Showing the changes to java/pkg/sun/jvmstat/perfdata/monitor/CountedTimerTaskUtils.java (1 of 18352 files). Show all
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| 1 | +/* | |
| 2 | + * Copyright (c) 2004, 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. Oracle designates this | |
| 8 | + * particular file as subject to the "Classpath" exception as provided | |
| 9 | + * by Oracle in the LICENSE file that accompanied this code. | |
| 10 | + * | |
| 11 | + * This code is distributed in the hope that it will be useful, but WITHOUT | |
| 12 | + * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or | |
| 13 | + * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License | |
| 14 | + * version 2 for more details (a copy is included in the LICENSE file that | |
| 15 | + * accompanied this code). | |
| 16 | + * | |
| 17 | + * You should have received a copy of the GNU General Public License version | |
| 18 | + * 2 along with this work; if not, write to the Free Software Foundation, | |
| 19 | + * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA. | |
| 20 | + * | |
| 21 | + * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA | |
| 22 | + * or visit www.oracle.com if you need additional information or have any | |
| 23 | + * questions. | |
| 24 | + */ | |
| 25 | + | |
| 26 | +package sun.jvmstat.perfdata.monitor; | |
| 27 | + | |
| 28 | +import java.util.*; | |
| 29 | + | |
| 30 | +/** | |
| 31 | + * Utility methods for use with {@link CountedTimerTask} instances. | |
| 32 | + * | |
| 33 | + * @author Brian Doherty | |
| 34 | + * @since 1.5 | |
| 35 | + */ | |
| 36 | +public class CountedTimerTaskUtils { | |
| 37 | + | |
| 38 | + private static final boolean DEBUG = false; | |
| 39 | + | |
| 40 | + /** | |
| 41 | + * Reschedule a CountedTimeTask at a different interval. Probably not | |
| 42 | + * named correctly. This method cancels the old task and computes the | |
| 43 | + * delay for starting the new task based on the new interval and the | |
| 44 | + * time at which the old task was last executed. | |
| 45 | + * | |
| 46 | + * @param timer the Timer for the task | |
| 47 | + * @param oldTask the old Task | |
| 48 | + * @param newTask the new Task | |
| 49 | + * @param oldInterval the old interval; use for debugging output | |
| 50 | + * purposes only. | |
| 51 | + * @param newInterval scheduling interval in milliseconds | |
| 52 | + */ | |
| 53 | + public static void reschedule(Timer timer, CountedTimerTask oldTask, | |
| 54 | + CountedTimerTask newTask, int oldInterval, | |
| 55 | + int newInterval) { | |
| 56 | + | |
| 57 | + long now = System.currentTimeMillis(); | |
| 58 | + long lastRun = oldTask.scheduledExecutionTime(); | |
| 59 | + long expired = now - lastRun; | |
| 60 | + | |
| 61 | + if (DEBUG) { | |
| 62 | + System.err.println("computing timer delay: " | |
| 63 | + + " oldInterval = " + oldInterval | |
| 64 | + + " newInterval = " + newInterval | |
| 65 | + + " samples = " + oldTask.executionCount() | |
| 66 | + + " expired = " + expired); | |
| 67 | + } | |
| 68 | + | |
| 69 | + /* | |
| 70 | + * check if original task ever ran - if not, then lastRun is | |
| 71 | + * undefined and we simply set the delay to 0. | |
| 72 | + */ | |
| 73 | + long delay = 0; | |
| 74 | + if (oldTask.executionCount() > 0) { | |
| 75 | + long remainder = newInterval - expired; | |
| 76 | + delay = remainder >= 0 ? remainder : 0; | |
| 77 | + } | |
| 78 | + | |
| 79 | + if (DEBUG) { | |
| 80 | + System.err.println("rescheduling sampler task: interval = " | |
| 81 | + + newInterval | |
| 82 | + + " delay = " + delay); | |
| 83 | + } | |
| 84 | + | |
| 85 | + timer.schedule(newTask, delay, newInterval); | |
| 86 | + } | |
| 87 | +} | |