);
      if (doFlush)
        flush(true, false, false);
    } catch (OutOfMemoryError oom) {
      hitOOM = true;
      throw oom;
    }
}

Deletes the document(s) containing term.

 public  void deleteDocuments(Term[] terms) throws IOException, CorruptIndexException 
{
    ensureOpen();
    try {
      boolean doFlush = docWriter.bufferDeleteTerms(terms);
      if (doFlush)
        flush(true, false, false);
    } catch (OutOfMemoryError oom) {
      hitOOM = true;
      throw oom;
    }
}

Deletes the document(s) containing any of the terms. All deletes are flushed at the same time.

 public  void deleteDocuments(Query query) throws IOException, CorruptIndexException 
{
    ensureOpen();
    boolean doFlush = docWriter.bufferDeleteQuery(query);
    if (doFlush)
      flush(true, false, false);
}

Deletes the document(s) matching the provided query.

 public  void deleteDocuments(Query[] queries) throws IOException, CorruptIndexException 
{
    ensureOpen();
    boolean doFlush = docWriter.bufferDeleteQueries(queries);
    if (doFlush)
      flush(true, false, false);
}

Deletes the document(s) matching any of the provided queries. All deletes are flushed at the same time.

  void doAfterFlush() throws IOException 
{

}

 public synchronized int docCount() 
{
    ensureOpen();
    return maxDoc();
}

Returns the number of documents currently in this index, not counting deletions.

 protected final synchronized  void ensureOpen() throws AlreadyClosedException 
{
    ensureOpen(true);
}

 protected final synchronized  void ensureOpen(boolean includePendingClose) throws AlreadyClosedException 
{
    if (closed || (includePendingClose && closing)) {
      throw new AlreadyClosedException("this IndexWriter is closed");
    }
}

Used internally to throw an AlreadyClosedException if this IndexWriter has been closed.

 public  void expungeDeletes() throws IOException, CorruptIndexException 
{
    expungeDeletes(true);
}

Expunges all deletes from the index. When an index has many document deletions (or updates to existing documents), it's best to either call optimize or expungeDeletes to remove all unused data in the index associated with the deleted documents. To see how many deletions you have pending in your index, call IndexReader#numDeletedDocs This saves disk space and memory usage while searching. expungeDeletes should be somewhat faster than optimize since it does not insist on reducing the index to a single segment (though, this depends on the MergePolicy ; see MergePolicy#findMergesToExpungeDeletes .). Note that this call does not first commit any buffered documents, so you must do so yourself if necessary. See also #expungeDeletes(boolean)

 public  void expungeDeletes(boolean doWait) throws IOException, CorruptIndexException 
{
    ensureOpen();
    if (infoStream != null)
      message("expungeDeletes: index now " + segString());
    MergePolicy.MergeSpecification spec;
    synchronized(this) {
      spec = mergePolicy.findMergesToExpungeDeletes(segmentInfos, this);
      if (spec != null) {
        final int numMerges = spec.merges.size();
        for(int i=0;i< numMerges;i++)
          registerMerge((MergePolicy.OneMerge) spec.merges.get(i));
      }
    }
    mergeScheduler.merge(this);
    if (spec != null && doWait) {
      final int numMerges = spec.merges.size();
      synchronized(this) {
        boolean running = true;
        while(running) {
          // Check each merge that MergePolicy asked us to
          // do, to see if any of them are still running and
          // if any of them have hit an exception.
          running = false;
          for(int i=0;i< numMerges;i++) {
            final MergePolicy.OneMerge merge = (MergePolicy.OneMerge) spec.merges.get(i);
            if (pendingMerges.contains(merge) || runningMerges.contains(merge))
              running = true;
            Throwable t = merge.getException();
            if (t != null) {
              IOException ioe = new IOException("background merge hit exception: " + merge.segString(directory));
              ioe.initCause(t);
              throw ioe;
            }
          }
          // If any of our merges are still running, wait:
          if (running)
            doWait();
        }
      }
    }
    // NOTE: in the ConcurrentMergeScheduler case, when
    // doWait is false, we can return immediately while
    // background threads accomplish the optimization
}

Just like #expungeDeletes() , except you can specify whether the call should block until the operation completes. This is only meaningful with a MergeScheduler that is able to run merges in background threads.

 protected  void finalize() throws Throwable 
{
    try {
      if (writeLock != null) {
        writeLock.release();                        // release write lock
        writeLock = null;
      }
    } finally {
      super.finalize();
    }
}

Release the write lock, if needed.

 public final  void flush() throws IOException, CorruptIndexException 
{
  
    if (hitOOM)
      throw new IllegalStateException("this writer hit an OutOfMemoryError; cannot flush");
    flush(true, false, true);
}

Flush all in-memory buffered updates (adds and deletes) to the Directory.

