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*
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* ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
* FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
* version 2 for more details (a copy is included in the LICENSE file that
* accompanied this code).
*
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/*
*******************************************************************************
* (C) Copyright IBM Corp. 1996-2005 - All Rights Reserved *
* *
* The original version of this source code and documentation is copyrighted *
* and owned by IBM, These materials are provided under terms of a License *
* Agreement between IBM and Sun. This technology is protected by multiple *
* US and International patents. This notice and attribution to IBM may not *
* to removed. *
*******************************************************************************
*/
package sun.text.normalizer;
import java.text.CharacterIterator;
/**
* Abstract class that defines an API for iteration on text objects.This is an
* interface for forward and backward iteration and random access into a text
* object. Forward iteration is done with post-increment and backward iteration
* is done with pre-decrement semantics, while the
* <code>java.text.CharacterIterator</code> interface methods provided forward
* iteration with "pre-increment" and backward iteration with pre-decrement
* semantics. This API is more efficient for forward iteration over code points.
* The other major difference is that this API can do both code unit and code point
* iteration, <code>java.text.CharacterIterator</code> can only iterate over
* code units and is limited to BMP (0 - 0xFFFF)
* @author Ram
* @stable ICU 2.4
*/
public abstract class UCharacterIterator
implements Cloneable {
/**
* Protected default constructor for the subclasses
* @stable ICU 2.4
*/
protected UCharacterIterator(){
}
/**
* Indicator that we have reached the ends of the UTF16 text.
* Moved from UForwardCharacterIterator.java
* @stable ICU 2.4
*/
public static final int DONE = -1;
// static final methods ----------------------------------------------------
/**
* Returns a <code>UCharacterIterator</code> object given a
* source string.
* @param source a string
* @return UCharacterIterator object
* @exception IllegalArgumentException if the argument is null
* @stable ICU 2.4
*/
public static final UCharacterIterator getInstance(String source){
return new ReplaceableUCharacterIterator(source);
}
//// for StringPrep
/**
* Returns a <code>UCharacterIterator</code> object given a
* source StringBuffer.
* @param source an string buffer of UTF-16 code units
* @return UCharacterIterator object
* @exception IllegalArgumentException if the argument is null
* @stable ICU 2.4
*/
public static final UCharacterIterator getInstance(StringBuffer source){
return new ReplaceableUCharacterIterator(source);
}
/**
* Returns a <code>UCharacterIterator</code> object given a
* CharacterIterator.
* @param source a valid CharacterIterator object.
* @return UCharacterIterator object
* @exception IllegalArgumentException if the argument is null
* @stable ICU 2.4
*/
public static final UCharacterIterator getInstance(CharacterIterator source){
return new CharacterIteratorWrapper(source);
}
// public methods ----------------------------------------------------------
/**
* Returns the code unit at the current index. If index is out
* of range, returns DONE. Index is not changed.
* @return current code unit
* @stable ICU 2.4
*/
public abstract int current();
/**
* Returns the length of the text
* @return length of the text
* @stable ICU 2.4
*/
public abstract int getLength();
/**
* Gets the current index in text.
* @return current index in text.
* @stable ICU 2.4
*/
public abstract int getIndex();
/**
* Returns the UTF16 code unit at index, and increments to the next
* code unit (post-increment semantics). If index is out of
* range, DONE is returned, and the iterator is reset to the limit
* of the text.
* @return the next UTF16 code unit, or DONE if the index is at the limit
* of the text.
* @stable ICU 2.4
*/
public abstract int next();
/**
* Returns the code point at index, and increments to the next code
* point (post-increment semantics). If index does not point to a
* valid surrogate pair, the behavior is the same as
* <code>next()</code>. Otherwise the iterator is incremented past
* the surrogate pair, and the code point represented by the pair
* is returned.
* @return the next codepoint in text, or DONE if the index is at
* the limit of the text.
* @stable ICU 2.4
*/
public int nextCodePoint(){
int ch1 = next();
if(UTF16.isLeadSurrogate((char)ch1)){
int ch2 = next();
if(UTF16.isTrailSurrogate((char)ch2)){
return UCharacterProperty.getRawSupplementary((char)ch1,
(char)ch2);
}else if (ch2 != DONE) {
// unmatched surrogate so back out
previous();
}
}
return ch1;
}
/**
* Decrement to the position of the previous code unit in the
* text, and return it (pre-decrement semantics). If the
* resulting index is less than 0, the index is reset to 0 and
* DONE is returned.
* @return the previous code unit in the text, or DONE if the new
* index is before the start of the text.
* @stable ICU 2.4
*/
public abstract int previous();
/**
* Sets the index to the specified index in the text.
* @param index the index within the text.
* @exception IndexOutOfBoundsException is thrown if an invalid index is
* supplied
* @stable ICU 2.4
*/
public abstract void setIndex(int index);
//// for StringPrep
/**
* Fills the buffer with the underlying text storage of the iterator
* If the buffer capacity is not enough a exception is thrown. The capacity
* of the fill in buffer should at least be equal to length of text in the
* iterator obtained by calling <code>getLength()</code>.
* <b>Usage:</b>
*
* <code>
* <pre>
* UChacterIterator iter = new UCharacterIterator.getInstance(text);
* char[] buf = new char[iter.getLength()];
* iter.getText(buf);
*
* OR
* char[] buf= new char[1];
* int len = 0;
* for(;;){
* try{
* len = iter.getText(buf);
* break;
* }catch(IndexOutOfBoundsException e){
* buf = new char[iter.getLength()];
* }
* }
* </pre>
* </code>
*
* @param fillIn an array of chars to fill with the underlying UTF-16 code
* units.
* @param offset the position within the array to start putting the data.
* @return the number of code units added to fillIn, as a convenience
* @exception IndexOutOfBounds exception if there is not enough
* room after offset in the array, or if offset < 0.
* @stable ICU 2.4
*/
public abstract int getText(char[] fillIn, int offset);
//// for StringPrep
/**
* Convenience override for <code>getText(char[], int)</code> that provides
* an offset of 0.
* @param fillIn an array of chars to fill with the underlying UTF-16 code
* units.
* @return the number of code units added to fillIn, as a convenience
* @exception IndexOutOfBounds exception if there is not enough
* room in the array.
* @stable ICU 2.4
*/
public final int getText(char[] fillIn) {
return getText(fillIn, 0);
}
//// for StringPrep
/**
* Convenience method for returning the underlying text storage as as string
* @return the underlying text storage in the iterator as a string
* @stable ICU 2.4
*/
public String getText() {
char[] text = new char[getLength()];
getText(text);
return new String(text);
}
/**
* Moves the current position by the number of code units
* specified, either forward or backward depending on the sign
* of delta (positive or negative respectively). If the resulting
* index would be less than zero, the index is set to zero, and if
* the resulting index would be greater than limit, the index is
* set to limit.
*
* @param delta the number of code units to move the current
* index.
* @return the new index.
* @exception IndexOutOfBoundsException is thrown if an invalid index is
* supplied
* @stable ICU 2.4
*
*/
public int moveIndex(int delta) {
int x = Math.max(0, Math.min(getIndex() + delta, getLength()));
setIndex(x);
return x;
}
/**
* Creates a copy of this iterator, independent from other iterators.
* If it is not possible to clone the iterator, returns null.
* @return copy of this iterator
* @stable ICU 2.4
*/
public Object clone() throws CloneNotSupportedException{
return super.clone();
}
}