Package org.eclipse.jgit.util

Class TemporaryBuffer

java.lang.Object

java.io.OutputStream

org.eclipse.jgit.util.TemporaryBuffer

All Implemented Interfaces:

java.io.Closeable, java.io.Flushable, java.lang.AutoCloseable

Direct Known Subclasses:

SmartOutputStream, TemporaryBuffer.Heap, TemporaryBuffer.LocalFile, TransportHttp.Service.HttpOutputStream

public abstract class TemporaryBuffer
extends java.io.OutputStream

A fully buffered output stream.

Subclasses determine the behavior when the in-memory buffer capacity has been exceeded and additional bytes are still being received for output.

Nested Class Summary

Nested Classes

Modifier and Type	Class	Description
(package private) static class	TemporaryBuffer.Block
private class	TemporaryBuffer.BlockInputStream
static class	TemporaryBuffer.Heap	A temporary buffer that will never exceed its in-memory limit.
static class	TemporaryBuffer.LocalFile	A fully buffered output stream using local disk storage for large data.

Field Summary

Fields

Modifier and Type	Field	Description
(package private) java.util.ArrayList<TemporaryBuffer.Block>	blocks	Chain of data, if we are still completely in-core; otherwise null.
protected static int	DEFAULT_IN_CORE_LIMIT	Default limit for in-core storage.
private int	inCoreLimit	Maximum number of bytes we will permit storing in memory.
private int	initialBlocks	Initial size of block list.
private java.io.OutputStream	overflow	If inCoreLimit has been reached, remainder goes here.

Constructor Summary

Constructors

Modifier	Constructor	Description
protected	TemporaryBuffer(int limit)	Create a new empty temporary buffer.
protected	TemporaryBuffer(int estimatedSize, int limit)	Create a new empty temporary buffer.

Method Summary

Modifier and Type	Method	Description
void	close()
void	copy(java.io.InputStream in)	Copy all bytes remaining on the input stream into this buffer.
void	destroy()	Clear this buffer so it has no data, and cannot be used again.
protected void	doFlush()	Dumps the entire buffer into the overflow stream, and flushes it.
private long	inCoreLength()
private TemporaryBuffer.Block	last()
long	length()	Obtain the length (in bytes) of the buffer.
java.io.InputStream	openInputStream()	Open an input stream to read from the buffered data.
java.io.InputStream	openInputStreamWithAutoDestroy()	Same as openInputStream() but handling destruction of any associated resources automatically when closing the returned stream.
protected abstract java.io.OutputStream	overflow()	Open the overflow output stream, so the remaining output can be stored.
private boolean	reachedInCoreLimit()
void	reset()	Reset this buffer for reuse, purging all buffered content.
private void	switchToOverflow()
byte[]	toByteArray()	Convert this buffer's contents into a contiguous byte array.
byte[]	toByteArray(int limit)	Convert this buffer's contents into a contiguous byte array.
void	write(byte[] b, int off, int len)
void	write(int b)
void	writeTo(java.io.OutputStream os, ProgressMonitor pm)	Send this buffer to an output stream.

Methods inherited from class java.io.OutputStream

flush, write

Methods inherited from class java.lang.Object

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

Field Detail

DEFAULT_IN_CORE_LIMIT

protected static final int DEFAULT_IN_CORE_LIMIT

Default limit for in-core storage.

See Also:

Constant Field Values

blocks

java.util.ArrayList<TemporaryBuffer.Block> blocks

Chain of data, if we are still completely in-core; otherwise null.

inCoreLimit

private int inCoreLimit

Maximum number of bytes we will permit storing in memory.

When this limit is reached the data will be shifted to a file on disk, preventing the JVM heap from growing out of control.

initialBlocks

private int initialBlocks

Initial size of block list.

overflow

private java.io.OutputStream overflow

If inCoreLimit has been reached, remainder goes here.

Constructor Detail

TemporaryBuffer

protected TemporaryBuffer(int limit)

Create a new empty temporary buffer.

Parameters:

limit - maximum number of bytes to store in memory before entering the overflow output path; also used as the estimated size.

TemporaryBuffer

protected TemporaryBuffer(int estimatedSize,
                          int limit)

Create a new empty temporary buffer.

