//
// $Id: ClassUtil.java,v 1.5 2002/02/10 02:13:31 mdb Exp $

package com.threerings.presents.util;

import java.lang.reflect.Method;
import java.util.HashMap;

import com.samskivert.util.MethodFinder;
import com.samskivert.util.StringUtil;

import com.threerings.presents.Log;

/**
 * Class related utility functions.
 */
public class ClassUtil
{
    /**
     * Locates and returns the first method in the supplied class whose
     * name is equal to the specified name. If a method is located, it
     * will be cached in the supplied cache so that subsequent requests
     * will immediately return the method from the cache rather than
     * re-reflecting.
     *
     * @return the method with the specified name or null if no method
     * with that name could be found.
     */
    public static Method getMethod (String name, Object target, HashMap cache)
    {
        Class tclass = target.getClass();
        String key = tclass.getName() + ":" + name;
        Method method = (Method)cache.get(key);

        if (method == null) {
            method = findMethod(tclass, name);
            if (method != null) {
                cache.put(key, method);
            }
        }

        return method;
    }

    /**
     * Looks up the method on the specified object that has a signature
     * that matches the supplied arguments array. This is very expensive,
     * so you shouldn't be doing this for something that happens
     * frequently.
     *
     * @return the best matching method with the specified name that
     * accepts the supplied arguments, or null if no method could be
     * found.
     *
     * @see MethodFinder
     */
    public static Method getMethod (String name, Object target, Object[] args)
    {
        Class tclass = target.getClass();
        Method meth = null;

        try {
            MethodFinder finder = new MethodFinder(tclass);
            meth = finder.findMethod(name, args);

        } catch (NoSuchMethodException nsme) {
            // nothing to do here but fall through and return null
            Log.info("No such method [name=" + name +
                     ", tclass=" + tclass.getName() + 
                     ", args=" + StringUtil.toString(args) +
                     ", error=" + nsme + "].");

        } catch (SecurityException se) {
            Log.warning("Unable to look up method? " +
                        "[tclass=" + tclass.getName() +
                        ", mname=" + name + "].");
        }

        return meth;
    }

    /**
     * Locates and returns the first method in the supplied class whose
     * name is equal to the specified name.
     *
     * @return the method with the specified name or null if no method
     * with that name could be found.
     */
    public static Method findMethod (Class clazz, String name)
    {
        Method[] methods = clazz.getMethods();
        for (int i = 0; i < methods.length; i++) {
            if  (methods[i].getName().equals(name)) {
                return methods[i];
            }
        }
        return null;
    }
}