001    /*
002     * Copyright (C) 2012 eXo Platform SAS.
003     *
004     * This is free software; you can redistribute it and/or modify it
005     * under the terms of the GNU Lesser General Public License as
006     * published by the Free Software Foundation; either version 2.1 of
007     * the License, or (at your option) any later version.
008     *
009     * This software is distributed in the hope that it will be useful,
010     * but WITHOUT ANY WARRANTY; without even the implied warranty of
011     * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
012     * Lesser General Public License for more details.
013     *
014     * You should have received a copy of the GNU Lesser General Public
015     * License along with this software; if not, write to the Free
016     * Software Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA
017     * 02110-1301 USA, or see the FSF site: http://www.fsf.org.
018     */
019    
020    package org.crsh.cli.impl.tokenizer;
021    
022    import org.crsh.cli.impl.Delimiter;
023    
024    import java.util.ArrayList;
025    import java.util.Iterator;
026    import java.util.NoSuchElementException;
027    
028    public abstract class Tokenizer implements Iterator<Token> {
029    
030      /** . */
031      private ArrayList<Token> stack;
032    
033      /** . */
034      private int ptr;
035    
036      /** . */
037      private int index = 0;
038    
039      protected Tokenizer() {
040        this.stack = new ArrayList<Token>();
041        this.ptr = 0;
042      }
043    
044      public final boolean hasNext() {
045        if (ptr < stack.size()) {
046          return true;
047        } else {
048          Token next = parse();
049          if (next != null) {
050            stack.add(next);
051          }
052          return next != null;
053        }
054      }
055    
056      public final void pushBack(int count) {
057        if (count < 0) {
058          throw new IllegalArgumentException();
059        }
060        if (ptr - count < 0) {
061          throw new IllegalStateException("Trying to push back too many tokens");
062        } else {
063          while (count > 0) {
064            index -= stack.get(--ptr).raw.length();
065            count--;
066          }
067        }
068      }
069    
070      public final Token peek() {
071        if (hasNext()) {
072          return stack.get(ptr);
073        } else {
074          return null;
075        }
076      }
077    
078      public final Token next() {
079        if (hasNext()) {
080          Token token = stack.get(ptr++);
081          index += token.raw.length();
082          return token;
083        } else {
084          throw new NoSuchElementException();
085        }
086      }
087    
088      public final void remove() {
089        throw new UnsupportedOperationException();
090      }
091    
092      public final void pushBack() {
093        pushBack(1);
094      }
095    
096      protected abstract Token parse();
097    
098      public final int getIndex() {
099        return index;
100      }
101    
102      public abstract Delimiter getDelimiter();
103    }