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
public static final String PREFIX_ISLOCALE = "__islocale__"; 
	/**
	 * URL parameter name to indicate the resource folder of all the report
	 * resources.
	 */
	public static final String PARAM_RESOURCE_FOLDER = "__resourceFolder"; 
	/**
	 * URL parameter name to indicate the target servlet pattern.
	 */
	public static final String PARAM_SERVLET_PATTERN = "__pattern"; 
	/**
	 * URL parameter name to indicate the target window.
	 */
	public static final String PARAM_TARGET = "__target"; 
	/**
	 * URL parameter name to indicate whether cache the parameter.
	 */
	public static final String PARAM_NOCACHE_PARAMETER = "__nocache"; 
	/**
	 * Custom request headers to identify the request is a normal HTTP request
	 * or a soap request by AJAX.
	 */
	public static final String HEADER_REQUEST_TYPE = "request-type"; 
	/**
	 * The request type of "soap".
	 */
	public static final String HEADER_REQUEST_TYPE_SOAP = "soap"; 
	/**
	 * Parameter name that gives the IID of the export data form.
	 */