StateMachine is now in charge of state transitions

git-svn-id: https://ipscan.svn.sourceforge.net/svnroot/ipscan/trunk@137 375186e5-ef17-0410-b0b6-91563547dcda

src/net/azib/ipscan/core/ScannerThread.java

@@ -38,6 +38,7 @@ public class ScannerThread extends Thread {
 		// this thread is daemon because we want JVM to terminate it
 		// automatically if user closes the program (Main thread, that is)
 		setDaemon(true);
+		
 		this.feeder = feeder;
 		this.scanner = scanner;
 		this.scanningResultList = scanningResults;
@@ -47,11 +48,8 @@ public class ScannerThread extends Thread {
 	}
 
 	public void run() {
-		stateMachine.transitionTo(ScanningState.SCANNING);
-				
-		while(feeder.hasNext() && stateMachine.isState(ScanningState.SCANNING)) {
+		while(feeder.hasNext() && stateMachine.inState(ScanningState.SCANNING)) {
 			try {
-				
 				// make a small delay between thread creation
 				Thread.sleep(config.threadDelay);
 								
@@ -81,13 +79,13 @@ public class ScannerThread extends Thread {
 				// scan each IP in parallel, in a separate thread
 				new IPThread(address, preparationNumber).start();
 			}
-			catch (InterruptedException e) {				
+			catch (InterruptedException e) {
 				return;
 			}
 		}
 		
 		// inform that no more addresses left
-		stateMachine.transitionTo(ScanningState.STOPPING);
+		stateMachine.stop();
 
 		// now wait for all threads, which are still running
 		try {
@@ -104,17 +102,9 @@ public class ScannerThread extends Thread {
 		scanner.cleanup();
 		
 		// finally, the scanning is complete
-		stateMachine.transitionTo(ScanningState.IDLE);
+		stateMachine.complete();
 	}
-		
-	public void forceStop() {
-		stateMachine.transitionTo(ScanningState.STOPPING);
-	}
-	
-	public void abort() {
-		stateMachine.transitionTo(ScanningState.KILLING);
-	}
-	
+			
 	// TODO: remove me and change to constructor injection
 	public void setResultsCallback(ScanningResultsCallback resultsCallback) {
 		this.resultsCallback = resultsCallback;

src/net/azib/ipscan/core/ScanningProgressCallback.java

@@ -7,23 +7,13 @@ package net.azib.ipscan.core;
 
 import java.net.InetAddress;
 
-import net.azib.ipscan.core.state.ScanningState;
-
 /**
  * This callback is called on scanning state updates.
  * 
  * @author anton
  */
 public interface ScanningProgressCallback {
-		
-	/**
-	 * This method is called on scanner state changes,
-	 * eg. when scanning is about to stop.
-	 * 
-	 * @param new state
-	 */
-	public void scannerStateChanged(ScanningState state);
-	
+			
 	/**
 	 * This method is called on scanning progress updates.
 	 * There are no guarantees that this method is called on every

src/net/azib/ipscan/core/state/ScanningState.java

@@ -6,8 +6,8 @@
 
 package net.azib.ipscan.core.state;
 
-import java.util.HashSet;
-import java.util.Set;
+import java.util.ArrayList;
+import java.util.List;
 
 /**
  * ScanningState enum - all possible states.
@@ -21,7 +21,7 @@ public enum ScanningState {
 	STOPPING,
 	KILLING;
 	
-	private Set<StateTransitionListener> listeners = new HashSet<StateTransitionListener>();
+	private List<StateTransitionListener> listeners = new ArrayList<StateTransitionListener>();
 	
 	/**
 	 * Transitions the state to the next one
@@ -31,6 +31,10 @@ public enum ScanningState {
 		return states[ordinal()+1 % states.length];
 	}
 	
+	public void addTransitionListener(StateTransitionListener listener) {
+		listeners.add(listener);
+	}
+	
 	/**
 	 * Notifies all registered listeners of the transition to this state.
 	 */

src/net/azib/ipscan/core/state/StateMachine.java

@@ -6,7 +6,10 @@
 
 package net.azib.ipscan.core.state;
 
-import net.azib.ipscan.core.ScanningProgressCallback;
+import java.util.logging.Logger;
+
+import net.azib.ipscan.config.LoggerFactory;
+
 
 /**
  * StateMachine
@@ -15,19 +18,15 @@ import net.azib.ipscan.core.ScanningProgressCallback;
  */
 public class StateMachine {
 	
-	private ScanningProgressCallback progressCallback;
+	private static final Logger LOG = LoggerFactory.getLogger();
+	
 	private ScanningState state = ScanningState.IDLE;
 	
-	public void transitionTo(ScanningState newState) {
-		this.state = newState;
-		progressCallback.scannerStateChanged(newState);
-	}
-
 	/**
 	 * @param state
 	 * @return true if current state is as specified
 	 */
-	public boolean isState(ScanningState state) {
+	public boolean inState(ScanningState state) {
 		return this.state == state;
 	}
 	
