Package wt.jmx.core

Class FileWatcher

java.lang.Object
wt.jmx.core.FileWatcher
Direct Known Subclasses:
FileWatcher.Adapter
public abstract class FileWatcher extends Object
Provides ability to watch and load a file upon changes via a fairly general URL abstraction.

Note this class is not itself properly configured for direct persistence via Encoder; rather it is suggested that controlling properties of interest be exposed in an aggregating MBean.

Supported API: true

Extendable: true

  • Nested Class Summary

    Nested Classes
    Modifier and Type
    Class
    Description
    static class 
    FileWatcher.Adapter
    FileWatcher subclass with no-op overrides of all abstract methods.

  • Constructor Summary

    Constructors
    Constructor
    Description
    FileWatcher()
    Constructs instance of FileWatcher which uses itself as the object to sychronize against.
    FileWatcher(Object lockObject)
    Constructs instance of FileWatcher which uses the specified object as the object to sychronize against.

  • Method Summary

    Modifier and Type
    Method
    Description
    int
    getFileCheckInterval()
    Get time interval at which file is checked for updates (in seconds); a non-positive time-interval implies no file update checking

    Supported API: true
    BufferedInputStream
    getFileInputStream()
    Get input stream for file

    Supported API: true
    protected OutputStream
    getFileOutputStream()
    Get output stream for file

    Supported API: true
    String
    getFileRef()
    Get URL, file path, or classpath-based resource reference string for file

    Supported API: true
    URL
    getFileURL()
    Get URL to file

    Supported API: true
    String
    getFileURLString()
    Get URL to file as String.
    Object
    getLockObject()
    Returns object used by this instance for locking purposes; default to 'this' unless FileWatcher(Object) constructor is used.
    boolean
    isExistingFileOnly()
    Whether only existing files are to be handled or whether reference may be to a file yet to be created.
    boolean
    isSavingCopy()
    Returns true if and only if in process of saveACopyAs().
    abstract void
    load()
    Method to load from file; to be overriden by subclasses

    Supported API: true
    void
    reload()
    Reload data from file

    Supported API: true
    void
    resetFileLastModified()
    Reset this object's record of the file's last modification date.
    final void
    save()
    Save data to file

    Supported API: true
    abstract void
    save(OutputStream out)
    Method to save data to the file; to be overriden by subclasses

    Supported API: true
    void
    saveACopyAs(String fileRef)
    Save data to another file but do not change this object to reference the new file

    Supported API: true
    void
    saveAs(String fileRef)
    Save data to another file and change this object to reference the new file

    Supported API: true
    void
    setExistingFileOnly(boolean existingFileOnly)
    Set whether only existing files are to be handled or whether reference may be to a file yet to be created.
    void
    setFileCheckInterval(int fileCheckIntervalInSeconds)
    Set time interval at which file is checked for updates (in seconds); a non-positive time-interval implies no file update checking

    Supported API: true
    void
    setFileRef(String fileRef)
    Set URL, file path, or classpath-based resource reference string for file

    Supported API: true
    void
    setFileURL(URL fileURL)
    Set URL to file

    Supported API: true
    void
    start()
    Starts file update checker.
    void
    stop()
    Stops file update checker.
    abstract void
    unload()
    Method to unload/clear data loaded from file (as part of a reload); to be overriden by subclasses

    Supported API: true

    Methods inherited from class java.lang.Object

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

  • Constructor Details

    • FileWatcher

      public FileWatcher()
      Constructs instance of FileWatcher which uses itself as the object to sychronize against.

      Supported API: true

    • FileWatcher

      public FileWatcher(Object lockObject)
      Constructs instance of FileWatcher which uses the specified object as the object to sychronize against.

      Supported API: true
      Parameters:
      lockObject - Object to synchronize against, if null, 'this' is used instead; see getLockObject()

  • Method Details

    • load

      public abstract void load() throws IOException
      Method to load from file; to be overriden by subclasses

      Supported API: true
      Throws:
      IOException

    • unload

      public abstract void unload()
      Method to unload/clear data loaded from file (as part of a reload); to be overriden by subclasses

      Supported API: true

    • save

      public abstract void save(OutputStream out) throws IOException, URISyntaxException
      Method to save data to the file; to be overriden by subclasses

      Supported API: true
      Throws:
      IOException
      URISyntaxException

    • getLockObject

      public Object getLockObject()
      Returns object used by this instance for locking purposes; default to 'this' unless FileWatcher(Object) constructor is used.

      Supported API: true

    • resetFileLastModified

      public void resetFileLastModified()
      Reset this object's record of the file's last modification date. This is set to the actual last modification date milliseconds if this can be obtained or '0' when it cannot be.

      Supported API: true

    • isExistingFileOnly

      public boolean isExistingFileOnly()
      Whether only existing files are to be handled or whether reference may be to a file yet to be created.

      Supported API: true

    • setExistingFileOnly

      public void setExistingFileOnly(boolean existingFileOnly)
      Set whether only existing files are to be handled or whether reference may be to a file yet to be created.

      Supported API: true

    • getFileURLString

      public String getFileURLString()
      Get URL to file as String.

      Supported API: true

    • getFileRef

      public String getFileRef()
      Get URL, file path, or classpath-based resource reference string for file

      Supported API: true

    • setFileRef

      public void setFileRef(String fileRef) throws IOException
      Set URL, file path, or classpath-based resource reference string for file

      Supported API: true
      Throws:
      IOException

    • getFileURL

      public URL getFileURL()
      Get URL to file

      Supported API: true

    • setFileURL

      public void setFileURL(URL fileURL) throws IOException
      Set URL to file

      Supported API: true
      Throws:
      IOException

    • getFileCheckInterval

      public int getFileCheckInterval()
      Get time interval at which file is checked for updates (in seconds); a non-positive time-interval implies no file update checking

      Supported API: true

    • setFileCheckInterval

      public void setFileCheckInterval(int fileCheckIntervalInSeconds)
      Set time interval at which file is checked for updates (in seconds); a non-positive time-interval implies no file update checking

      Supported API: true

    • reload

      public void reload() throws IOException
      Reload data from file

      Supported API: true
      Throws:
      IOException

    • getFileInputStream

      public BufferedInputStream getFileInputStream() throws IOException
      Get input stream for file

      Supported API: true
      Throws:
      IOException

    • getFileOutputStream

      protected OutputStream getFileOutputStream() throws IOException, URISyntaxException
      Get output stream for file

      Supported API: true
      Throws:
      IOException
      URISyntaxException

    • save

      public final void save() throws IOException, URISyntaxException
      Save data to file

      Supported API: true
      Throws:
      IOException
      URISyntaxException

    • saveAs

      public void saveAs(String fileRef) throws IOException, URISyntaxException
      Save data to another file and change this object to reference the new file

      Supported API: true
      Throws:
      IOException
      URISyntaxException

    • saveACopyAs

      public void saveACopyAs(String fileRef) throws IOException, URISyntaxException
      Save data to another file but do not change this object to reference the new file

      Supported API: true
      Throws:
      IOException
      URISyntaxException

    • isSavingCopy

      public boolean isSavingCopy()
      Returns true if and only if in process of saveACopyAs().

      Supported API: true

    • start

      public void start()
      Starts file update checker. When used within a SelfAwareMBean, this should generally be called from within the MBean's start() method.

      Supported API: true

    • stop

      public void stop()
      Stops file update checker. When used within a SelfAwareMBean, this should generally be called from within the MBean's stop() method.

      Supported API: true