org.apache.lucene.analysis

## Class CharArraySet

- java.lang.Object
- - java.util.AbstractCollection<E>
  - - 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 and Description
    --- | ---
    `static CharArraySet` | `EMPTY_SET` An empty `CharArraySet`.

  - ### Constructor Summary

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

  - ### Method Summary

    All Methods Static Methods Instance Methods Concrete 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(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, spliterator, toArray, toArray`

    - ### Methods inherited from interface java.util.Collection

      `parallelStream, removeIf, stream`

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

      `forEach`

- - ### Field Detail

    - #### EMPTY_SET

          public static final CharArraySet EMPTY_SET

      An empty `CharArraySet`.

  - ### Constructor Detail

    - #### 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 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(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 `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>`

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