1 /* 2 * Copyright 2008 University Corporation for Advanced Internet Development, Inc. 3 * 4 * Licensed under the Apache License, Version 2.0 (the "License"); 5 * you may not use this file except in compliance with the License. 6 * You may obtain a copy of the License at 7 * 8 * http://www.apache.org/licenses/LICENSE-2.0 9 * 10 * Unless required by applicable law or agreed to in writing, software 11 * distributed under the License is distributed on an "AS IS" BASIS, 12 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. 13 * See the License for the specific language governing permissions and 14 * limitations under the License. 15 */ 16 17 package org.opensaml.xml.util; 18 19 /** 20 * An interface for factory classes which implement a singleton pattern for producing an 21 * output class based on an input class. 22 * 23 * <p> 24 * Classes which implement this interface should ensure that exactly one instance of a given output 25 * class is returned from the factory for a given instance of an input class. 26 * </p> 27 * 28 * @param <Input> the factory input class type 29 * @param <Output> the factory output class type 30 */ 31 public interface SingletonFactory<Input, Output> { 32 33 /** 34 * Obtain an instance of the output class based on an input class instance. 35 * 36 * @param input the input class instance 37 * @return an output class instance 38 */ 39 public Output getInstance(Input input); 40 41 }