Note: while this will force buffered docs to be pushed into the index, it will not make these docs visible to a reader. Use #commit() instead

 protected final  void flush(boolean triggerMerge,
    boolean flushDocStores,
    boolean flushDeletes) throws IOException, CorruptIndexException 
{
    // We can be called during close, when closing==true, so we must pass false to ensureOpen:
    ensureOpen(false);
    if (doFlush(flushDocStores, flushDeletes) && triggerMerge)
      maybeMerge();
}

Flush all in-memory buffered udpates (adds and deletes) to the Directory.

 public Analyzer getAnalyzer() 
{
    ensureOpen();
    return analyzer;
}

Returns the analyzer used by this index.

 final synchronized int getBufferedDeleteTermsSize() 
{
    return docWriter.getBufferedDeleteTerms().size();
}

 public static PrintStream getDefaultInfoStream() 
{
    return IndexWriter.defaultInfoStream;
}

Returns the current default infoStream for newly instantiated IndexWriters.

 public static long getDefaultWriteLockTimeout() 
{
    return IndexWriter.WRITE_LOCK_TIMEOUT;
}

Returns default write lock timeout for newly instantiated IndexWriters.

 public Directory getDirectory() 
{
     
    // Pass false because the flush during closing calls getDirectory
    ensureOpen(false);
    return directory;
}

Returns the Directory used by this index.

 final synchronized int getDocCount(int i) 
{
    if (i  >= 0 && i <  segmentInfos.size()) {
      return segmentInfos.info(i).docCount;
    } else {
      return -1;
    }
}

 final synchronized int getFlushCount() 
{
    return flushCount;
}

 final synchronized int getFlushDeletesCount() 
{
    return flushDeletesCount;
}

 public PrintStream getInfoStream() 
{
    ensureOpen();
    return infoStream;
}

Returns the current infoStream in use by this writer.

 public int getMaxBufferedDeleteTerms() 
{
    ensureOpen();
    return docWriter.getMaxBufferedDeleteTerms();
}

Returns the number of buffered deleted terms that will trigger a flush if enabled.

 public int getMaxBufferedDocs() 
{
    ensureOpen();
    return docWriter.getMaxBufferedDocs();
}

Returns the number of buffered added documents that will trigger a flush if enabled.

 public int getMaxFieldLength() 
{
    ensureOpen();
    return maxFieldLength;
}

Returns the maximum number of terms that will be indexed for a single field in a document.

 public int getMaxMergeDocs() 
{
    return getLogMergePolicy().getMaxMergeDocs();
}

Returns the largest segment (measured by document count) that may be merged with other segments.

Note that this method is a convenience method: it just calls mergePolicy.getMaxMergeDocs as long as mergePolicy is an instance of LogMergePolicy . Otherwise an IllegalArgumentException is thrown.

 public double getMaxSyncPauseSeconds() 
{
    return maxSyncPauseSeconds;
}

Expert: returns max delay inserted before syncing a commit point. On Windows, at least, pausing before syncing can increase net indexing throughput. The delay is variable based on size of the segment's files, and is only inserted when using ConcurrentMergeScheduler for merges.

 public int getMergeFactor() 
{
    return getLogMergePolicy().getMergeFactor();
}

Returns the number of segments that are merged at once and also controls the total number of segments allowed to accumulate in the index.

