Bug 173582 Run servlet should not be affected by values in document.[0000]
viewer/org.eclipse.birt.report.viewer/birt/WEB-INF/classes/org/eclipse/birt/report/utility/ParameterAccessor.java
* @return
	 */
	public static String processRealPath( ServletContext context, String path,
			String defaultPath, boolean canWrite )
	{
		String realPath = null;
		
		if ( path == null || path.trim( ).length( ) <= 0 )
		{
			path = DataUtil.trimString( defaultPath );
		}
		
		if ( isRelativePath( path ) )
		{
			if ( !path.startsWith( "/" ) ) 
				path = "/" + path; 
			realPath = getRealPath( path, context );
			if ( realPath != null && makeDir( realPath ) )
			{
				if ( !canWrite )
					return trimSep( realPath );
				
				try
				{
					if ( canWrite && new File( realPath ).canWrite( ) )
						return trimSep( realPath );
				}
				catch ( Exception e )
				{
				}