libjava/ChangeLog:
[official-gcc.git] / libjava / classpath / gnu / xml / xpath / IdFunction.java
blobb3d2208c8e427e351e5fbb0917cdee9f2a983138
1 /* IdFunction.java --
2 Copyright (C) 2004 Free Software Foundation, Inc.
4 This file is part of GNU Classpath.
6 GNU Classpath is free software; you can redistribute it and/or modify
7 it under the terms of the GNU General Public License as published by
8 the Free Software Foundation; either version 2, or (at your option)
9 any later version.
11 GNU Classpath is distributed in the hope that it will be useful, but
12 WITHOUT ANY WARRANTY; without even the implied warranty of
13 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
14 General Public License for more details.
16 You should have received a copy of the GNU General Public License
17 along with GNU Classpath; see the file COPYING. If not, write to the
18 Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA
19 02110-1301 USA.
21 Linking this library statically or dynamically with other modules is
22 making a combined work based on this library. Thus, the terms and
23 conditions of the GNU General Public License cover the whole
24 combination.
26 As a special exception, the copyright holders of this library give you
27 permission to link this library with independent modules to produce an
28 executable, regardless of the license terms of these independent
29 modules, and to copy and distribute the resulting executable under
30 terms of your choice, provided that you also meet, for each linked
31 independent module, the terms and conditions of the license of that
32 module. An independent module is a module which is not derived from
33 or based on this library. If you modify this library, you may extend
34 this exception to your version of the library, but you are not
35 obligated to do so. If you do not wish to do so, delete this
36 exception statement from your version. */
38 package gnu.xml.xpath;
40 import java.util.Collection;
41 import java.util.List;
42 import javax.xml.namespace.QName;
43 import org.w3c.dom.Node;
45 /**
46 * The <code>id</code> function selects elements by their unique ID.
47 * When the argument to id is of type node-set, then the result is
48 * the union of the result of applying id to the string-value of each of the
49 * nodes in the argument node-set. When the argument to id is of any other
50 * type, the argument is converted to a string as if by a call to the string
51 * function; the string is split into a whitespace-separated list of tokens
52 * (whitespace is any sequence of characters matching the production S); the
53 * result is a node-set containing the elements in the same document as the
54 * context node that have a unique ID equal to any of the tokens in the
55 * list.
57 * @author <a href='mailto:dog@gnu.org'>Chris Burdess</a>
59 public final class IdFunction
60 extends Pattern
63 final Expr arg;
65 IdFunction(List<Expr> args)
67 this(args.get(0));
70 public IdFunction(Expr arg)
72 this.arg = arg;
75 public boolean matches(Node context)
77 Object ret = evaluate(context, 1, 1);
78 return !((Collection<?>) ret).isEmpty();
81 @Override
82 public Object evaluate(Node context, int pos, int len)
84 Object val = arg.evaluate(context, pos, len);
85 return _id(context, val);
88 public Expr clone(Object context)
90 return new IdFunction(arg.clone(context));
93 public boolean references(QName var)
95 return arg.references(var);
98 public String toString()
100 return "id(" + arg + ")";