ihierarchy.java

老外的在线考试

/*
 * SchoolEJB - CyberDemia's library of EJBs for educational related services.
 * Copyright (C) 2003 CyberDemia Research and Services
 *
 * This library is free software; you can redistribute it and/or
 * modify it under the terms of the GNU Library General Public
 * License as published by the Free Software Foundation; either
 * version 2 of the License, or (at your option) any later version.
 *
 * This library is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
 * Library General Public License for more details.
 * 
 * You should have received a copy of the GNU Library General Public
 * License along with this library; if not, write to the
 * Free Software Foundation, Inc., 59 Temple Place - Suite 330,
 * Boston, MA  02111-1307, USA.
 *
 * See the COPYING file located in the top-level-directory of
 * the archive of this library for complete text of license.
 */
package com.cyberdemia.school;

/**
 * IHierarchy is an interface that is implemented by all 
 * hierarchy node classes that may be part of the hierarchy tree
 * configured in <i>school.xml</i>.
 * IHierarchy defines the common methods for a node in the hierarchy tree.
 * 
 * @author Alexander Yap
 */
public interface IHierarchy
{
	/**
	* Gets the unique ID.
	* @return Unique ID.
	*/
	Integer getId();
	
	/**
	* Gets a String that encodes the hierarchy from the
	* root node to this hierarchy node.
	* Each hierarchy node has its own unique "hierarchy identifier" String.
	* @return The hierarchy identifier.
	*/
	String getHierarchyId();
		
	/**
	* Gets the name intended for display in user interface.
	* @return Name of this hierarchy node.
	*/
	String getName();
	
	/**
	 * Gets the type of this node, based on the depth within the hierarchy.
	 * All the nodes at a certain level are of the same type.
	 * A set of templates are defined in <i>school.xml</i> to map 
	 * the node levels to types.
	 * @return Node type.
	 */
	String getType();
	
	/**
	 * Gets the level of this node within the hierarchy.
	 * The root node has level 0.
	 * @return Node level.
	 */
	int getLevel();
	
	/**
	 * Gets the children of this node.
	 * @return Array of all children nodes.
	 */
	IHierarchy[] getChildren();
	
	/**
	 * Checks if this node has any children.
	 * @return true if this node has one or more children, otherwise false.
	 */
	boolean hasChildren();

	/**
	 * Gets a child of this node.
	 * @param id Child node ID.
	 * @return Child node, or null if no child with the ID.
	 */
	IHierarchy getChild(Integer id);
		
	/**
	 * Adds a child to this node.
	 * @param child Child node to add.
	 */
	void addChild(IHierarchy child);

	/**
	 * Gets the parent of this node.
	 * @return Parent node.
	 */
	IHierarchy getParent();
	
	/**
	 * Checks if this hierarchy node is the deepest node.
	 * @return true if this node is the deepest, otherwise false.
	 */
	boolean isDeepest();

	/**
	 * Separator between the different components of the hierarchy Id.
	 */
	String HIERARCHY_ID_SEPARATOR = ",";

}