catalogexchangeresponse.java

基于jxta的文件共享和聊天系统源代码,下载下来分析吧

/*
 * Created on 27-nov-2005
 *
 */
/**
 * @author magowiz
 *
 */
package catalog_exchange;

import java.io.InputStream;
import java.io.StringWriter;
import java.net.URL;
import java.util.Date;
import java.util.Enumeration;

import net.jxta.document.Document;
import net.jxta.document.Element;
import net.jxta.document.MimeMediaType;
import net.jxta.document.StructuredDocument;
import net.jxta.document.StructuredDocumentFactory;
import net.jxta.document.StructuredTextDocument;
import net.jxta.document.TextElement;

import org.apache.xerces.dom.DocumentImpl;
import org.w3c.dom.NodeList;

/**
 * Object that implements a Catalog Exchange Response, a XML JXTA Message that
 * will be sent by a peer to reply to a catalog exchange query. 
 * */
public class CatalogExchangeResponse {
	private org.w3c.dom.Document catalog;/**The catalog which is transported by response*/
	private Date dateDownload;/**The download date of the catalog*/
	private Date dateLastUpdate;/**The date of last update of the catalog*/
	private URL catalogUrl;/**The catalog URL*/
	private String catalogName;	/**catalog name, identifies the catalog*/
	private String got;/**status of the response, it tells if the peer has got 
	the catalog and if it's older or newer*/
	
	
	/**
	 * Returns the catalog transported by the response 
	 * 
	 * */
	
	public org.w3c.dom.Document  getCatalog()
	{
	 return catalog;
	}
	
	
	
	/**
	 * Returns the download date of the transported catalog 
	 * 
	 * */
	public long getDateDownload()
	{
	 return dateDownload.getTime(); 	
	}
	
	/**
	 * Returns the last update date of the transported catalog 
	 * 
	 * */
	public long getDateLastUpdate()
	{
	 return dateLastUpdate.getTime(); 	
	}
	
	/**
	 * Returns the URL of the transported catalog 
	 * 
	 * */
	public URL getCatalogUrl()
	{
	 return catalogUrl;
	}
	
	/**
	 * Returns the name of the transported catalog 
	 * 
	 * */
	public String getCatalogName()
	{
	 return catalogName;
	}
	
	
	/**
	 * Returns the got status of the transported catalog 
	 * can be false, newer, older,equal,true
	 * 
	 * */
	public String getGot()
	{
	 return got;	
	}
	
	
	/**
	 * Used in case which the peer send the catalog (newer,true)
	 * @param g got value, represents the status of the responsed catalog
	 * @param cn name of the catalog to send
	 * @param curl Url of the catalog
	 * @param dd download date of the catalog 
	 * @param dlu date of last update
	 * @param cat catalog to send
	 * */
	public CatalogExchangeResponse(String g,String cn,URL curl,long dd,long dlu,org.w3c.dom.Document  cat)
	{
		got=g;
		catalogName=cn;
		catalogUrl=curl;
		dateDownload=new Date(dd);
		dateLastUpdate=new Date(dlu);
		catalog=cat;
	}
	
	
	/**
	 * Used in case which the query peer and the response peer has the same catalog 
	 * or in case which the sender has got a older version(equal,older)
	 * @param g got value, represents the status of the responsed catalog
	 * @param cn name of the catalog to send
	 * @param curl Url of the catalog
	 * @param dlu date of last update
	 * 
	 * */
	public CatalogExchangeResponse(String g,String cn,URL curl,long dlu)
	{
		got=g;
		catalogName=cn;
		catalogUrl=curl;
		dateDownload=null;
		dateLastUpdate=new Date(dlu);
		catalog=null;
	}
	
	
	

	/**
	 * Used in case which the peer hasn't the catalog (false)
	 * @param g got value, represents the status of the responsed catalog
	 * @param cn name of the catalog to send
	 * @param curl Url of the catalog
	 * 
	 * */
	public CatalogExchangeResponse(String g,String cn,URL curl)
	{
		got=g;
		catalogName=cn;
		catalogUrl=curl;
		dateDownload=null;
		dateLastUpdate=null;
		catalog=null;
	}
	
