org.apache.derby.iapi.jdbc

Class CharacterStreamDescriptor

java.lang.Object

org.apache.derby.iapi.jdbc.CharacterStreamDescriptor

public class CharacterStreamDescriptor
extends java.lang.Object

A description of a byte stream representing characters. The description is used by decoders to properly configure themselves. Note that encoding is not included in the description, because all internal byte streams are expected to be using the modified UTF-8 encoding (see DataInput).

The information in the description is only guaranteed to be valid at the moment it is passed to the decoder object. As the decoder works on the stream, the information in the descriptor will be outdated.

To create a stream descriptor, obtain a Builder instance and set the required parameters.

See Also:

CharacterStreamDescriptor.Builder

Nested Class Summary

Nested Classes

Modifier and Type	Class and Description
static class	CharacterStreamDescriptor.Builder The builder for the CharacterStreamDescriptor class.

Field Summary

Fields

Modifier and Type	Field and Description
static long	BEFORE_FIRST Constant for the character position, when it is positioned before the first character in the stream (i.e.

Method Summary

Modifier and Type	Method and Description
long	getByteLength()
long	getCharLength()
long	getCurBytePos()
long	getCurCharPos() Returns the current character position.
long	getDataOffset() Returns the first index of the described stream that contains real data.
long	getMaxCharLength() Returns the imposed maximum character length on the described stream.
PositionedStream	getPositionedStream() Returns the associated positioned stream, if the stream is position aware.
java.io.InputStream	getStream() Returns the associated stream.
boolean	isBufferable() Tells if the described stream should be buffered or not.
boolean	isPositionAware() Tells if the described stream is aware of its own position, and that it can reposition itself on request.
java.lang.String	toString()

Methods inherited from class java.lang.Object

equals, getClass, hashCode, notify, notifyAll, wait, wait, wait

Field Detail

BEFORE_FIRST

public static final long BEFORE_FIRST

Constant for the character position, when it is positioned before the first character in the stream (i.e. at the very beginning of the stream or in the header).

See Also:

Constant Field Values

Method Detail

isBufferable

public boolean isBufferable()

Tells if the described stream should be buffered or not.

Some of the reasons a stream should not be buffered at this level, are the stream is already buffered, or it serves bytes directly from a byte array in memory.

Returns:

true if the stream should be buffered for improved performance, false if it should not be buffered.

isPositionAware

public boolean isPositionAware()

Tells if the described stream is aware of its own position, and that it can reposition itself on request.

Returns:

true if the stream is position aware, @{code false} otherwise.

getByteLength

public long getByteLength()

getCharLength

public long getCharLength()

getCurBytePos

public long getCurBytePos()

getCurCharPos

public long getCurCharPos()

Returns the current character position.

Returns:

The current character position, where the first character is at position 1, or BEFORE_FIRST if the stream is positioned before the first character.

getDataOffset

public long getDataOffset()

Returns the first index of the described stream that contains real data.

The information is typically used to filter out meta data at the head of the stream, and to correctly reset the stream.

Returns:

The first position in the stream containing real data.

getMaxCharLength

public long getMaxCharLength()

Returns the imposed maximum character length on the described stream.

The default value is Long.MAX_VALUE.

Returns:

The max allowed character length of the stream, or 0 if no limit has been set.

getStream

public java.io.InputStream getStream()

Returns the associated stream.

Returns:

An InputStream reference.

getPositionedStream

public PositionedStream getPositionedStream()

Returns the associated positioned stream, if the stream is position aware.

Returns:

A PositionedStream reference.

Throws:

java.lang.ClassCastException - if the stream cannot be cast to PositionedStream

java.lang.IllegalArgumentException - if the method is called and the assoicated stream isn't described as position aware.

See Also:

isPositionAware()

toString

public java.lang.String toString()

Overrides:

toString in class java.lang.Object