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
if ( design != null )
		{
			handle = design.getHandle( );
		}
		addException( handle, ex );
	}
	protected HashMap elementExceptions = new HashMap( );
	public void addException( DesignElementHandle element, BirtException ex )
	{
		ElementExceptionInfo exInfo = (ElementExceptionInfo) elementExceptions
				.get( element );
		if ( exInfo == null )
		{
			exInfo = new ElementExceptionInfo( element );
			if ( reportContent != null )
				reportContent.getErrors( ).add( exInfo );
			else
				onPrepareErrors.add( exInfo );
			elementExceptions.put( element, exInfo );
		}
		exInfo.addException( ex );
	}
	/**
	 * report object is the script object used in the script context.
	 * 
	 * All infos can get from this object.
	 * 
	 * 
	 */
	private class ReportObject