Source for gnu.xml.xpath.FunctionCall

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