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org.apache.derby.impl.drda
Class EXTDTAInputStream  

java.lang.Object
  java.io.InputStream
      org.apache.derby.impl.drda.EXTDTAInputStream

All Implemented Interfaces:

java.io.Closeable

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public class EXTDTAInputStream

extends java.io.InputStream

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Field Summary
(package private)  java.io.InputStream	binaryInputStream
(package private)  int	columnNumber
(package private)  long	dataLength
(package private)  java.sql.ResultSet	dataResultSet

 

Constructor Summary
private	EXTDTAInputStream(int dataLength, java.io.InputStream binaryInputStream)

 

Method Summary
int	available()           This method returns the number of bytes that can be read from this stream before a read can block.
void	close()           This method closes the stream.
boolean	equals(java.lang.Object arg0)           Determine whether this Object is semantically equal to another Object.
static EXTDTAInputStream	getEXTDTAStream(java.sql.ResultSet rs, int column, int drdaType)           Retrieve stream from the ResultSet and column specified.
private static long	getInputStreamLength(java.io.InputStream binaryInputStream)           Get the length of the InputStream This method is currently not used because there seems to be no way to reset the she stream.
int	hashCode()           Get a value that represents this Object, as uniquely as possible within the confines of an int.
long	length()           Return the length of the binary stream which was calculated when EXTDTAObject was created.
void	mark(int arg0)           This method marks a position in the input to which the stream can be "reset" by calling the reset() method.
boolean	markSupported()           This method returns a boolean that indicates whether the mark/reset methods are supported in this class.
int	read()           This method reads an unsigned byte from the input stream and returns it as an int in the range of 0-255.
int	read(byte[] arg0)           This method reads bytes from a stream and stores them into a caller supplied buffer.
int	read(byte[] arg0, int arg1, int arg2)           This method read bytes from a stream and stores them into a caller supplied buffer.
void	reset()           This method resets a stream to the point where the mark() method was called.
long	skip(long arg0)           This method skips the specified number of bytes in the stream.

 

Methods inherited from class java.lang.Object

clone, finalize, getClass, notify, notifyAll, toString, wait, wait, wait

 

Field Detail

dataLength

long dataLength

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binaryInputStream

java.io.InputStream binaryInputStream

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columnNumber

int columnNumber

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dataResultSet

java.sql.ResultSet dataResultSet

Constructor Detail

EXTDTAInputStream

private EXTDTAInputStream(int dataLength,
                          java.io.InputStream binaryInputStream)

Method Detail

getEXTDTAStream

public static EXTDTAInputStream getEXTDTAStream(java.sql.ResultSet rs,
                                                int column,
                                                int drdaType)
                                         throws java.sql.SQLException

Retrieve stream from the ResultSet and column specified. Create an input stream and length for the large object being retrieved. Do not hold locks until end of transaction. DERBY-255.

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getInputStreamLength

private static long getInputStreamLength(java.io.InputStream binaryInputStream)
                                  throws java.sql.SQLException

Get the length of the InputStream This method is currently not used because there seems to be no way to reset the she stream.

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length

public long length()
            throws java.sql.SQLException

Return the length of the binary stream which was calculated when EXTDTAObject was created.

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read

public int read()
         throws java.io.IOException

Description copied from class: java.io.InputStream

This method reads an unsigned byte from the input stream and returns it as an int in the range of 0-255. This method also will return -1 if the end of the stream has been reached.

This method will block until the byte can be read.

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available

public int available()
              throws java.io.IOException

Description copied from class: java.io.InputStream

This method returns the number of bytes that can be read from this stream before a read can block. A return of 0 indicates that blocking might (or might not) occur on the very next read attempt.

This method always returns 0 in this class

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close

public void close()
           throws java.io.IOException

Description copied from class: java.io.InputStream

This method closes the stream. Any futher attempts to read from the stream may generate an IOException

This method does nothing in this class, but subclasses may override this method in order to provide additional functionality.

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equals

public boolean equals(java.lang.Object arg0)

Description copied from class: java.lang.Object

Determine whether this Object is semantically equal to another Object.

There are some fairly strict requirements on this method which subclasses must follow:

• It must be transitive. If a.equals(b) and b.equals(c), then a.equals(c) must be true as well.
• It must be symmetric. a.equals(b) and b.equals(a) must have the same value.
• It must be reflexive. a.equals(a) must always be true.
• It must be consistent. Whichever value a.equals(b) returns on the first invocation must be the value returned on all later invocations.
• a.equals(null) must be false.
• It must be consistent with hashCode(). That is, a.equals(b) must imply a.hashCode() == b.hashCode(). The reverse is not true; two objects that are not equal may have the same hashcode, but that has the potential to harm hashing performance.

