#8 financer-web-client has a hard dependency on push-service

Introduce proxy for push service so it is completely optional

financer-web-client/pom.xml

@@ -62,6 +62,7 @@
         <dependency>
             <groupId>de.77zzcx7.push-service</groupId>
             <artifactId>push-service-client-lib</artifactId>
+            <optional>true</optional>
         </dependency>
 
         <!-- Financer dependencies -->

financer-web-client/src/main/java/de/financer/controller/AccountController.java

@@ -7,13 +7,13 @@ import de.financer.dto.Order;
 import de.financer.dto.SearchTransactionsResponseDto;
 import de.financer.form.NewAccountForm;
 import de.financer.model.*;
+import de.financer.notification.Notification;
+import de.financer.notification.PushServiceProxy;
+import de.financer.notification.Urgency;
 import de.financer.template.*;
 import de.financer.template.exception.FinancerRestException;
 import de.financer.util.ControllerUtils;
 import de.financer.util.TransactionUtils;
-import de.pushservice.client.dto.PayloadDto;
-import de.pushservice.client.model.Urgency;
-import de.pushservice.client.service.SubscriptionService;
 import org.apache.commons.collections4.IterableUtils;
 import org.apache.commons.lang3.BooleanUtils;
 import org.springframework.beans.factory.annotation.Autowired;
@@ -209,21 +209,22 @@ public class AccountController {
 
     // ---------------------------------------------
 
-    @Autowired(required = false)
+    @Autowired
-    private SubscriptionService subscriptionService;
+    private PushServiceProxy pushServiceProxy;
     private int counter = 0;
 
     @GetMapping("/sendTestNotification")
     public String sendTestNotification() {
-        if (this.subscriptionService != null && this.subscriptionService.isInitialized()) {
+        if (this.pushServiceProxy.isInitialized()) {
-            PayloadDto p = new PayloadDto("Hello from Financer!");
+            Notification notification = new Notification();
 
-            p.setTimestamp(System.currentTimeMillis());
+            notification.setTitle("Hello from Financer!");
-            p.setMessage("Test notification " + counter++);
+            notification.setTopic("FINANCER-TEST");
-            p.setVibration(new int[] {100, 200, 300, 400, 500});
+            notification.setMessage("Test notification " + counter++);
+            notification.setUrgency(Urgency.NORMAL);
 
             try {
-                this.subscriptionService.notify(p, "FINANCER-TEST", Urgency.NORMAL);
+                this.pushServiceProxy.notify(notification);
             }
             catch(Exception e) {
                 e.printStackTrace();

financer-web-client/src/main/java/de/financer/notification/Notification.java

@@ -0,0 +1,40 @@
+package de.financer.notification;
+
+public class Notification {
+    private String title;
+    private String topic;
+    private String message;
+    private Urgency urgency;
+
+    public String getTitle() {
+        return title;
+    }
+
+    public void setTitle(String title) {
+        this.title = title;
+    }
+
+    public String getTopic() {
+        return topic;
+    }
+
+    public void setTopic(String topic) {
+        this.topic = topic;
+    }
+
+    public String getMessage() {
+        return message;
+    }
+
+    public void setMessage(String message) {
+        this.message = message;
+    }
+
+    public Urgency getUrgency() {
+        return urgency;
+    }
+
+    public void setUrgency(Urgency urgency) {
+        this.urgency = urgency;
+    }
+}

