001    /*
002     * Sonar, open source software quality management tool.
003     * Copyright (C) 2008-2012 SonarSource
004     * mailto:contact AT sonarsource DOT com
005     *
006     * Sonar is free software; you can redistribute it and/or
007     * modify it under the terms of the GNU Lesser General Public
008     * License as published by the Free Software Foundation; either
009     * version 3 of the License, or (at your option) any later version.
010     *
011     * Sonar is distributed in the hope that it will be useful,
012     * but WITHOUT ANY WARRANTY; without even the implied warranty of
013     * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
014     * Lesser General Public License for more details.
015     *
016     * You should have received a copy of the GNU Lesser General Public
017     * License along with Sonar; if not, write to the Free Software
018     * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02
019     */
020    package org.sonar.duplications.token;
021    
022    import java.util.Iterator;
023    import java.util.LinkedList;
024    import java.util.List;
025    import java.util.ListIterator;
026    
027    public class TokenQueue implements Iterable<Token> {
028    
029      private final LinkedList<Token> tokenQueue;
030    
031      public TokenQueue(List<Token> tokenList) {
032        tokenQueue = new LinkedList<Token>(tokenList);
033      }
034    
035      public TokenQueue() {
036        tokenQueue = new LinkedList<Token>();
037      }
038    
039      /**
040       * Retrieves, but does not remove, token from this queue.
041       * 
042       * @return token from this queue, or <tt>null</tt> if this queue is empty.
043       */
044      public Token peek() {
045        return tokenQueue.peek();
046      }
047    
048      /**
049       * Retrieves and removes token from this queue.
050       * 
051       * @return token from this queue, or <tt>null</tt> if this queue is empty.
052       */
053      public Token poll() {
054        return tokenQueue.poll();
055      }
056    
057      public int size() {
058        return tokenQueue.size();
059      }
060    
061      public void add(Token token) {
062        tokenQueue.addLast(token);
063      }
064    
065      public boolean isNextTokenValue(String expectedValue) {
066        Token nextToken = tokenQueue.peek();
067        if (nextToken == null) {
068          // queue is empty
069          return false;
070        }
071        return nextToken.getValue().equals(expectedValue);
072      }
073    
074      public Iterator<Token> iterator() {
075        return tokenQueue.iterator();
076      }
077    
078      public void pushForward(List<Token> matchedTokenList) {
079        ListIterator<Token> iter = matchedTokenList.listIterator(matchedTokenList.size());
080        while (iter.hasPrevious()) {
081          tokenQueue.addFirst(iter.previous());
082        }
083      }
084    
085    }