/*

 * Copyright (c)  2017, 2018, Oracle and/or its affiliates. All rights reserved.

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

 *

 * This code is free software; you can redistribute it and/or modify it

 * under the terms of the GNU General Public License version 2 only, as

 * 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.

 *

 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA

 * or visit www.oracle.com if you need additional information or have any

 * questions.

 */

package jdk.incubator.sql2;

import java.time.Duration;

import java.util.function.Consumer;

/**

 * A description of some work to be done by the database and how to process the

 * database output. An {@link Operation} is created by an

 * {@link OperationGroup}, configured and submitted. If not submitted it is not

 * executed. If submitted it is possibly executed according to the attributes of

 * the {@link OperationGroup} that created it.

 * 

 * <p>

 * If execution of the work results in an error, the Operation is completed

 * exceptionally. The {@link Throwable} that completes the Operation is

 * implementation dependent. It is recommended that an implementation use

 * SqlException in the event of database problems. Other {@link Throwable}s such

 * as {@link java.io.IOException}, {@link NullPointerException}, etc can be used

 * as appropriate. An implementation should not wrap a useful exception in a

 * {@link SqlException} unless that provides valuable additional information. An

 * implementation should use whatever {@link Throwable} best facilitates

 * appropriate error handling.</p>

 * 

 * <p>

 * An Operation is not required to be thread safe. In general a single user

 * thread will configure and submit an Operation. Once an Operation is submitted

 * it is immutable. {@link OperationGroup} is an exception and is thread safe.</p>

 *

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

 */

public interface Operation<T> extends PrimitiveOperation<T> {

  /**

   * Provides an error handler for this {@link Operation}. If execution of this

   * {@link Operation} results in an error, before the Operation is completed,

   * the handler is called with the {@link Throwable} as the argument. The type

   * of the {@link Throwable} is implementation dependent.

   * 

   * @param handler

   * @return this {@link Operation}

   * @throws IllegalStateException if this method is called more than once on

   * this operation

   */

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

  /**

   * The minimum time before this {@link Operation} might be canceled

   * automatically. The default value is forever. The time is

   * counted from the beginning of Operation execution. The Operation will not

   * be canceled before {@code minTime} after the beginning of execution.

   * Some time at least {@code minTime} after the beginning of execution,

   * an attempt will be made to cancel the {@link Operation} if it has not yet

   * completed. Implementations are encouraged to attempt to cancel within a

   * reasonable time, though what is reasonable is implementation dependent.

   *

   * @param minTime minimum time to wait before attempting to cancel

   * @return this Operation

   * @throws IllegalArgumentException if minTime <= {@link java.time.Duration#ZERO}

   * @throws IllegalStateException if this method is called more than once on

   * this operation

   */

  public Operation<T> timeout(Duration minTime);

}