From ddfe3f54e46b3a00947b7e54876c7aba0eeb9025 Mon Sep 17 00:00:00 2001
From: gaohaoxiang <gaohaoxiang@jd.com>
Date: Tue, 26 Feb 2019 14:43:54 +0800
Subject: [PATCH] add cancel method for Future

---
 .../main/java/io/openmessaging/Future.java    | 23 +++++++++++++++++++
 1 file changed, 23 insertions(+)

diff --git a/openmessaging-api/src/main/java/io/openmessaging/Future.java b/openmessaging-api/src/main/java/io/openmessaging/Future.java
index b22ad541..e0973549 100644
--- a/openmessaging-api/src/main/java/io/openmessaging/Future.java
+++ b/openmessaging-api/src/main/java/io/openmessaging/Future.java
@@ -32,6 +32,29 @@
  * @since OMS 1.0.0
  */
 public interface Future<V> {
+    /**
+     * Attempts to cancel execution of this task.  This attempt will
+     * fail if the task has already completed, has already been cancelled,
+     * or could not be cancelled for some other reason. If successful,
+     * and this task has not started when {@code cancel} is called,
+     * this task should never run.  If the task has already started,
+     * then the {@code mayInterruptIfRunning} parameter determines
+     * whether the thread executing this task should be interrupted in
+     * an attempt to stop the task.
+     *
+     * <p>After this method returns, subsequent calls to {@link #isDone} will
+     * always return {@code true}.  Subsequent calls to {@link #isCancelled}
+     * will always return {@code true} if this method returned {@code true}.
+     *
+     * @param mayInterruptIfRunning {@code true} if the thread executing this
+     * task should be interrupted; otherwise, in-progress tasks are allowed
+     * to complete
+     * @return {@code false} if the task could not be cancelled,
+     * typically because it has already completed normally;
+     * {@code true} otherwise
+     */
+    boolean cancel(boolean mayInterruptIfRunning);
+
     /**
      * Returns {@code true} if this task was cancelled before it completed normally.
      *