Bug 165278 this.getDisplayContent()="" in script of text will destroy preview[0801]
Description: this.getDisplayContent()="" in script of text will destroy preview Build number:2.1.2.v20061120 and 2.2.0.v20061117 Steps to reproduce: 1. Insert a text item, select it and switch to script editor 2. Input this.getDisplayContent()="" and preview Expected result: Error message about the incorrect script. Actual result: In 2.1.2, I saw HTTP Status 500 - type Exception report message description The server encountered an internal error () that prevented it from fulfilling this request. In 2.2.0, I saw error dialog with java.lang.ClassCastException.
engine/org.eclipse.birt.report.engine/src/org/eclipse/birt/report/engine/executor/ExecutionContext.java
{
			HashMap emitterConfigs = config.getEmitterConfigs( );
			if ( emitterConfigs != null )
			{
				Object htmlEmitterConfig = emitterConfigs.get( "html" );
				if ( htmlEmitterConfig instanceof HTMLEmitterConfig )
				{
					HTMLEmitterConfig htmlConfig = (HTMLEmitterConfig) htmlEmitterConfig;
					return htmlConfig.getActionHandler( );
				}
			}
		}
		return null;
	}
	
	/**
	 * @return Returns the action handler.
	 */
	public IHTMLImageHandler getImageHandler( )
	{
		EngineConfig config = engine.getConfig( );
		if ( config != null )
		{
			HashMap emitterConfigs = config.getEmitterConfigs( );
			if ( emitterConfigs != null )
			{
				Object htmlEmitterConfig = emitterConfigs.get( "html" );
				if ( htmlEmitterConfig instanceof HTMLEmitterConfig )
				{
					HTMLEmitterConfig htmlConfig = (HTMLEmitterConfig) htmlEmitterConfig;