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SUMMARY: JavaDoc of org.apache.derby.impl.jdbc.EmbedBlob JAVADOC | Sourc code of org.apache.derby.impl.jdbc.EmbedBlob SOURCE | Download org.apache.derby.impl.jdbc.EmbedBlob DOWNLOAD | NESTED | FIELD | CONSTR | METHOD DETAIL: FIELD | CONSTR | METHOD

org.apache.derby.impl.jdbc
Class EmbedBlob  view EmbedBlob download EmbedBlob.java

java.lang.Object
  extended byorg.apache.derby.impl.jdbc.ConnectionChild
      extended byorg.apache.derby.impl.jdbc.EmbedBlob
All Implemented Interfaces:
java.sql.Blob
final class EmbedBlob
extends ConnectionChild
implements java.sql.Blob

Implements java.sql.Blob (see the JDBC 2.0 spec). A blob sits on top of a BINARY, VARBINARY or LONG VARBINARY column. If its data is small (less than 1 page) it is a byte array taken from the SQLBit class. If it is large (more than 1 page) it is a long column in the database. The long column is accessed as a stream, and is implemented in store as an OverflowInputStream. The Resetable interface allows sending messages to that stream to initialize itself (reopen its container and lock the corresponding row) and to reset itself to the beginning. NOTE: In the case that the data is large, it is represented as a stream. This stream is returned to the user in the getBinaryStream() method. This means that we have limited control over the state of the stream, since the user can read bytes from it at any time. Thus all methods here reset the stream to the beginning before doing any work. CAVEAT: The methods may not behave correctly if a user sets up multiple threads and sucks data from the stream (returned from getBinaryStream()) at the same time as calling the Blob methods.

Supports

Field Summary
private  BinaryToRawStream biStream
           
private static int BLOB_BUF_SIZE
           
private  byte[] buf
           
protected static boolean CLOSE
           
protected  org.apache.derby.jdbc.InternalDriver factory
          Factory for JDBC objects to be created.
private  boolean isBytes
           
protected  EmbedConnection localConn
           
private  byte[] myBytes
           
private  java.io.InputStream myStream
           
protected static boolean NOCLOSE
           
private  long pos
           
 
Constructor Summary
protected EmbedBlob(org.apache.derby.iapi.types.DataValueDescriptor dvd, EmbedConnection con)
           
 
Method Summary
private  boolean checkMatch(java.sql.Blob pattern)
           
private  boolean checkMatch(byte[] pattern)
           
protected  void commitIfAutoCommit()
          Perform a commit if autocommit is enabled.
protected  void commitIfNeeded()
          Perform a commit if one is needed.
protected  void finalize()
          Called on an object by the Virtual Machine at most once, at some point after the Object is determined unreachable but before it is destroyed.
 java.io.InputStream getBinaryStream()
          Retrieves the BLOB designated by this Blob instance as a stream.
 byte[] getBytes(long startPos, int length)
          Returns as an array of bytes part or all of the BLOB value that this Blob object designates.
protected  java.util.Calendar getCal()
          Get and save a unique calendar object for this JDBC object.
protected  java.lang.Object getConnectionSynchronization()
          Return an object to be used for connection synchronization.
 org.apache.derby.iapi.services.context.ContextManager getContextManager()
           
 org.apache.derby.iapi.db.Database getDatabase()
           
protected  EmbedConnection getEmbedConnection()
          Return a reference to the EmbedConnection
protected  java.sql.SQLException handleException(java.lang.Throwable t)
          Handle any exception.
protected  java.sql.SQLException handleException(java.lang.Throwable t, boolean close)
          Handle any exception.
private  java.sql.SQLException handleMyExceptions(java.lang.Throwable t)
           
 long length()
          Returns the number of bytes in the BLOB value designated by this Blob object.
protected  void needCommit()
          If Autocommit is on, note that a commit is needed.
protected  java.sql.SQLException newSQLException(java.lang.String messageId)
           
protected  java.sql.SQLException newSQLException(java.lang.String messageId, java.lang.Object arg1)
           
protected  java.sql.SQLException newSQLException(java.lang.String messageId, java.lang.Object arg1, java.lang.Object arg2)
           
