001/*
002 * Licensed to the Apache Software Foundation (ASF) under one or more
003 * contributor license agreements.  See the NOTICE file distributed with
004 * this work for additional information regarding copyright ownership.
005 * The ASF licenses this file to You under the Apache License, Version 2.0
006 * (the "License"); you may not use this file except in compliance with
007 * the License.  You may obtain a copy of the License at
008 *
009 *     http://www.apache.org/licenses/LICENSE-2.0
010 *
011 * Unless required by applicable law or agreed to in writing, software
012 * distributed under the License is distributed on an "AS IS" BASIS,
013 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
014 * See the License for the specific language governing permissions and
015 * limitations under the License.
016 */
017package org.apache.commons.configuration2.tree;
018
019import java.util.List;
020import java.util.Set;
021
022/**
023 * <p>
024 * An abstract base class for decorators of a {@code NodeHandler}.
025 * </p>
026 * <p>
027 * This class implements all methods of the {@code NodeHandler} interface by
028 * delegating to another instance. This is convenient if specific functionality
029 * of a {@code NodeHandler} is to be adapted for a special use case. Concrete
030 * sub classes have to implement the {@code getDecoratedNodeHandler()} method to
031 * provide the underlying handler.
032 * </p>
033 *
034 * @since 2.0
035 * @param <T> the type of the nodes supported by this handler
036 */
037public abstract class NodeHandlerDecorator<T> implements NodeHandler<T>
038{
039    @Override
040    public String nodeName(final T node)
041    {
042        return getDecoratedNodeHandler().nodeName(node);
043    }
044
045    @Override
046    public Object getValue(final T node)
047    {
048        return getDecoratedNodeHandler().getValue(node);
049    }
050
051    @Override
052    public T getParent(final T node)
053    {
054        return getDecoratedNodeHandler().getParent(node);
055    }
056
057    @Override
058    public List<T> getChildren(final T node)
059    {
060        return getDecoratedNodeHandler().getChildren(node);
061    }
062
063    @Override
064    public <C> List<T> getMatchingChildren(final T node, final NodeMatcher<C> matcher,
065            final C criterion)
066    {
067        return getDecoratedNodeHandler().getMatchingChildren(node, matcher,
068                criterion);
069    }
070
071    @Override
072    public <C> int getMatchingChildrenCount(final T node, final NodeMatcher<C> matcher,
073            final C criterion)
074    {
075        return getDecoratedNodeHandler().getMatchingChildrenCount(node,
076                matcher, criterion);
077    }
078
079    @Override
080    public List<T> getChildren(final T node, final String name)
081    {
082        return getDecoratedNodeHandler().getChildren(node, name);
083    }
084
085    @Override
086    public T getChild(final T node, final int index)
087    {
088        return getDecoratedNodeHandler().getChild(node, index);
089    }
090
091    @Override
092    public int indexOfChild(final T parent, final T child)
093    {
094        return getDecoratedNodeHandler().indexOfChild(parent, child);
095    }
096
097    @Override
098    public int getChildrenCount(final T node, final String name)
099    {
100        return getDecoratedNodeHandler().getChildrenCount(node, name);
101    }
102
103    @Override
104    public Set<String> getAttributes(final T node)
105    {
106        return getDecoratedNodeHandler().getAttributes(node);
107    }
108
109    @Override
110    public boolean hasAttributes(final T node)
111    {
112        return getDecoratedNodeHandler().hasAttributes(node);
113    }
114
115    @Override
116    public Object getAttributeValue(final T node, final String name)
117    {
118        return getDecoratedNodeHandler().getAttributeValue(node, name);
119    }
120
121    @Override
122    public boolean isDefined(final T node)
123    {
124        return getDecoratedNodeHandler().isDefined(node);
125    }
126
127    @Override
128    public T getRootNode()
129    {
130        return getDecoratedNodeHandler().getRootNode();
131    }
132
133    /**
134     * Returns the {@code NodeHandler} object that is decorated by this
135     * instance. All method calls are delegated to this object.
136     *
137     * @return the decorated {@code NodeHandler}
138     */
139    protected abstract NodeHandler<T> getDecoratedNodeHandler();
140}