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| author | tknall <tknall@7b5415b0-85f9-ee4d-85bd-d5d0c3b42d1c> | 2006-12-01 12:20:24 +0000 |
|---|---|---|
| committer | tknall <tknall@7b5415b0-85f9-ee4d-85bd-d5d0c3b42d1c> | 2006-12-01 12:20:24 +0000 |
| commit | 6025b6016517c6d898d8957d1d7e03ba71431912 (patch) | |
| tree | b15bd6fa5ffe9588a9bca3f2b8a7e358f83b6eba /src/main/java/com/lowagie/tools/SwingWorker.java | |
| parent | d2c77e820ab4aba8235d71275755021347b3ad10 (diff) | |
| download | pdf-as-3-REL-2.2@923.tar.gz pdf-as-3-REL-2.2@923.tar.bz2 pdf-as-3-REL-2.2@923.zip | |
Initial import of release 2.2.REL-2.2@923
git-svn-id: https://joinup.ec.europa.eu/svn/pdf-as/trunk@4 7b5415b0-85f9-ee4d-85bd-d5d0c3b42d1c
Diffstat (limited to 'src/main/java/com/lowagie/tools/SwingWorker.java')
| -rw-r--r-- | src/main/java/com/lowagie/tools/SwingWorker.java | 127 |
1 files changed, 127 insertions, 0 deletions
diff --git a/src/main/java/com/lowagie/tools/SwingWorker.java b/src/main/java/com/lowagie/tools/SwingWorker.java new file mode 100644 index 0000000..634a61a --- /dev/null +++ b/src/main/java/com/lowagie/tools/SwingWorker.java @@ -0,0 +1,127 @@ +package com.lowagie.tools;
+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 using this class, see:
+ *
+ * http://java.sun.com/docs/books/tutorial/uiswing/misc/threads.html
+ */
+public abstract class SwingWorker {
+ private Object value; // see getValue(), setValue()
+ private Thread thread;
+
+ /**
+ * 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 getValueX() {
+ return value;
+ }
+
+ /**
+ * Set the value produced by worker thread
+ */
+ private synchronized void setValueX(Object x) {
+ value = x;
+ }
+
+ /**
+ * Compute the value to be returned by the <code>get</code> method.
+ */
+ public abstract Object construct();
+
+ /**
+ * Called on the event dispatching thread (not on the worker thread)
+ * after the <code>construct</code> method has returned.
+ */
+ public void finished() {
+ }
+
+ /**
+ * 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 <code>construct</code> 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 <code>construct</code> method
+ */
+ public Object get() {
+ while (true) {
+ Thread t = threadVar.get();
+ if (t == null) {
+ return getValueX();
+ }
+ try {
+ t.join();
+ }
+ catch (InterruptedException e) {
+ Thread.currentThread().interrupt(); // propagate
+ return null;
+ }
+ }
+ }
+
+
+ /**
+ * Start a thread that will call the <code>construct</code> method
+ * and then exit.
+ */
+ public SwingWorker() {
+ final Runnable doFinished = new Runnable() {
+ public void run() { finished(); }
+ };
+
+ Runnable doConstruct = new Runnable() {
+ public void run() {
+ try {
+ setValueX(construct());
+ }
+ finally {
+ threadVar.clear();
+ }
+
+ 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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