[Chapter 16] StringCharacterIterator

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| Chapter 16 The java.text Package |

# StringCharacterIterator

## Name

StringCharacterIterator

## Synopsis

Class Name:

  `java.text.StringCharacterIterator`

Superclass:

  `java.lang.Object`

Immediate Subclasses:

  None

Interfaces Implemented:

  `java.text.CharacterIterator`

Availability:

  New as of JDK 1.1

## Description

The `StringCharacterIterator` class can move bidirectionally through a character string. In other words, the class iterates through the characters in a `String`. The class implements the `CharacterIterator` interface. The class is used by `BreakIterator` to find boundaries in text strings.

## Class Summary

    public final class java.text.StringCharacterIterator
                        extends java.lang.Object
                        implements java.text.CharacterIterator {
      // Constructors
      public StringCharacterIterator(String text);
      public StringCharacterIterator(String text, int pos);
      public StringCharacterIterator(String text, int begin, int end, int pos);
      // Instance Methods
      public Object clone();
      public char current();
      public boolean equals(Object obj);
      public char first();
      public int getBeginIndex();
      public int getEndIndex();
      public int getIndex();
      public int hashCode();
      public char last();
      public char next();
      public char previous();
      public char setIndex(int p);
    }

## Constructors

### StringCharacterIterator

#### public StringCharacterIterator(String text)

Parameters

  `text`

    The `String` to use.

Description

  This constructor creates a `StringCharacterIterator` that uses the given string. The initial index of the iterator is at the beginning of the string, or in other words, at index `0`.

#### public StringCharacterIterator(String text, int pos)

Parameters

  `text`

    The `String` to use.

  `pos`

    The initial position.

Description

  This constructor creates a `StringCharacterIterator` that uses the given string. The initial index of the iterator is set to the given initial position.

####

     public StringCharacterIterator(String text, int begin, int end, int pos)

Parameters

  `text`

    The `String` to use.

  `begin`

    The beginning index.

  `end`

    The ending index.

  `pos`

    The initial position.

Description

  This constructor creates a `StringCharacterIterator` that uses the specified range of the given string. In other words, the iterator uses the sequence of text from the specified beginning index to the specified ending index. The initial index of the iterator is set to the given initial position.

## Instance Methods

### clone

#### public Object clone()

Returns

  A copy of this`StringCharacterIterator`.

Implements

  `CharacterIterator.clone()`

Overrides

  `Object.clone()`

Description

  This method creates a copy of this `StringCharacterIterator` and returns it.

### current

#### public char current()

Returns

  The character at the current position of this `StringCharacterIterator` or `DONE` if the current position is not within the text sequence.

Implements

  `CharacterIterator.current()`

Description

  This method returns the character at the current position of this `CharacterIterator`. The current position is returned by `getIndex()`.

### equals

#### public boolean equals(Object obj)

Parameters

  `obj`

    The object to be compared with this object.

Returns

  `true` if the objects are equal; `false` if they are not.

Overrides

  `Object.equals()`

Description

  This method returns `true` if `obj` is an instance of `StringCharacterIterator` and is equivalent to this `StringCharacterIterator`.

### first

#### public char first()

Returns

  The first character in this `StringCharacterIterator`.

Implements

  `CharacterIterator.first()`

Description

  This method returns the character at the first position in this `StringCharacterIterator`. The first position is returned by `getBeginIndex()`. The current position of the iterator is set to this position.

### getBeginIndex

#### public int getBeginIndex()

Returns

  The index of the first character in this `StringCharacterIterator`.

Implements

  `CharacterIterator.getBeginIndex()`

Description

  This method returns the index of the beginning of the text for this `StringCharacterIterator`.

### getEndIndex

#### public int getEndIndex()

Returns

  The index after the last character in this `StringCharacterIterator`.

Implements

  `CharacterIterator.getEndIndex()`

Description

  This method returns the index of the character following the end of the text for this `StringCharacterIterator`.

### getIndex

#### public int getIndex()

Returns

  The index of the current character in this `StringCharacterIterator`.

Description

  This method returns the current position, or index, of this `StringCharacterIterator`.

### hashCode

#### public int hashCode()

Returns

  A hashcode for this object.

Overrides

  `Object.hashCode()`

Description

  This method returns a hashcode for this `StringCharacterIterator`.

### last

#### public char last()

Returns

  The last character in this `StringCharacterIterator`.

Implements

  `CharacterIterator.last()`

Description

  This method returns the character at the ending position of this `StringCharacterIterator`. The last position is the value of `getEndIndex()-1`. The current position of the iterator is set to this position.

### next

#### public char next()

Returns

  The next character in this `StringCharacterIterator` or `DONE` if the current position is already at the end of the text.

Implements

  `CharacterIterator.next()`

Description

  This method increments the current position of this `StringCharacterIterator` by 1 and returns the character at the new position. If the current position is already at `getEndIndex()`, the position is not changed and `DONE` is returned.

### previous

#### public char previous()

Returns

  The previous character in this `StringCharacterIterator` or `DONE` if the current position is already at the beginning of the text.

Implements

  `CharacterIterator.previous()`

Description

  This method decrements the current position of this `StringCharacterIterator` by 1 and returns the character at the new position. If the current position is already at `getBeginIndex()`, the position is not changed and `DONE` is returned.

### setIndex

#### public char setIndex(int p)

Parameters

  `p`

    The new position.

Returns

  The character at the specified position in this `StringCharacterIterator`.

Throws

  `IllegalArgumentException`

    If the given position is not between `getBeginIndex()` and `getEndIndex()-1`.

Implements

  `CharacterIterator.setIndex()`

Description

  This method sets the current position, or index, of this `StringCharacterIterator` to the given position.

## Inherited Methods

Method | Inherited From | Method | Inherited From
--- | --- | --- | ---
`finalize()` | `Object` | `getClass()` | `Object`
`notify()` | `Object` | `notifyAll()` | `Object`
`toString()` | `Object` | `wait()` | `Object`
`wait(long)` | `Object` | `wait(long, int)` | `Object`

## See Also

`BreakIterator`, `CharacterIterator`, `String`

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