/*
 * Copyright (c) 2002 - 2006 IBM Corporation.
 * All rights reserved. This program and the accompanying materials
 * are made available under the terms of the Eclipse Public License v1.0
 * which accompanies this distribution, and is available at
 * http://www.eclipse.org/legal/epl-v10.html
 *
 * Contributors:
 *     IBM Corporation - initial API and implementation
 */
package com.ibm.wala.cast.ipa.callgraph;

import com.ibm.wala.classLoader.CallSiteReference;
import com.ibm.wala.classLoader.IClass;
import com.ibm.wala.classLoader.IMethod;
import com.ibm.wala.core.util.strings.Atom;
import com.ibm.wala.ipa.callgraph.CGNode;
import com.ibm.wala.ipa.callgraph.MethodTargetSelector;
import com.ibm.wala.types.MethodReference;
import java.util.Map;

/**
 * A MethodTargetSelector implementation that supports multiple languages. It works by delegating to
 * a language-specific child selector based on the language associated with the MethodReference for
 * which a target is being chosen.
 *
 * <p>This provides a simple way to combine language-specific target selection policies---such as
 * those used for constructor calls in JavaScript and for bean methods in J2EE.
 *
 * @author Julian Dolby (dolby@us.ibm.com)
 */
public class CrossLanguageMethodTargetSelector implements MethodTargetSelector {

  private final Map<Atom, MethodTargetSelector> languageSelectors;

  public CrossLanguageMethodTargetSelector(Map<Atom, MethodTargetSelector> languageSelectors) {
    this.languageSelectors = languageSelectors;
  }

  private static Atom getLanguage(MethodReference target) {
    return target.getDeclaringClass().getClassLoader().getLanguage();
  }

  private static Atom getLanguage(CallSiteReference site) {
    return getLanguage(site.getDeclaredTarget());
  }

  private MethodTargetSelector getSelector(CallSiteReference site) {
    return languageSelectors.get(getLanguage(site));
  }

  @Override
  public IMethod getCalleeTarget(CGNode caller, CallSiteReference site, IClass receiver) {
    assert getSelector(site) != null : "no selector for " + getLanguage(site) + " method " + site;
    return getSelector(site).getCalleeTarget(caller, site, receiver);
  }
}
