Java tutorial
/******************************************************************************* * Copyright (c) 2010-2014 SAP AG and others. * All rights reserved. This program and the accompanying materials * are made available under the terms of the Eclipse Public License v1.0 * which accompanies this distribution, and is available at * http://www.eclipse.org/legal/epl-v10.html * * Contributors: * SAP AG - initial API and implementation *******************************************************************************/ package org.eclipse.skalli.services.scheduler; import org.apache.commons.lang.StringUtils; /** * Base class for schedules that can be executed. * Implementations must implement a suitable {@link Runnable#run() run} method * according to the following pattern to ensure that the {@link #getLastStarted()} * and {@link #getLastCompleted()} timestamps are correctly set: * <pre> * public void run() { * try { * setLastStarted(System.currentTimeMillis()); * LOG.info("Updating X..."); * // actual code goes here * LOG.info("Updating X: Finished"); * } catch (Exception e) { * LOG.error("Updating X: Failed", e); * } finally { * setLastCompleted(System.currentTimeMillis()); * } * } * </pre> */ public abstract class RunnableSchedule extends Schedule implements Runnable { private final String caption; private volatile long lastStarted = -1L; private volatile long lastCompleted = -1L; /** * Creates a <code>RunnableSchedule</code> from the given schedule * and defines a caption for the schedule. * * @param schedule the schedule to initialize from. If no * schedule is spezified, {@link Schedule#Schedule()} is assumed. * * @param caption the caption to display for the schedule. * If not caption is specified, the name of the schedule class * is applied. */ protected RunnableSchedule(Schedule schedule, String caption) { super(schedule); if (StringUtils.isBlank(caption)) { caption = schedule.getClass().getName(); } this.caption = caption; } /** * Returns the caption of the schedule. */ public String getCaption() { return caption; } /** * Returns the time (in milliseconds since midnight, January 1, 1970 UTC) * when excution of the scheduled action has been started last. */ public long getLastStarted() { return lastStarted; } /** * Sets the time when excution of the scheduled action has been started last. * Derived classes should call this method at the beginning of their run methods * and set the timestamp to the current system time. * * @param lastStarted the time (in milliseconds since midnight, January 1, 1970 UTC) * when excution of the scheduled action has been started last. */ protected void setLastStarted(long lastStarted) { this.lastStarted = lastStarted; } /** * Returns the time (in milliseconds since midnight, January 1, 1970 UTC) * when excution of the scheduled action has completed last, or -1 if * the execution has not completed yet, or execution was never started. */ public long getLastCompleted() { return lastCompleted; } /** * Sets the time when excution of the scheduled action has completed last. * Derived classes should call this method at the end of their run methods * and set the timestamp to the current system time, preferably in a * finally block. * * @param lastCompleted the time (in milliseconds since midnight, January 1, 1970 UTC) * when excution of the scheduled action has completed last. */ protected void setLastCompleted(long lastCompleted) { this.lastCompleted = lastCompleted; } @SuppressWarnings("nls") @Override public String toString() { StringBuilder sb = new StringBuilder(); sb.append(caption).append(' '); sb.append("'").append(super.toString()).append("'"); return sb.toString(); } }