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49 package org.jaxen.function;
50
51 import java.util.List;
52
53 import org.jaxen.Context;
54 import org.jaxen.Function;
55 import org.jaxen.FunctionCallException;
56 import org.jaxen.Navigator;
57
58 /***
59 * <p><b>4.2</b> <code><i>string</i> substring-after(<i>string</i>,<i>string</i>)</code></p>
60 *
61 *
62 * <blockquote src="http://www.w3.org/TR/xpath">
63 * The <b>substring-after</b> function returns the substring of the first argument string
64 * that follows the first occurrence of the second argument string in the first
65 * argument string, or the empty string if the first argument string does not contain the second argument string.
66 * For example, substring-after("1999/04/01","/") returns 04/01,
67 * and substring-after("1999/04/01","19") returns 99/04/01.
68 * </blockquote>
69 *
70 * @author bob mcwhirter (bob @ werken.com)
71 * @see <a href="http://www.w3.org/TR/xpath#function-substring-after" target="_top">Section 4.2 of the XPath Specification</a>
72 */
73 public class SubstringAfterFunction implements Function
74 {
75
76 /***
77 * Create a new <code>SubstringAfterFunction</code> object.
78 */
79 public SubstringAfterFunction() {}
80
81
82 /***
83 * Returns the part of the string-value of the first item in <code>args</code>
84 * that follows the string-value of the second item in <code>args</code>;
85 * or the empty string if the second string is not a substring of the first string.
86 *
87 * @param context the context at the point in the
88 * expression when the function is called
89 * @param args a list that contains two items
90 *
91 * @return a <code>String</code> containing that
92 * part of the string-value of the first item in <code>args</code>
93 * that comes before the string-value of the second item in <code>args</code>
94 *
95 * @throws FunctionCallException if <code>args</code> does not have length two
96 */
97 public Object call(Context context,
98 List args) throws FunctionCallException
99 {
100 if (args.size() == 2)
101 {
102 return evaluate( args.get(0),
103 args.get(1),
104 context.getNavigator() );
105 }
106
107 throw new FunctionCallException( "substring-after() requires two arguments." );
108 }
109
110
111 /***
112 * Returns the part of <code>strArg</code> that follows the first occurence
113 * of <code>matchArg</code>; or the empty string if the
114 * <code>strArg</code> does not contain <code>matchArg</code>
115 *
116 * @param strArg the string from which the substring is extracted
117 * @param matchArg the string that marks the boundary of the substring
118 * @param nav the <code>Navigator</code> used to calculate the string-values of
119 * the first two arguments
120 *
121 * @return a <code>String</code> containing
122 * the part of <code>strArg</code> that precedes the first occurence
123 * of <code>matchArg</code>
124 *
125 */
126 public static String evaluate(Object strArg,
127 Object matchArg,
128 Navigator nav)
129 {
130 String str = StringFunction.evaluate( strArg,
131 nav );
132
133 String match = StringFunction.evaluate( matchArg,
134 nav );
135
136 int loc = str.indexOf(match);
137
138 if ( loc < 0 )
139 {
140 return "";
141 }
142
143 return str.substring(loc+match.length());
144 }
145 }