question: public boolean logModified ( Logger log ) { if ( _isDigestModified ) { log . info ( _source . getNativePath ( ) + " digest is modified." ) ; return true ; } long sourceLastModified = _source . getLastModified ( ) ; long sourceLength = _source . length ( ) ; if ( ! _requireSource && sourceLastModified == 0 ) { return false ; } else if ( sourceLength != _length ) { log . info ( _source . getNativePath ( ) + " length is modified (" + _length + " -> " + sourceLength + ")" ) ; return true ; } else if ( sourceLastModified != _lastModified ) { log . info ( _source . getNativePath ( ) + " time is modified." ) ; return true ; } else return false ; }
target:  Log the reason for modification