/*
* 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;
/**
* <p>
* Definition of a <em>Visitor</em> interface for a configuration node
* structure.
* </p>
* <p>
* The <code>ConfigurationNode</code> interface defines a <code>visit()</code>,
* which simplifies traversal of a complex node hierarchy. A configuration node
* implementation must provide a way of visiting all nodes in the current
* hierarchy. This is a typical application of the GoF <em>Visitor</em>
* pattern.
* </p>
*
* @since 1.3
* @see ConfigurationNode
* @author Oliver Heger
*/
public interface ConfigurationNodeVisitor
{
/**
* Visits the specified node. This method is called before eventually
* existing children of this node are processed.
*
* @param node the node to be visited
*/
void visitBeforeChildren(ConfigurationNode node);
/**
* Visits the specified node. This method is called after eventually
* existing children of this node have been processed.
*
* @param node the node to be visited
*/
void visitAfterChildren(ConfigurationNode node);
/**
* Returns a flag whether the actual visit process should be aborted. This
* method allows a visitor implementation to state that it does not need any
* further data. It may be used e.g. by visitors that search for a certain
* node in the hierarchy. After that node was found, there is no need to
* process the remaining nodes, too.
*
* @return a flag if the visit process should be stopped
*/
boolean terminate();
}
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