@@ -38,8 +37,48 @@ public class StateMachine {
 		return state;
 	}
 
-	public void setScanningProgressCallback(ScanningProgressCallback progressCallback) {
-		this.progressCallback = progressCallback;
+	/**
+	 * Transitions to the specified state, notifying all listeners.
+	 * @param newState
+	 */
+	public void transitionTo(ScanningState newState) {
+		state = newState;
+		state.notifyOnEntry();
 	}
-	
+
+	/**
+	 * Transitions to the next state in the sequence.
+	 * Called when user presses the scan button.
+	 */
+	public void transitionToNext() {
+		// killing state cannot be transitioned from by pressing a button
+		if (state != ScanningState.KILLING) {
+			transitionTo(state.next());
+		}
+	}
+
+	/**
+	 * Transitions to the stopping state
+	 */
+	public void stop() {
+		if (state == ScanningState.SCANNING) {
+			transitionTo(ScanningState.STOPPING);
+		}
+		else {
+			LOG.warning("Attempt to stop from " + state);
+		}
+	}
+
+	/**
+	 * Transitions back to the idle state
+	 */
+	public void complete() {
+		if (state == ScanningState.STOPPING || state == ScanningState.KILLING) {
+			transitionTo(ScanningState.IDLE);
+		}		
+		else {
+			LOG.warning("Attempt to complete from " + state);
+		}
+	}
+
 }

src/net/azib/ipscan/gui/actions/StartStopScanningAction.java

@@ -13,6 +13,7 @@ import net.azib.ipscan.core.ScannerThreadFactory;
 import net.azib.ipscan.core.ScanningProgressCallback;
 import net.azib.ipscan.core.state.ScanningState;
 import net.azib.ipscan.core.state.StateMachine;
+import net.azib.ipscan.core.state.StateTransitionListener;
 import net.azib.ipscan.gui.ResultTable;
 import net.azib.ipscan.gui.ScanningResultsConsumer;
 import net.azib.ipscan.gui.StatusBar;
@@ -30,7 +31,7 @@ import org.eclipse.swt.widgets.Display;
  * 
  * @author anton
  */
-public class StartStopScanningAction implements SelectionListener, ScanningProgressCallback {
+public class StartStopScanningAction implements SelectionListener, ScanningProgressCallback, StateTransitionListener {
 	
 	private ScannerThreadFactory scannerThreadFactory;
 	private ScannerThread scannerThread;
@@ -53,10 +54,7 @@ public class StartStopScanningAction implements SelectionListener, ScanningProgr
 		this.feederRegistry = feederRegistry;
 		this.button = startStopButton;
 		this.display = button.getDisplay();
-		
 		this.stateMachine = stateMachine;
-		// TODO: remove this, use state transition notifications
-		this.stateMachine.setScanningProgressCallback(this);
 		
 		// pre-load button images
 		buttonImages[ScanningState.IDLE.ordinal()] = new Image(null, Labels.getInstance().getImageAsStream("button.start.img"));
@@ -69,6 +67,11 @@ public class StartStopScanningAction implements SelectionListener, ScanningProgr
 		buttonTexts[ScanningState.SCANNING.ordinal()] = Labels.getLabel("button.stop");
 		buttonTexts[ScanningState.STOPPING.ordinal()] = Labels.getLabel("button.kill");
 		buttonTexts[ScanningState.KILLING.ordinal()] = Labels.getLabel("button.kill");
+
+		// add listeners to all state changes
+		for (ScanningState state : ScanningState.values()) {
+			state.addTransitionListener(this);
+		}
 		
 		// set the defaultimage
 		ScanningState state = stateMachine.getState();
@@ -81,31 +84,13 @@ public class StartStopScanningAction implements SelectionListener, ScanningProgr
 	}
 
 	public void widgetSelected(SelectionEvent e) {
-		switch (stateMachine.getState()) {
-			case IDLE:
-				// start the scan!
-				resultTable.initNewScan(feederRegistry.current().getInfo());
-				ScanningResultsConsumer resultsConsumer = new ScanningResultsConsumer(resultTable);
-				scannerThread = scannerThreadFactory.createScannerThread(feederRegistry.current().getFeeder(), this);
-				// TODO: fix this: this is needed here to avoid cylic dependencies...
-				scannerThread.setResultsCallback(resultsConsumer);
-				scannerThread.start();
-				break;
-			case SCANNING:
-				scannerThread.forceStop();
-				break;
-			case STOPPING:
-				scannerThread.abort();
-				break;
-			case KILLING:
-				break;
-		}
+		stateMachine.transitionToNext();
 	}
 	
-	public void scannerStateChanged(final ScanningState state) {
+	public void transitionTo(final ScanningState state) {
 		if (display.isDisposed())
 			return;
-		display.asyncExec(new Runnable() {
+		display.syncExec(new Runnable() {
 			public void run() {
 				if (statusBar.isDisposed())
 					return;
@@ -116,6 +101,15 @@ public class StartStopScanningAction implements SelectionListener, ScanningProgr
 						statusBar.setStatusText(null);
 						statusBar.setProgress(0);
 						break;
+					case SCANNING:
+						// start the scan!
+						resultTable.initNewScan(feederRegistry.current().getInfo());
+						ScanningResultsConsumer resultsConsumer = new ScanningResultsConsumer(resultTable);
+						scannerThread = scannerThreadFactory.createScannerThread(feederRegistry.current().getFeeder(), StartStopScanningAction.this);
+						// TODO: fix this: this is needed here to avoid cylic dependencies...
+						scannerThread.setResultsCallback(resultsConsumer);
+						scannerThread.start();
+						break;
 					case STOPPING:
 						statusBar.setStatusText(Labels.getLabel("state.waitForThreads"));
 						break;
@@ -150,5 +144,5 @@ public class StartStopScanningAction implements SelectionListener, ScanningProgr
 			}
 		});
 	}
-	
+
 }