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
}
	/**
	 * convert path from System Properties Definition. For example:
	 * ${java.io.tmpdir}
	 * 
	 * @param path
	 * @return
	 */
	protected static String convertSystemPath( String path )
	{
		
		Pattern p = Pattern.compile( "\\$\\s*\\{([^\\}]*)\\}\\s*(.*)", 
				Pattern.CASE_INSENSITIVE );
		Matcher m = p.matcher( path );
		if ( m.find( ) )
		{
			String sysPath = trimSep( System.getProperty( m.group( 1 ).trim( ) ) );
			return DataUtil.trimString( sysPath ) + m.group( 2 ).trim( );
		}
		return path;
	}
	/**
	 * Process working folder setting. If path is a relative path, first
	 * relative to context.
	 * 
	 * @param context
	 * @param path
	 * @return
	 */
	public static String processWorkingFolder( ServletContext context,