001/** 
002 * Copyright (c) 2007-2008, Regents of the University of Colorado 
003 * All rights reserved.
004 * 
005 * Redistribution and use in source and binary forms, with or without
006 * modification, are permitted provided that the following conditions are met:
007 * 
008 * Redistributions of source code must retain the above copyright notice, this list of conditions and the following disclaimer. 
009 * Redistributions in binary form must reproduce the above copyright notice, this list of conditions and the following disclaimer in the documentation and/or other materials provided with the distribution. 
010 * Neither the name of the University of Colorado at Boulder nor the names of its contributors may be used to endorse or promote products derived from this software without specific prior written permission. 
011 * 
012 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
013 * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
014 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
015 * ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE
016 * LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
017 * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
018 * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
019 * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
020 * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
021 * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
022 * POSSIBILITY OF SUCH DAMAGE. 
023 */
024package org.cleartk.token.tokenizer;
025
026import java.util.ArrayList;
027import java.util.List;
028
029/**
030 * <br>
031 * Copyright (c) 2007-2008, Regents of the University of Colorado <br>
032 * All rights reserved.
033 * 
034 * <p>
035 */
036public abstract class Tokenizer_ImplBase implements Tokenizer {
037
038  public abstract String[] getTokenTexts(String text);
039
040  /**
041   * performs tokenization on the input text and returns the character offsets corresponding to the
042   * begining and end of each token w.r.t. the input text.
043   * 
044   * @param text
045   *          the text that you want tokenized.
046   * @return offsets corresponding to the begining and end of each token. The dimensions of the
047   *         returned array will be number of tokens returned by getTokens by 2 (one for token begin
048   *         and one for token end).
049   * 
050   *         <pre>
051   * 
052   *         <code> int[][] offsets = getTokenOffsets("example text"); int
053   *         beginFirstToken = offsets[0][0]; int endFirstToken =
054   *         offsets[0][1]; int begin4thToken = offsets[3][0]; int end4thToken
055   *         = offsets[3][1];
056   * 
057   * </pre>
058   * 
059   *         </code>
060   * 
061   */
062  public List<Token> getTokens(String text) {
063    List<Token> returnValues = new ArrayList<Token>();
064    String[] tokenTexts = getTokenTexts(text);
065    if (text.length() > 0) {
066      int offset = 0;
067      for (String tokenText : tokenTexts) {
068        while (text.charAt(offset) != tokenText.charAt(0))
069          offset++;
070
071        Token token = new Token(offset, offset + tokenText.length(), tokenText);
072        returnValues.add(token);
073        offset += tokenText.length();
074      }
075    }
076
077    return returnValues;
078  }
079
080}