edu.vt.middleware.dictionary
Class FileWordList

java.lang.Object
  edu.vt.middleware.dictionary.AbstractWordList
      edu.vt.middleware.dictionary.FileWordList

All Implemented Interfaces:

WordList

public class FileWordList
extends AbstractWordList

Provides an implementation of a WordList that is backed by a file. Each word is read from the file for every get, though the implementation supports a simple memory cache to improve read performance.

Version:

$Revision: 1252 $ $Date: 2010-04-16 17:24:23 -0400 (Fri, 16 Apr 2010) $

Author:

Middleware Services

Field Summary

protected java.util.TreeMap<java.lang.Integer,java.lang.Long>	cache cache of indexes to file positions.
static int	DEFAULT_CACHE_SIZE default cache size.
protected java.io.RandomAccessFile	file file containing words.
protected int	size size of the file.

Fields inherited from class edu.vt.middleware.dictionary.AbstractWordList

comparator

Constructor Summary

FileWordList(java.io.RandomAccessFile raf)
Creates a new case-sensitive word list from the supplied file.

FileWordList(java.io.RandomAccessFile raf, boolean caseSensitive)
Creates a new word list from the supplied file.

FileWordList(java.io.RandomAccessFile raf, boolean caseSensitive, int cachePercent)
Creates a new word list from the supplied file.

Method Summary

void	close() Closes the underlying file and make the cache available for garbage collection.
java.lang.String	get(int index) Gets the word at the given 0-based index.
java.io.RandomAccessFile	getFile() Returns the file backing this list.
int	size() Gets the number of words in the list.

Methods inherited from class edu.vt.middleware.dictionary.AbstractWordList

checkIsString, checkRange, getComparator, iterator, medianIterator

Methods inherited from class java.lang.Object

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

Field Detail

DEFAULT_CACHE_SIZE

public static final int DEFAULT_CACHE_SIZE

default cache size.

See Also:

Constant Field Values

file

protected java.io.RandomAccessFile file

file containing words.

size

protected int size

size of the file.

cache

protected java.util.TreeMap<java.lang.Integer,java.lang.Long> cache

cache of indexes to file positions.

Constructor Detail

FileWordList

public FileWordList(java.io.RandomAccessFile raf)
             throws java.io.IOException

Creates a new case-sensitive word list from the supplied file. The input file is read on initialization and is maintained by this class.

NOTE Attempts to close the source file will cause IOException when get(int) is called subsequently.

Parameters:

raf - File containing words, one per line.

Throws:

java.io.IOException - if an error occurs reading the supplied file

FileWordList

public FileWordList(java.io.RandomAccessFile raf,
                    boolean caseSensitive)
             throws java.io.IOException

Creates a new word list from the supplied file. The input file is read on initialization and is maintained by this class.

NOTE Attempts to close the source file will cause IOException when get(int) is called subsequently.

Parameters:

raf - File containing words, one per line.

caseSensitive - Set to true to create case-sensitive word list, false otherwise.

Throws:

java.io.IOException - if an error occurs reading the supplied file

FileWordList

public FileWordList(java.io.RandomAccessFile raf,
                    boolean caseSensitive,
                    int cachePercent)
             throws java.io.IOException

Creates a new word list from the supplied file. The input file is read on initialization and is maintained by this class.

NOTE Attempts to close the source file will cause IOException when get(int) is called subsequently.

Parameters:

raf - File containing words, one per line.

caseSensitive - Set to true to create case-sensitive word list, false otherwise.

cachePercent - Percent (0-100) of file to cache in memory for improved read performance.

Throws:

java.lang.IllegalArgumentException - if cache percent is out of range.

java.io.IOException - if an error occurs reading the supplied file

Method Detail

get

public java.lang.String get(int index)

Gets the word at the given 0-based index.

Parameters:

index - 0-based index.

Returns:

Word at given index.

size

public int size()

Gets the number of words in the list.

Returns:

Total number of words in list.

getFile

public java.io.RandomAccessFile getFile()

Returns the file backing this list.

Returns:

RandomAccessFile that is backing this list

close

public void close()
           throws java.io.IOException

Closes the underlying file and make the cache available for garbage collection.

Throws:

java.io.IOException - if an error occurs closing the file