Coverage Report - org.jaxen.function.StringLengthFunction

Classes in this File Line Coverage Branch Coverage Complexity
StringLengthFunction
90% 
100% 
4.667

 1  
 /*
 2  
  * $Header: /home/projects/jaxen/scm/jaxen/src/java/main/org/jaxen/function/StringLengthFunction.java,v 1.10 2005/06/28 13:44:45 elharo Exp $
 3  
  * $Revision: 1.10 $
 4  
  * $Date: 2005/06/28 13:44:45 $
 5  
  *
 6  
  * ====================================================================
 7  
  *
 8  
  * Copyright (C) 2000-2002 bob mcwhirter & James Strachan.
 9  
  * All rights reserved.
 10  
  *
 11  
  * Redistribution and use in source and binary forms, with or without
 12  
  * modification, are permitted provided that the following conditions
 13  
  * are met:
 14  
  * 
 15  
  * 1. Redistributions of source code must retain the above copyright
 16  
  *    notice, this list of conditions, and the following disclaimer.
 17  
  *
 18  
  * 2. Redistributions in binary form must reproduce the above copyright
 19  
  *    notice, this list of conditions, and the disclaimer that follows 
 20  
  *    these conditions in the documentation and/or other materials 
 21  
  *    provided with the distribution.
 22  
  *
 23  
  * 3. The name "Jaxen" must not be used to endorse or promote products
 24  
  *    derived from this software without prior written permission.  For
 25  
  *    written permission, please contact license@jaxen.org.
 26  
  * 
 27  
  * 4. Products derived from this software may not be called "Jaxen", nor
 28  
  *    may "Jaxen" appear in their name, without prior written permission
 29  
  *    from the Jaxen Project Management (pm@jaxen.org).
 30  
  * 
 31  
  * In addition, we request (but do not require) that you include in the 
 32  
  * end-user documentation provided with the redistribution and/or in the 
 33  
  * software itself an acknowledgement equivalent to the following:
 34  
  *     "This product includes software developed by the
 35  
  *      Jaxen Project <http://www.jaxen.org/>."
 36  
  * Alternatively, the acknowledgment may be graphical using the logos 
 37  
  * available at http://www.jaxen.org/
 38  
  *
 39  
  * THIS SOFTWARE IS PROVIDED ``AS IS'' AND ANY EXPRESSED OR IMPLIED
 40  
  * WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
 41  
  * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
 42  
  * DISCLAIMED.  IN NO EVENT SHALL THE Jaxen AUTHORS OR THE PROJECT
 43  
  * CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
 44  
  * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
 45  
  * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF
 46  
  * USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
 47  
  * ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
 48  
  * OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT
 49  
  * OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
 50  
  * SUCH DAMAGE.
 51  
  *
 52  
  * ====================================================================
 53  
  * This software consists of voluntary contributions made by many 
 54  
  * individuals on behalf of the Jaxen Project and was originally 
 55  
  * created by bob mcwhirter <bob@werken.com> and 
 56  
  * James Strachan <jstrachan@apache.org>.  For more information on the 
 57  
  * Jaxen Project, please see <http://www.jaxen.org/>.
 58  
  * 
 59  
  * $Id: StringLengthFunction.java,v 1.10 2005/06/28 13:44:45 elharo Exp $
 60  
  */
 61  
 
 62  
 
 63  
 package org.jaxen.function;
 64  
 
 65  
 import java.util.List;
 66  
 
 67  
 import org.jaxen.Context;
 68  
 import org.jaxen.Function;
 69  
 import org.jaxen.FunctionCallException;
 70  
 import org.jaxen.Navigator;
 71  
 