Note that this method is a convenience method: it just calls mergePolicy.getMergeFactor as long as mergePolicy is an instance of LogMergePolicy . Otherwise an IllegalArgumentException is thrown.

 public MergePolicy getMergePolicy() 
{
    ensureOpen();
    return mergePolicy;
}

Expert: returns the current MergePolicy in use by this writer.

 public MergeScheduler getMergeScheduler() 
{
    ensureOpen();
    return mergeScheduler;
}

Expert: returns the current MergePolicy in use by this writer.

 synchronized MergePolicy.OneMerge getNextMerge() 
{
    if (pendingMerges.size() == 0)
      return null;
    else {
      // Advance the merge from pending to running
      MergePolicy.OneMerge merge = (MergePolicy.OneMerge) pendingMerges.removeFirst();
      runningMerges.add(merge);
      return merge;
    }
}

Expert: the MergeScheduler calls this method to retrieve the next merge requested by the MergePolicy

 final synchronized int getNumBufferedDeleteTerms() 
{
    return docWriter.getNumBufferedDeleteTerms();
}

 final synchronized int getNumBufferedDocuments() 
{
    return docWriter.getNumDocsInRAM();
}

 public double getRAMBufferSizeMB() 
{
    return docWriter.getRAMBufferSizeMB();
}

Returns the value set by #setRAMBufferSizeMB if enabled.

 final synchronized int getSegmentCount() 
{
    return segmentInfos.size();
}

 public Similarity getSimilarity() 
{
    ensureOpen();
    return this.similarity;
}

Expert: Return the Similarity implementation used by this IndexWriter.

This defaults to the current value of Similarity#getDefault() .

 public int getTermIndexInterval() 
{
    // We pass false because this method is called by SegmentMerger while we are in the process of closing
    ensureOpen(false);
    return termIndexInterval;
}

Expert: Return the interval between indexed terms.

 public boolean getUseCompoundFile() 
{
    return getLogMergePolicy().getUseCompoundFile();
}

Get the current setting of whether newly flushed segments will use the compound file format. Note that this just returns the value previously set with setUseCompoundFile(boolean), or the default value (true). You cannot use this to query the status of previously flushed segments.

Note that this method is a convenience method: it just calls mergePolicy.getUseCompoundFile as long as mergePolicy is an instance of LogMergePolicy . Otherwise an IllegalArgumentException is thrown.

 public long getWriteLockTimeout() 
{
    ensureOpen();
    return writeLockTimeout;
}

Returns allowed timeout when acquiring the write lock.

 public synchronized boolean hasDeletions() throws IOException 
{
    ensureOpen();
    if (docWriter.hasDeletes())
      return true;
    for (int i = 0; i <  segmentInfos.size(); i++)
      if (segmentInfos.info(i).hasDeletions())
        return true;
    return false;
}

 public static boolean isLocked(Directory directory) throws IOException 
{
    return directory.makeLock(WRITE_LOCK_NAME).isLocked();
}

Returns true iff the index in the named directory is currently locked.

 public static boolean isLocked(String directory) throws IOException 
{
    Directory dir = FSDirectory.getDirectory(directory);
    try {
      return isLocked(dir);
    } finally {
      dir.close();
    }
}

Returns true iff the index in the named directory is currently locked.

 public synchronized int maxDoc() 
{
    int count;
    if (docWriter != null)
      count = docWriter.getNumDocsInRAM();
    else
      count = 0;
    for (int i = 0; i <  segmentInfos.size(); i++)
      count += segmentInfos.info(i).docCount;
    return count;
}

Returns total number of docs in this index, including docs not yet flushed (still in the RAM buffer), not counting deletions.

 public final  void maybeMerge() throws IOException, CorruptIndexException 
{
    maybeMerge(false);
}

Expert: asks the mergePolicy whether any merges are necessary now and if so, runs the requested merges and then iterate (test again if merges are needed) until no more merges are returned by the mergePolicy. Explicit calls to maybeMerge() are usually not necessary. The most common case is when merge policy parameters have changed.

 final  void merge(MergePolicy.OneMerge merge) throws IOException, CorruptIndexException 
{
    boolean success = false;
    try {
      try {
        try {
          mergeInit(merge);
          if (infoStream != null)
            message("now merge\n  merge=" + merge.segString(directory) + "\n  merge=" + merge + "\n  index=" + segString());
          mergeMiddle(merge);
          success = true;
        } catch (Throwable t) {
          handleMergeException(t, merge);
        }
      } finally {
        synchronized(this) {
          try {
            mergeFinish(merge);
            if (!success) {
              if (infoStream != null)
                message("hit exception during merge");
              if (merge.info != null && !segmentInfos.contains(merge.info))
                deleter.refresh(merge.info.name);
            }
            // This merge (and, generally, any change to the
            // segments) may now enable new merges, so we call
            // merge policy & update pending merges.
            if (success && !merge.isAborted() && !closed && !closing)
              updatePendingMerges(merge.maxNumSegmentsOptimize, merge.optimize);
          } finally {
            runningMerges.remove(merge);
          }
        }
      }
    } catch (OutOfMemoryError oom) {
      hitOOM = true;
      throw oom;
    }
}

