Package org.apache.lucene.analysis

# Class CharArraySet

java.lang.Object
java.util.AbstractCollection<Object>
java.util.AbstractSet<Object>
org.apache.lucene.analysis.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.

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
Description
`static final CharArraySet`
`EMPTY_SET`
An empty `CharArraySet`.

## Constructor Summary

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

## Method Summary

Modifier and Type
Method
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(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.Collection

`parallelStream, removeIf, stream, toArray`

### Methods inherited from interface java.lang.Iterable

`forEach`

### Methods inherited from interface java.util.Set

`addAll, containsAll, isEmpty, remove, retainAll, spliterator, toArray, toArray`

## Field Details

### EMPTY_SET

public static final CharArraySet EMPTY_SET
An empty `CharArraySet`.

## Constructor Details

### CharArraySet

public CharArraySet(int startSize, boolean ignoreCase)
Create set with enough capacity to hold startSize terms

Parameters:
  `startSize` - the initial capacity
  `ignoreCase` - `false` if and only if the set should be case sensitive otherwise `true`.

### CharArraySet

public CharArraySet(Collection<?> c, boolean ignoreCase)
Creates a set from a Collection of objects.

Parameters:
  `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 Details

### 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(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.

Parameters:
  `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 `Collection<Object>`
Specified by:
  `iterator` in interface `Iterable<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>`