    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}