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   package com.fc.taglibs.castor;
   
   import java.io.*;
   import java.util.ArrayList;
   import javax.naming.*;
   import javax.servlet.jsp.*;
   import javax.servlet.jsp.tagext.*;
   import org.apache.taglibs.standard.lang.support.*;
   
  
  
  import javax.naming.InitialContext;
  import org.exolab.castor.jdo.DataObjects;
  import org.exolab.castor.jdo.Database;
  import org.exolab.castor.jdo.PersistenceException;
  import org.exolab.castor.jdo.TransactionNotInProgressException;
  import org.exolab.castor.jdo.QueryException;
  import org.exolab.castor.jdo.OQLQuery;
  import org.exolab.castor.jdo.QueryResults;
  
  public class CastorQueryResultsTag extends BodyTagSupport implements IterationTag
  {
  	/***
  	* The name of this tag
  	*/
  	private static String _tagName = "CastorQueryResultsTag";
  	
  	/***
  	* The id by which we will refer to the Results object in the JSP page.
  	*/
  	private String id;
  	
  	/***
  	* The size of the results page
  	*/
  	private String size;
  	
  	/***
  	* The current page
  	*/
  	private String page;
  	
  	/***
  	* The name of a variable containing the current index of the loop
  	*/
  	private String indexId;
  	
  	/***
  	* These two booleans are to ensure 
  	* that paged results are set correctly
  	*/
  	private int _size = 0;
  	private int _page =0;
  	private boolean indexIdSet = false;
  	private boolean sizeSet = false;
  	private boolean pageSet = false;
  	private boolean pagedResults = false;
  	
  	/***
  	* For determining access mode
  	*/
  	private boolean accessModeSet = false;
  	private short _accessMode = Database.Shared;
  	private String accessMode = null;
  	
  	/***
  	* The castor objects we will need.
  	*/
  	private Database db = null;
  	private OQLQuery query = null;
  	private QueryResults results = null;
  	
  	int index = 0;
  
  	/***
  	* Sets the id by which this bean instance will be referred to in the page
  	*/
  	public void setId(String _id)
  	{
  		this.id = _id;
  	}
  
    	/***
     	* Sets the size
     	*/
    	public void setSize(String _size)
    	{
  		this.sizeSet = true;
      	this.size = _size;
    	}
  	
  
  	/***
  	* Sets current result page
  	*/
  	public void setPage(String _page)
  	{
  		this.pageSet = true;
  		this.page = _page;
 	}
 
   	/***
 	* Sets the name of the index int
 	*/
 	public void setIndexId(String _indexId)
 	{
 		this.indexIdSet = true;
 		this.indexId = _indexId;
 	}
 	
 	/***
 	* Sets the access mode string
 	*/
 	public void setAccessMode(String _accessModeStr)
 	{
 		this.accessModeSet = true;
 		this.accessMode = _accessModeStr;
 	}
 
 	
 	/***
    	* Do the start tag bit
    	*/
 	public int doStartTag() throws JspException
 	{
 		
 		try 
 		{	
 			/*** 
 			* Get the database from the enclosing transaction tag
 			* Throw an exception if outside one
 			*/
 			CastorTransactionInitiator t = (CastorTransactionInitiator)findAncestorWithClass(this, CastorTransactionInitiator.class);
 			if (t!=null) 
 			{
 				this.db = t.getDatabase();
 			}
 			else
 			{
 				String msg = "Tag not nested within a CastorTransactionTag.";
 				log(msg,null);
 				throw new Exception(msg);	
 			}
 			
 			/***
    			* Get the Oql query from the parent CastorOqlTag 
 			*/
 			CastorOqlTag parent = (CastorOqlTag)findAncestorWithClass(this, CastorOqlTag.class);
 			if (parent!=null)
 			{
 				query = parent.getOql();
 			}
 			else
 			{
 				String msg = "Tag must be used within CastorOqlTag.";
 				log(msg,null);
 				throw new Exception(msg);	
 			}
 			
