1 /*

     2  * Copyright (c) 2019, Oracle and/or its affiliates. All rights reserved.

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

     4  *

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

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

     7  * published by the Free Software Foundation.

     8  *

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

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

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

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

    13  * accompanied this code).

    14  *

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

    16  * 2 along with this work; if not, write to the Free Software Foundation,

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

    18  *

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

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

    21  * questions.

    22  */

    23 

    24 package org.reactivestreams;

    25 

    26 /**

    27  * A {@link Publisher} is a provider of a potentially unbounded number of sequenced elements, publishing them according to

    28  * the demand received from its {@link Subscriber}(s).

    29  * <p>

    30  * A {@link Publisher} can serve multiple {@link Subscriber}s subscribed {@link #subscribe(Subscriber)} dynamically

    31  * at various points in time.

    32  *

    33  * @param <T> the type of element signaled.

    34  */

    35 public interface Publisher<T> {

    36 

    37     /**

    38      * Request {@link Publisher} to start streaming data.

    39      * <p>

    40      * This is a "factory method" and can be called multiple times, each time starting a new {@link Subscription}.

    41      * <p>

    42      * Each {@link Subscription} will work for only a single {@link Subscriber}.

    43      * <p>

    44      * A {@link Subscriber} should only subscribe once to a single {@link Publisher}.

    45      * <p>

    46      * If the {@link Publisher} rejects the subscription attempt or otherwise fails it will

    47      * signal the error via {@link Subscriber#onError}.

    48      *

    49      * @param s the {@link Subscriber} that will consume signals from this {@link Publisher}

    50      */

    51     public void subscribe(Subscriber<? super T> s);

    52 }