libjava/classpath/gnu/xml/transform/ElementAvailableFunction.java

   1 /* ElementAvailableFunction.java --
   2    Copyright (C) 2004 Free Software Foundation, Inc.
   3
   4 This file is part of GNU Classpath.
   5
   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.
  10
  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.
  15
  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.
  20
  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.
  25
  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. */
  37
  38 package gnu.xml.transform;
  39
  40 import java.util.ArrayList;
  41 import java.util.Collection;
  42 import java.util.Collections;
  43 import java.util.Iterator;
  44 import java.util.List;
  45 import java.util.TreeSet;
  46 import javax.xml.namespace.QName;
  47 import javax.xml.namespace.NamespaceContext;
  48 import javax.xml.xpath.XPathFunction;
  49 import javax.xml.xpath.XPathFunctionException;
  50 import org.w3c.dom.Node;
  51 import gnu.xml.xpath.Expr;
  52 import gnu.xml.xpath.Function;
  53
  54 /**
  55  * The XSLT <code>element-available</code> function.
  56  *
  57  * @author <a href='mailto:dog@gnu.org'>Chris Burdess</a>
  58  */
  59 class ElementAvailableFunction
  60   extends Expr
  61   implements Function, XPathFunction
  62 {
  63
  64   static final Collection elements;
  65   static
  66   {
  67     TreeSet acc = new TreeSet();
  68     acc.add("stylesheet");
  69     acc.add("template");
  70     acc.add("param");
  71     acc.add("variable");
  72     acc.add("include");
  73     acc.add("import");
  74     acc.add("output");
  75     acc.add("preserve-space");
  76     acc.add("strip-space");
  77     acc.add("key");
  78     acc.add("decimal-format");
  79     acc.add("namespace-alias");
  80     acc.add("attribute-set");
  81     acc.add("apply-templates");
  82     acc.add("call-template");
  83     acc.add("value-of");
  84     acc.add("for-each");
  85     acc.add("if");
  86     acc.add("choose");
  87     acc.add("when");
  88     acc.add("otherwise");
  89     acc.add("element");
  90     acc.add("attribute");
  91     acc.add("text");
  92     acc.add("copy");
  93     acc.add("processing-instruction");
  94     acc.add("comment");
  95     acc.add("number");
  96     acc.add("copy-of");
  97     acc.add("message");
  98     acc.add("sort");
  99     acc.add("with-param");
 100     acc.add("fallback");
 101     acc.add("apply-imports");
 102     elements = Collections.unmodifiableSet(acc);
 103   }
 104
 105   final NamespaceContext nsctx;
 106   List args;
 107
 108   ElementAvailableFunction(NamespaceContext nsctx)
 109   {
 110     this.nsctx = nsctx;
 111   }
 112
 113   public Object evaluate(List args)
 114     throws XPathFunctionException
 115   {
 116     // Useless...
 117     return Collections.EMPTY_SET;
 118   }
 119
 120   public void setArguments(List args)
 121   {
 122     this.args = args;
 123   }
 124
 125   public Object evaluate(Node context, int pos, int len)
 126   {
 127     Expr arg = (Expr) args.get(0);
 128     Object val = arg.evaluate(context, pos, len);
 129     String name = _string(context, val);
 130     String prefix, localName, uri;
 131     int ci = name.indexOf(':');
 132     if (ci == -1)
 133       {
 134         prefix = null;
 135         localName = name;
 136       }
 137     else
 138       {
 139         prefix = name.substring(0, ci);
 140         localName = name.substring(ci + 1);
 141       }
 142     uri = nsctx.getNamespaceURI(prefix);
 143     if (Stylesheet.XSL_NS.equals(uri))
 144       {
 145         return elements.contains(localName) ?
 146           Boolean.TRUE : Boolean.FALSE;
 147       }
 148     // TODO extension elements
 149     return Boolean.FALSE;
 150   }
 151
 152   public Expr clone(Object context)
 153   {
 154     NamespaceContext n = nsctx;
 155     if (context instanceof NamespaceContext)
 156       n = (NamespaceContext) context;
 157     ElementAvailableFunction f = new ElementAvailableFunction(n);
 158     int len = args.size();
 159     List args2 = new ArrayList(len);
 160     for (int i = 0; i < len; i++)
 161       args2.add(((Expr) args.get(i)).clone(context));
 162     f.setArguments(args2);
 163     return f;
 164   }
 165
 166   public boolean references(QName var)
 167   {
 168     for (Iterator i = args.iterator(); i.hasNext(); )
 169       {
 170         if (((Expr) i.next()).references(var))
 171           return true;
 172       }
 173     return false;
 174   }
 175
 176   public String toString()
 177   {
 178     return "element-available(" + args.get(0) + ")";
 179   }
 180
 181 }
 182