/interpreter/tags/at2dist130208/src/edu/vub/util/regexp/REMatchEnumeration.java
http://ambienttalk.googlecode.com/ · Java · 135 lines · 49 code · 11 blank · 75 comment · 7 complexity · d6087a02b4255974dac50d9dccbd806f MD5 · raw file
- /* gnu/regexp/REMatchEnumeration.java
- Copyright (C) 1998-2001, 2004 Free Software Foundation, Inc.
- This file is part of GNU Classpath.
- GNU Classpath is free software; you can redistribute it and/or modify
- it under the terms of the GNU General Public License as published by
- the Free Software Foundation; either version 2, or (at your option)
- any later version.
- GNU Classpath is distributed in the hope that it will be useful, but
- WITHOUT ANY WARRANTY; without even the implied warranty of
- MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
- General Public License for more details.
- You should have received a copy of the GNU General Public License
- along with GNU Classpath; see the file COPYING. If not, write to the
- Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA
- 02110-1301 USA.
- Linking this library statically or dynamically with other modules is
- making a combined work based on this library. Thus, the terms and
- conditions of the GNU General Public License cover the whole
- combination.
- As a special exception, the copyright holders of this library give you
- permission to link this library with independent modules to produce an
- executable, regardless of the license terms of these independent
- modules, and to copy and distribute the resulting executable under
- terms of your choice, provided that you also meet, for each linked
- independent module, the terms and conditions of the license of that
- module. An independent module is a module which is not derived from
- or based on this library. If you modify this library, you may extend
- this exception to your version of the library, but you are not
- obligated to do so. If you do not wish to do so, delete this
- exception statement from your version. */
- package edu.vub.util.regexp;
- import java.io.Serializable;
- import java.util.Enumeration;
- import java.util.NoSuchElementException;
- /**
- * An REMatchEnumeration enumerates regular expression matches over a
- * given input text. You obtain a reference to an enumeration using
- * the <code>getMatchEnumeration()</code> methods on an instance of
- * RE.
- *
- * <P>
- *
- * REMatchEnumeration does lazy computation; that is, it will not
- * search for a match until it needs to. If you'd rather just get all
- * the matches at once in a big array, use the
- * <code>getAllMatches()</code> methods on RE. However, using an
- * enumeration can help speed performance when the entire text does
- * not need to be searched immediately.
- *
- * <P>
- *
- * The enumerated type is especially useful when searching on a Reader
- * or InputStream, because the InputStream read position cannot be
- * guaranteed after calling <code>getMatch()</code> (see the
- * description of that method for an explanation of why). Enumeration
- * also saves a lot of overhead required when calling
- * <code>getMatch()</code> multiple times.
- *
- * @author <A HREF="mailto:wes@cacas.org">Wes Biggs</A>
- */
- public class REMatchEnumeration implements Enumeration, Serializable {
- private static final int YES = 1;
- private static final int MAYBE = 0;
- private static final int NO = -1;
-
- private int more;
- private REMatch match;
- private RE expr;
- private CharIndexed input;
- private int eflags;
- private int index;
- // Package scope constructor is used by RE.getMatchEnumeration()
- REMatchEnumeration(RE expr, CharIndexed input, int index, int eflags) {
- more = MAYBE;
- this.expr = expr;
- this.input = input;
- this.index = index;
- this.eflags = eflags;
- }
- /** Returns true if there are more matches in the input text. */
- public boolean hasMoreElements() {
- return hasMoreMatches(null);
- }
- /** Returns true if there are more matches in the input text. */
- public boolean hasMoreMatches() {
- return hasMoreMatches(null);
- }
- /** Returns true if there are more matches in the input text.
- * Saves the text leading up to the match (or to the end of the input)
- * in the specified buffer.
- */
- public boolean hasMoreMatches(StringBuffer buffer) {
- if (more == MAYBE) {
- match = expr.getMatchImpl(input,index,eflags,buffer);
- if (match != null) {
- input.move((match.end[0] > 0) ? match.end[0] : 1);
-
- index = (match.end[0] > 0) ? match.end[0] + match.offset : index + 1;
- more = YES;
- } else more = NO;
- }
- return (more == YES);
- }
- /** Returns the next match in the input text. */
- public Object nextElement() throws NoSuchElementException {
- return nextMatch();
- }
- /**
- * Returns the next match in the input text. This method is provided
- * for convenience to avoid having to explicitly cast the return value
- * to class REMatch.
- */
- public REMatch nextMatch() throws NoSuchElementException {
- if (hasMoreElements()) {
- more = (input.isValid()) ? MAYBE : NO;
- return match;
- }
- throw new NoSuchElementException();
- }
- }