Parameters:

estimatedSize - estimated size of storage used, to size the initial list of block pointers.

limit - maximum number of bytes to store in memory before entering the overflow output path.

Since:

4.0

Method Detail

write

public void write(int b)
           throws java.io.IOException

Specified by:

write in class java.io.OutputStream

Throws:

java.io.IOException

write

public void write(byte[] b,
                  int off,
                  int len)
           throws java.io.IOException

Overrides:

write in class java.io.OutputStream

Throws:

java.io.IOException

doFlush

protected void doFlush()
                throws java.io.IOException

Dumps the entire buffer into the overflow stream, and flushes it.

Throws:

java.io.IOException - the overflow stream cannot be started, or the buffer contents cannot be written to it, or it failed to flush.

copy

public void copy(java.io.InputStream in)
          throws java.io.IOException

Copy all bytes remaining on the input stream into this buffer.

Parameters:

in - the stream to read from, until EOF is reached.

Throws:

java.io.IOException - an error occurred reading from the input stream, or while writing to a local temporary file.

length

public long length()

Obtain the length (in bytes) of the buffer.

The length is only accurate after close() has been invoked.

Returns:

total length of the buffer, in bytes.

inCoreLength

private long inCoreLength()

toByteArray

public byte[] toByteArray()
                   throws java.io.IOException

Convert this buffer's contents into a contiguous byte array.

The buffer is only complete after close() has been invoked.

Returns:

the complete byte array; length matches length().

Throws:

java.io.IOException - an error occurred reading from a local temporary file

toByteArray

public byte[] toByteArray(int limit)
                   throws java.io.IOException

Convert this buffer's contents into a contiguous byte array. If this size of the buffer exceeds the limit only return the first limit bytes

The buffer is only complete after close() has been invoked.

Parameters:

limit - the maximum number of bytes to be returned

Returns:

the byte array limited to limit bytes.

Throws:

java.io.IOException - an error occurred reading from a local temporary file

Since:

4.2

writeTo

public void writeTo(java.io.OutputStream os,
                    ProgressMonitor pm)
             throws java.io.IOException

Send this buffer to an output stream.

This method may only be invoked after close() has completed normally, to ensure all data is completely transferred.

Parameters:

os - stream to send this buffer's complete content to.

pm - if not null progress updates are sent here. Caller should initialize the task and the number of work units to length()/1024.

Throws:

java.io.IOException - an error occurred reading from a temporary file on the local system, or writing to the output stream.

openInputStream

public java.io.InputStream openInputStream()
                                    throws java.io.IOException

Open an input stream to read from the buffered data.

This method may only be invoked after close() has completed normally, to ensure all data is completely transferred.

Returns:

a stream to read from the buffer. The caller must close the stream when it is no longer useful.

Throws:

java.io.IOException - an error occurred opening the temporary file.

openInputStreamWithAutoDestroy

public java.io.InputStream openInputStreamWithAutoDestroy()
                                                   throws java.io.IOException

Same as openInputStream() but handling destruction of any associated resources automatically when closing the returned stream.

Returns:

an InputStream which will automatically destroy any associated temporary file on close()

Throws:

java.io.IOException - in case of an error.

Since:

4.11

reset

public void reset()

Reset this buffer for reuse, purging all buffered content.

overflow

protected abstract java.io.OutputStream overflow()
                                          throws java.io.IOException

Open the overflow output stream, so the remaining output can be stored.

Returns:

the output stream to receive the buffered content, followed by the remaining output.

Throws:

java.io.IOException - the buffer cannot create the overflow stream.

last

private TemporaryBuffer.Block last()

reachedInCoreLimit

private boolean reachedInCoreLimit()
                            throws java.io.IOException

Throws:

java.io.IOException

switchToOverflow

private void switchToOverflow()
                       throws java.io.IOException

Throws:

java.io.IOException

close

public void close()
           throws java.io.IOException

Specified by:

close in interface java.lang.AutoCloseable

Specified by:

close in interface java.io.Closeable

Overrides:

close in class java.io.OutputStream

Throws:

java.io.IOException

destroy

public void destroy()

Clear this buffer so it has no data, and cannot be used again.