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
if ( ( filePath == null ) || ( filePath.length( ) == 0 ) )
			return ""; 
		String sessionId = request.getSession( ).getId( );
		String fileSeparator = "\\"; 
		if ( filePath.lastIndexOf( fileSeparator ) == -1 )
			fileSeparator = "/"; 
		
		if ( filePath.lastIndexOf( fileSeparator ) != -1 )
		{
			documentName = filePath.substring( filePath
					.lastIndexOf( fileSeparator ) + 1 );
		}
		else
		{
			documentName = filePath;
		}
		String hashCode = Integer.toHexString( filePath.hashCode( ) );
		return documentFolder + File.separator + sessionId + File.separator
				+ hashCode + File.separator + documentName;
	}
	/**
	 * Clears the report document/image files which had been created last time
	 * the server starts up.
	 */
	protected static void clearTempFiles( )
	{
		
		File file = new File( documentFolder );
		deleteDir( file );
		makeDir( documentFolder );