com.devexperts.io

Class ChunkedOutput

java.lang.Object

java.io.OutputStream

com.devexperts.io.BufferedOutput

com.devexperts.io.ChunkedOutput

All Implemented Interfaces:

Closeable, DataOutput, Flushable, ObjectOutput, AutoCloseable

public class ChunkedOutput
extends BufferedOutput

Implementation of BufferedOutput using ChunkList as an output. Written chunks can be retrieved with getOutput method. Subclasses of this implementation can override flush method to write composed chunks to an underlying persistence mechanism as soon as they are complete.

Field Summary

Fields

Modifier and Type	Field and Description
protected static int	MAX_COPY_BYTES Maximal number of bytes to copy when making a decision to merge two chunks together in writeFromChunk(Chunk, Object) method.

Fields inherited from class com.devexperts.io.BufferedOutput

buffer, EMPTY_BYTE_ARRAY, limit, position, totalPositionBase

Constructor Summary

Constructors

Constructor and Description
ChunkedOutput() Constructs new chunked output with default pool.
ChunkedOutput(ChunkPool pool) Constructs new chunked output with a specified pool.

Method Summary

Modifier and Type	Method and Description
void	clear() Clears this chunked output and recycles all contained chunks.
void	close() This implementation does flush().
long	discard(long n) Discards n last bytes of output.
void	flush()
ChunkList	getOutput(Object owner) Retrieves generated output chunks for specified owner.
protected void	needSpace() This method is invoked when output methods need more space to write data.
String	toString() Returns a string representation of the object.
void	writeAllFromChunkList(ChunkList chunks, Object owner) Writes all data from specified chunk list into this buffered output.
void	writeFromChunk(Chunk chunk, Object owner) Writes data from specified chunk into this buffered output.

Methods inherited from class com.devexperts.io.BufferedOutput

checkEOB, totalPosition, write, write, write, writeBoolean, writeByte, writeByteArray, writeBytes, writeChar, writeChars, writeCompactInt, writeCompactLong, writeDouble, writeFloat, writeFromByteBuffer, writeFromDataInput, writeFromInputStream, writeInt, writeLong, writeMarshalled, writeObject, writeShort, writeUTF, writeUTFChar, writeUTFString

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, wait, wait, wait

Field Detail

MAX_COPY_BYTES

protected static final int MAX_COPY_BYTES

Maximal number of bytes to copy when making a decision to merge two chunks together in writeFromChunk(Chunk, Object) method.

Constructor Detail

ChunkedOutput

public ChunkedOutput()

Constructs new chunked output with default pool.

ChunkedOutput

public ChunkedOutput(ChunkPool pool)

Constructs new chunked output with a specified pool.

Parameters:

pool - chunk pool to use for acquiring new chunks

Method Detail

clear

public void clear()

Clears this chunked output and recycles all contained chunks. The totalPosition is reset to 0.

getOutput

public ChunkList getOutput(Object owner)

Retrieves generated output chunks for specified owner. This method preserves totalPosition.

Parameters:

owner - new owner for generated chunk list

Returns:

generated output chunk list or null if there is no output yet

close

public void close()
           throws IOException

This implementation does flush().

Specified by:

close in interface Closeable

Specified by:

close in interface ObjectOutput

Specified by:

close in interface AutoCloseable

Overrides:

close in class OutputStream

Throws:

IOException

flush

public void flush()
           throws IOException

Subclasses shall override flush, call getOutput from inside it to obtain completed chunks, and write them to an underlying persistence mechanism.

This implementation does nothing.

Specified by:

flush in interface Flushable

Specified by:

flush in interface ObjectOutput

Overrides:

flush in class OutputStream

Throws:

IOException

discard

public long discard(long n)

Discards n last bytes of output.

Parameters:

n - the number of bytes to be discarded

Returns:

the actual number of bytes discarded

writeFromChunk

public void writeFromChunk(Chunk chunk,
                           Object owner)
                    throws IOException

Writes data from specified chunk into this buffered output. Returns the chunk into the pool (or invalidates it if it does not correspond to any pool), unless the chunk was read-only. A reference to the chunk is considered to become invalid after invocation of this method and may no longer be used, unless the chunk was read-only.

Overrides:

writeFromChunk in class BufferedOutput

Parameters:

chunk - the source chunk of bytes

owner - current owner of the chunk

Throws:

IOException - if an I/O error occurs

writeAllFromChunkList

public void writeAllFromChunkList(ChunkList chunks,
                                  Object owner)
                           throws IOException

Writes all data from specified chunk list into this buffered output. Returns the chunk into the pool (or invalidates it if it does not correspond to any pool), unless the chunk list was read-only. A reference to the chunk list is considered to become invalid after invocation of this method and may no longer be used, unless the chunk list was read-only.

Overrides:

writeAllFromChunkList in class BufferedOutput

Parameters:

chunks - the source chunk list

owner - current owner of the chunk list

Throws:

IOException - if an I/O error occurs

needSpace

protected void needSpace()
                  throws IOException

Description copied from class: BufferedOutput

This method is invoked when output methods need more space to write data. This method must ensure that expression (position < limit) is true or throw an exception. This method may block if needed. This method is allowed to update BufferedOutput.buffer, BufferedOutput.position and BufferedOutput.limit fields as needed and should maintain BufferedOutput.totalPositionBase accordingly.

Specified by:

needSpace in class BufferedOutput

Throws:

IOException - if an I/O error occurs

toString

public String toString()

Returns a string representation of the object.

Overrides:

toString in class Object

Returns:

a string representation of the object.