libjava/classpath/gnu/xml/xpath/FunctionCall.java

   1 /* FunctionCall.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.xpath;
  39
  40 import gnu.java.lang.CPStringBuilder;
  41
  42 import java.util.ArrayList;
  43 import java.util.Collections;
  44 import java.util.Iterator;
  45 import java.util.List;
  46 import javax.xml.namespace.QName;
  47 import javax.xml.xpath.XPathFunction;
  48 import javax.xml.xpath.XPathFunctionException;
  49 import javax.xml.xpath.XPathFunctionResolver;
  50 import org.w3c.dom.Node;
  51
  52 /**
  53  * Executes an XPath core or extension function.
  54  *
  55  * @author <a href='mailto:dog@gnu.org'>Chris Burdess</a>
  56  */
  57 public final class FunctionCall
  58   extends Expr
  59 {
  60
  61   final XPathFunctionResolver resolver;
  62   final String name;
  63   final List<Expr> args;
  64
  65   public FunctionCall(XPathFunctionResolver resolver, String name)
  66   {
  67     this(resolver, name, null);
  68   }
  69
  70   public FunctionCall(XPathFunctionResolver resolver, String name, List<Expr> args)
  71   {
  72     this.resolver = resolver;
  73     this.name = name;
  74     if (args == null)
  75       this.args = Collections.emptyList();
  76     else
  77       this.args = args;
  78   }
  79
  80   @Override
  81   public Object evaluate(Node context, int pos, int len)
  82   {
  83     if (resolver != null)
  84       {
  85         QName qname = QName.valueOf(name);
  86                                 int arity = args.size();
  87         XPathFunction function = resolver.resolveFunction(qname, arity);
  88         if (function != null)
  89           {
  90             //System.err.println("Calling "+toString()+" with "+values);
  91             if (function instanceof Expr)
  92               {
  93                 if (function instanceof Function)
  94                   {
  95                     ((Function) function).setArguments(args);
  96                   }
  97                 return ((Expr) function).evaluate(context, pos, len);
  98               }
  99             else
 100               {
 101                 List<Object> values = new ArrayList<Object>(arity);
 102                 for (int i = 0; i < arity; i++)
 103                   {
 104                     Expr arg = (Expr) args.get(i);
 105                     values.add(arg.evaluate(context, pos, len));
 106                   }
 107                 try
 108                   {
 109                     return function.evaluate(values);
 110                   }
 111                 catch (XPathFunctionException e)
 112                   {
 113                     e.printStackTrace(System.err); // FIXME
 114                     throw new RuntimeException(e.getMessage(), e);
 115                   }
 116               }
 117           }
 118       }
 119     throw new IllegalArgumentException("Invalid function call: " +
 120                                        toString());
 121   }
 122
 123   public Expr clone(Object context)
 124   {
 125     int len = args.size();
 126     List<Expr> args2 = new ArrayList<Expr>(len);
 127     for (int i = 0; i < len; i++)
 128       {
 129         args2.add(args.get(i).clone(context));
 130       }
 131     XPathFunctionResolver r = resolver;
 132     if (context instanceof XPathFunctionResolver)
 133       {
 134         r = (XPathFunctionResolver) context;
 135       }
 136     return new FunctionCall(r, name, args2);
 137   }
 138
 139   public boolean references(QName var)
 140   {
 141     for (Iterator<Expr> i = args.iterator(); i.hasNext(); )
 142       {
 143         if (i.next().references(var))
 144           {
 145             return true;
 146           }
 147       }
 148     return false;
 149   }
 150
 151   public String toString()
 152   {
 153     CPStringBuilder buf = new CPStringBuilder();
 154     buf.append(name);
 155     buf.append('(');
 156     int len = args.size();
 157     for (int i = 0; i < len; i++)
 158       {
 159         if (i > 0)
 160           {
 161             buf.append(',');
 162           }
 163         buf.append(args.get(i));
 164       }
 165     buf.append(')');
 166     return buf.toString();
 167   }
 168
 169 }