GF-159: Points from review

human-diffusion-adapter/README.md

@@ -0,0 +1,12 @@
+# Human Adapter
+
+The Human Adapter is a Gateway Framework example that treats the user as the external system. Once configured and running The Human Adapter creates a GUI window for interaction. Users can publish a value, and they can set and get the current service state. The example illustrates how to publish values and correctly react to service state changes.
+
+![A running Human Adapter service](screen-shot.png)
+
+## Configuration
+
+Configuration is deliberately simple. A service takes two parameters.
+
+1. `greeting`'` - a string greeting to display in the GUI so the user can differentiate multiple services
+2. `topic` -  A Diffusion topic path to which values should be published./ 

human-diffusion-adapter/pom.xml

@@ -11,11 +11,6 @@
 
     <artifactId>human-diffusion-adapter</artifactId>
 
-    <properties>
-        <maven.compiler.source>11</maven.compiler.source>
-        <maven.compiler.target>11</maven.compiler.target>
-    </properties>
-
     <dependencies>
         <dependency>
             <groupId>org.apache.logging.log4j</groupId>

human-diffusion-adapter/src/main/java/com/diffusiondata/example/adapter/human/Application.java

@@ -1,6 +1,7 @@
 package com.diffusiondata.example.adapter.human;
 
 import static com.diffusiondata.example.adapter.human.Common.getParam;
+import static com.diffusiondata.example.adapter.human.Common.getResourceFileAsString;
 import static com.diffusiondata.gateway.framework.DiffusionGatewayFramework.newApplicationDetailsBuilder;
 import static com.diffusiondata.gateway.framework.ServiceMode.STREAMING_SOURCE;
 
@@ -18,7 +19,9 @@
 
 public class Application implements GatewayApplication  {
 
-    private static final String GUI_SERVICE_SCHEMA = Common.getResourceFileAsString(Application.class, "human.schema.json");
+    private static final String GUI_SERVICE_SCHEMA = getResourceFileAsString(
+        Application.class,
+        "human.schema.json");
 
     @Override
     public ApplicationDetails getApplicationDetails() throws ApplicationConfigurationException {
@@ -33,8 +36,11 @@ public ApplicationDetails getApplicationDetails() throws ApplicationConfiguratio
     }
 
     @Override
-    public StreamingSourceHandler addStreamingSource(ServiceDefinition serviceDefinition, Publisher publisher, StateHandler stateHandler) throws InvalidConfigurationException {
-
+    public StreamingSourceHandler addStreamingSource(
+        ServiceDefinition serviceDefinition,
+        Publisher publisher,
+        StateHandler stateHandler
+    ) throws InvalidConfigurationException {
         final Map<String, Object> params = serviceDefinition.getParameters();
         final String greeting = getParam(params, "greeting", String.class, "Hello Human!");
         final String topicPath = getParam(params, "topic", String.class, "human/says");

human-diffusion-adapter/src/main/java/com/diffusiondata/example/adapter/human/Common.java

@@ -12,7 +12,11 @@
 import java.util.Map;
 import java.util.stream.Collectors;
 
-public class Common {
+final class Common {
+
+    private Common() {
+        /* this is a namespace */
+    }
 
     /**
      * Fetch a text resource relative to a given class for initialising a constant.

human-diffusion-adapter/src/main/java/com/diffusiondata/example/adapter/human/Constraints.java

@@ -8,7 +8,7 @@
  */
 public class Constraints {
 
-    GridBagConstraints result = new GridBagConstraints();
+    private final GridBagConstraints result = new GridBagConstraints();
 
     private Constraints(int x, int y, int width, int height) {
         this.result.gridx = x;

human-diffusion-adapter/src/main/java/com/diffusiondata/example/adapter/human/EventHandlers.java

@@ -1,18 +1,17 @@
 package com.diffusiondata.example.adapter.human;
 
 import java.util.ArrayList;
+import java.util.List;
 import java.util.function.Consumer;
 
-public class EventHandlers<T> extends ArrayList<Consumer<T>> {
-    public EventHandlers(int initialCapacity) {
-        super(initialCapacity);
-    }
+public class EventHandlers<T> {
+    private List<Consumer<T>> consumers = new ArrayList<>();
 
-    public EventHandlers() {
-        this(1);
+    void dispatch(T event) {
+        consumers.forEach(l -> l.accept(event));
     }
 
-    void dispatch(T event) {
-        this.forEach(l -> l.accept(event));
+    public void add(Consumer<T> handler) {
+        consumers.add(handler);
     }
 }

human-diffusion-adapter/src/main/java/com/diffusiondata/example/adapter/human/HumanGui.java

@@ -21,7 +21,6 @@
 import org.slf4j.Logger;
 import org.slf4j.LoggerFactory;
 
-import javax.imageio.ImageIO;
 import javax.swing.AbstractAction;
 import javax.swing.Action;
 import javax.swing.ActionMap;
@@ -51,7 +50,6 @@
 import java.awt.event.KeyEvent;
 import java.awt.event.MouseAdapter;
 import java.awt.event.MouseEvent;
-import java.io.IOException;
 import java.util.function.Consumer;
 import java.util.function.Function;
 import java.util.function.Supplier;
@@ -66,13 +64,17 @@ public class HumanGui {
     private final JFrame frame;
     private final JTextArea messageTextArea;
     private final JButton sendButton;
+    private final Supplier<ServiceState> serviceStateSupplier;
+    private final Function<SetStateEvent, ServiceState> setStateListener;
     private JLabel serviceStateText;
 
