com.sun.labs.minion.indexer.postings.io
Class StreamPostingsInput

java.lang.Object
  com.sun.labs.minion.indexer.postings.io.StreamPostingsInput

All Implemented Interfaces:

PostingsInput

public class StreamPostingsInput
extends java.lang.Object
implements PostingsInput

A postings input that can be used when streaming through a lot of postings sequentially as when merging or evaluating field queries. Random access is not supported, but sequential access should work well.

Field Summary

protected byte[]	b Our in-memory buffer.
protected static java.lang.String	logTag
protected long	me The offset of the end of our in-memory buffer.
protected long	ms The offset of the start of our in-memory buffer.

Constructor Summary

StreamPostingsInput(java.io.RandomAccessFile postFile, int buffSize)
Creates a stream postings input.

StreamPostingsInput(java.io.RandomAccessFile postFile, long offset, int buffSize)
Creates a stream postings input.

Method Summary

protected int	read(long off) Reads some bytes from the stream.
ReadableBuffer	read(long offset, int size) Returns a buffer constructed from our internal buffer.

Methods inherited from class java.lang.Object

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

Field Detail

ms

protected long ms

The offset of the start of our in-memory buffer.

me

protected long me

The offset of the end of our in-memory buffer.

b

protected byte[] b

Our in-memory buffer.

logTag

protected static java.lang.String logTag

Constructor Detail

StreamPostingsInput

public StreamPostingsInput(java.io.RandomAccessFile postFile,
                           int buffSize)
                    throws java.io.IOException

Creates a stream postings input.

Parameters:

postFile - The file from which the postings should be read.

buffSize - The size of the buffer to use.

Throws:

java.io.IOException - If there is any error reading the postings.

StreamPostingsInput

public StreamPostingsInput(java.io.RandomAccessFile postFile,
                           long offset,
                           int buffSize)
                    throws java.io.IOException

Creates a stream postings input.

Parameters:

postFile - The file from which the postings should be read.

offset - The offset at which the postings start.

buffSize - The size of the buffer to use.

Throws:

java.io.IOException - If there is any error reading the postings.

Method Detail

read

protected int read(long off)
            throws java.io.IOException

Reads some bytes from the stream.

Parameters:

off - The offset in the file from which the bytes should be read.

Returns:

The number of bytes read.

Throws:

java.io.IOException - If there is any error reading from the stream.

read

public ReadableBuffer read(long offset,
                           int size)
                    throws java.io.IOException

Returns a buffer constructed from our internal buffer.

Specified by:

read in interface PostingsInput

Parameters:

offset - The offset in the input at which the postings can be found.

size - The number of bytes to read to get the postings.

Returns:

A readable buffer containing the postings.

Throws:

java.io.IOException - if there is any error reading the postings.