| /* |
| ******************************************************************************* |
| * Copyright (C) 1996-2004, International Business Machines Corporation and * |
| * others. All Rights Reserved. * |
| ******************************************************************************* |
| */ |
| package com.ibm.icu.text; |
| |
| |
| import java.text.CharacterIterator; |
| |
| import com.ibm.icu.impl.CharacterIteratorWrapper; |
| import com.ibm.icu.impl.ReplaceableUCharacterIterator; |
| import com.ibm.icu.impl.UCharArrayIterator; |
| import com.ibm.icu.impl.UCharacterIteratorWrapper; |
| import com.ibm.icu.impl.UCharacterProperty; |
| |
| |
| /** |
| * 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,UForwardCharacterIterator { |
| |
| /** |
| * Protected default constructor for the subclasses |
| * @stable ICU 2.4 |
| */ |
| protected UCharacterIterator(){ |
| } |
| |
| // static final methods ---------------------------------------------------- |
| |
| /** |
| * Returns a <code>UCharacterIterator</code> object given a |
| * <code>Replaceable</code> object. |
| * @param source a valid source as a <code>Replaceable</code> object |
| * @return UCharacterIterator object |
| * @exception IllegalArgumentException if the argument is null |
| * @stable ICU 2.4 |
| */ |
| public static final UCharacterIterator getInstance(Replaceable source){ |
| return new ReplaceableUCharacterIterator(source); |
| } |
| |
| /** |
| * 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); |
| } |
| |
| /** |
| * Returns a <code>UCharacterIterator</code> object given a |
| * source character array. |
| * @param source an array of UTF-16 code units |
| * @return UCharacterIterator object |
| * @exception IllegalArgumentException if the argument is null |
| * @stable ICU 2.4 |
| */ |
| public static final UCharacterIterator getInstance(char[] source){ |
| return getInstance(source,0,source.length); |
| } |
| |
| /** |
| * Returns a <code>UCharacterIterator</code> object given a |
| * source character array. |
| * @param source an array of UTF-16 code units |
| * @return UCharacterIterator object |
| * @exception IllegalArgumentException if the argument is null |
| * @stable ICU 2.4 |
| */ |
| public static final UCharacterIterator getInstance(char[] source, int start, int limit){ |
| return new UCharArrayIterator(source,start,limit); |
| } |
| /** |
| * 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 a <code>java.text.CharacterIterator</code> object for |
| * the underlying text of this iterator. The returned iterator is |
| * independent of this iterator. |
| * @return java.text.CharacterIterator object |
| * @stable ICU 2.4 |
| */ |
| public CharacterIterator getCharacterIterator(){ |
| return new UCharacterIteratorWrapper(this); |
| } |
| |
| /** |
| * 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 codepoint at the current index. |
| * If the current index is invalid, DONE is returned. |
| * If the current index points to a lead surrogate, and there is a following |
| * trail surrogate, then the code point is returned. Otherwise, the code |
| * unit at index is returned. Index is not changed. |
| * @return current codepoint |
| * @stable ICU 2.4 |
| */ |
| public int currentCodePoint(){ |
| int ch = current(); |
| if(UTF16.isLeadSurrogate((char)ch)){ |
| // advance the index to get the |
| // next code point |
| next(); |
| // due to post increment semantics |
| // current() after next() actually |
| // returns the char we want |
| int ch2 = current(); |
| // current should never change |
| // the current index so back off |
| previous(); |
| |
| if(UTF16.isTrailSurrogate((char)ch2)){ |
| // we found a surrogate pair |
| // return the codepoint |
| return UCharacterProperty.getRawSupplementary( |
| (char)ch,(char)ch2 |
| ); |
| } |
| } |
| return ch; |
| } |
| |
| /** |
| * 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(); |
| |
| |
| /** |
| * Retreat to the start of the previous code point in the text, |
| * and return it (pre-decrement semantics). If the index is not |
| * preceeded by a valid surrogate pair, the behavior is the same |
| * as <code>previous()</code>. Otherwise the iterator is |
| * decremented to the start of the surrogate pair, and the code |
| * point represented by the pair is returned. |
| * @return the previous code point in the text, or DONE if the new |
| * index is before the start of the text. |
| * @stable ICU 2.4 |
| */ |
| public int previousCodePoint(){ |
| int ch1 = previous(); |
| if(UTF16.isTrailSurrogate((char)ch1)){ |
| int ch2 = previous(); |
| if(UTF16.isLeadSurrogate((char)ch2)){ |
| return UCharacterProperty.getRawSupplementary((char)ch2, |
| (char)ch1); |
| }else if (ch2 != DONE) { |
| //unmatched trail surrogate so back out |
| next(); |
| } |
| } |
| return ch1; |
| } |
| |
| /** |
| * 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); |
| |
| /** |
| * Sets the current index to the limit. |
| * @stable ICU 2.4 |
| */ |
| public void setToLimit() { |
| setIndex(getLength()); |
| } |
| |
| /** |
| * Sets the current index to the start. |
| * @stable ICU 2.4 |
| */ |
| public void setToStart() { |
| setIndex(0); |
| } |
| |
| /** |
| * 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); |
| |
| /** |
| * 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); |
| } |
| |
| /** |
| * 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; |
| } |
| |
| /** |
| * Moves the current position by the number of code points |
| * specified, either forward or backward depending on the sign of |
| * delta (positive or negative respectively). If the current index |
| * is at a trail surrogate then the first adjustment is by code |
| * unit, and the remaining adjustments are by code points. 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 delta is |
| * supplied |
| * @stable ICU 2.4 |
| */ |
| public int moveCodePointIndex(int delta){ |
| if(delta>0){ |
| while(delta>0 && nextCodePoint() != DONE){delta--;} |
| }else{ |
| while(delta<0 && previousCodePoint() != DONE){delta++;} |
| } |
| if(delta!=0){ |
| throw new IndexOutOfBoundsException(); |
| } |
| |
| return getIndex(); |
| } |
| |
| /** |
| * 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(); |
| } |
| |
| } |
| |