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
{
			Map.Entry entry = (Map.Entry) entries.next( );
			List elementExceptions = ( (ElementExceptionInfo) entry.getValue( ) )
					.getErrorList( );
			errors.addAll( elementExceptions );
		}
		return errors;
	}
	/**
	 * @return the mAX_ERRORS
	 */
	public int getMaxErrors( )
	{
		return MAX_ERRORS;
	}
	
	/**
	 * @param max_errors the mAX_ERRORS to set
	 */
	public void setMaxErrors( int maxErrors )
	{
		MAX_ERRORS = maxErrors;
	}
	
	/**
	 *  to remember the current report item is in master page or not.
	 */
	boolean isExecutingMasterPage = false;
	
	/**