Groovy example source code file (MethodKey.java)

This example Groovy source code file (MethodKey.java) is included in the DevDaily.com "Java Source Code Warehouse" project. The intent of this project is to help you "Learn Java by Example" ^TM.

Java - Groovy tags/keywords

arraylist, class, class, defaultmethodkey, list, list, methodkey, methodkey, string, string, util

The Groovy MethodKey.java source code

/*
 * Copyright 2003-2007 the original author or authors.
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *     http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */
package org.codehaus.groovy.runtime;

import java.util.ArrayList;
import java.util.Collections;
import java.util.List;


/**
 * An abstract base class for a key used for comparators and Map keys to lookup a method by
 * name and parameter types
 * 
 * @author <a href="mailto:james@coredevelopers.net">James Strachan
 * @version $Revision: 7753 $
 */
public abstract class MethodKey {

    private int hash;
    private String name;
    private Class sender;
    private boolean isCallToSuper;
    
    public MethodKey(Class sender, String name, boolean isCallToSuper) {
        this.sender = sender;
        this.name = name;
        this.isCallToSuper = isCallToSuper;
    }

    /**
     * Creates an immutable copy that we can cache. 
     */
    public MethodKey createCopy() {
        int size = getParameterCount();
        Class[] paramTypes = new Class[size];
        for (int i = 0; i < size; i++) {
            paramTypes[i] = getParameterType(i);
        }
        return new DefaultMethodKey(sender, name, paramTypes, isCallToSuper);
    }

    public boolean equals(Object that) {
        if (this == that) {
            return true;
        }
        else if (that instanceof MethodKey) {
            return equals((MethodKey) that);
        }
        return false;
    }

    public boolean equals(MethodKey that) {
      int size;
      if (sender!=that.sender) return false;
      if (isCallToSuper!=that.isCallToSuper) return false;
      if (!name.equals(that.name)) return false;
      if ((size = getParameterCount()) != that.getParameterCount()) return false;
      
      for (int i = 0; i < size; i++) {
          if (getParameterType(i) != that.getParameterType(i)) {
              return false;
          }
      }
      return true;
    }

    public int hashCode() {
        if (hash == 0) {
            hash = createHashCode();
            if (hash == 0) {
                hash = 0xcafebabe;
            }
        }
        return hash;
    }

    public String toString() {
        return super.toString() + "[name:" + name + "; params:" + getParamterTypes();
    }

    public String getName() {
        return name;
    }

    public List getParamterTypes() {
        int size = getParameterCount();
        if (size <= 0) {
            return Collections.EMPTY_LIST;
        }
        List params = new ArrayList(size);
        for (int i = 0; i < size; i++) {
            params.add(getParameterType(i));
        }
        return params;
    }

    public abstract int getParameterCount();
    public abstract Class getParameterType(int index);

    protected int createHashCode() {
        int answer = name.hashCode();
        int size = getParameterCount();

        /** @todo we should use the real Josh Bloch algorithm here */

        // can't remember the exact Josh Bloch algorithm and I've not got the book handy
        // but its something like this IIRC
        for (int i = 0; i < size; i++) {
            answer *= 37;
            answer += 1 + getParameterType(i).hashCode();
        }
        answer *= 37;
        answer += isCallToSuper?1:0;
        answer *= 37;
        answer += 1 + sender.hashCode();
        return answer;
    }
}