Merges the indicated segments, replacing them in the stack with a single segment.

 final synchronized  void mergeFinish(MergePolicy.OneMerge merge) throws IOException 
{
    
    // Optimize, addIndexes or finishMerges may be waiting
    // on merges to finish.
    notifyAll();
    if (merge.increfDone)
      decrefMergeSegments(merge);
    assert merge.registerDone;
    final SegmentInfos sourceSegments = merge.segments;
    final int end = sourceSegments.size();
    for(int i=0;i< end;i++)
      mergingSegments.remove(sourceSegments.info(i));
    mergingSegments.remove(merge.info);
    merge.registerDone = false;
}

Does fininishing for a merge, which is fast but holds the synchronized lock on IndexWriter instance.

 final synchronized  void mergeInit(MergePolicy.OneMerge merge) throws IOException 
{
    boolean success = false;
    try {
      _mergeInit(merge);
      success = true;
    } finally {
      if (!success) {
        mergeFinish(merge);
        runningMerges.remove(merge);
      }
    }
}

Does initial setup for a merge, which is fast but holds the synchronized lock on IndexWriter instance.

 public  void message(String message) 
{
    if (infoStream != null)
      infoStream.println("IW " + messageID + " [" + Thread.currentThread().getName() + "]: " + message);
}

Prints a message to the infoStream (if non-null), prefixed with the identifying information for this writer and the thread that's calling it.

 final String newSegmentName() 
{
    // Cannot synchronize on IndexWriter because that causes
    // deadlock
    synchronized(segmentInfos) {
      // Important to increment changeCount so that the
      // segmentInfos is written on close.  Otherwise we
      // could close, re-open and re-return the same segment
      // name that was previously returned which can cause
      // problems at least with ConcurrentMergeScheduler.
      changeCount++;
      return "_" + Integer.toString(segmentInfos.counter++, Character.MAX_RADIX);
    }
}

 SegmentInfo newestSegment() 
{
    return segmentInfos.info(segmentInfos.size()-1);
}

 public synchronized int numDocs() throws IOException 
{
    int count;
    if (docWriter != null)
      count = docWriter.getNumDocsInRAM();
    else
      count = 0;
    for (int i = 0; i <  segmentInfos.size(); i++) {
      final SegmentInfo info = segmentInfos.info(i);
      count += info.docCount - info.getDelCount();
    }
    return count;
}

Returns total number of docs in this index, including docs not yet flushed (still in the RAM buffer), and including deletions. NOTE: buffered deletions are not counted. If you really need these to be counted you should call #commit() first.

 public final synchronized int numRamDocs() 
{
    ensureOpen();
    return docWriter.getNumDocsInRAM();
}

Expert: Return the number of documents currently buffered in RAM.

 public  void optimize() throws IOException, CorruptIndexException 
{
                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                   
    optimize(true);
}

Requests an "optimize" operation on an index, priming the index for the fastest available search. Traditionally this has meant merging all segments into a single segment as is done in the default merge policy, but individaul merge policies may implement optimize in different ways.

 public  void optimize(int maxNumSegments) throws IOException, CorruptIndexException 
{
    optimize(maxNumSegments, true);
}

Optimize the index down to <= maxNumSegments. If maxNumSegments==1 then this is the same as #optimize() .

 public  void optimize(boolean doWait) throws IOException, CorruptIndexException 
{
    optimize(1, doWait);
}

Just like #optimize() , except you can specify whether the call should block until the optimize completes. This is only meaningful with a MergeScheduler that is able to run merges in background threads.

