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Java in a Nutshell

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The java.text Package
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29.2 java.text.CharacterIterator (JDK 1.1)

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()


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