protected function isOutputExpired() {
		if ($this->inputFiles->isEmpty()) {
			throw new OperationError('Nothing to assemble, you should add at least one item');
		}
		
		if (! is_file($this->outputFile)) {
			return true;
		}
		
		$outputMtime = $this->getFileMTime($this->outputFile);
		
		foreach ($this->inputFiles as $path) {
			if ($outputMtime < $this->getFileMTime($path)) {
				return true;
			}
		}
		
		return false;
	}
protected function isOutputExpired() {
		if ($this->inputFiles->isEmpty()) {
			throw new OperationError('Nothing to assemble, you should add at least one item');
		}
		
		if (! is_file($this->outputFile)) {
			return true;
		}
		
		$outputMtime = $this->getFileMTime($this->outputFile);
		
		foreach ($this->inputFiles as $path) {
			if ($outputMtime < $this->getFileMTime($path)) {
				return true;
			}
		}
		
		return false;
	}
protected function isOutputExpired ( ) { if ( $ this -> inputFiles -> isEmpty ( ) ) { throw new OperationError ( 'Nothing to assemble, you should add at least one item' ) ; } if ( ! is_file ( $ this -> outputFile ) ) { return true ; } $ outputMtime = $ this -> getFileMTime ( $ this -> outputFile ) ; foreach ( $ this -> inputFiles as $ path ) { if ( $ outputMtime < $ this -> getFileMTime ( $ path ) ) { return true ; } } return false ; }
Is output file expired ?

@return bool
@throws OperationError
Is output file expired ?