 public  void optimize(int maxNumSegments,
    boolean doWait) throws IOException, CorruptIndexException 
{
    ensureOpen();
    if (maxNumSegments <  1)
      throw new IllegalArgumentException("maxNumSegments must be  >= 1; got " + maxNumSegments);
    if (infoStream != null)
      message("optimize: index now " + segString());
    flush(true, false, true);
    synchronized(this) {
      resetMergeExceptions();
      segmentsToOptimize = new HashSet();
      final int numSegments = segmentInfos.size();
      for(int i=0;i< numSegments;i++)
        segmentsToOptimize.add(segmentInfos.info(i));
      // Now mark all pending & running merges as optimize
      // merge:
      Iterator it = pendingMerges.iterator();
      while(it.hasNext()) {
        final MergePolicy.OneMerge merge = (MergePolicy.OneMerge) it.next();
        merge.optimize = true;
        merge.maxNumSegmentsOptimize = maxNumSegments;
      }
      it = runningMerges.iterator();
      while(it.hasNext()) {
        final MergePolicy.OneMerge merge = (MergePolicy.OneMerge) it.next();
        merge.optimize = true;
        merge.maxNumSegmentsOptimize = maxNumSegments;
      }
    }
    maybeMerge(maxNumSegments, true);
    if (doWait) {
      synchronized(this) {
        while(true) {
          if (mergeExceptions.size()  > 0) {
            // Forward any exceptions in background merge
            // threads to the current thread:
            final int size = mergeExceptions.size();
            for(int i=0;i< size;i++) {
              final MergePolicy.OneMerge merge = (MergePolicy.OneMerge) mergeExceptions.get(0);
              if (merge.optimize) {
                IOException err = new IOException("background merge hit exception: " + merge.segString(directory));
                final Throwable t = merge.getException();
                if (t != null)
                  err.initCause(t);
                throw err;
              }
            }
          }
          if (optimizeMergesPending())
            doWait();
          else
            break;
        }
      }
      // If close is called while we are still
      // running, throw an exception so the calling
      // thread will know the optimize did not
      // complete
      ensureOpen();
    }
    // NOTE: in the ConcurrentMergeScheduler case, when
    // doWait is false, we can return immediately while
    // background threads accomplish the optimization
}

Just like #optimize(int) , except you can specify whether the call should block until the optimize completes. This is only meaningful with a MergeScheduler that is able to run merges in background threads.

 public final  void prepareCommit() throws IOException, CorruptIndexException 
{
    ensureOpen();
    prepareCommit(false);
}

Expert: prepare for commit. This does the first phase of 2-phase commit. You can only call this when autoCommit is false. This method does all steps necessary to commit changes since this writer was opened: flushes pending added and deleted docs, syncs the index files, writes most of next segments_N file. After calling this you must call either #commit() to finish the commit, or #rollback() to revert the commit and undo all changes done since the writer was opened.

You can also just call #commit() directly without prepareCommit first in which case that method will internally call prepareCommit.

 public final long ramSizeInBytes() 
{
    ensureOpen();
    return docWriter.getRAMUsed();
}

Expert: Return the total size of all index files currently cached in memory. Useful for size management with flushRamDocs()

 final synchronized boolean registerMerge(MergePolicy.OneMerge merge) throws MergePolicy.MergeAbortedException 
{
    if (merge.registerDone)
      return true;
    if (stopMerges) {
      merge.abort();
      throw new MergePolicy.MergeAbortedException("merge is aborted: " + merge.segString(directory));
    }
    final int count = merge.segments.size();
    boolean isExternal = false;
    for(int i=0;i< count;i++) {
      final SegmentInfo info = merge.segments.info(i);
      if (mergingSegments.contains(info))
        return false;
      if (segmentInfos.indexOf(info) == -1)
        return false;
      if (info.dir != directory)
        isExternal = true;
    }
    ensureContiguousMerge(merge);
    pendingMerges.add(merge);
    if (infoStream != null)
      message("add merge to pendingMerges: " + merge.segString(directory) + " [total " + pendingMerges.size() + " pending]");
    merge.mergeGen = mergeGen;
    merge.isExternal = isExternal;
    // OK it does not conflict; now record that this merge
    // is running (while synchronized) to avoid race
    // condition where two conflicting merges from different
    // threads, start
    for(int i=0;i< count;i++)
      mergingSegments.add(merge.segments.info(i));
    // Merge is now registered
    merge.registerDone = true;
    return true;
}

