|
Java™ Platform Standard Ed. 6 |
|||||||||
PREV CLASS NEXT CLASS | FRAMES NO FRAMES | |||||||||
SUMMARY: NESTED | FIELD | CONSTR | METHOD | DETAIL: FIELD | CONSTR | METHOD |
public interface CharacterIterator
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.
Iterators maintain a current character index, whose valid range is from getBeginIndex() to getEndIndex(); the value getEndIndex() is included to allow handling of zero-length text ranges and for historical reasons. The current index can be retrieved by calling getIndex() and set directly by calling setIndex(), first(), and last().
The methods previous() and next() are used for iteration. They return DONE if they would move outside the range from getBeginIndex() to getEndIndex() -1, signaling that the iterator has reached the end of the sequence. DONE is also returned by other methods to indicate that the current index is outside this range.
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.previous()) { 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.previous()) { } int start = iter.getIndex(); processSection(start, end); }
StringCharacterIterator
,
AttributedCharacterIterator
Field Summary | |
---|---|
static char |
DONE
Constant that is returned when the iterator has reached either the end or the beginning of the text. |
Method Summary | |
---|---|
Object |
clone()
Create a copy of this iterator |
char |
current()
Gets the character at the current position (as returned by getIndex()). |
char |
first()
Sets the position to getBeginIndex() and returns the character at that position. |
int |
getBeginIndex()
Returns the start index of the text. |
int |
getEndIndex()
Returns the end index of the text. |
int |
getIndex()
Returns the current index. |
char |
last()
Sets the position to getEndIndex()-1 (getEndIndex() if the text is empty) and returns the character at that position. |
char |
next()
Increments the iterator's index by one and returns the character at the new index. |
char |
previous()
Decrements the iterator's index by one and returns the character at the new index. |
char |
setIndex(int position)
Sets the position to the specified position in the text and returns that character. |
Field Detail |
---|
static final char DONE
Method Detail |
---|
char first()
getBeginIndex()
char last()
getEndIndex()
char current()
getIndex()
char next()
char previous()
char setIndex(int position)
position
- the position within the text. Valid values range from
getBeginIndex() to getEndIndex(). An IllegalArgumentException is thrown
if an invalid value is supplied.
int getBeginIndex()
int getEndIndex()
int getIndex()
Object clone()
|
Java™ Platform Standard Ed. 6 |
|||||||||
PREV CLASS NEXT CLASS | FRAMES NO FRAMES | |||||||||
SUMMARY: NESTED | FIELD | CONSTR | METHOD | DETAIL: FIELD | CONSTR | METHOD |
Copyright © 1993, 2010, Oracle and/or its affiliates. All rights reserved.