[Chapter 29] 29.2 java.text.CharacterIterator (JDK 1.1)

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| Chapter 29 The java.text Package |

## 29.2 java.text.CharacterIterator (JDK 1.1)

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This interface defines an API for portably iterating through the characters that comprise a string of text, regardless of the encoding of that text. Such an API is necessary because the number of bytes per character is different for different encodings, and some encodings even use variable-width characters within the same string of text. In addition to allowing iteration, a class that implements the `CharacterIterator` interface for non-Unicode text also performs translation of characters from their native encoding to standard Java Unicode characters.

`CharacterIterator` is similar to `java.util.Enumeration`, but is somewhat more complex than that interface. The `first()` and `last()` methods return the first and last characters in the text, and the `next()` and `prev()` methods allow you to loop forward or backwards through the characters of the text. These methods return the `DONE` constant when they go beyond the first or last character in the text--a test for this constant can be used to terminate a loop.

The `CharacterIterator` interface also allows random access to the characters in a string of text. The `getBeginIndex()` and `getEndIndex()` methods return the character positions for the start and end of the string, and `setIndex()` sets the current position. `getIndex()` returns the index of the current position, and `current()` returns the character at that position.

    public abstract interface CharacterIterator extends Cloneable {
        // Constants
                public static final char DONE;
        // Public Instance Methods
                public abstract Object clone();  // Overrides Object
                public abstract char current();
                public abstract char first();
                public abstract int getBeginIndex();
                public abstract int getEndIndex();
                public abstract int getIndex();
                public abstract char last();
                public abstract char next();
                public abstract char previous();
                public abstract char setIndex(int position);
    }

### Implemented By:

StringCharacterIterator

### Passed To:

BreakIterator.setText()

### Returned By:

BreakIterator.getText()

java.text.BreakIterator (JDK 1.1) |  | java.text.ChoiceFormat (JDK 1.1)