| /* |
| ******************************************************************************* |
| * Copyright (C) 1996-2004, International Business Machines Corporation and * |
| * others. All Rights Reserved. * |
| ******************************************************************************* |
| */ |
| package com.ibm.icu.text; |
| |
| import java.util.*; |
| |
| /** |
| * UnicodeSetIterator iterates over the contents of a UnicodeSet. It |
| * iterates over either code points or code point ranges. After all |
| * code points or ranges have been returned, it returns the |
| * multicharacter strings of the UnicodSet, if any. |
| * |
| * <p>To iterate over code points, use a loop like this: |
| * <pre> |
| * UnicodeSetIterator it(set); |
| * while (set.next()) { |
| * if (set.codepoint != UnicodeSetIterator::IS_STRING) { |
| * processCodepoint(set.codepoint); |
| * } else { |
| * processString(set.string); |
| * } |
| * } |
| * </pre> |
| * |
| * <p>To iterate over code point ranges, use a loop like this: |
| * <pre> |
| * UnicodeSetIterator it(set); |
| * while (set.nextRange()) { |
| * if (set.codepoint != UnicodeSetIterator::IS_STRING) { |
| * processCodepointRange(set.codepoint, set.codepointEnd); |
| * } else { |
| * processString(set.string); |
| * } |
| * } |
| * </pre> |
| * @author M. Davis |
| * @stable ICU 2.0 |
| */ |
| public class UnicodeSetIterator { |
| |
| /** |
| * Value of <tt>codepoint</tt> if the iterator points to a string. |
| * If <tt>codepoint == IS_STRING</tt>, then examine |
| * <tt>string</tt> for the current iteration result. |
| * @stable ICU 2.0 |
| */ |
| public static int IS_STRING = -1; |
| |
| /** |
| * Current code point, or the special value <tt>IS_STRING</tt>, if |
| * the iterator points to a string. |
| * @stable ICU 2.0 |
| */ |
| public int codepoint; |
| |
| /** |
| * When iterating over ranges using <tt>nextRange()</tt>, |
| * <tt>codepointEnd</tt> contains the inclusive end of the |
| * iteration range, if <tt>codepoint != IS_STRING</tt>. If |
| * iterating over code points using <tt>next()</tt>, or if |
| * <tt>codepoint == IS_STRING</tt>, then the value of |
| * <tt>codepointEnd</tt> is undefined. |
| * @stable ICU 2.0 |
| */ |
| public int codepointEnd; |
| |
| /** |
| * If <tt>codepoint == IS_STRING</tt>, then <tt>string</tt> points |
| * to the current string. If <tt>codepoint != IS_STRING</tt>, the |
| * value of <tt>string</tt> is undefined. |
| * @stable ICU 2.0 |
| */ |
| public String string; |
| |
| /** |
| * Create an iterator over the given set. |
| * @param set set to iterate over |
| * @stable ICU 2.0 |
| */ |
| public UnicodeSetIterator(UnicodeSet set) { |
| reset(set); |
| } |
| |
| /** |
| * Create an iterator over nothing. <tt>next()</tt> and |
| * <tt>nextRange()</tt> return false. This is a convenience |
| * constructor allowing the target to be set later. |
| * @stable ICU 2.0 |
| */ |
| public UnicodeSetIterator() { |
| reset(new UnicodeSet()); |
| } |
| |
| /** |
| * Returns the next element in the set, either a single code point |
| * or a string. If there are no more elements in the set, return |
| * false. If <tt>codepoint == IS_STRING</tt>, the value is a |
| * string in the <tt>string</tt> field. Otherwise the value is a |
| * single code point in the <tt>codepoint</tt> field. |
| * |
| * <p>The order of iteration is all code points in sorted order, |
| * followed by all strings sorted order. <tt>codepointEnd</tt> is |
| * undefined after calling this method. <tt>string</tt> is |
| * undefined unless <tt>codepoint == IS_STRING</tt>. Do not mix |
| * calls to <tt>next()</tt> and <tt>nextRange()</tt> without |
| * calling <tt>reset()</tt> between them. The results of doing so |
| * are undefined. |
| * |
| * @return true if there was another element in the set and this |
| * object contains the element. |
| * @stable ICU 2.0 |
