question: public CacheObject load ( Object key ) { if ( key != null ) { String dtedFramePath = key . toString ( ) ; DTEDSubframedFrame frame = new DTEDSubframedFrame ( dtedFramePath , dtedFramePath . endsWith ( "dt0" ) ) ; frame . initSubframes ( numXSubframes , numYSubframes ) ; if ( frame . frame_is_valid ) { return new DTEDCacheObject ( dtedFramePath , frame ) ; } } return null ; }
target:  Load a dted frame into the cache, based on the path of the frame as a key.