hierarchynode.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;
import java.util.*;

/**
* HierarchyNode models a hierarchy tree node.
* The hierarchy is configured in <i>school.xml</i>.
* HierarchyNode instances are not persisted to the underlying database.
* It is only created by SchoolConfig, not by client code.
*
* @author Alexander Yap
* @see com.cyberdemia.school.SchoolConfig
*/
public class HierarchyNode implements IHierarchy,java.io.Serializable
{
	/**
	* Creates a HierarchyNode.
	* @param id  Unique ID.
	* @param nm  Name for user interface display.
	*/
	public HierarchyNode(int id, String nm, String type, int level, IHierarchy parent, boolean deepest)
	{
		m_id = new Integer(id);
		m_name = nm;
		m_type = type;
		m_level = level;
		m_parent = parent;
		m_deepest = deepest;
		m_hierarchyId = ( (m_parent!=null) ? (m_parent.getHierarchyId()+HIERARCHY_ID_SEPARATOR) : "")+getId();
	}
	
	/**
	* Sets the unique ID.
	* @param id  Unique ID.
	*/
	public void setId(Integer id)
	{
		m_id = id;
	}

	/**
	* Gets the unique ID.
	* @return Unique ID.
	*/
	public Integer getId()
	{
		return m_id;
	}
	
	/**
	* Gets the name intended for display in user interface.
	* @return Name of this HierarchyNode.
	*/
	public String getName()
	{
		return m_name;
	}
	
	/**
	* Sets the name intended for display in user interface.
	* @param nm  Name of this HierarchyNode.
	*/
	public void setName(String nm)
	{
		m_name = nm;
	}

	/**
	* Performs equality comparison with another HierarchyNode.
	* @return true if obj has the same unique ID as this HierarchyNode, otherwise false. 
	*/
	public boolean equals(Object obj)
	{
		if (!(obj instanceof HierarchyNode))
			return false;
		return m_id.equals(((HierarchyNode)obj).m_id);
	}

	/**
	 * 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.
	 */
	public String getType()
	{
		return m_type;
	}
	
	/**
	 * Gets the level of this node within the hierarchy.
	 * The root node has level 0.
	 * @return Node level.
	 */
	public int getLevel()
	{
		return m_level;
	}
	
	/**
	 * Gets the parent of this node.
	 * @return Parent node.
	 */
	public IHierarchy getParent()
	{
		return m_parent;
	}
	
	/**
	 * Gets the children of this node.
	 * @return Array of all children nodes.
	 */
	public IHierarchy[] getChildren()
	{
		return (IHierarchy[])m_childrenMap.values().toArray(new IHierarchy[0]);
	}
	
	/**
	 * Checks if this node has any children.
	 * @return true if this node has one or mode children, otherwise false.
	 */
	public boolean hasChildren()
	{
		return !m_childrenMap.isEmpty();
	}
	
	/**
	 * Gets a child of this node.
	 * @param id Child node ID.
	 * @return Child node, or null if no child with the ID.
	 */
	public IHierarchy getChild(Integer id)
	{
		return (IHierarchy)m_childrenMap.get(id);
	}
		
	/**
	 * Adds a child to this node.
	 * @param child Child node to add.
	 */
	public void addChild(IHierarchy child)
	{
		m_childrenMap.put(child.getId(), child);
	}
	
	/**
	* Gets a String that encodes the hierarchy from the
	* root node to this node.
	* Each node has its own unique "hierarchy identifier" String.
	* @return The hierarchy identifier of this node.
	*/
	public String getHierarchyId()
	{
		return m_hierarchyId;
	}
	
	/**
	 * Checks if this hierarchy node is the deepest node.
	 * @return true if this node is the deepest, otherwise false.
	 */
	public boolean isDeepest()
	{
		return m_deepest;
	}


	private Integer m_id=null;
	private String m_name=null;
	private String m_type = null;
	private int m_level = -1;
	private IHierarchy m_parent = null;
	private String m_hierarchyId = null;
	private boolean m_deepest = false;
	private Map m_childrenMap = new HashMap(); 	
}