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.logging.log4j.core.config;
018
019import java.util.ArrayList;
020import java.util.HashMap;
021import java.util.List;
022import java.util.Map;
023
024import org.apache.logging.log4j.core.config.plugins.util.PluginType;
025
026/**
027 * A Configuration node.
028 */
029public class Node {
030
031    /**
032     * Main plugin category for plugins which are represented as a configuration node. Such plugins tend to be
033     * available as XML elements in a configuration file.
034     *
035     * @since 2.1
036     */
037    public static final String CATEGORY = "Core";
038
039    private final Node parent;
040    private final String name;
041    private String value;
042    private final PluginType<?> type;
043    private final Map<String, String> attributes = new HashMap<>();
044    private final List<Node> children = new ArrayList<>();
045    private Object object;
046
047
048    /**
049     * Creates a new instance of {@code Node} and initializes it
050     * with a name and the corresponding XML element.
051     *
052     * @param parent the node's parent.
053     * @param name the node's name.
054     * @param type The Plugin Type associated with the node.
055     */
056    public Node(final Node parent, final String name, final PluginType<?> type) {
057        this.parent = parent;
058        this.name = name;
059        this.type = type;
060    }
061
062    public Node() {
063        this.parent = null;
064        this.name = null;
065        this.type = null;
066    }
067
068    public Node(final Node node) {
069        this.parent = node.parent;
070        this.name = node.name;
071        this.type = node.type;
072        this.attributes.putAll(node.getAttributes());
073        this.value = node.getValue();
074        for (final Node child : node.getChildren()) {
075            this.children.add(new Node(child));
076        }
077        this.object = node.object;
078    }
079
080    public Map<String, String> getAttributes() {
081        return attributes;
082    }
083
084    public List<Node> getChildren() {
085        return children;
086    }
087
088    public boolean hasChildren() {
089        return !children.isEmpty();
090    }
091
092    public String getValue() {
093        return value;
094    }
095
096    public void setValue(final String value) {
097        this.value = value;
098    }
099
100    public Node getParent() {
101        return parent;
102    }
103
104    public String getName() {
105        return name;
106    }
107
108    public boolean isRoot() {
109        return parent == null;
110    }
111
112    public void setObject(final Object obj) {
113        object = obj;
114    }
115
116    @SuppressWarnings("unchecked")
117    public <T> T getObject() {
118        return (T) object;
119    }
120
121    /**
122     * Returns this node's object cast to the given class.
123     *
124     * @param clazz the class to cast this node's object to.
125     * @param <T>   the type to cast to.
126     * @return this node's object.
127     * @since 2.1
128     */
129    public <T> T getObject(final Class<T> clazz) {
130        return clazz.cast(object);
131    }
132
133    /**
134     * Determines if this node's object is an instance of the given class.
135     *
136     * @param clazz the class to check.
137     * @return {@code true} if this node's object is an instance of the given class.
138     * @since 2.1
139     */
140    public boolean isInstanceOf(final Class<?> clazz) {
141        return clazz.isInstance(object);
142    }
143
144    public PluginType<?> getType() {
145        return type;
146    }
147
148    @Override
149    public String toString() {
150        if (object == null) {
151            return "null";
152        }
153        return type.isObjectPrintable() ? object.toString() :
154            type.getPluginClass().getName() + " with name " + name;
155    }
156}