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<?php |
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declare( strict_types = 1 ); |
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namespace BatchingIterator\Fetchers; |
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use BatchingIterator\BatchingFetcher; |
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use InvalidArgumentException; |
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/** |
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* A fetcher that sequentially fetches values from its child fetchers. |
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* Comparable to @see MultipleIterator |
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* |
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* Recursion might be used over the fetchers. So a big amount of fetchers |
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* can cause the stack to be blown. |
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* |
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* @since 2.0 |
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* |
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* @licence GNU GPL v2+ |
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* @author Jeroen De Dauw < [email protected] > |
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*/ |
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class MultipleBatchingFetcher implements BatchingFetcher { |
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/** |
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* @var BatchingFetcher[] |
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*/ |
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private $fetchers; |
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/** |
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* @param BatchingFetcher|BatchingFetcher[] $firstFetcher |
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* @param BatchingFetcher ... |
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* |
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* @throws InvalidArgumentException |
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*/ |
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public function __construct( $firstFetcher ) { |
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if ( is_array( $firstFetcher ) ) { |
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if ( func_num_args() !== 1 ) { |
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throw new InvalidArgumentException( 'When providing an array of BatchingFetcher, no further arguments are accepted' ); |
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} |
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$this->attachFetchers( $firstFetcher ); |
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} |
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else { |
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$this->attachFetchers( func_get_args() ); |
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} |
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} |
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private function attachFetchers( array $fetchers ) { |
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foreach ( $fetchers as $fetcher ) { |
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if ( !( $fetcher instanceof BatchingFetcher ) ) { |
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throw new InvalidArgumentException( 'All constructor arguments should implement BatchingFetcher' ); |
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} |
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$this->attachFetcher( $fetcher ); |
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} |
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} |
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private function attachFetcher( BatchingFetcher $fetcher ) { |
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$this->fetchers[] = $fetcher; |
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} |
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/** |
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* @see BatchingFetcher::fetchNext |
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* |
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* @param int $maxFetchCount |
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* |
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* @return mixed[] |
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*/ |
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public function fetchNext( int $maxFetchCount ): array { |
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if ( key( $this->fetchers ) === null ) { |
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return []; |
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} |
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/** |
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* @var BatchingFetcher $fetcher |
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*/ |
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$fetcher = current( $this->fetchers ); |
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$results = $fetcher->fetchNext( $maxFetchCount ); |
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if ( !empty( $results ) ) { |
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return $results; |
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} |
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next( $this->fetchers ); |
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return $this->fetchNext( $maxFetchCount ); |
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} |
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/** |
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* @see BatchingFetcher::rewind |
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*/ |
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public function rewind() { |
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foreach ( $this->fetchers as $fetcher ) { |
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$fetcher->rewind(); |
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} |
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reset( $this->fetchers ); |
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} |
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} |
JeroenDeDauw /
BatchingIterator