	
	/**
     * Method that creates and return the xml document which represents
     * the response.
     * @param asMimeType MimeType of the output document.
     * @return The query in xml document format.
     */
	public Document getDocument(MimeMediaType asMimeType)  	
	  {
		 StructuredDocument document = (StructuredTextDocument) 
	          StructuredDocumentFactory.newStructuredDocument(
	              asMimeType, "example:ExampleResponse");
	      Element element;	      
	      element = document.createElement("got",got);
	      document.appendChild(element);
	      element = document.createElement("catalogName",catalogName);
	      document.appendChild(element);
	  	  element=document.createElement("catalogUrl",catalogUrl.toString());
	      document.appendChild(element);	
	      if(dateDownload!=null)
	      {element=document.createElement("dateDownload",String.valueOf(dateDownload.getTime()));
	  	  document.appendChild(element);}
	      if(dateLastUpdate!=null){
	      	element=document.createElement("dateLastUpdate",String.valueOf(dateLastUpdate.getTime()));
	  	  document.appendChild(element);}
	  	  if(catalog!=null)
	  	  	{
	  	  		element = document.createElement("catalog");
	  	  		document.appendChild(element);
	  	  		domToJxtaDocElements(catalog,document,element);
	  	  	}
	      return document;
	  }

	
	/**
     * Needed for the peer who receive the response to easily extract
     * info from response.
     * @param stream is the response xml document received
     */
	public CatalogExchangeResponse (InputStream stream) 
	 {
	     StructuredTextDocument document=null;
	     try{document = (StructuredTextDocument) 
	         StructuredDocumentFactory.newStructuredDocument(
	             new MimeMediaType("text/xml"), stream);}
	     catch(Exception e){e.printStackTrace();}

	     Enumeration elements = document.getChildren();
	     
	     elements = document.getChildren();
	     while (elements.hasMoreElements())
	     {
	        
	         Element el = (Element) elements.nextElement();
	         TextElement element = (TextElement) el;
	         if(element.getName().equals("catalogName"))
	         {
	             catalogName = element.getTextValue();
	             continue;
	         }
	         if(element.getName().equals("catalogUrl"))
	         {
	             try{catalogUrl = new URL (element.getTextValue());}
	             catch(Exception e){e.printStackTrace();}
	             continue;
	         }
	         if(element.getName().equals("dateLastUpdate"))
	         {
	         	 long t=Long.valueOf(element.getTextValue()).longValue();
	             dateLastUpdate= new Date(t);
	             continue;
	         }
	         if(element.getName().equals("dateDownload"))
	         {
	         	 long t=Long.valueOf(element.getTextValue()).longValue();
	         	 dateDownload = new Date(t);
	             continue;
	         }
	        
	         if(element.getName().equals("got"))
	         {
	         	got=element.getTextValue();
	         	continue;
	         }
	         if(element.getName().equals("catalog"))
	         {
	         	catalog=jxtaDocToDom(element);
	         }
	         
	     } 
	     
	 }
	 
	/**
     * Extracts the catalog from response to a xml dom tree
     * @param c element that contains the catalog
     */
	private org.w3c.dom.Document jxtaDocToDom(Element c)
	{
		org.w3c.dom.Document doc=null;
		doc= new DocumentImpl();
		org.w3c.dom.Element root = doc.createElement("catalog");
		doc.appendChild(root);		
		Enumeration elements=c.getChildren();
		while(elements.hasMoreElements())
		{
			Element el=(Element)elements.nextElement();
			TextElement element = (TextElement) el;
			if(element.getName().equals("university"))
			{
				org.w3c.dom.Element un= doc.createElement("university");
				org.w3c.dom.Node n1=doc.createTextNode(element.getTextValue());
				un.appendChild(n1);
				root.appendChild(un);				
			}
			else if(element.getName().equals("faculty"))
			{
				org.w3c.dom.Element fa= doc.createElement("faculty");
				org.w3c.dom.Node n2=doc.createTextNode(element.getTextValue());
				fa.appendChild(n2);
				root.appendChild(fa);				
			}
			else if (element.getName().equals("download"))
			{
				org.w3c.dom.Element ed=doc.createElement("download");
				root.appendChild(ed);
				catalogItem(element,doc,ed);
			}			
			else
			{
				org.w3c.dom.Element ed=doc.createElement(element.getName());
				org.w3c.dom.Node n=null;
				if(element.getTextValue()!=null) n=doc.createTextNode(element.getTextValue());
				else n=doc.createTextNode(" ");
				ed.appendChild(n);
				root.appendChild(ed);				
			}
			
