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1: /* gnu/regexp/REMatchEnumeration.java 2: Copyright (C) 1998-2001, 2004 Free Software Foundation, Inc. 3: 4: This file is part of GNU Classpath. 5: 6: GNU Classpath is free software; you can redistribute it and/or modify 7: it under the terms of the GNU General Public License as published by 8: the Free Software Foundation; either version 2, or (at your option) 9: any later version. 10: 11: GNU Classpath is distributed in the hope that it will be useful, but 12: WITHOUT ANY WARRANTY; without even the implied warranty of 13: MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU 14: General Public License for more details. 15: 16: You should have received a copy of the GNU General Public License 17: along with GNU Classpath; see the file COPYING. If not, write to the 18: Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 19: 02110-1301 USA. 20: 21: Linking this library statically or dynamically with other modules is 22: making a combined work based on this library. Thus, the terms and 23: conditions of the GNU General Public License cover the whole 24: combination. 25: 26: As a special exception, the copyright holders of this library give you 27: permission to link this library with independent modules to produce an 28: executable, regardless of the license terms of these independent 29: modules, and to copy and distribute the resulting executable under 30: terms of your choice, provided that you also meet, for each linked 31: independent module, the terms and conditions of the license of that 32: module. An independent module is a module which is not derived from 33: or based on this library. If you modify this library, you may extend 34: this exception to your version of the library, but you are not 35: obligated to do so. If you do not wish to do so, delete this 36: exception statement from your version. */ 37: 38: package gnu.java.util.regex; 39: import java.io.Serializable; 40: import java.util.Enumeration; 41: import java.util.NoSuchElementException; 42: 43: /** 44: * An REMatchEnumeration enumerates regular expression matches over a 45: * given input text. You obtain a reference to an enumeration using 46: * the <code>getMatchEnumeration()</code> methods on an instance of 47: * RE. 48: * 49: * <P> 50: * 51: * REMatchEnumeration does lazy computation; that is, it will not 52: * search for a match until it needs to. If you'd rather just get all 53: * the matches at once in a big array, use the 54: * <code>getAllMatches()</code> methods on RE. However, using an 55: * enumeration can help speed performance when the entire text does 56: * not need to be searched immediately. 57: * 58: * <P> 59: * 60: * The enumerated type is especially useful when searching on a Reader 61: * or InputStream, because the InputStream read position cannot be 62: * guaranteed after calling <code>getMatch()</code> (see the 63: * description of that method for an explanation of why). Enumeration 64: * also saves a lot of overhead required when calling 65: * <code>getMatch()</code> multiple times. 66: * 67: * @author <A HREF="mailto:wes@cacas.org">Wes Biggs</A> 68: */ 69: public class REMatchEnumeration implements Enumeration, Serializable { 70: private static final int YES = 1; 71: private static final int MAYBE = 0; 72: private static final int NO = -1; 73: 74: private int more; 75: private REMatch match; 76: private RE expr; 77: private CharIndexed input; 78: private int eflags; 79: private int index; 80: 81: // Package scope constructor is used by RE.getMatchEnumeration() 82: REMatchEnumeration(RE expr, CharIndexed input, int index, int eflags) { 83: more = MAYBE; 84: this.expr = expr; 85: this.input = input; 86: this.index = index; 87: this.eflags = eflags; 88: } 89: 90: /** Returns true if there are more matches in the input text. */ 91: public boolean hasMoreElements() { 92: return hasMoreMatches(null); 93: } 94: 95: /** Returns true if there are more matches in the input text. */ 96: public boolean hasMoreMatches() { 97: return hasMoreMatches(null); 98: } 99: 100: /** Returns true if there are more matches in the input text. 101: * Saves the text leading up to the match (or to the end of the input) 102: * in the specified buffer. 103: */ 104: public boolean hasMoreMatches(StringBuffer buffer) { 105: if (more == MAYBE) { 106: match = expr.getMatchImpl(input,index,eflags,buffer); 107: if (match != null) { 108: input.move((match.end[0] > 0) ? match.end[0] : 1); 109: 110: index = (match.end[0] > 0) ? match.end[0] + match.offset : index + 1; 111: more = YES; 112: } else more = NO; 113: } 114: return (more == YES); 115: } 116: 117: /** Returns the next match in the input text. */ 118: public Object nextElement() throws NoSuchElementException { 119: return nextMatch(); 120: } 121: 122: /** 123: * Returns the next match in the input text. This method is provided 124: * for convenience to avoid having to explicitly cast the return value 125: * to class REMatch. 126: */ 127: public REMatch nextMatch() throws NoSuchElementException { 128: if (hasMoreElements()) { 129: more = (input.isValid()) ? MAYBE : NO; 130: return match; 131: } 132: throw new NoSuchElementException(); 133: } 134: }