Package org.apache.wiki

Class WikiBackgroundThread

java.lang.Object
java.lang.Thread
org.apache.wiki.WikiBackgroundThread
All Implemented Interfaces:
java.lang.Runnable, java.util.EventListener, WikiEventListener
Direct Known Subclasses:
RSSThread
public abstract class WikiBackgroundThread
extends java.lang.Thread
implements WikiEventListener
Abstract Thread subclass that operates in the background; when it detects the WikiEngineEvent.SHUTDOWN event, it terminates itself. Subclasses of this method need only implement the method backgroundTask(), instead of the normal Thread.run(), and provide a constructor that passes the Engine and sleep interval. This class is thread-safe.

  • Nested Class Summary

    Nested classes/interfaces inherited from class java.lang.Thread

    java.lang.Thread.State, java.lang.Thread.UncaughtExceptionHandler

  • Field Summary

    Fields inherited from class java.lang.Thread

    MAX_PRIORITY, MIN_PRIORITY, NORM_PRIORITY

  • Constructor Summary

    Constructors
    Constructor Description
    WikiBackgroundThread​(Engine engine, int sleepInterval)
    Constructs a new instance of this background thread with a specified sleep interval, and adds the new instance to the wiki engine's event listeners.

  • Method Summary

    Modifier and Type Method Description
    void actionPerformed​(WikiEvent event)
    Listens for WikiEngineEvent.SHUTDOWN and, if detected, marks the thread for death.
    abstract void backgroundTask()
    Abstract method that performs the actual work for this background thread; subclasses must implement this method.
    Engine getEngine()
    Returns the Engine that created this background thread.
    void run()
    Runs the background thread's backgroundTask() method at the interval specified at construction.
    void shutdown()
    Requests the shutdown of this background thread.
    void shutdownTask()
    Executes a task after shutdown signal was detected.
    void startupTask()
    Executes a task just after the thread's Thread.run() method starts, but before the backgroundTask() task executes.

    Methods inherited from class java.lang.Thread

    activeCount, checkAccess, clone, countStackFrames, currentThread, dumpStack, enumerate, getAllStackTraces, getContextClassLoader, getDefaultUncaughtExceptionHandler, getId, getName, getPriority, getStackTrace, getState, getThreadGroup, getUncaughtExceptionHandler, holdsLock, interrupt, interrupted, isAlive, isDaemon, isInterrupted, join, join, join, onSpinWait, resume, setContextClassLoader, setDaemon, setDefaultUncaughtExceptionHandler, setName, setPriority, setUncaughtExceptionHandler, sleep, sleep, start, stop, suspend, toString, yield

    Methods inherited from class java.lang.Object

    equals, finalize, getClass, hashCode, notify, notifyAll, wait, wait, wait

  • Constructor Details

    • WikiBackgroundThread

      public WikiBackgroundThread​(Engine engine, int sleepInterval)
      Constructs a new instance of this background thread with a specified sleep interval, and adds the new instance to the wiki engine's event listeners.
      Parameters:
      engine - the wiki engine
      sleepInterval - the interval between invocations of the thread's Thread.run() method, in seconds

  • Method Details

    • actionPerformed

      public final void actionPerformed​(WikiEvent event)
      Listens for WikiEngineEvent.SHUTDOWN and, if detected, marks the thread for death.
      Specified by:
      actionPerformed in interface WikiEventListener
      Parameters:
      event - a WikiEvent object
      See Also:
      WikiEventListener.actionPerformed(org.apache.wiki.event.WikiEvent)

    • backgroundTask

      public abstract void backgroundTask() throws java.lang.Exception
      Abstract method that performs the actual work for this background thread; subclasses must implement this method.
      Throws:
      java.lang.Exception - Any exception can be thrown

    • getEngine

      public Engine getEngine()
      Returns the Engine that created this background thread.
      Returns:
      the wiki engine

    • shutdown

      public void shutdown()
      Requests the shutdown of this background thread. Note that the shutdown is not immediate.
      Since:
      2.4.92

    • run

      public final void run()
      Runs the background thread's backgroundTask() method at the interval specified at construction. The thread will initially pause for a full sleep interval before starting, after which it will execute startupTask(). This method will cleanly terminate the thread if it has previously been marked as dead, before which it will execute shutdownTask(). If any of the three methods return an exception, it will be re-thrown as a InternalWikiException.
      Specified by:
      run in interface java.lang.Runnable
      Overrides:
      run in class java.lang.Thread
      See Also:
      Thread.run()

    • shutdownTask

      public void shutdownTask() throws java.lang.Exception
      Executes a task after shutdown signal was detected. By default, this method does nothing; override it to implement custom functionality.
      Throws:
      java.lang.Exception - Any exception can be thrown.

    • startupTask

      public void startupTask() throws java.lang.Exception
      Executes a task just after the thread's Thread.run() method starts, but before the backgroundTask() task executes. By default, this method does nothing; override it to implement custom functionality.
      Throws:
      java.lang.Exception - Any exception can be thrown.