     // Mutable state
-    private Supplier<ServiceState> serviceStateSupplier = null;
-    private Function<SetStateEvent, ServiceState> setStateListeners = null;
 
-    public HumanGui(String greeting) {
+    public HumanGui(
+        String greeting,
+        Supplier<ServiceState> serviceStateSupplier,
+        Function<SetStateEvent, ServiceState> setStateListener
+    ) {
         this.frame = new JFrame(greeting);
         frame.setDefaultCloseOperation(DO_NOTHING_ON_CLOSE);
         frame.setSize(400, 300);
@@ -112,6 +114,9 @@ public void actionPerformed(ActionEvent e) {
 
         frame.setLocationRelativeTo(null); // Center on screen
         frame.add(splitPane);
+
+        this.serviceStateSupplier = serviceStateSupplier;
+        this.setStateListener = setStateListener;
     }
 
     private JComponent buildStatusPanel() {
@@ -201,8 +206,8 @@ private JComponent buildStatusPanel() {
         result.add(formPanel, CENTER);
         final JButton setStatusButton = new JButton("Set Status");
         setStatusButton.addActionListener((ev) -> {
-            if (this.setStateListeners != null) {
-                final ServiceState serviceState = this.setStateListeners.apply(new SetStateEvent(
+            if (this.setStateListener != null) {
+                final ServiceState serviceState = this.setStateListener.apply(new SetStateEvent(
                     (StateHandler.Status)statusCombo.getSelectedItem(),
                     titleText.getText(),
                     descriptionText.getText())
@@ -225,7 +230,12 @@ public void actionPerformed(ActionEvent e) {
         return result;
     }
 
-    private static void bindKeyStrokeToAction(JComponent component, KeyStroke keyStroke, String actionKey, Action action) {
+    private static void bindKeyStrokeToAction(
+        JComponent component,
+        KeyStroke keyStroke,
+        String actionKey,
+        Action action
+    ) {
         final InputMap inputMap = component.getInputMap(JComponent.WHEN_IN_FOCUSED_WINDOW);
         ActionMap actionMap = component.getActionMap();
 
@@ -246,32 +256,24 @@ public void addSendEventHandler(Consumer<SendMessageEvent> handler) {
         this.sendMessageListeners.add(handler);
     }
 
-    public void addSetStateEventHandler(Function<SetStateEvent, ServiceState> handler) {
-        this.setStateListeners = handler;
-    }
-
-    public void setServiceStateProducer(java.util.function.Supplier<ServiceState> supplier) {
-        this.serviceStateSupplier = supplier;
-    }
-
     public static void main(String[] args) {
         invokeLater(() -> {
             try {
                 setLookAndFeel(getSystemLookAndFeelClassName());
             }
-            catch (UnsupportedLookAndFeelException | ClassNotFoundException | InstantiationException | IllegalAccessException ex) {
+            catch (UnsupportedLookAndFeelException | ClassNotFoundException |
+                   InstantiationException | IllegalAccessException ex) {
                 LOG.warn("Cannot set look and feel", ex);
             }
 
-            final HumanGui gui = new HumanGui("Simple test");
+            final HumanGui gui = new HumanGui("Simple test",
+                () -> ServiceState.INITIAL,
+                ev ->ServiceState.INITIAL);
             gui.setVisible(true);
             gui.addSendEventHandler(ev -> LOG.info("Sending: {}", ev));
-            gui.addSetStateEventHandler(ev ->{LOG.info("Setting status: {}", ev); return ServiceState.INITIAL;});
-            gui.setServiceStateProducer(() -> ServiceState.INITIAL);
         });
     }
 
-
 }
 
 class SendMessageEvent {

human-diffusion-adapter/src/main/java/com/diffusiondata/example/adapter/human/HumanStreamingSourceHandler.java

@@ -22,9 +22,18 @@ public class HumanStreamingSourceHandler implements StreamingSourceHandler {
     private final StateHandler stateHandler;
     private final HumanGui gui;
 
-    public HumanStreamingSourceHandler(Publisher publisher, StateHandler stateHandler, String greeting, String topicPath) {
+    public HumanStreamingSourceHandler(
+        Publisher publisher,
+        StateHandler stateHandler,
+        String greeting,
+        String topicPath
+    ) {
         this.stateHandler = stateHandler;
-        this.gui = new HumanGui(greeting);
+        this.gui = new HumanGui(
+            greeting,
+            this.stateHandler::getState,
+            ev -> this.stateHandler.reportStatus(ev.getStatus(), ev.getTitle(), ev.getDescription())
+        );
         this.gui.addSendEventHandler((ev) -> {
             try {
                 publisher.publish(topicPath, ev.getMessage()).get(1, TimeUnit.SECONDS);
@@ -33,10 +42,6 @@ public HumanStreamingSourceHandler(Publisher publisher, StateHandler stateHandle
                 LOG.error("Cannot publish '{}' to {}", ev.getMessage(), topicPath, ex);
             }
         });
-        this.gui.addSetStateEventHandler(ev ->
-            this.stateHandler.reportStatus(ev.getStatus(), ev.getTitle(), ev.getDescription())
-        );
-        this.gui.setServiceStateProducer(this.stateHandler::getState);
     }
 
     @Override