
/*******************************************************************************
 * Copyright (c) 2004, 2005 Actuate Corporation.
 * All rights reserved. This program and the accompanying materials
 * are made available under the terms of the Eclipse Public License v1.0
 * which accompanies this distribution, and is available at
 * http://www.eclipse.org/legal/epl-v10.html
 *
 * Contributors:
 *  Actuate Corporation  - initial API and implementation
 *******************************************************************************/
package org.eclipse.birt.data.engine.impl.document.stream;

import java.io.DataInputStream;
import java.io.IOException;
import java.util.HashMap;

import org.eclipse.birt.core.archive.RAInputStream;
import org.eclipse.birt.data.engine.api.DataEngineContext;
import org.eclipse.birt.data.engine.core.DataException;
import org.eclipse.birt.data.engine.i18n.ResourceConstants;

/**
 * 
 */

public class DataStreamReader extends StreamReader
{

	/**
	 * 
	 * @param context
	 * @param id
	 * @throws DataException
	 */
	public DataStreamReader( DataEngineContext context, StreamID id ) throws DataException
	{
		try
		{
			this.streamMap = new HashMap();
			this.id = id;
			this.context = context;
			RAInputStream is = context.getInputStream( id.getStartStream( ),
					id.getSubQueryStream( ),
					DataEngineContext.DATASET_DATA_STREAM );
			
			DataInputStream metaIndexStream = new DataInputStream( is );
			
			
			
			int type = is.readInt( );
			int size = is.readInt( );
			long offset = is.getOffset( );
			this.streamMap.put( new Integer( type ),
					new WrapperedRAInputStream( (RAInputStream)context.getInputStream( id.getStartStream( ),
							id.getSubQueryStream( ),
							DataEngineContext.DATASET_DATA_STREAM ),offset,size) );
			metaIndexStream.close( );
			
		}
		catch ( IOException e )
		{
			throw new DataException( e.getLocalizedMessage( ) );
		}
	}

	/*
	 * (non-Javadoc)
	 * @see org.eclipse.birt.data.engine.impl.document.stream.StreamReader#getRAInputStream(int)
	 */
	public RAInputStream getRAInputStream( int streamType )
			throws DataException
	{
		Object temp = this.streamMap.get( new Integer( streamType ) );
		if( temp == null )
		{
			throw new DataException( ResourceConstants.DOCUMENT_ERROR_CANNOT_LOAD_STREAM,
					DataEngineContext.getPath( id.getStartStream( ),
							id.getSubQueryStream( ),
							streamType ) );
		}
		else
		{
			return (RAInputStream)temp;

		}
	}

}
