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The Fedora Client is a Java Library that allows API access to a Fedora Repository. The client is typically one part of a full Fedora installation.
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/*
* -----------------------------------------------------------------------------
*
* License and Copyright: The contents of this file are subject to 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.fedora-commons.org/licenses.
*
* Software distributed under the License is distributed on an "AS IS" basis,
* WITHOUT WARRANTY OF ANY KIND, either express or implied. See the License for
* the specific language governing rights and limitations under the License.
*
* The entire file consists of original code.
* Copyright © 2008 Fedora Commons, Inc.
*
Copyright © 2002-2007 The Rector and Visitors of the University of
* Virginia and Cornell University
* All rights reserved.
*
* -----------------------------------------------------------------------------
*/
package fedora.client;
import java.util.HashMap;
import javax.swing.SwingUtilities;
/**
* This is the 3rd version of SwingWorker (also known as
* SwingWorker 3), an abstract class that you subclass to
* perform GUI-related work in a dedicated thread. For
* instructions on and examples of using this class, see:
*
* http://java.sun.com/docs/books/tutorial/uiswing/misc/threads.html
*
* Note that the API changed slightly in the 3rd version:
* You must now invoke start() on the SwingWorker after
* creating it.
*/
public abstract class SwingWorker {
private Object value; // see getValue(), setValue()
public boolean done; // set to true only upon finish
public Exception thrownException;
/**
* Class to maintain reference to current worker thread
* under separate synchronization control.
*/
private static class ThreadVar {
private Thread thread;
ThreadVar(Thread t) { thread = t; }
synchronized Thread get() { return thread; }
synchronized void clear() { thread = null; }
}
private ThreadVar threadVar;
/**
* Get the value produced by the worker thread, or null if it
* hasn't been constructed yet.
*/
protected synchronized Object getValue() {
return value;
}
/**
* Set the value produced by worker thread
*/
public synchronized void setValue(Object x) {
value = x;
}
/**
* Compute the value to be returned by the get
method.
*/
public abstract Object construct();
/**
* Called on the event dispatching thread (not on the worker thread)
* after the construct
method has returned.
*/
public void finished() {
done=true;
}
/**
* A new method that interrupts the worker thread. Call this method
* to force the worker to stop what it's doing.
*/
public void interrupt() {
Thread t = threadVar.get();
if (t != null) {
t.interrupt();
}
threadVar.clear();
}
/**
* Return the value created by the construct
method.
* Returns null if either the constructing thread or the current
* thread was interrupted before a value was produced.
*
* @return the value created by the construct
method
*/
public Object get() {
while (true) {
Thread t = threadVar.get();
if (t == null) {
return getValue();
}
try {
t.join();
}
catch (InterruptedException e) {
Thread.currentThread().interrupt(); // propagate
return null;
}
}
}
public HashMap parms;
/**
* Start a thread that will call the construct
method
* and then exit.
*/
public SwingWorker(HashMap parms) {
this.parms=parms;
final Runnable doFinished = new Runnable() {
public void run() { finished(); }
};
Runnable doConstruct = new Runnable() {
public void run() {
try {
setValue(construct());
}
finally {
threadVar.clear();
}
done=true;
SwingUtilities.invokeLater(doFinished);
}
};
Thread t = new Thread(doConstruct);
threadVar = new ThreadVar(t);
}
/**
* Start the worker thread.
*/
public void start() {
Thread t = threadVar.get();
if (t != null) {
t.start();
}
}
}
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