1.1 --- /dev/null Thu Jan 01 00:00:00 1970 +0000
1.2 +++ b/rt/emul/compact/src/main/java/java/util/TimerTask.java Sat Nov 02 16:40:37 2013 +0100
1.3 @@ -0,0 +1,158 @@
1.4 +/*
1.5 + * Copyright (c) 1999, 2004, Oracle and/or its affiliates. All rights reserved.
1.6 + * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
1.7 + *
1.8 + * This code is free software; you can redistribute it and/or modify it
1.9 + * under the terms of the GNU General Public License version 2 only, as
1.10 + * published by the Free Software Foundation. Oracle designates this
1.11 + * particular file as subject to the "Classpath" exception as provided
1.12 + * by Oracle in the LICENSE file that accompanied this code.
1.13 + *
1.14 + * This code is distributed in the hope that it will be useful, but WITHOUT
1.15 + * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
1.16 + * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
1.17 + * version 2 for more details (a copy is included in the LICENSE file that
1.18 + * accompanied this code).
1.19 + *
1.20 + * You should have received a copy of the GNU General Public License version
1.21 + * 2 along with this work; if not, write to the Free Software Foundation,
1.22 + * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
1.23 + *
1.24 + * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
1.25 + * or visit www.oracle.com if you need additional information or have any
1.26 + * questions.
1.27 + */
1.28 +
1.29 +package java.util;
1.30 +
1.31 +/**
1.32 + * A task that can be scheduled for one-time or repeated execution by a Timer.
1.33 + *
1.34 + * @author Josh Bloch
1.35 + * @see Timer
1.36 + * @since 1.3
1.37 + */
1.38 +
1.39 +public abstract class TimerTask implements Runnable {
1.40 + /**
1.41 + * This object is used to control access to the TimerTask internals.
1.42 + */
1.43 + final Object lock = new Object();
1.44 +
1.45 + /**
1.46 + * The state of this task, chosen from the constants below.
1.47 + */
1.48 + int state = VIRGIN;
1.49 +
1.50 + /**
1.51 + * This task has not yet been scheduled.
1.52 + */
1.53 + static final int VIRGIN = 0;
1.54 +
1.55 + /**
1.56 + * This task is scheduled for execution. If it is a non-repeating task,
1.57 + * it has not yet been executed.
1.58 + */
1.59 + static final int SCHEDULED = 1;
1.60 +
1.61 + /**
1.62 + * This non-repeating task has already executed (or is currently
1.63 + * executing) and has not been cancelled.
1.64 + */
1.65 + static final int EXECUTED = 2;
1.66 +
1.67 + /**
1.68 + * This task has been cancelled (with a call to TimerTask.cancel).
1.69 + */
1.70 + static final int CANCELLED = 3;
1.71 +
1.72 + /**
1.73 + * Next execution time for this task in the format returned by
1.74 + * System.currentTimeMillis, assuming this task is scheduled for execution.
1.75 + * For repeating tasks, this field is updated prior to each task execution.
1.76 + */
1.77 + long nextExecutionTime;
1.78 +
1.79 + /**
1.80 + * Period in milliseconds for repeating tasks. A positive value indicates
1.81 + * fixed-rate execution. A negative value indicates fixed-delay execution.
1.82 + * A value of 0 indicates a non-repeating task.
1.83 + */
1.84 + long period = 0;
1.85 +
1.86 + /**
1.87 + * Creates a new timer task.
1.88 + */
1.89 + protected TimerTask() {
1.90 + }
1.91 +
1.92 + /**
1.93 + * The action to be performed by this timer task.
1.94 + */
1.95 + public abstract void run();
1.96 +
1.97 + /**
1.98 + * Cancels this timer task. If the task has been scheduled for one-time
1.99 + * execution and has not yet run, or has not yet been scheduled, it will
1.100 + * never run. If the task has been scheduled for repeated execution, it
1.101 + * will never run again. (If the task is running when this call occurs,
1.102 + * the task will run to completion, but will never run again.)
1.103 + *
1.104 + * <p>Note that calling this method from within the <tt>run</tt> method of
1.105 + * a repeating timer task absolutely guarantees that the timer task will
1.106 + * not run again.
1.107 + *
1.108 + * <p>This method may be called repeatedly; the second and subsequent
1.109 + * calls have no effect.
1.110 + *
1.111 + * @return true if this task is scheduled for one-time execution and has
1.112 + * not yet run, or this task is scheduled for repeated execution.
1.113 + * Returns false if the task was scheduled for one-time execution
1.114 + * and has already run, or if the task was never scheduled, or if
1.115 + * the task was already cancelled. (Loosely speaking, this method
1.116 + * returns <tt>true</tt> if it prevents one or more scheduled
1.117 + * executions from taking place.)
1.118 + */
1.119 + public boolean cancel() {
1.120 + synchronized(lock) {
1.121 + boolean result = (state == SCHEDULED);
1.122 + state = CANCELLED;
1.123 + return result;
1.124 + }
1.125 + }
1.126 +
1.127 + /**
1.128 + * Returns the <i>scheduled</i> execution time of the most recent
1.129 + * <i>actual</i> execution of this task. (If this method is invoked
1.130 + * while task execution is in progress, the return value is the scheduled
1.131 + * execution time of the ongoing task execution.)
1.132 + *
1.133 + * <p>This method is typically invoked from within a task's run method, to
1.134 + * determine whether the current execution of the task is sufficiently
1.135 + * timely to warrant performing the scheduled activity:
1.136 + * <pre>
1.137 + * public void run() {
1.138 + * if (System.currentTimeMillis() - scheduledExecutionTime() >=
1.139 + * MAX_TARDINESS)
1.140 + * return; // Too late; skip this execution.
1.141 + * // Perform the task
1.142 + * }
1.143 + * </pre>
1.144 + * This method is typically <i>not</i> used in conjunction with
1.145 + * <i>fixed-delay execution</i> repeating tasks, as their scheduled
1.146 + * execution times are allowed to drift over time, and so are not terribly
1.147 + * significant.
1.148 + *
1.149 + * @return the time at which the most recent execution of this task was
1.150 + * scheduled to occur, in the format returned by Date.getTime().
1.151 + * The return value is undefined if the task has yet to commence
1.152 + * its first execution.
1.153 + * @see Date#getTime()
1.154 + */
1.155 + public long scheduledExecutionTime() {
1.156 + synchronized(lock) {
1.157 + return (period < 0 ? nextExecutionTime + period
1.158 + : nextExecutionTime - period);
1.159 + }
1.160 + }
1.161 +}