org.apache.lucene.analysis.util

Class CharArraySet

java.lang.Object

java.util.AbstractCollection<E>

java.util.AbstractSet<Object>

org.apache.lucene.analysis.util.CharArraySet

All Implemented Interfaces:

Iterable<Object>, Collection<Object>, Set<Object>

public class CharArraySet
extends AbstractSet<Object>

A simple class that stores Strings as char[]'s in a hash table. Note that this is not a general purpose class. For example, it cannot remove items from the set, nor does it resize its hash table to be smaller, etc. It is designed to be quick to test if a char[] is in the set without the necessity of converting it to a String first.

You must specify the required Version compatibility when creating CharArraySet:

• As of 3.1, supplementary characters are properly lowercased.

Before 3.1 supplementary characters could not be lowercased correctly due to the lack of Unicode 4 support in JDK 1.4. To use instances of CharArraySet with the behavior before Lucene 3.1 pass a Version < 3.1 to the constructors.

Please note: This class implements Set but does not behave like it should in all cases. The generic type is Set<Object>, because you can add any object to it, that has a string representation. The add methods will use Object.toString() and store the result using a char[] buffer. The same behavior have the contains() methods. The iterator() returns an Iterator<char[]>.

Field Summary

Fields

Modifier and Type	Field and Description
static CharArraySet	EMPTY_SET

Constructor Summary

Constructors

Constructor and Description
CharArraySet(Version matchVersion, Collection<?> c, boolean ignoreCase) Creates a set from a Collection of objects.
CharArraySet(Version matchVersion, int startSize, boolean ignoreCase) Create set with enough capacity to hold startSize terms

Method Summary

Methods

Modifier and Type	Method and Description
boolean	add(char[] text) Add this char[] directly to the set.
boolean	add(CharSequence text) Add this CharSequence into the set
boolean	add(Object o)
boolean	add(String text) Add this String into the set
void	clear() Clears all entries in this set.
boolean	contains(char[] text, int off, int len) true if the len chars of text starting at off are in the set
boolean	contains(CharSequence cs) true if the CharSequence is in the set
boolean	contains(Object o)
static CharArraySet	copy(Version matchVersion, Set<?> set) Returns a copy of the given set as a CharArraySet.
Iterator<Object>	iterator() Returns an Iterator for char[] instances in this set.
int	size()
String	toString()
static CharArraySet	unmodifiableSet(CharArraySet set) Returns an unmodifiable CharArraySet.

Methods inherited from class java.util.AbstractSet

equals, hashCode, removeAll

Methods inherited from class java.util.AbstractCollection

addAll, containsAll, isEmpty, remove, retainAll, toArray, toArray

Methods inherited from class java.lang.Object

clone, finalize, getClass, notify, notifyAll, wait, wait, wait

Methods inherited from interface java.util.Set

addAll, containsAll, isEmpty, remove, retainAll, toArray, toArray

Field Detail

EMPTY_SET

public static final CharArraySet EMPTY_SET

Constructor Detail

CharArraySet

public CharArraySet(Version matchVersion,
            int startSize,
            boolean ignoreCase)

Create set with enough capacity to hold startSize terms

Parameters:

matchVersion - compatibility match version see Version note above for details.

startSize - the initial capacity

ignoreCase - false if and only if the set should be case sensitive otherwise true.

CharArraySet

public CharArraySet(Version matchVersion,
            Collection<?> c,
            boolean ignoreCase)

Creates a set from a Collection of objects.

Parameters:

matchVersion - compatibility match version see Version note above for details.

c - a collection whose elements to be placed into the set

ignoreCase - false if and only if the set should be case sensitive otherwise true.

Method Detail

clear

public void clear()

Clears all entries in this set. This method is supported for reusing, but not Set.remove(java.lang.Object).

Specified by:

clear in interface Collection<Object>

Specified by:

clear in interface Set<Object>

Overrides:

clear in class AbstractCollection<Object>

contains

public boolean contains(char[] text,
               int off,
               int len)

true if the len chars of text starting at off are in the set

contains

public boolean contains(CharSequence cs)

true if the CharSequence is in the set

contains

public boolean contains(Object o)

Specified by:

contains in interface Collection<Object>

Specified by:

contains in interface Set<Object>

Overrides:

contains in class AbstractCollection<Object>

add

public boolean add(Object o)

Specified by:

add in interface Collection<Object>

Specified by:

add in interface Set<Object>

Overrides:

add in class AbstractCollection<Object>

add

public boolean add(CharSequence text)

Add this CharSequence into the set

add

public boolean add(String text)

Add this String into the set

add

public boolean add(char[] text)

Add this char[] directly to the set. If ignoreCase is true for this Set, the text array will be directly modified. The user should never modify this text array after calling this method.

size

public int size()

Specified by:

size in interface Collection<Object>

Specified by:

size in interface Set<Object>

Specified by:

size in class AbstractCollection<Object>

unmodifiableSet

public static CharArraySet unmodifiableSet(CharArraySet set)

Returns an unmodifiable CharArraySet. This allows to provide unmodifiable views of internal sets for "read-only" use.

Parameters:

set - a set for which the unmodifiable set is returned.

Returns:

an new unmodifiable CharArraySet.

Throws:

NullPointerException - if the given set is null.

copy

public static CharArraySet copy(Version matchVersion,
                Set<?> set)

Returns a copy of the given set as a CharArraySet. If the given set is a CharArraySet the ignoreCase property will be preserved.

Note: If you intend to create a copy of another CharArraySet where the Version of the source set differs from its copy CharArraySet(Version, Collection, boolean) should be used instead. The copy(Version, Set) will preserve the Version of the source set it is an instance of CharArraySet.

Parameters:

matchVersion - compatibility match version see Version note above for details. This argument will be ignored if the given set is a CharArraySet.

set - a set to copy

Returns:

a copy of the given set as a CharArraySet. If the given set is a CharArraySet the ignoreCase property as well as the matchVersion will be of the given set will be preserved.

iterator

public Iterator<Object> iterator()

Returns an Iterator for char[] instances in this set.

Specified by:

iterator in interface Iterable<Object>

Specified by:

iterator in interface Collection<Object>

Specified by:

iterator in interface Set<Object>

Specified by:

iterator in class AbstractCollection<Object>

toString

public String toString()

Overrides:

toString in class AbstractCollection<Object>