Checks whether this merge involves any segments already participating in a merge. If not, this merge is "registered", meaning we record that its segments are now participating in a merge, and true is returned. Else (the merge conflicts) false is returned.

 synchronized  void releaseRead() 
{
    readCount--;
    assert readCount  >= 0;
    notifyAll();
}

 synchronized  void releaseWrite() 
{
    assert Thread.currentThread() == writeThread;
    writeThread = null;
    notifyAll();
}

 public  void rollback() throws IOException 
{
    ensureOpen();
    if (autoCommit)
      throw new IllegalStateException("rollback() can only be called when IndexWriter was opened with autoCommit=false");
    // Ensure that only one thread actually gets to do the closing:
    if (shouldClose())
      rollbackInternal();
}

Close the IndexWriter without committing any changes that have occurred since the last commit (or since it was opened, if commit hasn't been called). This removes any temporary files that had been created, after which the state of the index will be the same as it was when this writer was first opened. This can only be called when this IndexWriter was opened with autoCommit=false. This also clears a previous call to #prepareCommit .

 public synchronized String segString() 
{
    return segString(segmentInfos);
}

 public static  void setDefaultInfoStream(PrintStream infoStream) 
{
    IndexWriter.defaultInfoStream = infoStream;
}

If non-null, this will be the default infoStream used by a newly instantiated IndexWriter.

 public static  void setDefaultWriteLockTimeout(long writeLockTimeout) 
{
    IndexWriter.WRITE_LOCK_TIMEOUT = writeLockTimeout;
}

Sets the default (for any instance of IndexWriter) maximum time to wait for a write lock (in milliseconds).

 public  void setInfoStream(PrintStream infoStream) 
{
    ensureOpen();
    setMessageID(infoStream);
    docWriter.setInfoStream(infoStream);
    deleter.setInfoStream(infoStream);
    if (infoStream != null)
      messageState();
}

If non-null, information about merges, deletes and a message when maxFieldLength is reached will be printed to this.

 public  void setMaxBufferedDeleteTerms(int maxBufferedDeleteTerms) 
{
    ensureOpen();
    if (maxBufferedDeleteTerms != DISABLE_AUTO_FLUSH
        && maxBufferedDeleteTerms <  1)
      throw new IllegalArgumentException(
          "maxBufferedDeleteTerms must at least be 1 when enabled");
    docWriter.setMaxBufferedDeleteTerms(maxBufferedDeleteTerms);
    if (infoStream != null)
      message("setMaxBufferedDeleteTerms " + maxBufferedDeleteTerms);
}

Determines the minimal number of delete terms required before the buffered in-memory delete terms are applied and flushed. If there are documents buffered in memory at the time, they are merged and a new segment is created.

Disabled by default (writer flushes by RAM usage).

 public  void setMaxBufferedDocs(int maxBufferedDocs) 
{
    ensureOpen();
    if (maxBufferedDocs != DISABLE_AUTO_FLUSH && maxBufferedDocs <  2)
      throw new IllegalArgumentException(
          "maxBufferedDocs must at least be 2 when enabled");
    if (maxBufferedDocs == DISABLE_AUTO_FLUSH
        && getRAMBufferSizeMB() == DISABLE_AUTO_FLUSH)
      throw new IllegalArgumentException(
          "at least one of ramBufferSize and maxBufferedDocs must be enabled");
    docWriter.setMaxBufferedDocs(maxBufferedDocs);
    pushMaxBufferedDocs();
    if (infoStream != null)
      message("setMaxBufferedDocs " + maxBufferedDocs);
}

Determines the minimal number of documents required before the buffered in-memory documents are flushed as a new Segment. Large values generally gives faster indexing.

When this is set, the writer will flush every maxBufferedDocs added documents. Pass in #DISABLE_AUTO_FLUSH to prevent triggering a flush due to number of buffered documents. Note that if flushing by RAM usage is also enabled, then the flush will be triggered by whichever comes first.

Disabled by default (writer flushes by RAM usage).

 public  void setMaxFieldLength(int maxFieldLength) 
{
    ensureOpen();
    this.maxFieldLength = maxFieldLength;
    docWriter.setMaxFieldLength(maxFieldLength);
    if (infoStream != null)
      message("setMaxFieldLength " + maxFieldLength);
}

The maximum number of terms that will be indexed for a single field in a document. This limits the amount of memory required for indexing, so that collections with very large files will not crash the indexing process by running out of memory. This setting refers to the number of running terms, not to the number of different terms.

