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Posted to log4j-dev@logging.apache.org by ca...@apache.org on 2007/04/11 21:30:37 UTC
svn commit: r527630 - in
/logging/log4j/trunk/src/java/org/apache/log4j/scheduler: Job.java
Scheduler.java
Author: carnold
Date: Wed Apr 11 12:30:35 2007
New Revision: 527630
URL: http://svn.apache.org/viewvc?view=rev&rev=527630
Log:
Bug 42092: Checkstyle fixes in org.apache.log4j.scheduler
Modified:
logging/log4j/trunk/src/java/org/apache/log4j/scheduler/Job.java
logging/log4j/trunk/src/java/org/apache/log4j/scheduler/Scheduler.java
Modified: logging/log4j/trunk/src/java/org/apache/log4j/scheduler/Job.java
URL: http://svn.apache.org/viewvc/logging/log4j/trunk/src/java/org/apache/log4j/scheduler/Job.java?view=diff&rev=527630&r1=527629&r2=527630
==============================================================================
--- logging/log4j/trunk/src/java/org/apache/log4j/scheduler/Job.java (original)
+++ logging/log4j/trunk/src/java/org/apache/log4j/scheduler/Job.java Wed Apr 11 12:30:35 2007
@@ -1,9 +1,10 @@
/*
- * Copyright 1999,2004 The Apache Software Foundation.
- *
- * Licensed under the Apache License, Version 2.0 (the "License");
- * you may not use this file except in compliance with the License.
- * You may obtain a copy of the License at
+ * Licensed to the Apache Software Foundation (ASF) under one or more
+ * contributor license agreements. See the NOTICE file distributed with
+ * this work for additional information regarding copyright ownership.
+ * The ASF licenses this file to You under the Apache License, Version 2.0
+ * (the "License"); you may not use this file except in compliance with
+ * the License. You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
@@ -18,15 +19,18 @@
/**
- * Job is a very simple interface. It only has a single method {@link #execute}
+ * Job is a very simple interface. It only has a single method {@link #execute}
* which is called by the {@link Scheduler} when a task is ready for execution.
- *
- * It is assumed that the execution context are contained within the implementing
- * {@ink Job} itself.
- *
- * @author Ceki Gülcü
+ * <p/>
+ * It is assumed that the execution context
+ * are contained within the implementing
+ * {@link Job} itself.
*
+ * @author Ceki Gülcü
*/
public interface Job {
- public void execute();
+ /**
+ * Execute job.
+ */
+ void execute();
}
Modified: logging/log4j/trunk/src/java/org/apache/log4j/scheduler/Scheduler.java
URL: http://svn.apache.org/viewvc/logging/log4j/trunk/src/java/org/apache/log4j/scheduler/Scheduler.java?view=diff&rev=527630&r1=527629&r2=527630
==============================================================================
--- logging/log4j/trunk/src/java/org/apache/log4j/scheduler/Scheduler.java (original)
+++ logging/log4j/trunk/src/java/org/apache/log4j/scheduler/Scheduler.java Wed Apr 11 12:30:35 2007
@@ -1,9 +1,10 @@
/*
- * Copyright 1999,2004 The Apache Software Foundation.
- *
- * Licensed under the Apache License, Version 2.0 (the "License");
- * you may not use this file except in compliance with the License.
- * You may obtain a copy of the License at
+ * Licensed to the Apache Software Foundation (ASF) under one or more
+ * contributor license agreements. See the NOTICE file distributed with
+ * this work for additional information regarding copyright ownership.
+ * The ASF licenses this file to You under the Apache License, Version 2.0
+ * (the "License"); you may not use this file except in compliance with
+ * the License. You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
@@ -21,215 +22,286 @@
/**
* A simple but still useful implementation of a Scheduler (in memory only).
- *
+ * <p/>
* This implementation will work very well when the number of scheduled job is
* small, say less than 100 jobs. If a larger number of events need to be
* scheduled, than a better adapted data structure for the jobList can give
* improved performance.