		}
		System.out.println(" jxta to dom "+doc.toString());
		return doc;		
	}
	
	/**
     * Extracts the catalog item to a xml dom tree
     * @param ci catalog item element in jxta response
     * @param  r xml document
     * @param e xml dom root element 
     */
	private void catalogItem(Element ci, org.w3c.dom.Document r, org.w3c.dom.Element e )
	{
		Enumeration elements=ci.getChildren();
		while(elements.hasMoreElements()){
			Element el=(Element)elements.nextElement();
			TextElement element = (TextElement) el;	
			org.w3c.dom.Element ed=r.createElement(element.getName());
			org.w3c.dom.Node n=null;
			if (element.getTextValue()!=null)n=r.createTextNode(element.getTextValue());
			else n=r.createTextNode(" ");
			ed.appendChild(n);
			e.appendChild(ed);				
		}
	}
	
	
	/**
     * Inserts the catalog from a xml dom tree to jxta response
     * @param c catalog in xml dom format
     * @param r xml response document
     * @param rc element of jxta response that contains catalogs
     */
	private void domToJxtaDocElements(org.w3c.dom.Document c,StructuredDocument r, Element rc)
	{
		//NodeList nl3=c.getElementsByTagName("catalog");		
		NodeList nl1=c.getElementsByTagName("university");
		Element e1=r.createElement("university",nl1.item(0).getFirstChild().getNodeValue());
		rc.appendChild(e1);
		NodeList nl2=c.getElementsByTagName("faculty");
		Element e2=r.createElement("faculty",nl2.item(0).getFirstChild().getNodeValue());
		rc.appendChild(e2);
		NodeList nl=c.getElementsByTagName("download");
		Element e=null;
		for(int i=0; i<nl.getLength();i++)
		{
			e=r.createElement("download");
			rc.appendChild(e);
			catalogItem((org.w3c.dom.Element) nl.item(i),r,e);
		}
		System.out.println(" dom to jxta "+r.toString());
	}
	
	/**
     * Extracts the catalog item to a xml dom tree
     * @param ci catalog item element in dom xml tree
     * @param  r jxta response document
     * @param e jxta response root element 
     */
	private void catalogItem(org.w3c.dom.Element ci, StructuredDocument r,Element e)
	{
		NodeList nl=ci.getChildNodes();
		for (int i=0;i<nl.getLength();i++)
		{
			if(nl.item(i).getNodeType()==org.w3c.dom.Node.ELEMENT_NODE)
			{
				org.w3c.dom.Element el= (org.w3c.dom.Element) nl.item(i);
				Element itemEl=null;
				if(el.getFirstChild()!=null)
					itemEl=r.createElement(el.getNodeName(),el.getFirstChild().getNodeValue());
				else
					itemEl=r.createElement(el.getNodeName()," ");
			 	e.appendChild(itemEl);
			}
		}
	}
	
	/**
     * Method that returns the xml response document as String.
     * @return String rapresentation of the response.
     */
	 public String toString()
	 {
	     try
	     {
	         StringWriter out = new StringWriter();
	         StructuredTextDocument doc = 
	             (StructuredTextDocument) getDocument(
	                 new MimeMediaType("text/xml"));
	         doc.sendToWriter(out);
	         return out.toString();
	     }
	     catch (Exception e)
	     {
	     	 e.printStackTrace();
	         return "";
	         
	     }
	 }

}