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
Set entries = params.entrySet( );
		Iterator iterator = entries.iterator( );
		while ( iterator.hasNext( ) )
		{
			Map.Entry entry = (Map.Entry) iterator.next( );
			ParameterAttribute parameter = (ParameterAttribute) entry
					.getValue( );
			result.put( entry.getKey( ), parameter.getValue( ) );
		}
		return result;
	}
	public String getParameterDisplayText( String name )
	{
		Object parameter = params.get( name );
		if ( parameter != null )
		{
			return ( (ParameterAttribute) parameter ).getDisplayText( );
		}
		return null;		
	}
	
	public void setParameterDisplayText( String name, String displayText )
	{
		Object parameter = params.get( name );
		if ( parameter != null )
		{
			( (ParameterAttribute) parameter ).setDisplayText( displayText );
		}
	}
	/*