| // © 2016 and later: Unicode, Inc. and others. |
| // License & terms of use: http://www.unicode.org/copyright.html#License |
| /* |
| ******************************************************************************* |
| * Copyright (C) 1996-2016, 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; |
| |
| /** |
| * 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 Character.toCodePoint((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 |
| */ |
| @Override |
| 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 |
| */ |
| @Override |
| public int nextCodePoint() { |
| int ch1 = next(); |
| if (UTF16.isLeadSurrogate((char) ch1)) { |
| int ch2 = next(); |
| if (UTF16.isTrailSurrogate((char) ch2)) { |
| return Character.toCodePoint((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 Character.toCodePoint((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> |
| * |
| * <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> |
| * |
| * @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 IndexOutOfBoundsException |
| * 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 IndexOutOfBoundsException |
| * 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 |
| */ |
| @Override |
| public Object clone() throws CloneNotSupportedException { |
| return super.clone(); |
| } |
| |
| } |