Bug 180842 Config memory buffer size in data engine execution.
To tuning the performance, it is necessary for DtE to expose API for clients to config the size of memory it used to store the final result set. A new AppContext string, "org.eclipse.birt.data.cache.memory.size" is proposed. The new appcontext entry only accept positive integer as input, the unit of which would be MB.
data/org.eclipse.birt.data/src/org/eclipse/birt/data/engine/impl/ServiceForQueryResults.java
}
	/*
	 * @see org.eclipse.birt.data.engine.impl.IServiceForQueryResults#getAllBindingExprs()
	 */
	public List getAllBindingExprs( )
	{
		return this.exprManager.getBindingExprs( );
	}
	/*
	 * @see org.eclipse.birt.data.engine.impl.IServiceForQueryResults#getAllAutoBindingExprs()
	 */
	public Map getAllAutoBindingExprs( )
	{
		return this.exprManager.getAutoBindingExprMap( );
	}
	
	/*
	 * @see org.eclipse.birt.data.engine.impl.IServiceForQueryResults#initAutoBinding()
	 */
	public void initAutoBinding( ) throws DataException
	{
		if ( needAutoBinding( ) == false )
			return;
		Context cx = Context.enter( );
		IResultMetaData metaData = getResultMetaData( );
		int columnCount = metaData.getColumnCount( );
		for ( int i = 0; i < columnCount; i++ )
		{
			int colIndex = i + 1;
			try