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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>string</i> substring-after(<i>string</i>,<i>string</i>)</code>
74 *
75 *
76 * <blockquote src="http://www.w3.org/TR/xpath">
77 * The <b>substring-after</b> function returns the substring of the first argument string
78 * that follows the first occurrence of the second argument string in the first
79 * argument string, or the empty string if the first argument string does not contain the second argument string.
80 * For example, substring-after("1999/04/01","/") returns 04/01,
81 * and substring-after("1999/04/01","19") returns 99/04/01.
82 * </blockquote>
83 *
84 * @author bob mcwhirter (bob @ werken.com)
85 * @see <a href="http://www.w3.org/TR/xpath#function-substring-after" target="_top">Section 4.2 of the XPath Specification</a>
86 */
87 public class SubstringAfterFunction implements Function
88 {
89
90 /***
91 * Create a new <code>SubstringAfterFunction</code> object.
92 */
93 public SubstringAfterFunction() {}
94
95
96 /***
97 * Returns the part of the string-value of the first item in <code>args</code>
98 * that follows the string-value of the second item in <code>args</code>;
99 * or the empty string if the second string is not a substring of the first string.
100 *
101 * @param context the context at the point in the
102 * expression when the function is called
103 * @param args a list that contains two items
104 *
105 * @return a <code>String</code> containing that
106 * part of the string-value of the first item in <code>args</code>
107 * that comes before the string-value of the second item in <code>args</code>
108 *
109 * @throws FunctionCallException if <code>args</code> does not have length two
110 */
111 public Object call(Context context,
112 List args) throws FunctionCallException
113 {
114 if (args.size() == 2)
115 {
116 return evaluate( args.get(0),
117 args.get(1),
118 context.getNavigator() );
119 }
120
121 throw new FunctionCallException( "substring-after() requires two arguments." );
122 }
123
124
125 /***
126 * Returns the part of <code>strArg</code> that follows the first occurence
127 * of <code>matchArg</code>; or the empty string if the
128 * <code>strArg</code> does not contain <code>matchArg</code>
129 *
130 * @param strArg the string from which the substring is extracted
131 * @param matchArg the string that marks the boundary of the substring
132 * @param nav the <code>Navigator</code> used to calculate the string-values of
133 * the first two arguments
134 *
135 * @return a <code>String</code> containing
136 * the part of <code>strArg</code> that precedes the first occurence
137 * of <code>matchArg</code>
138 *
139 */
140 public static String evaluate(Object strArg,
141 Object matchArg,
142 Navigator nav)
143 {
144 String str = StringFunction.evaluate( strArg,
145 nav );
146
147 String match = StringFunction.evaluate( matchArg,
148 nav );
149
150 int loc = str.indexOf(match);
151
152 if ( loc < 0 )
153 {
154 return "";
155 }
156
157 return str.substring(loc+match.length());
158 }
159 }