public interface CharacterIterator
extends Cloneable
This interface defines a protocol for bidirectional iteration over text. The iterator iterates over a bounded sequence of characters. Characters are indexed with values beginning with the value returned by getBeginIndex and continuing through the value returned by getEndIndex()-1. The index of the current character can be retrieved by calling getIndex. Calling setIndex will move the iterator to a new position within the sequence of characters. If at any time the iterator's current index moves outside the range of getBeginIndex and getEndIndex, previous() and next() will return DONE, signaling that the iterator has reached the end of the sequence.
Examples:
Traverse the text from start to finish
public void traverseForward(CharacterIterator iter) {
for(char c = iter.first(); c != CharacterIterator.DONE; c = iter.next()) {
processChar(c);
}
}
Traverse the text backwards, from end to start
public void traverseBackward(CharacterIterator iter) {
for(char c = iter.last(); c != CharacterIterator.DONE; c = iter.prev()) {
processChar(c);
}
}
Traverse both forward and backward from a given position in the text.
Calls to notBoundary() in this example represents some
additional stopping criteria.
public void traverseOut(CharacterIterator iter, int pos) {
for (char c = iter.setIndex(pos);
c != CharacterIterator.DONE && notBoundary(c);
c = iter.next()) {}
int end = iter.getIndex();
for (char c = iter.setIndex(pos);
c != CharacterIterator.DONE && notBoundary(c);
c = iter.prev()) {}
int start = iter.getIndex();
processSection(start,end);
}