question: public boolean isModified ( ) { synchronized ( this ) { if ( _isChecking || _isModified ) { return _isModified ; } _isChecking = true ; } try { long now ; now = CurrentTime . currentTime ( ) ; if ( now < _lastCheckTime + _checkInterval ) return _isModified ; _lastCheckTime = now ; for ( int i = _dependencyList . size ( ) - 1 ; i >= 0 ; i -- ) { Dependency dependency = _dependencyList . get ( i ) ; if ( dependency . isModified ( ) ) { dependency . logModified ( log ( ) ) ; _isModified = true ; return _isModified ; } } return _isModified ; } finally { _isChecking = false ; } }
target:  Returns true if the underlying dependencies have changed.