Package org.eclipse.jgit.internal.storage.io

Class BlockSource

java.lang.Object

org.eclipse.jgit.internal.storage.io.BlockSource

All Implemented Interfaces:

AutoCloseable

public abstract class BlockSource
extends Object
implements AutoCloseable

Provides content blocks of file.

BlockSource implementations must decide if they will be thread-safe, or not.

Constructor Summary

Constructors

Constructor	Description
BlockSource()

Method Summary

Modifier and Type	Method	Description
void	adviseSequentialRead(long startPos, long endPos)	Advise the BlockSource a sequential scan is starting.
abstract void	close()
static BlockSource	from(byte[] content)	Wrap a byte array as a BlockSource.
static BlockSource	from(FileInputStream in)	Read from a FileInputStream.
static BlockSource	from(FileChannel ch)	Read from a FileChannel.
abstract ByteBuffer	read(long position, int blockSize)	Read a block from the file.
abstract long	size()	Determine the size of the file.

Methods inherited from class java.lang.Object

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

Constructor Detail

BlockSource

public BlockSource()

Method Detail

from

public static BlockSource from(byte[] content)

Wrap a byte array as a BlockSource.

Parameters:

content - input file.

Returns:

block source to read from content.

from

public static BlockSource from(FileInputStream in)

Read from a FileInputStream.

The returned BlockSource is not thread-safe, as it must seek the file channel to read a block.

Parameters:

in - the file. The BlockSource will close in.

Returns:

wrapper for in.

from

public static BlockSource from(FileChannel ch)

Read from a FileChannel.

The returned BlockSource is not thread-safe, as it must seek the file channel to read a block.

Parameters:

ch - the file. The BlockSource will close ch.

Returns:

wrapper for ch.

read

public abstract ByteBuffer read(long position,
                                int blockSize)
                         throws IOException

Read a block from the file.

To reduce copying, the returned ByteBuffer should have an accessible array and arrayOffset() == 0. The caller will discard the ByteBuffer and directly use the backing array.

Parameters:

position - position of the block in the file, specified in bytes from the beginning of the file.

blockSize - size to read.

Returns:

buffer containing the block content.

Throws:

IOException - if block cannot be read.

size

public abstract long size()
                   throws IOException

Determine the size of the file.

Returns:

total number of bytes in the file.

Throws:

IOException - if size cannot be obtained.

adviseSequentialRead

public void adviseSequentialRead(long startPos,
                                 long endPos)

Advise the BlockSource a sequential scan is starting.

Parameters:

startPos - starting position.

endPos - ending position.

close

public abstract void close()

Specified by:

close in interface AutoCloseable