adolphenom
144 lines
3.9 KiB
Java
144 lines
3.9 KiB
Java
package mars.simulator;
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import javax.swing.SwingUtilities;
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/*-----------------------------------------------------
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* This file downloaded from the Sun Microsystems URL given below.
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*
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* I will subclass it to create worker thread for running
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* MIPS simulated execution.
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*/
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/**
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* This is the 3rd version of SwingWorker (also known as
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* SwingWorker 3), an abstract class that you subclass to
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* perform GUI-related work in a dedicated thread. For
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* instructions on and examples of using this class, see:
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*
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* http://java.sun.com/docs/books/tutorial/uiswing/misc/threads.html
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*
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* Note that the API changed slightly in the 3rd version:
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* You must now invoke start() on the SwingWorker after
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* creating it.
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*/
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public abstract class SwingWorker {
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private Object value; // see getValue(), setValue()
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/**
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* Class to maintain reference to current worker thread
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* under separate synchronization control.
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*/
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private static class ThreadVar {
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private Thread thread;
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ThreadVar(Thread t) { thread = t; }
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synchronized Thread get() { return thread; }
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synchronized void clear() { thread = null; }
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}
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private ThreadVar threadVar;
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/**
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* Get the value produced by the worker thread, or null if it
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* hasn't been constructed yet.
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*/
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protected synchronized Object getValue() {
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return value;
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}
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/**
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* Set the value produced by worker thread
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*/
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private synchronized void setValue(Object x) {
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value = x;
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}
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/**
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* Compute the value to be returned by the <code>get</code> method.
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*/
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public abstract Object construct();
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/**
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* Called on the event dispatching thread (not on the worker thread)
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* after the <code>construct</code> method has returned.
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*/
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public void finished() {
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}
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/**
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* A new method that interrupts the worker thread. Call this method
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* to force the worker to stop what it's doing.
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*/
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public void interrupt() {
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Thread t = threadVar.get();
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if (t != null) {
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t.interrupt();
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}
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threadVar.clear();
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}
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/**
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* Return the value created by the <code>construct</code> method.
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* Returns null if either the constructing thread or the current
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* thread was interrupted before a value was produced.
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*
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* @return the value created by the <code>construct</code> method
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*/
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public Object get() {
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while (true) {
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Thread t = threadVar.get();
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if (t == null) {
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return getValue();
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}
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try {
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t.join();
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}
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catch (InterruptedException e) {
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Thread.currentThread().interrupt(); // propagate
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return null;
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}
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}
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}
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/**
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* Start a thread that will call the <code>construct</code> method
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* and then exit.
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* @param useSwing Set true if MARS is running from GUI, false otherwise.
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*/
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public SwingWorker(final boolean useSwing) {
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final Runnable doFinished = new Runnable() {
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public void run() { finished(); }
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};
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Runnable doConstruct = new Runnable() {
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public void run() {
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try {
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setValue(construct());
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}
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finally {
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threadVar.clear();
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}
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if (useSwing) SwingUtilities.invokeLater(doFinished);
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else doFinished.run();
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}
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};
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// Thread that represents executing MIPS program...
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Thread t = new Thread(doConstruct, "MIPS");
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//t.setPriority(Thread.NORM_PRIORITY-1);//******************
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threadVar = new ThreadVar(t);
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}
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/**
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* Start the worker thread.
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*/
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public void start() {
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Thread t = threadVar.get();
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if (t != null) {
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t.start();
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}
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}
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}
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