 72  
 /**
 73  
  * <p><b>4.2</b> <code><i>number</i> string-length(<i>string</i>)</code></p> 
 74  
  * 
 75  
  * <p>
 76  
  * The <b>string-length</b> function returns the number of <strong>Unicode characters</strong>
 77  
  * in its argument. This is <strong>not</strong> necessarily 
 78  
  * the same as the number <strong>Java chars</strong>
 79  
  * in the corresponding Java string. In particular, if the Java <code>String</code>
 80  
  * contains surrogate pairs each such pair will be counted as only one character
 81  
  * by this function. If the argument is omitted, 
 82  
  * it returns the length of the string-value of the context node.
 83  
  * </p>
 84  
  * 
 85  
  * @author bob mcwhirter (bob @ werken.com)
 86  
  * @see <a href="http://www.w3.org/TR/xpath#function-string-length" target="_top">Section 
 87  
  *      4.2 of the XPath Specification</a>
 88  
  */
 89  
 public class StringLengthFunction implements Function
 90  
 {
 91  
 
 92  
     
 93  
     /**
 94  
      * Create a new <code>StringLengthFunction</code> object.
 95  
      */
 96  294
     public StringLengthFunction() {}
 97  
     
 98  
     
 99  
     /**
 100  
      * <p>
 101  
      * Returns the number of Unicode characters in the string-value of the argument.
 102  
      * </p>
 103  
      * 
 104  
      * @param context the context at the point in the
 105  
      *         expression when the function is called
 106  
      * @param args a list containing the item whose string-value is to be counted.
 107  
      *     If empty, the length of the context node's string-value is returned.
 108  
      * 
 109  
      * @return a <code>Double</code> giving the number of Unicode characters
 110  
      * 
 111  
      * @throws FunctionCallException if args has more than one item
 112  
      */
 113  
     public Object call(Context context,
 114  
                        List args) throws FunctionCallException
 115  
     {
 116  42
         if (args.size() == 0)
 117  
         {
 118  6
             return evaluate( context.getNodeSet(),
 119  
                              context.getNavigator() );
 120  
         } 
 121  36
         else if (args.size() == 1)
 122  
         {
 123  30
             return evaluate( args.get(0),
 124  
                              context.getNavigator() );
 125  
         }
 126  
 
 127  6
         throw new FunctionCallException( "string-length() requires one argument." );
 128  
     }
 129  
 
 130  
     /**
 131  
      * <p>
 132  
      * Returns the number of Unicode characters in the string-value of 
 133  
      * an object.
 134  
      * </p>
 135  
      * 
 136  
      * @param obj the object whose string-value is counted
 137  
      * @param nav used to calculate the string-values of the first two arguments
 138  
      * 
 139  
      * @return a <code>Double</code> giving the number of Unicode characters
 140  
      * 
 141  
      * @throws FunctionCallException if the string contains mismatched surrogates
 142  
      */
 143  
     public static Double evaluate(Object obj, Navigator nav) throws FunctionCallException
 144  
     {
 145  
         
 146  
         // could/should I push the mismnatching checks into StringFunction.evaluate()????
 147  336
         String str = StringFunction.evaluate( obj, nav );
 148  
         // String.length() counts UTF-16 code points; not Unicode characters
 149  336
         char[] data = str.toCharArray();
 150  336
         int length = 0;
 151  1818
         for (int i = 0; i < data.length; i++) {
 152  1488
             char c = data[i];
 153  1488
             length++;
 154  
             // if this is a high surrogate; assume the next character is
 155  
             // is a low surrogate and skip it
 156  1488
             if (c >= 0xD800) {
 157  
                 try {
 158  30
                     char low = data[i+1];
 159  30
                     if (low < 0xDC00 || low > 0xDFFF) {
 160  6
                         throw new FunctionCallException("Bad surrogate pair in string " + str);
 161  
                     }
 162  24
                     i++; // increment past low surrogate
 163  
                 }
 164  0
                 catch (ArrayIndexOutOfBoundsException ex) {
 165  0
                     throw new FunctionCallException("Bad surrogate pair in string " + str);
 166  24
                 }
 167  
             }
 168  
         }
 169  330
         return new Double(length);
 170  
     }
 171  
     
 172  
 }