O3-5370: Auto-Generate Billable Items from Medication Orders

api/pom.xml

@@ -48,6 +48,11 @@
 			<artifactId>stockmanagement-api</artifactId>
 		</dependency>
 
+		<dependency>
+			<groupId>org.openmrs</groupId>
+			<artifactId>event-api</artifactId>
+		</dependency>
+
 		<dependency>
 			<groupId>org.openmrs.module</groupId>
 			<artifactId>uiframework-api</artifactId>

api/src/main/java/org/openmrs/module/billing/BillingModuleActivator.java

@@ -13,18 +13,32 @@
  */
 package org.openmrs.module.billing;
 
+import java.util.ArrayList;
+import java.util.List;
+
+import lombok.Setter;
 import lombok.extern.slf4j.Slf4j;
+import org.openmrs.api.context.Context;
+import org.openmrs.event.Event;
 import org.openmrs.module.BaseModuleActivator;
+import org.openmrs.module.DaemonToken;
+import org.openmrs.module.DaemonTokenAware;
 import org.openmrs.module.Module;
 import org.openmrs.module.ModuleFactory;
+import org.openmrs.module.billing.api.billing.BillingEventListener;
 import org.openmrs.module.billing.web.CashierWebConstants;
 import org.openmrs.module.web.WebModuleUtil;
 
 /**
  * This class contains the logic that is run every time this module is either started or stopped.
  */
 @Slf4j
-public class BillingModuleActivator extends BaseModuleActivator {
+@Setter
+public class BillingModuleActivator extends BaseModuleActivator implements DaemonTokenAware {
+
+	private DaemonToken daemonToken;
+
+	private final List<BillingEventListener> subscribedListeners = new ArrayList<>();
 
 	/**
 	 * @see BaseModuleActivator#contextRefreshed()
@@ -40,16 +54,50 @@ public void contextRefreshed() {
 	@Override
 	public void started() {
 		log.info("OpenMRS Billing Module started");
+
+		subscribeBillingEventListeners();
 	}
 
 	/**
 	 * @see BaseModuleActivator#stopped()
 	 */
 	@Override
 	public void stopped() {
+		unsubscribeBillingEventListeners();
+
 		Module module = ModuleFactory.getModuleById(CashierWebConstants.OPENHMIS_CASHIER_MODULE_ID);
 		WebModuleUtil.unloadFilters(module);
 
 		log.info("OpenMRS Billing Module stopped");
 	}
+
+	private void subscribeBillingEventListeners() {
+		List<BillingEventListener> listeners = Context.getRegisteredComponents(BillingEventListener.class);
+		for (BillingEventListener listener : listeners) {
+			try {
+				listener.setDaemonToken(daemonToken);
+				Event.subscribe(listener.getSubscribedClass(), listener.getSubscribedAction().name(), listener);
+				subscribedListeners.add(listener);
+				log.info("Subscribed {} to {} {} events", listener.getClass().getSimpleName(),
+				    listener.getSubscribedClass().getSimpleName(), listener.getSubscribedAction());
+			}
+			catch (Exception e) {
+				log.error("Failed to subscribe {}", listener.getClass().getSimpleName(), e);
+			}
+		}
+	}
+
+	private void unsubscribeBillingEventListeners() {
+		for (BillingEventListener listener : subscribedListeners) {
+			try {
+				Event.unsubscribe(listener.getSubscribedClass(), listener.getSubscribedAction(), listener);
+				log.info("Unsubscribed {} from {} {} events", listener.getClass().getSimpleName(),
+				    listener.getSubscribedClass().getSimpleName(), listener.getSubscribedAction());
+			}
+			catch (Exception e) {
+				log.error("Failed to unsubscribe {}", listener.getClass().getSimpleName(), e);
+			}
+		}
+		subscribedListeners.clear();
+	}
 }