| /* |
| * 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.commons.configuration2.tree; |
| |
| import java.util.List; |
| |
| /** |
| * <p> |
| * An extension of the {@link NodeHandler} interface which allows access to |
| * so-called <em>references</em> stored for a node. |
| * </p> |
| * <p> |
| * Some specialized configuration implementations needs to store additional data |
| * for the nodes representing configuration properties. This interface provides |
| * methods for querying this data. For instance, it is possible to query a |
| * reference object stored for a specific node. |
| * </p> |
| * <p> |
| * {@link InMemoryNodeModel} supports references. It can be queried for a |
| * {@code ReferenceNodeHandler} which can then be used for dealing with |
| * references. |
| * </p> |
| * |
| * @version $Id$ |
| * @since 2.0 |
| */ |
| public interface ReferenceNodeHandler extends NodeHandler<ImmutableNode> |
| { |
| /** |
| * Returns the reference object associated with the specified node. If no |
| * reference data is associated with this node, result is <b>null</b>. |
| * |
| * @param node the node in question |
| * @return the reference object for this node or <b>null</b> |
| */ |
| Object getReference(ImmutableNode node); |
| |
| /** |
| * Returns a list with the reference objects for nodes which have been |
| * removed. Whenever a node associated with a reference object is removed |
| * from the nodes structure managed by the owning model, the reference |
| * object is recorded. This is necessary for instance to free some |
| * resources. With this method all recorded reference objects can be |
| * queried. They are typically returned in the order in which they have been |
| * removed. |
| * |
| * @return a list with reference objects for nodes removed from the model |
| */ |
| List<Object> removedReferences(); |
| } |