| /* |
| * 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. |
| */ |
| package org.apache.sling.discovery; |
| |
| import org.osgi.annotation.versioning.ConsumerType; |
| |
| /** |
| * The <code>PropertyProvider</code> service interface may be implemented by |
| * components that wish to define properties on the local instance which then |
| * are broadcast to the <code>TopologyView</code> instances. |
| * <p> |
| * The provided properties are registered with the {@link #PROPERTY_PROPERTIES} |
| * service property. |
| * If the set of provided properties changes or one of the provided values |
| * change, the service registration of the provider should be updated. |
| * This avoids periodic polling for changes. |
| */ |
| @ConsumerType |
| public interface PropertyProvider { |
| |
| /** |
| * The name of the service registration property containing the names |
| * of the properties provided by this provider. |
| * The value is either a string or an array of strings. |
| * A property name must only contain alphanumeric characters plus <code>.</code>, |
| * <code>_</code>, <code>-</code>. |
| */ |
| String PROPERTY_PROPERTIES = "instance.properties"; |
| |
| /** |
| * Retrieves a property that is subsequently set on the local instance |
| * and broadcast to the <code>TopologyView</code> instances. |
| * |
| * These properties are non-persistent and disappear after the local instance goes down. |
| * |
| * @param name The property name |
| * @return The value of the property or <code>null</code>. If the property |
| * value can't be provided or if the provider does not support this |
| * property, it must return <code>null</code>. |
| */ |
| String getProperty(final String name); |
| } |