com.nt.udc.ei.transport

Class SynchronizedDirectory

java.lang.Object

com.nt.udc.ei.transport.SynchronizedDirectory

public class SynchronizedDirectory
extends java.lang.Object

This class is used to let threads synchronize on a common directory into which and from which files are placed and processed. This was needed in order for one or more threads to handle populating the directory (as producers) and one or more other threads to process the files (as consumers). This class not only provides a lock and unlock capability, but it also provides methods for letting the producer notify the consumer when files are available.

Field Summary

Fields

Modifier and Type	Field and Description
protected int	busyCount
protected java.lang.Thread	lockOwner

Constructor Summary

Constructors

Constructor and Description
SynchronizedDirectory(java.io.File dir) Instantiate with a known directory.

Method Summary

Methods

Modifier and Type	Method and Description
java.io.File	getDirectory() Returns the directory of interest.
void	lock() Used to "grab" the lock on the directory of interest.
void	notifyMoreFiles() Used by a producer to notify any consumers that files have been placed in the directory of interest.
void	unlock() Release the lock on the directory.
java.lang.String[]	waitForMoreFiles(java.io.FilenameFilter f) Used by a thread that consumes files from the directory of interest.

Methods inherited from class java.lang.Object

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

Field Detail

lockOwner

protected java.lang.Thread lockOwner

busyCount

protected int busyCount

Constructor Detail

SynchronizedDirectory

public SynchronizedDirectory(java.io.File dir)

Instantiate with a known directory. This is the directory into which the producer will place files and from which the consumer will process files.

Method Detail

lock

public void lock()

Used to "grab" the lock on the directory of interest. This method will wait until the lock is available.

unlock

public void unlock()

Release the lock on the directory. This method keeps track of reentrant locks via the busyCount variable.

getDirectory

public java.io.File getDirectory()

Returns the directory of interest.

waitForMoreFiles

public java.lang.String[] waitForMoreFiles(java.io.FilenameFilter f)

Used by a thread that consumes files from the directory of interest. If no files are there, this method will cause the thread to wait until a producer places files in the directory.

Parameters:

f - A required FilenameFilter for identifying only files of interest.

Returns:

an array with the names of all the files found

notifyMoreFiles

public void notifyMoreFiles()

Used by a producer to notify any consumers that files have been placed in the directory of interest. Onc common approach to using this method is as follows:

File myDir = new File("some_directory"); SynchronizedDirectory sd = new SynchronizedDirectory(myDir); . . . // time to place files in the directory: sd.lock(); // Now that the directory is locked: produceFiles(); // Now unlock and notify: sd.unlock(); sd.notifyMoreFiles();