--- /dev/null Thu Jan 01 00:00:00 1970 +0000
+++ b/src/java.base/share/classes/java/util/TimerTask.java Tue Sep 12 19:03:39 2017 +0200
@@ -0,0 +1,162 @@
+/*
+ * Copyright (c) 1999, 2013, 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 java.util;
+
+/**
+ * A task that can be scheduled for one-time or repeated execution by a
+ * {@link Timer}.
+ *
+ * <p>A timer task is <em>not</em> reusable. Once a task has been scheduled
+ * for execution on a {@code Timer} or cancelled, subsequent attempts to
+ * schedule it for execution will throw {@code IllegalStateException}.
+ *
+ * @author Josh Bloch
+ * @since 1.3
+ */
+
+public abstract class TimerTask implements Runnable {
+ /**
+ * This object is used to control access to the TimerTask internals.
+ */
+ final Object lock = new Object();
+
+ /**
+ * The state of this task, chosen from the constants below.
+ */
+ int state = VIRGIN;
+
+ /**
+ * This task has not yet been scheduled.
+ */
+ static final int VIRGIN = 0;
+
+ /**
+ * This task is scheduled for execution. If it is a non-repeating task,
+ * it has not yet been executed.
+ */
+ static final int SCHEDULED = 1;
+
+ /**
+ * This non-repeating task has already executed (or is currently
+ * executing) and has not been cancelled.
+ */
+ static final int EXECUTED = 2;
+
+ /**
+ * This task has been cancelled (with a call to TimerTask.cancel).
+ */
+ static final int CANCELLED = 3;
+
+ /**
+ * Next execution time for this task in the format returned by
+ * System.currentTimeMillis, assuming this task is scheduled for execution.
+ * For repeating tasks, this field is updated prior to each task execution.
+ */
+ long nextExecutionTime;
+
+ /**
+ * Period in milliseconds for repeating tasks. A positive value indicates
+ * fixed-rate execution. A negative value indicates fixed-delay execution.
+ * A value of 0 indicates a non-repeating task.
+ */
+ long period = 0;
+
+ /**
+ * Creates a new timer task.
+ */
+ protected TimerTask() {
+ }
+
+ /**
+ * The action to be performed by this timer task.
+ */
+ public abstract void run();
+
+ /**
+ * Cancels this timer task. If the task has been scheduled for one-time
+ * execution and has not yet run, or has not yet been scheduled, it will
+ * never run. If the task has been scheduled for repeated execution, it
+ * will never run again. (If the task is running when this call occurs,
+ * the task will run to completion, but will never run again.)
+ *
+ * <p>Note that calling this method from within the {@code run} method of
+ * a repeating timer task absolutely guarantees that the timer task will
+ * not run again.
+ *
+ * <p>This method may be called repeatedly; the second and subsequent
+ * calls have no effect.
+ *
+ * @return true if this task is scheduled for one-time execution and has
+ * not yet run, or this task is scheduled for repeated execution.
+ * Returns false if the task was scheduled for one-time execution
+ * and has already run, or if the task was never scheduled, or if
+ * the task was already cancelled. (Loosely speaking, this method
+ * returns {@code true} if it prevents one or more scheduled
+ * executions from taking place.)
+ */
+ public boolean cancel() {
+ synchronized(lock) {
+ boolean result = (state == SCHEDULED);
+ state = CANCELLED;
+ return result;
+ }
+ }
+
+ /**
+ * Returns the <i>scheduled</i> execution time of the most recent
+ * <i>actual</i> execution of this task. (If this method is invoked
+ * while task execution is in progress, the return value is the scheduled
+ * execution time of the ongoing task execution.)
+ *
+ * <p>This method is typically invoked from within a task's run method, to
+ * determine whether the current execution of the task is sufficiently
+ * timely to warrant performing the scheduled activity:
+ * <pre>{@code
+ * public void run() {
+ * if (System.currentTimeMillis() - scheduledExecutionTime() >=
+ * MAX_TARDINESS)
+ * return; // Too late; skip this execution.
+ * // Perform the task
+ * }
+ * }</pre>
+ * This method is typically <i>not</i> used in conjunction with
+ * <i>fixed-delay execution</i> repeating tasks, as their scheduled
+ * execution times are allowed to drift over time, and so are not terribly
+ * significant.
+ *
+ * @return the time at which the most recent execution of this task was
+ * scheduled to occur, in the format returned by Date.getTime().
+ * The return value is undefined if the task has yet to commence
+ * its first execution.
+ * @see Date#getTime()
+ */
+ public long scheduledExecutionTime() {
+ synchronized(lock) {
+ return (period < 0 ? nextExecutionTime + period
+ : nextExecutionTime - period);
+ }
+ }
+}