/*
* Copyright (c) 1998-2011 Caucho Technology -- all rights reserved
*
* This file is part of Resin(R) Open Source
*
* Each copy or derived work must preserve the copyright notice and this
* notice unmodified.
*
* Resin Open Source is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation; either version 2 of the License, or
* (at your option) any later version.
*
* Resin Open Source is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE, or any warranty
* of NON-INFRINGEMENT. See the GNU General Public License for more
* details.
*
* You should have received a copy of the GNU General Public License
* along with Resin Open Source; if not, write to the
* Free SoftwareFoundation, Inc.
* 59 Temple Place, Suite 330
* Boston, MA 02111-1307 USA
*
* @author Scott Ferguson
*/
package com.caucho.es.wrapper;
import com.caucho.es.Call;
import com.caucho.es.ESBase;
import com.caucho.es.ESNull;
/**
* Dynamic selection of overloaded methods. This is really a last
* resort.
*/
public class MethodDispatcher {
private Class [][]parameterTypes;
public MethodDispatcher(Class [][]parameterTypes)
{
this.parameterTypes = parameterTypes;
}
/**
* Selects the best method among the list.
*/
public int select(Call call, int length)
throws Exception
{
int bestCost = Integer.MAX_VALUE;
int bestMethod = -1;
for (int i = 0; i < parameterTypes.length; i++) {
Class []parameters = parameterTypes[i];
int cost = 0;
for (int j = 0; j < parameters.length; j++) {
ESBase obj = call.getArg(j, length);
Class cl = obj.getJavaType();
Class param = parameters[j];
if (cl.equals(param))
continue;
// cl is the actual class, so don't need to worry about casting
else if (param.isAssignableFrom(cl))
cost += 10;
else if (obj instanceof ESNull)
cost += 50;
else if (cl.equals(void.class))
cost += 50;
else if (cl.isPrimitive() && param.isPrimitive())
cost += 100;
else {
cost = Integer.MAX_VALUE;
break;
}
}
if (cost < bestCost) {
bestMethod = i;
bestCost = cost;
}
}
return bestMethod;
}
}