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Java > Open Source Codes > net > sf > saxon > functions > StringFn


1 package net.sf.saxon.functions;
2 import net.sf.saxon.expr.Expression;
3 import net.sf.saxon.expr.StaticContext;
4 import net.sf.saxon.expr.XPathContext;
5 import net.sf.saxon.om.Item;
6 import net.sf.saxon.trans.XPathException;
7 import net.sf.saxon.value.StringValue;
8
9 /**
10 * Implement XPath function string()
11 */
12
13 public class StringFn extends SystemFunction {
14
15     /**
16     * Simplify and validate.
17     * This is a pure function so it can be simplified in advance if the arguments are known
18     */
19
20      public Expression simplify(StaticContext env) throws XPathException {
21         useContextItemAsDefault();
22         return simplifyArguments(env);
23     }
24
25     /**
26     * Evaluate the function
27     */
28
29     public Item evaluateItem(XPathContext c) throws XPathException {
30         Item arg = argument[0].evaluateItem(c);
31         if (arg==null) {
32             return StringValue.EMPTY_STRING;
33         } else {
34             return StringValue.makeStringValue(arg.getStringValueCS());
35         }
36     }
37
38 }
39
40
41 //
42 // The contents of this file are subject to the Mozilla Public License Version 1.0 (the "License");
43 // you may not use this file except in compliance with the License. You may obtain a copy of the
44 // License at http://www.mozilla.org/MPL/
45 //
46 // Software distributed under the License is distributed on an "AS IS" basis,
47 // WITHOUT WARRANTY OF ANY KIND, either express or implied.
48 // See the License for the specific language governing rights and limitations under the License.
49 //
50 // The Original Code is: all this file.
51 //
52 // The Initial Developer of the Original Code is Michael H. Kay.
53 //
54 // Portions created by (your name) are Copyright (C) (your legal entity). All Rights Reserved.
55 //
56 // Contributor(s): none.
57 //
58
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