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 }