content: /*
   * 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.ambari.server.api.util;
  
  import java.util.Collection;
  
  /**
   * Tree where each node can have a name, properties and an associated object.
   */
  public interface TreeNode<T> {
    /**
     * Obtain the parent node or null if this node is the root.
     *
     * @return the parent node or null if this node is the root
     */
    TreeNode<T> getParent();
  
    /**
     * Obtain the list of child nodes.
     *
     * @return a list of child nodes or an empty list if a leaf node
     */
    Collection<TreeNode<T>> getChildren();
  
    /**
     * Obtain the object associated with this node.
     *
     * @return the object associated with this node or null
     */
    T getObject();
  
    /**
     * Obtain the name of the node.
     *
     * @return the name of the node or null
     */
    String getName();
  
    /**
     * Set the name of the node.
     *
     * @param name the name to set
     */
    void setName(String name);
  
    /**
     * Set the parent node.
     *
     * @param parent the parent node to set
     */
    void setParent(TreeNode<T> parent);
  
    /**
     * Add a child node for the provided object.
     *
     * @param child the object associated with the new child node
     * @param name  the name of the child node
     * @return the newly created child node
     */
    TreeNode<T> addChild(T child, String name);
  
    /**
     * Add the specified child node.
     *
     * @param child the child node to add
     * @return the added child node
     */
    TreeNode<T> addChild(TreeNode<T> child);
  
    /**
     * Remove a child from this resource.
     *
     * @param name  name of child to remove
     *
     * @return the previous value associated with key, or null if there was no mapping for key
     */
    TreeNode<T> removeChild(String name);
  
    /**
     * Set a property on the node.
     *
     * @param name  the name of the property
     * @param value the value of the property
     */
    void setProperty(String name, Object value);
  
    /**
     * Get the specified node property.
     *
     * @param name property name
     * @return the requested property value or null
     */
    Object getProperty(String name);
  
    /**
     * Get the specified node property as a String.
     *
     * @param name property name
     * @return the requested property value (as a String) or null
     */
    String getStringProperty(String name);
  
    /**
     * Remove a property from the node.
     *
     * @param name  name of property to be removed
     */
    void removeProperty(String name);
  
    /**
     * Find a child node by name.
     * The name may contain '/' to delimit names to find a child more then one level deep.
     * To find a node named 'bar' that is a child of a child named 'foo', use the name 'foo/bar'.
     *
     * @param name  the name of the child.  May contain the '/' path separator.
     *
     * @return the requested node or null if the child was not found
     */
    TreeNode<T> getChild(String name);
  }
  