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


1 package net.sf.saxon.functions;
2 import net.sf.saxon.expr.XPathContext;
3 import net.sf.saxon.om.Item;
4 import net.sf.saxon.om.SequenceIterator;
5 import net.sf.saxon.trans.XPathException;
6 import net.sf.saxon.value.AtomicValue;
7 import net.sf.saxon.value.NumericValue;
8
9 /**
10 * The XPath 2.0 insert-before() function
11 */
12
13
14 public class Insert extends SystemFunction {
15
16     /**
17     * Evaluate the function to return an iteration of selected nodes.
18     */
19
20     public SequenceIterator iterate(XPathContext context) throws XPathException {
21         SequenceIterator seq = argument[0].iterate(context);
22         AtomicValue n0 = (AtomicValue)argument[1].evaluateItem(context);
23         NumericValue n = (NumericValue)n0.getPrimitiveValue();
24         int pos = (int)n.longValue();
25         SequenceIterator ins = argument[2].iterate(context);
26         return new InsertIterator(seq, ins, pos);
27     }
28
29     public static class InsertIterator implements SequenceIterator {
30
31         private SequenceIterator base;
32         private SequenceIterator insert;
33         private int insertPosition;
34         private int position = 0;
35         private Item current = null;
36         private boolean inserting = false;
37
38         public InsertIterator(SequenceIterator base, SequenceIterator insert, int insertPosition) {
39             this.base = base;
40             this.insert = insert;
41             this.insertPosition = (insertPosition<1 ? 1 : insertPosition);
42             this.inserting = (insertPosition==1);
43         }
44
45
46         public Item next() throws XPathException {
47             Item nextItem;
48             if (inserting) {
49                 nextItem = insert.next();
50                 if (nextItem == null) {
51                     inserting = false;
52                     nextItem = base.next();
53                 }
54             } else {
55                 if (position == insertPosition-1) {
56                     nextItem = insert.next();
57                     if (nextItem == null) {
58                         nextItem = base.next();
59                     } else {
60                         inserting = true;
61                     }
62                 } else {
63                     nextItem = base.next();
64                     if (nextItem==null && position < insertPosition-1) {
65                         inserting = true;
66                         nextItem = insert.next();
67                     }
68                 }
69             }
70             if (nextItem == null) {
71                 current = null;
72                 position = -1;
73                 return null;
74             } else {
75                 current = nextItem;
76                 position++;
77                 return current;
78             }
79         }
80
81         public Item current() {
82             return current;
83         }
84
85         public int position() {
86             return position;
87         }
88
89         public SequenceIterator getAnother() throws XPathException {
90             return new InsertIterator( base.getAnother(),
91                                         insert.getAnother(),
92                                         insertPosition);
93         }
94
95         /**
96          * Get properties of this iterator, as a bit-significant integer.
97          *
98          * @return the properties of this iterator. This will be some combination of
99          * properties such as {@link GROUNDED}, {@link LAST_POSITION_FINDER},
100          * and {@link LOOKAHEAD}. It is always
101          * acceptable to return the value zero, indicating that there are no known special properties.
102          * It is acceptable for the properties of the iterator to change depending on its state.
103          */
104
105         public int getProperties() {
106             return 0;
107         }
108
109     }
110
111 }
112
113
114
115
116 //
117 // The contents of this file are subject to the Mozilla Public License Version 1.0 (the "License");
118 // you may not use this file except in compliance with the License. You may obtain a copy of the
119 // License at http://www.mozilla.org/MPL/
120 //
121 // Software distributed under the License is distributed on an "AS IS" basis,
122 // WITHOUT WARRANTY OF ANY KIND, either express or implied.
123 // See the License for the specific language governing rights and limitations under the License.
124 //
125 // The Original Code is: all this file.
126 //
127 // The Initial Developer of the Original Code is Michael H. Kay
128 //
129 // Portions created by (your name) are Copyright (C) (your legal entity). All Rights Reserved.
130 //
131 // Contributor(s): none.
132 //
133
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