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/*
* (C) Copyright Taligent, Inc. 1996, 1997 - All Rights Reserved
* (C) Copyright IBM Corp. 1996 - 1998 - All Rights Reserved
*
* The original version of this source code and documentation
* is copyrighted and owned by Taligent, Inc., a wholly-owned
* subsidiary of IBM. These materials are provided under terms
* of a License Agreement between Taligent and Sun. This technology
* is protected by multiple US and International patents.
*
* This notice and attribution to Taligent may not be removed.
* Taligent is a registered trademark of Taligent, Inc.
*
*/
package java.text;
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);
}
See Also: Since: 1.1
/**
* 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.
* <p>
* 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().
* <p>
* 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.
*
* <P>Examples:<P>
*
* Traverse the text from start to finish
* <pre>{@code
* public void traverseForward(CharacterIterator iter) {
* for(char c = iter.first(); c != CharacterIterator.DONE; c = iter.next()) {
* processChar(c);
* }
* }
* }</pre>
*
* Traverse the text backwards, from end to start
* <pre>{@code
* public void traverseBackward(CharacterIterator iter) {
* for(char c = iter.last(); c != CharacterIterator.DONE; c = iter.previous()) {
* processChar(c);
* }
* }
* }</pre>
*
* Traverse both forward and backward from a given position in the text.
* Calls to notBoundary() in this example represents some
* additional stopping criteria.
* <pre>{@code
* 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);
* }
* }</pre>
*
* @since 1.1
* @see StringCharacterIterator
* @see AttributedCharacterIterator
*/
public interface CharacterIterator extends Cloneable
{
Constant that is returned when the iterator has reached either the end
or the beginning of the text. The value is '\\uFFFF', the "not a
character" value which should not occur in any valid Unicode string.
/**
* Constant that is returned when the iterator has reached either the end
* or the beginning of the text. The value is '\\uFFFF', the "not a
* character" value which should not occur in any valid Unicode string.
*/
public static final char DONE = '\uFFFF';
Sets the position to getBeginIndex() and returns the character at that
position.
See Also: Returns: the first character in the text, or DONE if the text is empty
/**
* Sets the position to getBeginIndex() and returns the character at that
* position.
* @return the first character in the text, or DONE if the text is empty
* @see #getBeginIndex()
*/
public char first();
Sets the position to getEndIndex()-1 (getEndIndex() if the text is empty)
and returns the character at that position.
See Also: Returns: the last character in the text, or DONE if the text is empty
/**
* Sets the position to getEndIndex()-1 (getEndIndex() if the text is empty)
* and returns the character at that position.
* @return the last character in the text, or DONE if the text is empty
* @see #getEndIndex()
*/
public char last();
Gets the character at the current position (as returned by getIndex()).
See Also: Returns: the character at the current position or DONE if the current
position is off the end of the text.
/**
* Gets the character at the current position (as returned by getIndex()).
* @return the character at the current position or DONE if the current
* position is off the end of the text.
* @see #getIndex()
*/
public char current();
Increments the iterator's index by one and returns the character
at the new index. If the resulting index is greater or equal
to getEndIndex(), the current index is reset to getEndIndex() and
a value of DONE is returned.
Returns: the character at the new position or DONE if the new
position is off the end of the text range.
/**
* Increments the iterator's index by one and returns the character
* at the new index. If the resulting index is greater or equal
* to getEndIndex(), the current index is reset to getEndIndex() and
* a value of DONE is returned.
* @return the character at the new position or DONE if the new
* position is off the end of the text range.
*/
public char next();
Decrements the iterator's index by one and returns the character
at the new index. If the current index is getBeginIndex(), the index
remains at getBeginIndex() and a value of DONE is returned.
Returns: the character at the new position or DONE if the current
position is equal to getBeginIndex().
/**
* Decrements the iterator's index by one and returns the character
* at the new index. If the current index is getBeginIndex(), the index
* remains at getBeginIndex() and a value of DONE is returned.
* @return the character at the new position or DONE if the current
* position is equal to getBeginIndex().
*/
public char previous();
Sets the position to the specified position in the text and returns that
character.
Params: - position – the position within the text. Valid values range from
getBeginIndex() to getEndIndex(). An IllegalArgumentException is thrown
if an invalid value is supplied.
Returns: the character at the specified position or DONE if the specified position is equal to getEndIndex()
/**
* Sets the position to the specified position in the text and returns that
* character.
* @param position the position within the text. Valid values range from
* getBeginIndex() to getEndIndex(). An IllegalArgumentException is thrown
* if an invalid value is supplied.
* @return the character at the specified position or DONE if the specified position is equal to getEndIndex()
*/
public char setIndex(int position);
Returns the start index of the text.
Returns: the index at which the text begins.
/**
* Returns the start index of the text.
* @return the index at which the text begins.
*/
public int getBeginIndex();
Returns the end index of the text. This index is the index of the first
character following the end of the text.
Returns: the index after the last character in the text
/**
* Returns the end index of the text. This index is the index of the first
* character following the end of the text.
* @return the index after the last character in the text
*/
public int getEndIndex();
Returns the current index.
Returns: the current index.
/**
* Returns the current index.
* @return the current index.
*/
public int getIndex();
Create a copy of this iterator
Returns: A copy of this
/**
* Create a copy of this iterator
* @return A copy of this
*/
public Object clone();
}