org.passay.dictionary

Class MemoryMappedFileWordList

java.lang.Object

org.passay.dictionary.AbstractWordList

org.passay.dictionary.AbstractFileWordList

org.passay.dictionary.MemoryMappedFileWordList

All Implemented Interfaces:

WordList

public class MemoryMappedFileWordList
extends AbstractFileWordList

Provides an implementation of a WordList that is backed by a file and leverages a MappedByteBuffer. Each word is read from the file for every get, though the implementation supports a simple memory cache to improve read performance. This implementation does not support files greater than 2GB in size. Use this implementation when the initialization cost of FileWordList is too high.

Author:

Middleware Services

Nested Class Summary

Nested classes/interfaces inherited from class org.passay.dictionary.AbstractFileWordList

AbstractFileWordList.FileWord

Field Summary

Fields inherited from class org.passay.dictionary.AbstractFileWordList

DEFAULT_CACHE_PERCENT, file, size

Fields inherited from class org.passay.dictionary.AbstractWordList

comparator

Constructor Summary

Constructors

Constructor and Description
MemoryMappedFileWordList(RandomAccessFile raf) Creates a new case-sensitive word list from the supplied file.
MemoryMappedFileWordList(RandomAccessFile raf, boolean caseSensitive) Creates a new word list from the supplied file.
MemoryMappedFileWordList(RandomAccessFile raf, boolean caseSensitive, int cachePercent) Creates a new word list from the supplied file.
MemoryMappedFileWordList(RandomAccessFile raf, boolean caseSensitive, int cachePercent, CharsetDecoder decoder) Creates a new word list from the supplied file.
MemoryMappedFileWordList(RandomAccessFile raf, boolean caseSensitive, int cachePercent, CharsetDecoder decoder, boolean allocateDirect) Creates a new word list from the supplied file.

Method Summary

Modifier and Type	Method and Description
protected ByteBuffer	buffer() Returns the buffer providing the backing file data.
protected void	fill() Fills the buffer from the backing file.
protected void	seek(long offset) Positions the read head of the backing file at the given byte offset.

Methods inherited from class org.passay.dictionary.AbstractFileWordList

close, get, getFile, initialize, readWord, size, toString

Methods inherited from class org.passay.dictionary.AbstractWordList

checkIsString, checkRange, getComparator, iterator, medianIterator

Methods inherited from class java.lang.Object

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

Constructor Detail

MemoryMappedFileWordList

public MemoryMappedFileWordList(RandomAccessFile raf)
                         throws 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 AbstractFileWordList.get(int) is called subsequently.

Parameters:

raf - File containing words, one per line.

Throws:

IOException - if an error occurs reading the supplied file

MemoryMappedFileWordList

public MemoryMappedFileWordList(RandomAccessFile raf,
                                boolean caseSensitive)
                         throws 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 AbstractFileWordList.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:

IOException - if an error occurs reading the supplied file

MemoryMappedFileWordList

public MemoryMappedFileWordList(RandomAccessFile raf,
                                boolean caseSensitive,
                                int cachePercent)
                         throws IOException

Creates a new word list from the supplied file. The input file is read on initialization and is maintained by this class. cachePercent is a percentage of the file size in bytes.

NOTE Attempts to close the source file will cause IOException when AbstractFileWordList.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:

IllegalArgumentException - if cache percent is out of range.

IOException - if an error occurs reading the supplied file

MemoryMappedFileWordList

public MemoryMappedFileWordList(RandomAccessFile raf,
                                boolean caseSensitive,
                                int cachePercent,
                                CharsetDecoder decoder)
                         throws IOException

Creates a new word list from the supplied file. The input file is read on initialization and is maintained by this class. cachePercent is a percentage of the file size in bytes.

NOTE Attempts to close the source file will cause IOException when AbstractFileWordList.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.

decoder - Charset decoder for converting file bytes to characters

Throws:

IllegalArgumentException - if cache percent is out of range.

IOException - if an error occurs reading the supplied file

MemoryMappedFileWordList

public MemoryMappedFileWordList(RandomAccessFile raf,
                                boolean caseSensitive,
                                int cachePercent,
                                CharsetDecoder decoder,
                                boolean allocateDirect)
                         throws IOException

Creates a new word list from the supplied file. The input file is read on initialization and is maintained by this class. cachePercent is a percentage of the file size in bytes.

NOTE Attempts to close the source file will cause IOException when AbstractFileWordList.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.

decoder - Charset decoder for converting file bytes to characters

allocateDirect - whether buffers should be allocated with ByteBuffer.allocateDirect(int)

Throws:

IllegalArgumentException - if cache percent is out of range.

IOException - if an error occurs reading the supplied file

Method Detail

seek

protected void seek(long offset)

Description copied from class: AbstractFileWordList

Positions the read head of the backing file at the given byte offset.

Specified by:

seek in class AbstractFileWordList

Parameters:

offset - byte offset into file.

buffer

protected ByteBuffer buffer()

Description copied from class: AbstractFileWordList

Returns the buffer providing the backing file data.

Specified by:

buffer in class AbstractFileWordList

Returns:

Buffer around backing file.

fill

protected void fill()

Description copied from class: AbstractFileWordList

Fills the buffer from the backing file. This method may be a no-op if the buffer contains all file contents.

Specified by:

fill in class AbstractFileWordList