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 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: }