Checks, whether the given Class 'clazz' overrides the given method in the Class 'base Clazz'. - Java Reflection

Java examples for Reflection:Super Class

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Description

Checks, whether the given Class 'clazz' overrides the given method in the Class 'base Clazz'.

Demo Code

/**//from   w w  w. j  a  va  2s .c  om
 * Copyright (c) 2007-2011, JAGaToo Project Group all rights reserved.
 * 
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions are met:
 * 
 * Redistributions of source code must retain the above copyright notice,
 * this list of conditions and the following disclaimer.
 * 
 * Redistributions in binary form must reproduce the above copyright notice,
 * this list of conditions and the following disclaimer in the documentation
 * and/or other materials provided with the distribution.
 * 
 * Neither the name of the 'Xith3D Project Group' nor the names of its
 * contributors may be used to endorse or promote products derived from this
 * software without specific prior written permission.
 * 
 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
 * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
 * ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE
 * LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
 * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
 * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
 * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
 * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) A
 * RISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
 * POSSIBILITY OF SUCH DAMAGE
 */
//package com.java2s;
import java.lang.reflect.Method;

public class Main {
    public static void main(String[] argv) throws Exception {
        Class baseClazz = String.class;
        Class clazz = String.class;
        String methodName = "java2s.com";
        Class parameterTypes = String.class;
        System.out.println(overridesMethod(baseClazz, clazz, methodName,
                parameterTypes));
    }

    /**
     * Checks, whether the given Class 'clazz' overrides the given method in the Class 'baseClazz'.
     * 
     * @param baseClazz the Class declaring the base method
     * @param clazz the sub class possibly overriding the method
     * @param methodName the name of the method
     * @param parameterTypes the parameters of the method
     * 
     * @return <code>true</code>, if the class overrides the given method, <code>false</code> if not, null, if the method doesn't exist or another error occurrs.
     */
    public static Boolean overridesMethod(Class<?> baseClazz,
            Class<?> clazz, String methodName, Class<?>... parameterTypes) {
        Method m = findMethod(clazz, methodName, parameterTypes);

        if (m == null)
            return (null);

        return (m.getDeclaringClass() != baseClazz);
    }

    /**
     * Gets the method from the given class without exceptions and also searches super classes.
     * 
     * @param clazz
     * @param methodName
     * @param parameterTypes
     * 
     * @return the method or null, if it doesn't exist or other problems occurr.
     */
    public static Method findMethod(Class<?> clazz, String methodName,
            Class<?>... parameterTypes) {
        Method m = getPublicMethod(clazz, methodName, parameterTypes);

        if (m != null)
            return (m);

        return (findMethod_(clazz, methodName, parameterTypes));
    }

    /**
     * Gets the public method from the given class without exceptions.
     * 
     * @param clazz
     * @param methodName
     * @param parameterTypes
     * 
     * @return the method or null, if it doesn't exist or other problems occurr.
     */
    public static Method getPublicMethod(Class<?> clazz, String methodName,
            Class<?>... parameterTypes) {
        Method m = null;

        try {
            m = clazz.getMethod(methodName, parameterTypes);
        } catch (Throwable t) {
        }

        return (m);
    }

    private static Method findMethod_(Class<?> clazz, String methodName,
            Class<?>... parameterTypes) {
        Method m = null;

        try {
            m = clazz.getDeclaredMethod(methodName, parameterTypes);
        } catch (Throwable t) {
        }

        if ((m == null) && (clazz.getSuperclass() != null))
            return (findMethod_(clazz.getSuperclass(), methodName,
                    parameterTypes));

        return (m);
    }
}

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