- *
- * @author Ceki
*
+ * @author Ceki
*/
public class Scheduler extends Thread {
-
- List jobList;
- boolean shutdown = false;
-
- public Scheduler() {
- jobList = new Vector();
- }
-
- /**
- * Find the index of a given job. Returns -1 if the job could not be found.
- *
- */
- int findIndex(Job job) {
- int size = jobList.size();
- boolean found = false;
-
- int i = 0;
- for (; i < size; i++) {
- ScheduledJobEntry se = (ScheduledJobEntry) jobList.get(i);
- if(se.job == job) {
- found = true;
- break;
- }
- }
- if(found) {
- return i;
- } else {
- return -1;
- }
- }
-
- /**
- * Delete the given job. Returns true if the job could be deleted, and
- * false if the job could not be found or if the Scheduler is about to
- * shutdown in which case deletions are not permitted.
- */
- public synchronized boolean delete(Job job) {
- // if already shutdown in the process of shutdown, there is no
- // need to remove Jobs as they will never be executed.
- if(shutdown) {
- return false;
- }
- int i = findIndex(job);
- if(i != -1) {
- ScheduledJobEntry se = (ScheduledJobEntry) jobList.remove(i);
- if(se.job != job) { // this should never happen
- new IllegalStateException("Internal programming error");
- }
- // if the job is the first on the list, then notify the scheduler thread
- // to schedule a new job
- if(i == 0) {
- this.notifyAll();
- }
- return true;
- } else {
- return false;
- }
- }
-
-
-
- /**
- * Schedule a {@link Job} for execution at system time given by
- * the <code>desiredTime</code> parameter.
- */
- public synchronized void schedule(Job job, long desiredTime) {
- schedule(new ScheduledJobEntry(job, desiredTime));
- }
-
- /**
- * Schedule a {@link Job} for execution at system time given by
- * the <code>desiredTime</code> parameter.
- *
- * The job will be rescheduled. It will execute with a frequency determined
- * by the period parameter.
- */
- public synchronized void schedule(Job job, long desiredTime, long period) {
- schedule(new ScheduledJobEntry(job, desiredTime, period));
- }
-
- /**
- * Change the period of a job. The original job must exist for its period
- * to be changed.
- *
- * The method returns true if the period could be changes, and false
- * otherwise.
- */
- public synchronized boolean changePeriod(Job job, long newPeriod) {
- if(newPeriod <= 0) {
- throw new IllegalArgumentException("Period must be an integer langer than zero");
- }
-
- int i = findIndex(job);
- if(i == -1) {
- return false;
- } else {
- ScheduledJobEntry se = (ScheduledJobEntry) jobList.get(i);
- se.period = newPeriod;
- return true;
- }
- }
-
- private synchronized void schedule(ScheduledJobEntry newSJE) {
- // disallow new jobs after shutdown
- if(shutdown) {
- return;
- }
- int max = jobList.size();
- long desiredExecutionTime = newSJE.desiredExecutionTime;
-
- // find the index i such that timeInMillis < jobList[i]
- int i = 0;
- for (; i < max; i++) {
-
- ScheduledJobEntry sje = (ScheduledJobEntry) jobList.get(i);
-
- if (desiredExecutionTime < sje.desiredExecutionTime) {
- break;
- }
- }
- jobList.add(i, newSJE);
- // if the jobList was empty, then notify the scheduler thread
- if(i == 0) {
- this.notifyAll();
- }
- }
-
- public synchronized void shutdown() {
- shutdown = true;
- }
-
- public synchronized void run() {
- while (!shutdown) {
- if (jobList.isEmpty()) {
- linger();
- } else {
- ScheduledJobEntry sje = (ScheduledJobEntry) jobList.get(0);
- long now = System.currentTimeMillis();
- if(now >= sje.desiredExecutionTime) {
- executeInABox(sje.job);
- jobList.remove(0);
- if(sje.period > 0) {
- sje.desiredExecutionTime = now + sje.period;
- schedule(sje);
- }
+
+ /**
+ * Job list.
+ */
+ List jobList;
+ /**
+ * If set true, scheduler has or should shut down.
