svn commit: r1585181 - /commons/proper/configuration/branches/immutableNodes/src/main/java/org/apache/commons/configuration/tree/ReferenceNodeHandler.java

[oh...@apache.org]

Author: oheger
Date: Sat Apr  5 19:44:12 2014
New Revision: 1585181

URL: http://svn.apache.org/r1585181
Log:
Added ReferenceNodeHandler interface.

This interface allows access to reference objects which can be associated with
the nodes stored in a NodeModel.

Added:
    commons/proper/configuration/branches/immutableNodes/src/main/java/org/apache/commons/configuration/tree/ReferenceNodeHandler.java

Added: commons/proper/configuration/branches/immutableNodes/src/main/java/org/apache/commons/configuration/tree/ReferenceNodeHandler.java
URL: http://svn.apache.org/viewvc/commons/proper/configuration/branches/immutableNodes/src/main/java/org/apache/commons/configuration/tree/ReferenceNodeHandler.java?rev=1585181&view=auto
==============================================================================
--- commons/proper/configuration/branches/immutableNodes/src/main/java/org/apache/commons/configuration/tree/ReferenceNodeHandler.java (added)
+++ commons/proper/configuration/branches/immutableNodes/src/main/java/org/apache/commons/configuration/tree/ReferenceNodeHandler.java Sat Apr  5 19:44:12 2014
@@ -0,0 +1,64 @@
+/*
+ * 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.configuration.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();
+}