Bug 176681 Issue about creating context-parameter path in read-only path[0601]
Description: Issue about creating context-parameter path in read-only path Build number:2.2.0.v20070308 Steps to reproduce: 1. Deploy birt. 2. Set BIRT_VIEWER_DOCUMENT_FOLDER/BIRT_VIEWER_IMAGE_DIR/.. to a read-only path. 3. Preview report. Expected result: Because the path is read-only, folders should be created in ${java.io.tmpdir} Actual result: No folders are created in ${java.io.tmpdir} and reports cannot be previewed in frameset mode.
viewer/org.eclipse.birt.report.viewer/birt/WEB-INF/classes/org/eclipse/birt/report/utility/ParameterAccessor.java
assert request != null && name != null;
		boolean isExist = false;
		Map paramMap = request.getParameterMap( );
		String ISOName = toISOString( name );
		if ( paramMap != null && paramMap.containsKey( ISOName ) )
		{
			isExist = true;
		}
		Set nullParams = getParameterValues( request, PARAM_ISNULL );
		if ( nullParams != null && nullParams.contains( name ) )
		{
			isExist = true;
		}
		return isExist;
	}
	/**
	 * If set isWorkingFolderAccessOnly as true, check the file if exist in
	 * working folder.
	 * 
	 * @param filePath
	 * @return boolean
	 */
	public static boolean isValidFilePath( String filePath )
	{
		if ( filePath == null )
			return false;
		if ( isWorkingFolderAccessOnly )
		{
			File docFile = new File( filePath );
			if ( !docFile.isAbsolute( ) )