This is typically overridden to throw a java.lang.ClassCastException if the argument is not comparable to the class performing the comparison, but that is not a requirement. It is legal for a.equals(b) to be true even though a.getClass() != b.getClass(). Also, it is typical to never cause a java.lang.NullPointerException.

In general, the Collections API (java.util) use the equals method rather than the == operator to compare objects. However, java.util.IdentityHashMap is an exception to this rule, for its own good reasons.

The default implementation returns this == o.

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hashCode

public int hashCode()

Description copied from class: java.lang.Object

Get a value that represents this Object, as uniquely as possible within the confines of an int.

There are some requirements on this method which subclasses must follow:

• Semantic equality implies identical hashcodes. In other words, if a.equals(b) is true, then a.hashCode() == b.hashCode() must be as well. However, the reverse is not necessarily true, and two objects may have the same hashcode without being equal.
• It must be consistent. Whichever value o.hashCode() returns on the first invocation must be the value returned on all later invocations as long as the object exists. Notice, however, that the result of hashCode may change between separate executions of a Virtual Machine, because it is not invoked on the same object.

Notice that since hashCode is used in java.util.Hashtable and other hashing classes, a poor implementation will degrade the performance of hashing (so don't blindly implement it as returning a constant!). Also, if calculating the hash is time-consuming, a class may consider caching the results.

The default implementation returns System.identityHashCode(this)

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mark

public void mark(int arg0)

Description copied from class: java.io.InputStream

This method marks a position in the input to which the stream can be "reset" by calling the reset() method. The parameter @code{readlimit} is the number of bytes that can be read from the stream after setting the mark before the mark becomes invalid. For example, if mark() is called with a read limit of 10, then when 11 bytes of data are read from the stream before the reset() method is called, then the mark is invalid and the stream object instance is not required to remember the mark.

This method does nothing in this class, but subclasses may override it to provide mark/reset functionality.

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markSupported

public boolean markSupported()

Description copied from class: java.io.InputStream

This method returns a boolean that indicates whether the mark/reset methods are supported in this class. Those methods can be used to remember a specific point in the stream and reset the stream to that point.

This method always returns false in this class, but subclasses can override this method to return true if they support mark/reset functionality.

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read

public int read(byte[] arg0)
         throws java.io.IOException

Description copied from class: java.io.InputStream

This method reads bytes from a stream and stores them into a caller supplied buffer. This method attempts to completely fill the buffer, but can return before doing so. The actual number of bytes read is returned as an int. A -1 is returned to indicate the end of the stream.

This method will block until some data can be read.

This method operates by calling an overloaded read method like so: read(b, 0, b.length)

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read

public int read(byte[] arg0,
                int arg1,
                int arg2)
         throws java.io.IOException

Description copied from class: java.io.InputStream

This method read bytes from a stream and stores them into a caller supplied buffer. It starts storing the data at index off into the buffer and attempts to read len bytes. This method can return before reading the number of bytes requested. The actual number of bytes read is returned as an int. A -1 is returned to indicate the end of the stream.

This method will block until some data can be read.

This method operates by calling the single byte read() method in a loop until the desired number of bytes are read. The read loop stops short if the end of the stream is encountered or if an IOException is encountered on any read operation except the first. If the first attempt to read a bytes fails, the IOException is allowed to propagate upward. And subsequent IOException is caught and treated identically to an end of stream condition. Subclasses can (and should if possible) override this method to provide a more efficient implementation.

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reset

public void reset()
           throws java.io.IOException

Description copied from class: java.io.InputStream

This method resets a stream to the point where the mark() method was called. Any bytes that were read after the mark point was set will be re-read during subsequent reads.

This method always throws an IOException in this class, but subclasses can override this method if they provide mark/reset functionality.

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skip

public long skip(long arg0)
          throws java.io.IOException

Description copied from class: java.io.InputStream

This method skips the specified number of bytes in the stream. It returns the actual number of bytes skipped, which may be less than the requested amount.

This method reads and discards bytes into a byte array until the specified number of bytes were skipped or until either the end of stream is reached or a read attempt returns a short count. Subclasses can override this metho to provide a more efficient implementation where one exists.

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Overview  Package   Class  Use  Deprecated  Index
Home >> All >> org >> apache >> derby >> impl >> [ drda overview ]	PREV CLASS  NEXT CLASS
SUMMARY:  JAVADOC |  SOURCE |  DOWNLOAD | NESTED | FIELD | CONSTR | METHOD	DETAIL: FIELD | CONSTR | METHOD

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