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 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.

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 * published by the Free Software Foundation.  Oracle designates this

 * particular file as subject to the "Classpath" exception as provided

 * by Oracle in the LICENSE file that accompanied this code.

 * 

 * This code is distributed in the hope that it will be useful, but WITHOUT

 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or

 * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License

 * version 2 for more details (a copy is included in the LICENSE file that

 * accompanied this code).

 * 

 * You should have received a copy of the GNU General Public License version

 * 2 along with this work; if not, write to the Free Software Foundation,

 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.

 * 

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package jdk.incubator.sql2;

import java.time.Duration;

import java.util.concurrent.CompletionStage;

import java.util.function.BiConsumer;

import java.util.function.Consumer;

import java.util.function.Function;

/**

 * A multi-operation is an {@link Operation} that returns one or more results in

 * addition to the out result defined by the {@link Operation}. Each result is

 * processed by an {@link Operation}. The {@link Operation}s can be created by

 * calling

 * or {@link MultiOperation#rowCountOperation} if the kind of results is known.

 * These results are processed in the order the {@link Operation}s are

 * submitted. Any results not processed by an explicit {@link Operation} is

 * processed by calling the appropriate handler specified by

 * {@link MultiOperation#onRows} or {@link MultiOperation#onCount}. If any

 * result is an error that error is processed by calling the handler specified

 * by {@link Operation#onError} of the corresponding {@link Operation}. If the

 * appropriate handler is not specified that result is ignored, including

 * errors.

 *

 * ISSUE: Should this have a collector?

 *

 * @param <T> The type of the result of this {@link Operation}

 */

public interface MultiOperation<T> extends OutOperation<T> {

  /**

   * Returns a {@link RowOperation} to process a row sequence result. The

   * {@link Operation}s are executed in the order they are submitted. If a

   * result is of the wrong type for the next submitted {@link Operation} the

   * {@code MultiOperation} is completed with {@link IllegalStateException}.

   *

   * @return a {@link RowOperation} that is part of this {@code MultiOperation}

   */

  public RowOperation<T> rowOperation();

  /**

   * Returns a {@link RowPublisherOperation} to process a row sequence result.

   * The {@link Operation}s are executed in the order they are submitted. If a

   * result is of the wrong type for the next submitted {@link Operation} the

   * {@code MultiOperation} is completed with {@link IllegalStateException}.

   *

   * @return a {@link RowPublisherOperation} that is part of this

   * {@code MultiOperation}

   */

  public RowPublisherOperation<T> rowPublisherOperation();

  /**

   * Returns a {@link RowCountOperation} to process a count result. The

   * {@link Operation}s are executed in the order they are submitted. If a

   * result is of the wrong type for the next submitted Operation the

   * {@code MultiOperation} is completed with {@link IllegalStateException}.

   *

   * @return a {@link RowCountOperation} that is part of this

   * {@code MultiOperation}

   */

  public RowCountOperation<T> rowCountOperation();

  /**

   * Provides a handler for trailing count results. The provided handler is

   * called for each count result not processed by RowCountOperation. When

   * called the first argument is the number of results that preceeded the

   * current result. The second argument is a {@link RowCountOperation} that

   * will process the current result. This {@link RowCountOperation} has not

   * been configured in any way nor has it been submitted. The handler

   * configures the {@link RowCountOperation} and submits it. The count result

   * is processed when the {@link RowCountOperation} is submitted. If the

   * {@link RowCountOperation} is not submitted when the handler returns the

   * count result is ignored.

   *

   * If this method is not called any trailing count results are ignored.

   *

   * @param handler not null

   * @return this {@code MultiOperation}

   * @throws IllegalStateException if this method was called previously

   */

  public MultiOperation<T> onCount(BiConsumer<Integer, RowCountOperation<T>> handler);

  /**

   * Provides a handler for trailing row sequence results. The provided handler

   * is called for each row sequence result not processed by a RowOperation.

   * When called the first argument is the number of results that preceeded the

   * current result. The second argument is a {@link RowOperation} that will

   * process the current result. This {@link RowOperation} has not been

   * configured in any way nor has it been submitted. The handler configures the

   * {@link RowOperation} and submits it. The row sequence result is processed

   * when the {@link RowOperation} is submitted. If the {@link RowOperation} is

   * not submitted when the handler returns, the row sequence result is ignored.

   *

   * If this method is not called any trailing row sequence results are ignored.

   *

   * ISSUE: Should there be a version of this method that provides

   * RowProcessorOperations? If so only one of that method or this one can be

   * called.

   *

   * @param handler

   * @return This {@code MultiOperation}

   * @throws IllegalStateException if this method was called previously

   */

  public MultiOperation<T> onRows(BiConsumer<Integer, RowOperation<T>> handler);

  /**

   * Provides an error handler for this {@link Operation}. The provided handler

   * is called for each error that occurs. When called the first argument is the

   * number of results, including errors, that preceeded the current error. The

   * second argument is a {@link Throwable} corresponding to the error. When the

   * handler returns processing of the {@code MultiOperation} results continues. Only

   * one onError method may be called.

   *

   * @param handler a BiConsumer that handles an error

   * @return this {@code MultiOperation}

   * @throws IllegalStateException if this method or

   * {@link MultiOperation#onError(java.util.function.Consumer)} was called

   * previously

   */

  public MultiOperation<T> onError(BiConsumer<Integer, Throwable> handler);

  // Covariant overrides

  /**

   * This handler is called if the execution fails completely. If the execution

   * returns any individual results, even if any or all of those results are

   * errors, this handler is not called.

   *

   * {@inheritDoc}

   *

   * @return this {@code MultiOperation}

   */

  @Override

  public MultiOperation<T> onError(Consumer<Throwable> handler);

  /**

   * {@inheritDoc}

   *

   * @return this {@code MultiOperation}

   */

  @Override

  public MultiOperation<T> apply(Function<Result.OutColumn, ? extends T> processor);

  /**

   * {@inheritDoc}

   *

   * @return this {@code MultiOperation}

   */

  @Override

  public MultiOperation<T> outParameter(String id, SqlType type);

  /**

   * {@inheritDoc}

   *

   * @return this {@code MultiOperation}

   */

  @Override

  public MultiOperation<T> set(String id, Object value, SqlType type);

  /**

   * {@inheritDoc}

   *

   * @return this {@code MultiOperation}

   */

  @Override

  public MultiOperation<T> set(String id, Object value);

  /**

   * {@inheritDoc}

   *

   * @return this {@code MultiOperation}

   */

  @Override

  public MultiOperation<T> set(String id, CompletionStage<?> source, SqlType type);

  /**

   * {@inheritDoc}

   *

   * @return this {@code MultiOperation}

   */

  @Override

  public MultiOperation<T> set(String id, CompletionStage<?> source);

  /**

   * {@inheritDoc}

   *

   * @return this {@code MultiOperation}

   */

  @Override

  public MultiOperation<T> timeout(Duration minTime);

}