 long position(java.sql.Blob pattern, long start)
          Determines the byte position in the BLOB value designated by this Blob object at which pattern begins.
 long position(byte[] pattern, long start)
          Determines the byte position at which the specified byte pattern begins within the BLOB value that this Blob object represents.
private  int read()
           
protected  void restoreContextStack()
          Setup the context stack (a.k.a.
 java.io.OutputStream setBinaryStream(long pos)
          JDBC 3.0 Retrieves a stream that can be used to write to the BLOB value that this Blob object represents.
 int setBytes(long pos, byte[] bytes)
          JDBC 3.0 Writes the given array of bytes to the BLOB value that this Blob object represents, starting at position pos, and returns the number of bytes written.
 int setBytes(long pos, byte[] bytes, int offset, int len)
          JDBC 3.0 Writes all or part of the given array of byte array to the BLOB value that this Blob object represents and returns the number of bytes written.
private  void setPosition(long newPos)
           
protected  void setupContextStack()
          Setup the context stack (a.k.a.
 void truncate(long len)
          JDBC 3.0 Truncates the BLOB value that this Blob object represents to be len bytes in length.
 
Methods inherited from class java.lang.Object
clone, equals, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait
 

Field Detail

isBytes

private boolean isBytes

myStream

private java.io.InputStream myStream

myBytes

private byte[] myBytes

pos

private long pos

biStream

private BinaryToRawStream biStream

BLOB_BUF_SIZE

private static int BLOB_BUF_SIZE

buf

private byte[] buf

CLOSE

protected static final boolean CLOSE
See Also:
Constant Field Values

NOCLOSE

protected static final boolean NOCLOSE
See Also:
Constant Field Values

localConn

protected EmbedConnection localConn

factory

protected final org.apache.derby.jdbc.InternalDriver factory
Factory for JDBC objects to be created.

Constructor Detail

EmbedBlob

protected EmbedBlob(org.apache.derby.iapi.types.DataValueDescriptor dvd,
                    EmbedConnection con)
             throws org.apache.derby.iapi.error.StandardException
Method Detail

setPosition

private void setPosition(long newPos)
                  throws org.apache.derby.iapi.error.StandardException,
                         java.io.IOException

read

private int read()
          throws java.io.IOException

length

public long length()
            throws java.sql.SQLException
Returns the number of bytes in the BLOB value designated by this Blob object.

Specified by:
length in interface java.sql.Blob

getBytes

public byte[] getBytes(long startPos,
                       int length)
                throws java.sql.SQLException
Returns as an array of bytes part or all of the BLOB value that this Blob object designates. The byte array contains up to length consecutive bytes starting at position pos.

Specified by:
getBytes in interface java.sql.Blob

getBinaryStream

public java.io.InputStream getBinaryStream()
                                    throws java.sql.SQLException
Retrieves the BLOB designated by this Blob instance as a stream.

Specified by:
getBinaryStream in interface java.sql.Blob

position

public long position(byte[] pattern,
                     long start)
              throws java.sql.SQLException
Determines the byte position at which the specified byte pattern begins within the BLOB value that this Blob object represents. The search for patternstart

Specified by:
position in interface java.sql.Blob

checkMatch

private boolean checkMatch(byte[] pattern)
                    throws java.io.IOException

position

public long position(java.sql.Blob pattern,
                     long start)
              throws java.sql.SQLException
Determines the byte position in the BLOB value designated by this Blob object at which pattern begins. The search begins at position start.

Specified by:
position in interface java.sql.Blob

checkMatch

private boolean checkMatch(java.sql.Blob pattern)
                    throws java.io.IOException

handleMyExceptions

private java.sql.SQLException handleMyExceptions(java.lang.Throwable t)
                                          throws java.sql.SQLException

finalize

protected void finalize()
Description copied from class: java.lang.Object
Called on an object by the Virtual Machine at most once, at some point after the Object is determined unreachable but before it is destroyed. You would think that this means it eventually is called on every Object, but this is not necessarily the case. If execution terminates abnormally, garbage collection does not always happen. Thus you cannot rely on this method to always work. For finer control over garbage collection, use references from the java.lang.ref package.

Virtual Machines are free to not call this method if they can determine that it does nothing important; for example, if your class extends Object and overrides finalize to do simply super.finalize().

finalize() will be called by a java.lang.Thread that has no locks on any Objects, and may be called concurrently. There are no guarantees on the order in which multiple objects are finalized. This means that finalize() is usually unsuited for performing actions that must be thread-safe, and that your implementation must be use defensive programming if it is to always work.