+ */
+ boolean shutdown = false;
+
+ /**
+ * Create new instance.
+ */
+ public Scheduler() {
+ super();
+ jobList = new Vector();
+ }
+
+ /**
+ * Find the index of a given job.
+ * @param job job
+ * @return -1 if the job could not be found.
+ */
+ int findIndex(final Job job) {
+ int size = jobList.size();
+ boolean found = false;
+
+ int i = 0;
+ for (; i < size; i++) {
+ ScheduledJobEntry se = (ScheduledJobEntry) jobList.get(i);
+ if (se.job == job) {
+ found = true;
+ break;
+ }
+ }
+ if (found) {
+ return i;
} else {
- linger(sje.desiredExecutionTime - now);
+ return -1;
}
- }
}
- // clear out the job list to facilitate garbage collection
- jobList.clear();
- jobList = null;
- System.out.println("Leaving scheduler run method");
- }
-
- /**
- * We do not want a single failure to affect the whole scheduler.
- */
- void executeInABox(Job job) {
- try {
- job.execute();
- } catch(Exception e) {
- System.err.println("The execution of the job threw an exception");
- e.printStackTrace(System.err);
- }
- }
-
- void linger() {
- try {
- while (jobList.isEmpty() && !shutdown)
- this.wait();
- } catch (InterruptedException ie) {
- shutdown = true;
- }
- }
-
- void linger(long timeToLinger) {
- try {
- this.wait(timeToLinger);
- } catch (InterruptedException ie) {
- shutdown = true;
- }
- }
-}
+ /**
+ * Delete the given job.
+ * @param job job.
+ * @return true if the job could be deleted, and
+ * false if the job could not be found or if the Scheduler is about to
+ * shutdown in which case deletions are not permitted.
+ */
+ public synchronized boolean delete(final Job job) {
+ // if already shutdown in the process of shutdown, there is no
+ // need to remove Jobs as they will never be executed.
+ if (shutdown) {
+ return false;
+ }
+ int i = findIndex(job);
+ if (i != -1) {
+ ScheduledJobEntry se = (ScheduledJobEntry) jobList.remove(i);
+ if (se.job != job) { // this should never happen
+ new IllegalStateException("Internal programming error");
+ }
+ // if the job is the first on the list,
+ // then notify the scheduler thread to schedule a new job
+ if (i == 0) {
+ this.notifyAll();
+ }
+ return true;
+ } else {
+ return false;
+ }
+ }
-class ScheduledJobEntry {
- long desiredExecutionTime;
- Job job;
- long period = 0;
-
- ScheduledJobEntry(Job job, long desiredTime) {
- this(job, desiredTime, 0);
- }
- ScheduledJobEntry(Job job, long desiredTime, long period) {
- this.desiredExecutionTime = desiredTime;
- this.job = job;
- this.period = period;
- }
+ /**
+ * Schedule a {@link Job} for execution at system time given by
+ * the <code>desiredTime</code> parameter.
+ * @param job job to schedule.
+ * @param desiredTime desired time of execution.
+ */
+ public synchronized void schedule(final Job job,
+ final long desiredTime) {
+ schedule(new ScheduledJobEntry(job, desiredTime));
+ }
+
+ /**
+ * Schedule a {@link Job} for execution at system time given by
+ * the <code>desiredTime</code> parameter.
+ * <p/>
+ * The job will be rescheduled. It will execute with a frequency determined
+ * by the period parameter.
+ * @param job job to schedule.
+ * @param desiredTime desired time of execution.
+ * @param period repeat period.
+ */
+ public synchronized void schedule(final Job job,
+ final long desiredTime,
+ final long period) {
+ schedule(new ScheduledJobEntry(job, desiredTime, period));
+ }
+
+ /**
+ * Change the period of a job. The original job must exist for its period
+ * to be changed.
+ * <p/>
+ * The method returns true if the period could be changed, and false
+ * otherwise.
+ * @param job job.
+ * @param newPeriod new repeat period.
+ * @return true if period could be changed.