| */ |
| public boolean next() { |
| if (nextElement <= endElement) { |
| codepoint = codepointEnd = nextElement++; |
| return true; |
| } |
| if (range < endRange) { |
| loadRange(++range); |
| codepoint = codepointEnd = nextElement++; |
| return true; |
| } |
| |
| // stringIterator == null iff there are no string elements remaining |
| |
| if (stringIterator == null) return false; |
| codepoint = IS_STRING; // signal that value is actually a string |
| string = (String)stringIterator.next(); |
| if (!stringIterator.hasNext()) stringIterator = null; |
| return true; |
| } |
| |
| /** |
| * Returns the next element in the set, either a code point range |
| * or a string. If there are no more elements in the set, return |
| * false. If <tt>codepoint == IS_STRING</tt>, the value is a |
| * string in the <tt>string</tt> field. Otherwise the value is a |
| * range of one or more code points from <tt>codepoint</tt> to |
| * <tt>codepointeEnd</tt> inclusive. |
| * |
| * <p>The order of iteration is all code points ranges in sorted |
| * order, followed by all strings sorted order. Ranges are |
| * disjoint and non-contiguous. <tt>string</tt> is undefined |
| * unless <tt>codepoint == IS_STRING</tt>. Do not mix calls to |
| * <tt>next()</tt> and <tt>nextRange()</tt> without calling |
| * <tt>reset()</tt> between them. The results of doing so are |
| * undefined. |
| * |
| * @return true if there was another element in the set and this |
| * object contains the element. |
| * @stable ICU 2.0 |
| */ |
| public boolean nextRange() { |
| if (nextElement <= endElement) { |
| codepointEnd = endElement; |
| codepoint = nextElement; |
| nextElement = endElement+1; |
| return true; |
| } |
| if (range < endRange) { |
| loadRange(++range); |
| codepointEnd = endElement; |
| codepoint = nextElement; |
| nextElement = endElement+1; |
| return true; |
| } |
| |
| // stringIterator == null iff there are no string elements remaining |
| |
| if (stringIterator == null) return false; |
| codepoint = IS_STRING; // signal that value is actually a string |
| string = (String)stringIterator.next(); |
| if (!stringIterator.hasNext()) stringIterator = null; |
| return true; |
| } |
| |
| /** |
| * Sets this iterator to visit the elements of the given set and |
| * resets it to the start of that set. The iterator is valid only |
| * so long as <tt>set</tt> is valid. |
| * @param set the set to iterate over. |
| * @stable ICU 2.0 |
| */ |
| public void reset(UnicodeSet set) { |
| this.set = set; |
| reset(); |
| } |
| |
| /** |
| * Resets this iterator to the start of the set. |
| * @stable ICU 2.0 |
| */ |
| public void reset() { |
| endRange = set.getRangeCount() - 1; |
| range = 0; |
| endElement = -1; |
| nextElement = 0; |
| if (endRange >= 0) { |
| loadRange(range); |
| } |
| stringIterator = null; |
| if (set.strings != null) { |
| stringIterator = set.strings.iterator(); |
| if (!stringIterator.hasNext()) stringIterator = null; |
| } |
| } |
| |
| /** |
| * Gets the current string from the iterator. Only use after calling next(), not nextRange(). |
| * @internal |
| */ |
| public String getString() { |
| if (codepoint != IS_STRING) { |
| return UTF16.valueOf(codepoint); |
| } |
| return string; |
| } |
| |
| // ======================= PRIVATES =========================== |
| |
| private UnicodeSet set; |
| private int endRange = 0; |
| private int range = 0; |
| /** |
| * @internal |
| */ |
| protected int endElement; |
| /** |
| * @internal |
| */ |
| protected int nextElement; |
| private Iterator stringIterator = null; |
| |
| /** |
| * Invariant: stringIterator is null when there are no (more) strings remaining |
| */ |
| |
| /** |
| * @internal |
| */ |
| protected void loadRange(int range) { |
| nextElement = set.getRangeStart(range); |
| endElement = set.getRangeEnd(range); |
| } |
| } |
