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


1 package net.sf.saxon.functions;
2 import net.sf.saxon.expr.*;
3 import net.sf.saxon.om.Item;
4 import net.sf.saxon.om.FastStringBuffer;
5 import net.sf.saxon.trans.XPathException;
6 import net.sf.saxon.value.AtomicValue;
7 import net.sf.saxon.value.StringValue;
8
9 import java.util.StringTokenizer JavaDoc;
10
11 /**
12  * Implement the XPath normalize-space() function
13  */
14
15 public class NormalizeSpace extends SystemFunction {
16
17     /**
18     * Simplify and validate.
19     */
20
21      public Expression simplify(StaticContext env) throws XPathException {
22         return simplifyArguments(env);
23     }
24     /**
25      * Determine the intrinsic dependencies of an expression, that is, those which are not derived
26      * from the dependencies of its subexpressions. For example, position() has an intrinsic dependency
27      * on the context position, while (position()+1) does not. The default implementation
28      * of the method returns 0, indicating "no dependencies".
29      *
30      * @return a set of bit-significant flags identifying the "intrinsic"
31      * dependencies. The flags are documented in class net.sf.saxon.value.StaticProperty
32      */
33
34     public int getIntrinsicDependencies() {
35         int d = super.getIntrinsicDependencies();
36         if (argument.length == 0) {
37             d |= StaticProperty.DEPENDS_ON_CONTEXT_ITEM;
38         }
39         return d;
40     }
41
42     /**
43     * Pre-evaluate a function at compile time. Functions that do not allow
44     * pre-evaluation, or that need access to context information, can override this method.
45     */
46
47     public Expression preEvaluate(StaticContext env) throws XPathException {
48         if (argument.length == 0) {
49             return this;
50         } else {
51             return ExpressionTool.eagerEvaluate(this, null);
52         }
53     }
54
55     /**
56     * Evaluate in a general context
57     */
58
59     public Item evaluateItem(XPathContext c) throws XPathException {
60         if (argument.length == 0) {
61             return StringValue.makeStringValue(normalize(c.getContextItem().getStringValueCS()));
62         } else {
63             AtomicValue sv = (AtomicValue)argument[0].evaluateItem(c);
64             if (sv==null) return StringValue.EMPTY_STRING;
65             return StringValue.makeStringValue(normalize(sv.getStringValueCS()));
66         }
67     }
68
69     /**
70     * The algorithm that does the work
71     */
72
73     public static CharSequence JavaDoc normalize(CharSequence JavaDoc s) {
74         FastStringBuffer sb = new FastStringBuffer(s.length());
75         StringTokenizer JavaDoc st = new StringTokenizer JavaDoc(s.toString());
76         while (st.hasMoreTokens()) {
77             sb.append(st.nextToken());
78             if (st.hasMoreTokens()) {
79                 sb.append(' ');
80             }
81         }
82         return sb.condense();
83     }
84
85 }
86
87
88
89
90 //
91 // The contents of this file are subject to the Mozilla Public License Version 1.0 (the "License");
92 // you may not use this file except in compliance with the License. You may obtain a copy of the
93 // License at http://www.mozilla.org/MPL/
94 //
95 // Software distributed under the License is distributed on an "AS IS" basis,
96 // WITHOUT WARRANTY OF ANY KIND, either express or implied.
97 // See the License for the specific language governing rights and limitations under the License.
98 //
99 // The Original Code is: all this file.
100 //
101 // The Initial Developer of the Original Code is Michael H. Kay.
102 //
103 // Portions created by (your name) are Copyright (C) (your legal entity). All Rights Reserved.
104 //
105 // Contributor(s): none.
106 //
107
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