Java Reflection Interface Get getAllInterfaces(Class cls)

Description

Gets a List of all interfaces implemented by the given class and its superclasses.

The order is determined by looking through each interface in turn as declared in the source file and following its hierarchy up.

License

Apache License

Parameter

Parameter	Description
cls	the class to look up, may be <code>null</code>

Return

the List of interfaces in order, null if null input

Declaration

public static List getAllInterfaces(Class cls)

Method Source Code

//package com.java2s;
/*/*w w w . j a v  a  2 s.c o m*/
 * Licensed to the Apache Software Foundation (ASF) under one or more
 * contributor license agreements.  See the NOTICE file distributed with
 * this work for additional information regarding copyright ownership.
 * The ASF licenses this file to You 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.
 */

import java.util.ArrayList;

import java.util.List;

public class Main {
    /**
     * <p>Gets a <code>List</code> of all interfaces implemented by the given
     * class and its superclasses.</p>
     *
     * <p>The order is determined by looking through each interface in turn as
     * declared in the source file and following its hierarchy up. Then each
     * superclass is considered in the same way. Later duplicates are ignored,
     * so the order is maintained.</p>
     *
     * @param cls  the class to look up, may be <code>null</code>
     * @return the <code>List</code> of interfaces in order,
     *  <code>null</code> if null input
     */
    public static List getAllInterfaces(Class cls) {
        if (cls == null) {
            return null;
        }

        List interfacesFound = new ArrayList();
        getAllInterfaces(cls, interfacesFound);

        return interfacesFound;
    }

    /**
     * Get the interfaces for the specified class.
     *
     * @param cls  the class to look up, may be <code>null</code>
     * @param interfacesFound the <code>Set</code> of interfaces for the class
     */
    private static void getAllInterfaces(Class cls, List interfacesFound) {
        while (cls != null) {
            Class[] interfaces = cls.getInterfaces();

            for (int i = 0; i < interfaces.length; i++) {
                if (!interfacesFound.contains(interfaces[i])) {
                    interfacesFound.add(interfaces[i]);
                    getAllInterfaces(interfaces[i], interfacesFound);
                }
            }

            cls = cls.getSuperclass();
        }
    }
}