com.baidu.jprotobuf.pbrpc.utils.ReflectionUtils Maven / Gradle / Ivy

Go to download
Show more of this group Show more artifacts with this name
Show all versions of jprotobuf-rpc-core Show documentation
The core module of jprotobuf rpc socket implementation
There is a newer version: 4.2.2
/*
 * Copyright 2002-2007 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 com.baidu.jprotobuf.pbrpc.utils;

import java.lang.reflect.Method;

/**
 * Simple utility class for working with the reflection API and handling
 * reflection exceptions.
 *
 *
 * @author xiemalin
 * @since 1.0
 */
public class ReflectionUtils {

    /**
     * Perform the given callback operation on all matching methods of the
     * given class and superclasses.
     * The same named method occurring on subclass and superclass will
     * appear twice, unless excluded by a {@link MethodFilter}.
     *
     * @param targetClass class to start looking at
     * @param mc the callback to invoke for each method
     * @throws IllegalArgumentException the illegal argument exception
     * @see #doWithMethods(Class, MethodCallback, MethodFilter)
     */
    public static void doWithMethods(Class targetClass, MethodCallback mc) throws IllegalArgumentException {
        doWithMethods(targetClass, mc, null);
    }

    /**
     * Perform the given callback operation on all matching methods of the
     * given class and superclasses.
     * The same named method occurring on subclass and superclass will
     * appear twice, unless excluded by the specified {@link MethodFilter}.
     *
     * @param targetClass class to start looking at
     * @param mc the callback to invoke for each method
     * @param mf the filter that determines the methods to apply the callback to
     * @throws IllegalArgumentException the illegal argument exception
     */
    public static void doWithMethods(Class targetClass, MethodCallback mc, MethodFilter mf)
            throws IllegalArgumentException {

        // Keep backing up the inheritance hierarchy.
        do {
            Method[] methods = targetClass.getDeclaredMethods();
            for (int i = 0; i < methods.length; i++) {
                if (mf != null && !mf.matches(methods[i])) {
                    continue;
                }
                try {
                    mc.doWith(methods[i]);
                }
                catch (IllegalAccessException ex) {
                    throw new IllegalStateException(
                            "Shouldn't be illegal to access method '" + methods[i].getName() + "': " + ex);
                }
            }
            targetClass = targetClass.getSuperclass();
        }
        while (targetClass != null);
    }
    
    /**
     * Checks if is void.
     *
     * @param cls the cls
     * @return true, if is void
     */
    public static boolean isVoid(Class cls) {
        if (cls == Void.class || cls == void.class) {
            return true;
        }
        return false;
    }
    
    /**
     * Action to take on each method.
     */
    public static interface MethodCallback {

        /**
         * Perform an operation using the given method.
         *
         * @param method the method to operate on
         * @throws IllegalArgumentException the illegal argument exception
         * @throws IllegalAccessException the illegal access exception
         */
        void doWith(Method method) throws IllegalArgumentException, IllegalAccessException;
    }


    /**
     * Callback optionally used to method fields to be operated on by a method callback.
     */
    public static interface MethodFilter {

        /**
         * Determine whether the given method matches.
         *
         * @param method the method to check
         * @return true, if successful
         */
        boolean matches(Method method);
    }
}