Note: this silently truncates large documents, excluding from the index all terms that occur further in the document. If you know your source documents are large, be sure to set this value high enough to accomodate the expected size. If you set it to Integer.MAX_VALUE, then the only limit is your memory, but you should anticipate an OutOfMemoryError.

By default, no more than #DEFAULT_MAX_FIELD_LENGTH terms will be indexed for a field.

 public  void setMaxMergeDocs(int maxMergeDocs) 
{
    getLogMergePolicy().setMaxMergeDocs(maxMergeDocs);
}

Determines the largest segment (measured by document count) that may be merged with other segments. Small values (e.g., less than 10,000) are best for interactive indexing, as this limits the length of pauses while indexing to a few seconds. Larger values are best for batched indexing and speedier searches.

The default value is Integer#MAX_VALUE .

Note that this method is a convenience method: it just calls mergePolicy.setMaxMergeDocs as long as mergePolicy is an instance of LogMergePolicy . Otherwise an IllegalArgumentException is thrown.

The default merge policy (LogByteSizeMergePolicy ) also allows you to set this limit by net size (in MB) of the segment, using LogByteSizeMergePolicy#setMaxMergeMB .

 public  void setMaxSyncPauseSeconds(double seconds) 
{
    maxSyncPauseSeconds = seconds;
}

Expert: sets the max delay before syncing a commit point.

 public  void setMergeFactor(int mergeFactor) 
{
    getLogMergePolicy().setMergeFactor(mergeFactor);
}

Determines how often segment indices are merged by addDocument(). With smaller values, less RAM is used while indexing, and searches on unoptimized indices are faster, but indexing speed is slower. With larger values, more RAM is used during indexing, and while searches on unoptimized indices are slower, indexing is faster. Thus larger values (> 10) are best for batch index creation, and smaller values (< 10) for indices that are interactively maintained.

Note that this method is a convenience method: it just calls mergePolicy.setMergeFactor as long as mergePolicy is an instance of LogMergePolicy . Otherwise an IllegalArgumentException is thrown.

This must never be less than 2. The default value is 10.

 public  void setMergePolicy(MergePolicy mp) 
{
    ensureOpen();
    if (mp == null)
      throw new NullPointerException("MergePolicy must be non-null");
    if (mergePolicy != mp)
      mergePolicy.close();
    mergePolicy = mp;
    pushMaxBufferedDocs();
    if (infoStream != null)
      message("setMergePolicy " + mp);
}

Expert: set the merge policy used by this writer.

 public synchronized  void setMergeScheduler(MergeScheduler mergeScheduler) throws IOException, CorruptIndexException 
{
    ensureOpen();
    if (mergeScheduler == null)
      throw new NullPointerException("MergeScheduler must be non-null");
    if (this.mergeScheduler != mergeScheduler) {
      finishMerges(true);
      this.mergeScheduler.close();
    }
    this.mergeScheduler = mergeScheduler;
    if (infoStream != null)
      message("setMergeScheduler " + mergeScheduler);
}

Expert: set the merge scheduler used by this writer.

 public  void setRAMBufferSizeMB(double mb) 
{
    if (mb != DISABLE_AUTO_FLUSH && mb < = 0.0)
      throw new IllegalArgumentException(
          "ramBufferSize should be  > 0.0 MB when enabled");
    if (mb == DISABLE_AUTO_FLUSH && getMaxBufferedDocs() == DISABLE_AUTO_FLUSH)
      throw new IllegalArgumentException(
          "at least one of ramBufferSize and maxBufferedDocs must be enabled");
    docWriter.setRAMBufferSizeMB(mb);
    if (infoStream != null)
      message("setRAMBufferSizeMB " + mb);
}

Determines the amount of RAM that may be used for buffering added documents before they are flushed as a new Segment. Generally for faster indexing performance it's best to flush by RAM usage instead of document count and use as large a RAM buffer as you can.

When this is set, the writer will flush whenever buffered documents use this much RAM. Pass in #DISABLE_AUTO_FLUSH to prevent triggering a flush due to RAM usage. Note that if flushing by document count is also enabled, then the flush will be triggered by whichever comes first.

