1 /* 2 * Licensed to the Apache Software Foundation (ASF) under one or more 3 * contributor license agreements. See the NOTICE file distributed with 4 * this work for additional information regarding copyright ownership. 5 * The ASF licenses this file to You under the Apache License, Version 2.0 6 * (the "License"); you may not use this file except in compliance with 7 * the License. You may obtain a copy of the License at 8 * 9 * http://www.apache.org/licenses/LICENSE-2.0 10 * 11 * Unless required by applicable law or agreed to in writing, software 12 * distributed under the License is distributed on an "AS IS" BASIS, 13 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. 14 * See the License for the specific language governing permissions and 15 * limitations under the License. 16 */ 17 18 package javax.security.auth.callback; 19 20 import java.io.IOException; 21 22 /** 23 * Needs to be implemented by classes that want to handle authentication 24 * {@link Callback}s. A single method {@link #handle(Callback[])} must be 25 * provided that checks the type of the incoming {@code Callback}s and reacts 26 * accordingly. {@code CallbackHandler}s can be installed per application. It is 27 * also possible to configure a system-default {@code CallbackHandler} by 28 * setting the {@code auth.login.defaultCallbackHandler} property in the 29 * standard {@code security.properties} file. 30 */ 31 public interface CallbackHandler { 32 33 /** 34 * Handles the actual {@link Callback}. A {@code CallbackHandler} needs to 35 * implement this method. In the method, it is free to select which {@code 36 * Callback}s it actually wants to handle and in which way. For example, a 37 * console-based {@code CallbackHandler} might choose to sequentially ask 38 * the user for login and password, if it implements these {@code Callback} 39 * s, whereas a GUI-based one might open a single dialog window for both 40 * values. If a {@code CallbackHandler} is not able to handle a specific 41 * {@code Callback}, it needs to throw an 42 * {@link UnsupportedCallbackException}. 43 * 44 * @param callbacks 45 * the array of {@code Callback}s that need handling 46 * @throws IOException 47 * if an I/O related error occurs 48 * @throws UnsupportedCallbackException 49 * if the {@code CallbackHandler} is not able to handle a 50 * specific {@code Callback} 51 */ handle(Callback[] callbacks)52 void handle(Callback[] callbacks) throws IOException, UnsupportedCallbackException; 53 54 } 55