HPCC4J-370 Remove Observable pattern from codebase

wsclient/src/main/java/org/hpccsystems/ws/client/utils/DataSingleton.java

@@ -7,8 +7,6 @@
  ******************************************************************************/
 package org.hpccsystems.ws.client.utils;
 
-import java.util.Observable;
-
 import org.apache.axis2.AxisFault;
 import org.apache.axis2.client.Stub;
 

wsclient/src/main/java/org/hpccsystems/ws/client/utils/DataSingletonCollection.java

@@ -10,7 +10,6 @@
 import java.util.Collection;
 import java.util.HashMap;
 import java.util.Map;
-import java.util.Observable;
 
 public class DataSingletonCollection extends Observable
 {

wsclient/src/main/java/org/hpccsystems/ws/client/utils/Observable.java

@@ -0,0 +1,126 @@
+/*******************************************************************************
+ * Copyright (c) 2025 HPCC Systems. All rights reserved. This program and the accompanying materials are made available
+ * under the terms of the Eclipse Public License v1.0 which accompanies this distribution, and is available at
+ * http://www.eclipse.org/legal/epl-v10.html
+ *
+ * Contributors: HPCC Systems - initial API and implementation
+ ******************************************************************************/
+package org.hpccsystems.ws.client.utils;
+
+import java.util.ArrayList;
+import java.util.List;
+
+/**
+ * A simple observable pattern implementation to replace the deprecated java.util.Observable.
+ * This class allows observers to be notified when the state of an object changes.
+ */
+public class Observable
+{
+    private final List<Observer> observers = new ArrayList<>();
+    private boolean changed = false;
+
+    /**
+     * Adds an observer to the set of observers for this object.
+     *
+     * @param o the observer to be added
+     * @throws NullPointerException if the parameter o is null
+     */
+    public synchronized void addObserver(Observer o)
+    {
+        if (o == null)
+        {
+            throw new NullPointerException();
+        }
+        if (!observers.contains(o))
+        {
+            observers.add(o);
+        }
+    }
+
+    /**
+     * Deletes an observer from the set of observers of this object.
+     *
+     * @param o the observer to be deleted
+     */
+    public synchronized void deleteObserver(Observer o)
+    {
+        observers.remove(o);
+    }
+
+    /**
+     * Notifies all observers if this object has been marked as changed.
+     */
+    public void notifyObservers()
+    {
+        notifyObservers(null);
+    }
+
+    /**
+     * Notifies all observers if this object has been marked as changed.
+     *
+     * @param arg an argument to pass to observers
+     */
+    public void notifyObservers(Object arg)
+    {
+        Object[] arrLocal;
+
+        synchronized (this)
+        {
+            if (!changed)
+            {
+                return;
+            }
+            arrLocal = observers.toArray();
+            clearChanged();
+        }
+
+        for (int i = arrLocal.length - 1; i >= 0; i--)
+        {
+            ((Observer) arrLocal[i]).update(this, arg);
+        }
+    }
+
+    /**
+     * Deletes all observers from the set of observers of this object.
+     */
+    public synchronized void deleteObservers()
+    {
+        observers.clear();
+    }
+
+    /**
+     * Marks this Observable object as having been changed.
+     */
+    protected synchronized void setChanged()
+    {
+        changed = true;
+    }
+
+    /**
+     * Clears the changed state of this object.
+     */
+    protected synchronized void clearChanged()
+    {
+        changed = false;
+    }
+
+    /**
+     * Tests if this object has changed.
+     *
+     * @return true if this object has been marked as changed, false otherwise
+     */
+    public synchronized boolean hasChanged()
+    {
+        return changed;
+    }
+
+    /**
+     * Returns the number of observers of this Observable object.
+     *
+     * @return the number of observers
+     */
+    public synchronized int countObservers()
+    {
+        return observers.size();
+    }
+}

wsclient/src/main/java/org/hpccsystems/ws/client/utils/Observer.java

@@ -0,0 +1,23 @@
+/*******************************************************************************
+ * Copyright (c) 2025 HPCC Systems. All rights reserved. This program and the accompanying materials are made available
+ * under the terms of the Eclipse Public License v1.0 which accompanies this distribution, and is available at
+ * http://www.eclipse.org/legal/epl-v10.html
+ *
+ * Contributors: HPCC Systems - initial API and implementation
+ ******************************************************************************/
+package org.hpccsystems.ws.client.utils;
+
+/**
+ * A simple observer interface to replace the deprecated java.util.Observer.
+ * An object that implements this interface can observe changes in Observable objects.
+ */
+public interface Observer
+{
+    /**
+     * This method is called whenever the observed object is changed.
+     *
+     * @param o   the observable object
+     * @param arg an argument passed to the notifyObservers method
+     */
+    void update(Observable o, Object arg);
+}