org.archive.wayback.util.flatfile
Class FlatFile

java.lang.Object
  org.archive.wayback.util.flatfile.FlatFile

Direct Known Subclasses:

CachedFile, CDXIndex

public class FlatFile
extends java.lang.Object

Subclass of File, which allows binary searching, returning Iterators that allow scanning forwards and backwards thru the (sorted) file starting from a particular prefix.

Version:

$Date: 2008-06-03 17:08:01 -0700 (Tue, 03 Jun 2008) $, $Revision: 2279 $

Author:

brad

Constructor Summary

FlatFile()

FlatFile(java.io.File parent, java.lang.String child)

FlatFile(java.lang.String path)

Method Summary

long	findKeyOffset(java.io.RandomAccessFile fh, java.lang.String key) Binary search thru RandomAccessFile argument to locate the first line prefixed by key argument.
long	getLastMatchOffset()
java.lang.String	getPath()
java.util.Iterator<java.lang.String>	getRecordIterator(java.lang.String prefix)
ReverseRecordIterator	getReverseRecordIterator(java.lang.String prefix)
CloseableIterator<java.lang.String>	getSequentialIterator()
static void	main(java.lang.String[] args)
void	setPath(java.lang.String path)
void	store(java.util.Iterator<java.lang.String> itr)

Methods inherited from class java.lang.Object

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

Constructor Detail

FlatFile

public FlatFile()

FlatFile

public FlatFile(java.io.File parent,
                java.lang.String child)

Parameters:

parent -

child -

FlatFile

public FlatFile(java.lang.String path)

Parameters:

path -

Method Detail

setPath

public void setPath(java.lang.String path)

Parameters:

path - to set

getPath

public java.lang.String getPath()

Returns:

current String path, or null if none has been set

findKeyOffset

public long findKeyOffset(java.io.RandomAccessFile fh,
                          java.lang.String key)
                   throws java.io.IOException

Binary search thru RandomAccessFile argument to locate the first line prefixed by key argument. As a side effect, the RandomAccessFile's position is also set to the start of the first matching line.

Parameters:

fh -

key -

Returns:

long offset where first record prefixed with key is found

Throws:

java.io.IOException

getLastMatchOffset

public long getLastMatchOffset()

Returns:

Returns the lastMatchOffset.

getSequentialIterator

public CloseableIterator<java.lang.String> getSequentialIterator()
                                                          throws java.io.IOException

Returns:

Iterator returning one String object for each line in the file.

Throws:

java.io.IOException

getRecordIterator

public java.util.Iterator<java.lang.String> getRecordIterator(java.lang.String prefix)
                                                       throws java.io.IOException

Parameters:

prefix -

Returns:

Iterator for records beggining with key

Throws:

java.io.IOException

getReverseRecordIterator

public ReverseRecordIterator getReverseRecordIterator(java.lang.String prefix)
                                               throws java.io.IOException

Parameters:

prefix -

Returns:

ReverseRecordIterator positioned to return the first line BEFORE prefix at the first call to readPrevLine().

Throws:

java.io.IOException

store

public void store(java.util.Iterator<java.lang.String> itr)
           throws java.io.IOException

Throws:

java.io.IOException

main

public static void main(java.lang.String[] args)

Parameters:

args -