Bug 177504 Engine doesn't provide SubQuery for extended item
Engine doesn't provide SubQuery for extended item, so chart can't use container's binding to execute the query. If possible, engine could provide an option for extended item to choose whether engine could create the query, so extended item won't create SubQuery by itself.
engine/org.eclipse.birt.report.engine/src/org/eclipse/birt/report/engine/extension/internal/ExtensionManager.java
{
		return formats.keySet();
	}
	
	/**
	 * return all emitter informations
	 * @return all emitter informations
	 */
	public EmitterInfo[] getEmitterInfo( )
	{
		EmitterInfo[] infos = new EmitterInfo[emitters.size( )];
		Object[] keys = emitters.keySet( ).toArray( );
		for ( int index = 0, length = keys.length; index < length; index++ )
		{
			infos[index] = (EmitterInfo) emitters.get( keys[index].toString( ) );
		}
		return infos;
	}
	
	/**
	 * @param config
	 * @param property 
	 * @return
	 */
	protected Object createObject(IConfigurationElement config, String property)
	{
		try
		{
			Object object = config.createExecutableExtension(property);
			if (object != null)