java.text.CharacterIterator Maven / Gradle / Ivy
/*
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may also be used to produce "compilation stubs," which allow
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Any work generated from this file, such as unified javadocs or compiled
stub files, must be accompanied by this notice in its entirety.
This work corresponds to the API signatures of JSR 219: Foundation
Profile 1.1. In the event of a discrepency between this work and the
JSR 219 specification, which is available at
http://www.jcp.org/en/jsr/detail?id=219, the latter takes precedence.
*/
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 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.
*/
public static final char DONE = 65535;
/**
* 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.
* @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()).
* @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.
* @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.
* @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.
* @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.
* @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.
* @return the index after the last character in the text
*/
public int getEndIndex();
/**
* Returns the current index.
* @return the current index.
*/
public int getIndex();
/**
* Create a copy of this iterator
* @return A copy of this
*/
public Object clone();
}