1 /* 2 * Copyright [2006] [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.saml2.metadata.provider; 18 19 import java.util.List; 20 21 /** 22 * A metadata provider that provides event notification to observers. This may be used, for example, to signal an update 23 * of an internal cache of metadata allowing other subsystems to perform some action based on that. 24 * 25 */ 26 public interface ObservableMetadataProvider extends MetadataProvider { 27 28 /** 29 * Gets the list of observers for the provider. New observers may be added to the list or old ones removed. 30 * 31 * @return the list of observers 32 */ 33 public List<Observer> getObservers(); 34 35 /** 36 * An observer of metadata provider changes. 37 * 38 * <strong>NOTE:</strong> The metadata provider that has changed is passed in to the 39 * {@link #onEvent(MetadataProvider)} method. Observers should <strong>NOT</strong> keep a reference to this 40 * provider as this may prevent proper garbage collection. 41 */ 42 public interface Observer { 43 44 /** 45 * Called when a provider signals an event has occured. 46 * 47 * @param provider the provider being observed 48 */ 49 public void onEvent(MetadataProvider provider); 50 } 51 }