financer-web-client/src/main/java/de/financer/notification/PushServiceProxy.java

@@ -0,0 +1,138 @@
+package de.financer.notification;
+
+import org.slf4j.Logger;
+import org.slf4j.LoggerFactory;
+import org.springframework.beans.factory.InitializingBean;
+import org.springframework.beans.factory.annotation.Autowired;
+import org.springframework.beans.factory.config.AutowireCapableBeanFactory;
+import org.springframework.stereotype.Component;
+
+/**
+ * Class to really loosely couple the PushService to financer.
+ * The PushService dependency is optional in the POM, so if it is not available instantiation would fail,
+ * that's why the actual classes get proxied and coupling is done via reflection.
+ */
+@Component
+public class PushServiceProxy implements InitializingBean {
+    private static final Logger LOGGER = LoggerFactory.getLogger(PushServiceProxy.class);
+
+    // #### Service constants
+    private static final String SERVICE_CLASS_NAME = "de.pushservice.client.service.SubscriptionService";
+    private static final String SERVICE_METHOD_IS_INITIALIZED = "isInitialized";
+    private static final String SERVICE_METHOD_NOTIFY = "notify";
+
+    // #### Payload constants
+    private static final String PAYLOAD_CLASS_NAME = "de.pushservice.client.dto.PayloadDto";
+    private static final String PAYLOAD_METHOD_SET_TIMESTAMP = "setTimestamp";
+    private static final String PAYLOAD_METHOD_SET_MESSAGE = "setMessage";
+
+    // #### Urgency constants
+    private static final String URGENCY_CLASS_NAME = "de.pushservice.client.model.Urgency";
+
+    private Class<?> subscriptionServiceClass;
+    private Class<?> payloadClass;
+    private Class<?> urgencyClass;
+    private Object subscriptionServiceInstance;
+
+    @Autowired
+    private AutowireCapableBeanFactory autowireCapableBeanFactory;
+
+    // #### Public methods mimicking SubscriptionService interface
+
+    public boolean isInitialized() {
+        return this.subscriptionServiceInstance != null && this.isInitializedInternal();
+    }
+
+    public void notify(Notification notification) {
+        if(!this.isInitialized()) {
+            LOGGER.warn("notify() called but not initialized!");
+        }
+
+        try {
+            this.subscriptionServiceClass
+                    .getMethod(SERVICE_METHOD_NOTIFY, this.payloadClass, String.class, this.urgencyClass)
+                    .invoke(this.subscriptionServiceInstance, toPayload(notification), notification
+                            .getTopic(), toUrgency(notification));
+        } catch (ReflectiveOperationException e) {
+            LOGGER.error("Error while sending notification!", e);
+        }
+    }
+
+    // #### Initialization
+
+    @Override
+    public void afterPropertiesSet() throws Exception {
+        try {
+            this.subscriptionServiceClass = Class.forName(SERVICE_CLASS_NAME);
+
+            // Since we create the instance ourself no auto wiring by Spring
+            this.subscriptionServiceInstance = this.subscriptionServiceClass.getDeclaredConstructor().newInstance();
+
+            // Do the Spring wiring magic
+            this.autowireCapableBeanFactory.autowireBean(this.subscriptionServiceInstance);
+
+            this.payloadClass = Class.forName(PAYLOAD_CLASS_NAME);
+            this.urgencyClass = Class.forName(URGENCY_CLASS_NAME);
+        } catch (ReflectiveOperationException e) {
+            LOGGER.error("Error while sending notification!", e);
+        }
+    }
+
+    // #### Internal methods
+
+    private Object toUrgency(Notification notification) {
+        Object urgencyInstance = null;
+
+        try {
+            // Urgency is an Enum in PushClient as well
+            // Works by having the same name in both Urgency enums
+            urgencyInstance = this.urgencyClass.getDeclaredField(notification.getUrgency().name()).get(null);
+        } catch (ReflectiveOperationException e) {
+            LOGGER.error("Error while sending notification!", e);
+        }
+
+        return urgencyInstance;
+    }
+
+    private Object toPayload(Notification notification) {
+        Object payloadInstance = null;
+
+        try {
+            payloadInstance = this.payloadClass.getConstructor(String.class)
+                                               .newInstance(notification.getTitle());
+
+            this.payloadClass.getMethod(PAYLOAD_METHOD_SET_TIMESTAMP, long.class)
+                             .invoke(payloadInstance, System.currentTimeMillis());
+
+            this.payloadClass.getMethod(PAYLOAD_METHOD_SET_MESSAGE, String.class)
+                             .invoke(payloadInstance, notification.getMessage());
+        } catch (ReflectiveOperationException e) {
+            LOGGER.error("Error while sending notification!", e);
+        }
+
+        return payloadInstance;
+    }
+
+    private boolean isInitializedInternal() {
+        boolean retVal = false;
+
+        try {
+            final Object tmpRetVal = this.subscriptionServiceClass.getMethod(SERVICE_METHOD_IS_INITIALIZED)
+                                                                  .invoke(this.subscriptionServiceInstance);
+
+            if (Boolean.class.isAssignableFrom(tmpRetVal.getClass())) {
+                retVal = ((Boolean) tmpRetVal).booleanValue();
+            } else {
+                LOGGER.warn("Proxied isInitialized call returned non java.lang.Boolean value");
+            }
+        } catch (ReflectiveOperationException e) {
+            LOGGER.error("Error while sending notification!", e);
+        }
+
+        if(LOGGER.isDebugEnabled()) {
+            LOGGER.debug(String.format("isInitializedInternal() returns with %s", retVal));
+        }
+
+        return retVal;
+    }
+}

financer-web-client/src/main/java/de/financer/notification/Urgency.java

@@ -0,0 +1,8 @@
+package de.financer.notification;
+
+public enum Urgency {
+    VERY_LOW,
+    LOW,
+    NORMAL,
+    HIGH;
+}