 			/***
 			* Determine the accessmode
 			*/
 			if (this.accessModeSet)
 			{
 				if (this.accessMode.equals("DbLocked"))
 					this._accessMode = Database.DbLocked;
 				else if (this.accessMode.equals("Exclusive"))
 					this._accessMode = Database.Exclusive;
 				else if (this.accessMode.equals("Shared"))
 					this._accessMode = Database.Shared;
 				else if (this.accessMode.equals("ReadOnly"))
 					this._accessMode = Database.ReadOnly;
 				else
 				{
 					String msg = "Invalid Access Mode set.";
 					log(msg , null);
 					throw new JspTagException(msg);
 				}
 			}
 			
 			
 			/***
    			* Check whether results will be paged
 			*/
 			if (pageSet && sizeSet)
 				pagedResults=true;
 			else if (!pageSet && !sizeSet)
 				pagedResults=false;
 			else
 			{
 				String msg = "Both size and page must be set, or neither.";
 				log(msg , null);
 				throw new JspTagException(msg);
 			}
 			/***
    			* Evaluate expressions for page and size (in case EL values are used)
 			*/
 			if (pagedResults)
 			{
 				_page = ((Integer)ExpressionEvaluatorManager.evaluate("page",this.page, Integer.class, this, pageContext)).intValue();
 				_size = ((Integer)ExpressionEvaluatorManager.evaluate("size",this.size, Integer.class, this, pageContext)).intValue();
 			}
 			
 			
 			/***
    			* Execute the query
 			*/
 			results = query.execute(_accessMode);
 			
 		
 			/***
    			* Find out what part of the result set to display
    			*/
 			if (pagedResults)
 			{
 				if (this._page >1)
 				{
 					//we are on a later page so move to the relevent row in the result set
 					int currentRow = ((this._page - 1) * this._size);
 					results.absolute(currentRow);
 				}
 			}
 			
 			//ensure that index is initialised to zero
 			index=0;
 			
 			//perform the first iteration
 			if ((results.hasMore() && !pagedResults) 
 				|| (results.hasMore() && pagedResults && (index < this._size)))		
 			{
 				pageContext.setAttribute(this.id, results.next());
 				if (indexIdSet)
 					pageContext.setAttribute(this.indexId, new Integer(index));
 				//increment index
 				index++;
 				return EVAL_BODY_INCLUDE;
  			}
  			else 
 			{
 				//don't iterate, skip body
      			return SKIP_BODY;
  			}
 
 						
 		}
 		
 		catch(QueryException e)
 		{
 			log(e.getMessage() , e);
 			throw new JspTagException(e.getMessage());
 		}
 		catch(TransactionNotInProgressException e)
 		{
 			log(e.getMessage() , e);
 			throw new JspTagException(e.getMessage());
 		}
 		catch(PersistenceException e)
 		{
 			log(e.getMessage() , e);
 			throw new JspTagException(e.getMessage());
 		}
 		catch(Exception  e)
 		{
 			log(e.getMessage() , e);
 			throw new JspTagException(e.getMessage());
 		}
 	}
  	
 	public int doAfterBody() throws JspException
 	{
 		try 
 		{		
 	       if ((results.hasMore() && !pagedResults) 
 				|| (results.hasMore() && pagedResults && (index < this._size)))	
 			{
 	     		pageContext.setAttribute(this.id, results.next());
 				if (indexIdSet)
 					pageContext.setAttribute(this.indexId, new Integer(index));
 				//increment index
 				index++;	
 				return EVAL_BODY_AGAIN;
 			}
 			else 
 			{
 			 	return SKIP_BODY;
 			}
 		}
 		catch(Exception  e)
 		{
 			log(e.getMessage() , e);
 			throw new JspTagException(e.getMessage());
 		}
 		//return SKIP_BODY;
  	}
 
  	
 	public int doEndTag() throws JspException
 	{
 		return EVAL_PAGE;
 	}
 	
 	
  	
 	private void log(String msg,Exception e)
 	{	
 		if (e!=null)
 		{
 			System.err.println(_tagName + ": " + msg);
 			e.printStackTrace();
 		}
 		else
 		{
 			System.out.println(_tagName + ": " + msg);
 		}
 	}
 	
 	
 }