If an Exception is thrown from finalize() during garbage collection, it will be patently ignored and the Object will still be destroyed.

It is allowed, although not typical, for user code to call finalize() directly. User invocation does not affect whether automatic invocation will occur. It is also permitted, although not recommended, for a finalize() method to "revive" an object by making it reachable from normal code again.

Unlike constructors, finalize() does not get called for an object's superclass unless the implementation specifically calls super.finalize().

The default implementation does nothing.

setBytes

public int setBytes(long pos,
                    byte[] bytes)
             throws java.sql.SQLException
JDBC 3.0 Writes the given array of bytes to the BLOB value that this Blob object represents, starting at position pos, and returns the number of bytes written.

Specified by:
setBytes in interface java.sql.Blob

setBytes

public int setBytes(long pos,
                    byte[] bytes,
                    int offset,
                    int len)
             throws java.sql.SQLException
JDBC 3.0 Writes all or part of the given array of byte array to the BLOB value that this Blob object represents and returns the number of bytes written. Writing starts at position pos in the BLOB value; len bytes from the given byte array are written.

Specified by:
setBytes in interface java.sql.Blob

setBinaryStream

public java.io.OutputStream setBinaryStream(long pos)
                                     throws java.sql.SQLException
JDBC 3.0 Retrieves a stream that can be used to write to the BLOB value that this Blob object represents. The stream begins at position pos.

Specified by:
setBinaryStream in interface java.sql.Blob

truncate

public void truncate(long len)
              throws java.sql.SQLException
JDBC 3.0 Truncates the BLOB value that this Blob object represents to be len bytes in length.

Specified by:
truncate in interface java.sql.Blob

getEmbedConnection

protected final EmbedConnection getEmbedConnection()
Return a reference to the EmbedConnection

getConnectionSynchronization

protected final java.lang.Object getConnectionSynchronization()
Return an object to be used for connection synchronization.

handleException

protected final java.sql.SQLException handleException(java.lang.Throwable t)
                                               throws java.sql.SQLException
Handle any exception.

handleException

protected final java.sql.SQLException handleException(java.lang.Throwable t,
                                                      boolean close)
                                               throws java.sql.SQLException
Handle any exception.

needCommit

protected final void needCommit()
If Autocommit is on, note that a commit is needed.

commitIfNeeded

protected final void commitIfNeeded()
                             throws java.sql.SQLException
Perform a commit if one is needed.

commitIfAutoCommit

protected final void commitIfAutoCommit()
                                 throws java.sql.SQLException
Perform a commit if autocommit is enabled.

setupContextStack

protected final void setupContextStack()
                                throws java.sql.SQLException
Setup the context stack (a.k.a. context manager) for this connection.

restoreContextStack

protected final void restoreContextStack()
                                  throws java.sql.SQLException
Setup the context stack (a.k.a. context manager) for this connection.

getContextManager

public org.apache.derby.iapi.services.context.ContextManager getContextManager()

getDatabase

public org.apache.derby.iapi.db.Database getDatabase()

getCal

protected java.util.Calendar getCal()
Get and save a unique calendar object for this JDBC object. No need to synchronize because multiple threads should not be using a single JDBC object. Even if they do there is only a small window where each would get its own Calendar for a single call.

newSQLException

protected java.sql.SQLException newSQLException(java.lang.String messageId)

newSQLException

protected java.sql.SQLException newSQLException(java.lang.String messageId,
                                                java.lang.Object arg1)

newSQLException

protected java.sql.SQLException newSQLException(java.lang.String messageId,
                                                java.lang.Object arg1,
                                                java.lang.Object arg2)
Overview  Package   Class  Use  Deprecated  Index 
Home >> All >> org >> apache >> derby >> impl >> [ jdbc overview ]  PREV CLASS  NEXT CLASS
SUMMARY: JavaDoc of org.apache.derby.impl.jdbc.EmbedBlob JAVADOC | Sourc code of org.apache.derby.impl.jdbc.EmbedBlob SOURCE | Download org.apache.derby.impl.jdbc.EmbedBlob DOWNLOAD | NESTED | FIELD | CONSTR | METHOD DETAIL: FIELD | CONSTR | METHOD