The default value is #DEFAULT_RAM_BUFFER_SIZE_MB .

 public  void setSimilarity(Similarity similarity) 
{
    ensureOpen();
    this.similarity = similarity;
    docWriter.setSimilarity(similarity);
}

Expert: Set the Similarity implementation used by this IndexWriter.

 public  void setTermIndexInterval(int interval) 
{
    ensureOpen();
    this.termIndexInterval = interval;
}

Expert: Set the interval between indexed terms. Large values cause less memory to be used by IndexReader, but slow random-access to terms. Small values cause more memory to be used by an IndexReader, and speed random-access to terms. This parameter determines the amount of computation required per query term, regardless of the number of documents that contain that term. In particular, it is the maximum number of other terms that must be scanned before a term is located and its frequency and position information may be processed. In a large index with user-entered query terms, query processing time is likely to be dominated not by term lookup but rather by the processing of frequency and positional data. In a small index or when many uncommon query terms are generated (e.g., by wildcard queries) term lookup may become a dominant cost. In particular, numUniqueTerms/interval terms are read into memory by an IndexReader, and, on average, interval/2 terms must be scanned for each random term access.

 public  void setUseCompoundFile(boolean value) 
{
    getLogMergePolicy().setUseCompoundFile(value);
    getLogMergePolicy().setUseCompoundDocStore(value);
}

Setting to turn on usage of a compound file. When on, multiple files for each segment are merged into a single file when a new segment is flushed.

Note that this method is a convenience method: it just calls mergePolicy.setUseCompoundFile as long as mergePolicy is an instance of LogMergePolicy . Otherwise an IllegalArgumentException is thrown.

 public  void setWriteLockTimeout(long writeLockTimeout) 
{
    ensureOpen();
    this.writeLockTimeout = writeLockTimeout;
}

Sets the maximum time to wait for a write lock (in milliseconds) for this instance of IndexWriter. @see

 boolean testPoint(String name) 
{
  
  // Used only by assert for testing.  Current points:
  //   startDoFlush
  //   startCommitMerge
  //   startStartCommit
  //   midStartCommit
  //   midStartCommit2
  //   midStartCommitSuccess
  //   finishStartCommit
  //   startCommitMergeDeletes
  //   startMergeInit
  //   startApplyDeletes
  //   DocumentsWriter.ThreadState.init start
    return true;
}

 public static  void unlock(Directory directory) throws IOException 
{
    directory.makeLock(IndexWriter.WRITE_LOCK_NAME).release();
}

Forcibly unlocks the index in the named directory.

Caution: this should only be used by failure recovery code, when it is known that no other process nor thread is in fact currently accessing this index.

 public  void updateDocument(Term term,
    Document doc) throws IOException, CorruptIndexException 
{
    ensureOpen();
    updateDocument(term, doc, getAnalyzer());
}

Updates a document by first deleting the document(s) containing term and then adding the new document. The delete and then add are atomic as seen by a reader on the same index (flush may happen only after the add).

 public  void updateDocument(Term term,
    Document doc,
    Analyzer analyzer) throws IOException, CorruptIndexException 
{
    ensureOpen();
    try {
      boolean doFlush = false;
      boolean success = false;
      try {
        doFlush = docWriter.updateDocument(term, doc, analyzer);
        success = true;
      } finally {
        if (!success) {
          if (infoStream != null)
            message("hit exception updating document");
          synchronized (this) {
            // If docWriter has some aborted files that were
            // never incref'd, then we clean them up here
            final Collection files = docWriter.abortedFiles();
            if (files != null)
              deleter.deleteNewFiles(files);
          }
        }
      }
      if (doFlush)
        flush(true, false, false);
    } catch (OutOfMemoryError oom) {
      hitOOM = true;
      throw oom;
    }
}

Updates a document by first deleting the document(s) containing term and then adding the new document. The delete and then add are atomic as seen by a reader on the same index (flush may happen only after the add).

 synchronized  void upgradeReadToWrite() 
{
    assert readCount  > 0;
    upgradeCount++;
    while(readCount  > upgradeCount || writeThread != null) {
      doWait();
    }
    writeThread = Thread.currentThread();
    readCount--;
    upgradeCount--;
}