Bug 123523 Previewing a scripted data set mapped to a java event handler throws NPE
When previewing a scripted data set we try to get a class loader from the ExecutionContext. (See ScriptExecutor.getClassUsingCustomClassPath). The context will be null in this case. The reason for using the context is to use cached class loaders when possible. Need to use some other mechanism to get the class loader if the context is null. We can either provide an external map to use as cache, or not bother with caching at all.
engine/org.eclipse.birt.report.engine/src/org/eclipse/birt/report/engine/executor/ExecutionContext.java
*/
	public IReportContent getReportContent( )
	{
		return reportContent;
	}
	public void setReportContent( IReportContent content )
	{
		this.reportContent = content;
		content.getErrors( ).addAll( onPrepareErrors );
	}
	/*
	 * (non-Javadoc)
	 * 
	 * @see org.eclipse.birt.report.engine.executor.IPrensentationContext#getParams()
	 */
	public Map getParams( )
	{
		return params;
	}
	/**
	 * Loads scripts that are stored in an external file. Used to support
	 * include-script. Each script file should be load only once. and the script
	 * in the file must be encoded in UTF-8.
	 * 
	 * @param fileName
	 *            script file name
	 */
	public void loadScript( String fileName )
	{
		ReportDesignHandle reportDesign = this.getDesign( );