From dccac30557d7110728c84ea80103d18e0fed6d50 Mon Sep 17 00:00:00 2001
From: navid <navid>
Date: Mon, 5 Jan 2009 18:29:07 +0000
Subject: [PATCH] *** empty log message ***

---
 .../jcarderbenchmarks/modelview/Main.java     | 31 +++++++++
 .../jcarderbenchmarks/modelview/Model.java    | 68 +++++++++++++++++++
 .../jcarderbenchmarks/modelview/View.java     | 33 +++++++++
 3 files changed, 132 insertions(+)
 create mode 100644 Robust/Transactions/jcarderbenchmarks/modelview/Main.java
 create mode 100644 Robust/Transactions/jcarderbenchmarks/modelview/Model.java
 create mode 100644 Robust/Transactions/jcarderbenchmarks/modelview/View.java

diff --git a/Robust/Transactions/jcarderbenchmarks/modelview/Main.java b/Robust/Transactions/jcarderbenchmarks/modelview/Main.java
new file mode 100644
index 00000000..8392d9cf
--- /dev/null
+++ b/Robust/Transactions/jcarderbenchmarks/modelview/Main.java
@@ -0,0 +1,31 @@
+
+
+public class Main {
+    public static void main(String[] args) throws Exception {
+        int timeToSleep;
+        if (args.length > 0) {
+            timeToSleep = Integer.parseInt(args[0]);
+        } else {
+            timeToSleep = 0;
+        }
+
+        Model dataModel = new Model();
+
+        @SuppressWarnings("unused")
+        View view1 = new View(dataModel);
+        View view2 = new View(dataModel);
+        dataModel.setDataAsynchronously();
+        Thread.sleep(timeToSleep);
+
+        // For some (here unspecified) reason, we want to freeze view2
+        // so that it doesn't receive any notifications about changed
+        // data.
+        view2.freeze();
+        System.out.println("sfg");
+        // Now we want notifications about updates again.
+        view2.thaw();
+        
+
+        System.out.println("Main thread finished");
+    }
+}
diff --git a/Robust/Transactions/jcarderbenchmarks/modelview/Model.java b/Robust/Transactions/jcarderbenchmarks/modelview/Model.java
new file mode 100644
index 00000000..0dd59a65
--- /dev/null
+++ b/Robust/Transactions/jcarderbenchmarks/modelview/Model.java
@@ -0,0 +1,68 @@
+
+
+import java.util.ArrayList;
+import java.util.List;
+
+/**
+ * This class is an example of a data model that implements the
+ * Observer pattern and also tries to be thread-safe. Updates to the
+ * model are considered taking a long time and are therefore performed
+ * in a background thread.
+ */
+public class Model {
+    public interface Listener {
+        /** Called when the model has been updated. */
+        void modelUpdated();
+    }
+
+    /** A list of listeners. */
+    private List<Listener> mListeners = new ArrayList<Listener>();
+
+    // Some mutable data fields here...
+
+    /**
+     * Register a new listener to changes of data in the model.
+     *
+     * @param listener Listener to subscribe.
+     */
+    synchronized public void registerListener(Listener listener) {
+        mListeners.add(listener);
+    }
+
+    /**
+     * Unregister a listener.
+     *
+     * @param listener Listener to unsubscribe.
+     */
+    synchronized public void unregisterListener(Listener listener) {
+        mListeners.remove(listener);
+    }
+
+    /**
+     * Modify the model's data.
+     *
+     * Since the update can take a long time, it is performed in a
+     * background thread. When the update has been completed, the
+     * listeners are notified.
+     */
+    public void setDataAsynchronously() {
+        Thread updateThread = new Thread("modelUpdateThread") {
+            public void run() {
+                System.out.println("Updating the model");
+                // Set data fields here...
+                notifyListeners();
+            };
+        };
+        updateThread.start();
+    }
+
+    /**
+     * Notify listeners that the data has been modified.
+     */
+    synchronized private void notifyListeners() {
+        System.out.println("Notifying listeners");
+        for (Listener listener : mListeners) {
+            listener.modelUpdated();
+        }
+    }
+}
diff --git a/Robust/Transactions/jcarderbenchmarks/modelview/View.java b/Robust/Transactions/jcarderbenchmarks/modelview/View.java
new file mode 100644
index 00000000..a5be00aa
--- /dev/null
+++ b/Robust/Transactions/jcarderbenchmarks/modelview/View.java
@@ -0,0 +1,33 @@
+
+
+public class View implements Model.Listener {
+    private Model mDataModel;
+    private boolean mFrozen = false;
+
+    public View(Model dataModel) {
+       mDataModel = dataModel;
+       System.out.println("Registering view in data model");
+       dataModel.registerListener(this);
+    }
+
+    synchronized void freeze() {
+        if (!mFrozen) {
+           System.out.println("Freezing view");
+           mDataModel.unregisterListener(this);
+            System.out.println("Freezing view2");
+           mFrozen = true;
+       }
+    }
+
+    synchronized void thaw() {
+       if (mFrozen) {
+           System.out.println("Thawing view");
+           mDataModel.registerListener(this);
+           mFrozen = false;
+       }
+    }
+
+     synchronized public void modelUpdated() {
+         // ...
+     }
+}
-- 
2.34.1