Bug 173836 NPE was thrown when click "Preview " button quickly twice[00]
NPE was thrown when click "Preview " button quickly twice[00] Build number: 2.2.0.v20070212-0630 Steps to reproduce: 1.open attached report 2.click "Preview" button quickly twice Expected result: Report can be previewed properly Actual result: NPE was thrown in second preview Error log: see screen shot
viewer/org.eclipse.birt.report.viewer/birt/WEB-INF/classes/org/eclipse/birt/report/context/BaseAttributeBean.java
{
	/**
	 * Identify the incoming request category.
	 */
	protected String category;
	/**
	 * Need to store the exception.
	 */
	protected Exception exception = null;
	/**
	 * Get report parameters passed in by URL.
	 */
	protected HashMap parameters = null;
	/**
	 * Whether missing parameters.
	 */
	protected boolean missingParameter = false;
	/**
	 * scalar parameter bean.
	 */
	protected ParameterAttributeBean parameterBean = null;
	/**
	 * Viewer report design handle
	 */
	protected IViewerReportDesignHandle reportDesignHandle = null;