+ */
+ public synchronized boolean changePeriod(final Job job,
+ final long newPeriod) {
+ if (newPeriod <= 0) {
+ throw new IllegalArgumentException(
+ "Period must be an integer langer than zero");
+ }
+
+ int i = findIndex(job);
+ if (i == -1) {
+ return false;
+ } else {
+ ScheduledJobEntry se = (ScheduledJobEntry) jobList.get(i);
+ se.period = newPeriod;
+ return true;
+ }
+ }
+
+ /**
+ * Schedule a job.
+ * @param newSJE new job entry.
+ */
+ private synchronized void schedule(final ScheduledJobEntry newSJE) {
+ // disallow new jobs after shutdown
+ if (shutdown) {
+ return;
+ }
+ int max = jobList.size();
+ long desiredExecutionTime = newSJE.desiredExecutionTime;
+
+ // find the index i such that timeInMillis < jobList[i]
+ int i = 0;
+ for (; i < max; i++) {
+
+ ScheduledJobEntry sje = (ScheduledJobEntry) jobList.get(i);
+
+ if (desiredExecutionTime < sje.desiredExecutionTime) {
+ break;
+ }
+ }
+ jobList.add(i, newSJE);
+ // if the jobList was empty, then notify the scheduler thread
+ if (i == 0) {
+ this.notifyAll();
+ }
+ }
+
+ /**
+ * Shut down scheduler.
+ */
+ public synchronized void shutdown() {
+ shutdown = true;
+ }
+
+ /**
+ * Run scheduler.
+ */
+ public synchronized void run() {
+ while (!shutdown) {
+ if (jobList.isEmpty()) {
+ linger();
+ } else {
+ ScheduledJobEntry sje = (ScheduledJobEntry) jobList.get(0);
+ long now = System.currentTimeMillis();
+ if (now >= sje.desiredExecutionTime) {
+ executeInABox(sje.job);
+ jobList.remove(0);
+ if (sje.period > 0) {
+ sje.desiredExecutionTime = now + sje.period;
+ schedule(sje);
+ }
+ } else {
+ linger(sje.desiredExecutionTime - now);
+ }
+ }
+ }
+ // clear out the job list to facilitate garbage collection
+ jobList.clear();
+ jobList = null;
+ System.out.println("Leaving scheduler run method");
+ }
+
+ /**
+ * We do not want a single failure to affect the whole scheduler.
+ * @param job job to execute.
+ */
+ void executeInABox(final Job job) {
+ try {
+ job.execute();
+ } catch (Exception e) {
+ System.err.println("The execution of the job threw an exception");
+ e.printStackTrace(System.err);
+ }
+ }
+
+ /**
+ * Wait for notification.
+ */
+ void linger() {
+ try {
+ while (jobList.isEmpty() && !shutdown) {
+ this.wait();
+ }
+ } catch (InterruptedException ie) {
+ shutdown = true;
+ }
+ }
+
+ /**
+ * Wait for notification or time to elapse.
+ * @param timeToLinger time to linger.
+ */
+ void linger(final long timeToLinger) {
+ try {
+ this.wait(timeToLinger);
+ } catch (InterruptedException ie) {
+ shutdown = true;
+ }
+ }
+
+ /**
+ * Represents an entry in job scheduler.
+ */
+ static final class ScheduledJobEntry {
+ /**
+ * Desired execution time.
+ */
+ long desiredExecutionTime;
+ /**
+ * Job to run.
+ */
+ Job job;
+ /**
+ * Repeat period.
+ */
+ long period = 0;
+
+ /**
+ * Create new instance.
+ * @param job job
+ * @param desiredTime desired time.
+ */
+ ScheduledJobEntry(final Job job, final long desiredTime) {
+ this(job, desiredTime, 0);
+ }
+
+ /**
+ * Create new instance.
+ * @param job job
+ * @param desiredTime desired time
+ * @param period repeat period
+ */
+ ScheduledJobEntry(final Job job,
+ final long desiredTime,
+ final long period) {
+ super();
+ this.desiredExecutionTime = desiredTime;
+ this.job = job;
+ this.period = period;
+ }
+ }
+
}
+
+
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