001    /*
002     * Copyright (C) 2010 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.shell.impl.command;
021    
022    import org.crsh.command.ScriptException;
023    
024    /**
025     * @author <a href="mailto:julien.viet@exoplatform.com">Julien Viet</a>
026     * @version $Revision$
027     */
028    class Tokenizer {
029    
030      /** . */
031      private final CharSequence s;
032    
033      /** . */
034      private int index;
035    
036      /** . */
037      private Character c;
038    
039      /**
040       * Create a new tokenizer.
041       *
042       * @param s the sequence to tokenize
043       * @throws NullPointerException if the sequence is null
044       */
045      public Tokenizer(CharSequence s) throws NullPointerException {
046        if (s == null) {
047          throw new NullPointerException();
048        }
049        this.s = s;
050        this.index = 0;
051    
052        // Initialize state
053        // index points to next char to read
054        // c = s.charAt(index - 1);
055        this.c = index < s.length() ? s.charAt(index++) : null;
056      }
057    
058      private void next() {
059        if (index < s.length()) {
060          c = s.charAt(index++);
061        } else {
062          c = null;
063        }
064      }
065    
066      public Token nextToken() {
067        if (c == null) {
068          return Token.EOF;
069        } else {
070          switch (c) {
071            case '+':
072              next();
073              return Token.PLUS;
074            case '|':
075              next();
076              return Token.PIPE;
077            default:
078              return parseCommand();
079          }
080        }
081      }
082    
083      private Token parseCommand() throws ScriptException {
084    
085        //
086        StringBuilder line = new StringBuilder();
087    
088        //
089        Character lastQuote = null;
090        while (c != null) {
091          if (lastQuote == null && (c == '+' || c == '|')) {
092            break;
093          } else {
094            line.append(c);
095            switch (c) {
096              case '"':
097              case '\'':
098                if (lastQuote == null) {
099                  lastQuote = c;
100                } else if (lastQuote != c) {
101                } else {
102                  lastQuote = null;
103                }
104                break;
105              default:
106                break;
107            }
108          }
109    
110          //
111          next();
112        }
113    
114        //
115        return new Token.Command(line.toString());
116      }
117    }