Entitlement plugin

pom.xml

@@ -101,6 +101,11 @@
             <artifactId>killbill-platform-osgi-bundles-lib-killbill</artifactId>
             <scope>provided</scope>
         </dependency>
+        <dependency>
+            <groupId>org.kill-bill.billing.plugin</groupId>
+            <artifactId>killbill-plugin-api-entitlement</artifactId>
+            <scope>provided</scope>
+        </dependency>
         <dependency>
             <groupId>org.kill-bill.billing.plugin</groupId>
             <artifactId>killbill-plugin-api-invoice</artifactId>

src/main/java/org/killbill/billing/plugin/helloworld/HelloWorldActivator.java

@@ -25,6 +25,7 @@
 import javax.servlet.Servlet;
 import javax.servlet.http.HttpServlet;
 
+import org.killbill.billing.entitlement.plugin.api.EntitlementPluginApi;
 import org.killbill.billing.invoice.plugin.api.InvoicePluginApi;
 import org.killbill.billing.osgi.api.Healthcheck;
 import org.killbill.billing.osgi.api.OSGIPluginProperties;
@@ -91,6 +92,10 @@ public void start(final BundleContext context) throws Exception {
         final InvoicePluginApi invoicePluginApi = new HelloWorldInvoicePluginApi(killbillAPI, configProperties, null);
         registerInvoicePluginApi(context, invoicePluginApi);
 
+        final EntitlementPluginApi entitlementPluginApi = new HelloWorldEntitlementPluginApi(killbillAPI);
+        registerEntitlementPluginApi(context, entitlementPluginApi);
+
+
         // Register a servlet (optional)
         final PluginApp pluginApp = new PluginAppBuilder(PLUGIN_NAME, killbillAPI, dataSource, super.clock,
                                                          configProperties).withRouteClass(HelloWorldServlet.class)
@@ -139,4 +144,10 @@ private void registerHealthcheck(final BundleContext context, final Healthcheck
         props.put(OSGIPluginProperties.PLUGIN_NAME_PROP, PLUGIN_NAME);
         registrar.registerService(context, Healthcheck.class, healthcheck, props);
     }
+
+    private void registerEntitlementPluginApi(final BundleContext context, final EntitlementPluginApi api) {
+        final Hashtable<String, String> props = new Hashtable<String, String>();
+        props.put(OSGIPluginProperties.PLUGIN_NAME_PROP, PLUGIN_NAME);
+        registrar.registerService(context, EntitlementPluginApi.class, api, props);
+    }
 }

src/main/java/org/killbill/billing/plugin/helloworld/HelloWorldEntitlementPluginApi.java

@@ -0,0 +1,86 @@
+/*
+ * Copyright 2020-2024 Equinix, Inc
+ * Copyright 2014-2024 The Billing Project, LLC
+ *
+ * The Billing Project licenses this file to you under the Apache License, version 2.0
+ * (the "License"); you may not use this file except in compliance with the
+ * License.  You may obtain a copy of the License at:
+ *
+ *    http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
+ * WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.  See the
+ * License for the specific language governing permissions and limitations
+ * under the License.
+ */
+
+package org.killbill.billing.plugin.helloworld;
+
+import java.util.List;
+
+import org.killbill.billing.catalog.api.Plan;
+import org.killbill.billing.entitlement.api.BaseEntitlementWithAddOnsSpecifier;
+import org.killbill.billing.entitlement.api.Subscription;
+import org.killbill.billing.entitlement.api.SubscriptionApiException;
+import org.killbill.billing.entitlement.api.SubscriptionBundle;
+import org.killbill.billing.entitlement.plugin.api.EntitlementContext;
+import org.killbill.billing.entitlement.plugin.api.EntitlementPluginApi;
+import org.killbill.billing.entitlement.plugin.api.EntitlementPluginApiException;
+import org.killbill.billing.entitlement.plugin.api.OnFailureEntitlementResult;
+import org.killbill.billing.entitlement.plugin.api.OnSuccessEntitlementResult;
+import org.killbill.billing.entitlement.plugin.api.OperationType;
+import org.killbill.billing.entitlement.plugin.api.PriorEntitlementResult;
+import org.killbill.billing.entitlement.plugin.api.boilerplate.plugin.PriorEntitlementResultImp;
+import org.killbill.billing.osgi.libs.killbill.OSGIKillbillAPI;
+import org.killbill.billing.payment.api.PluginProperty;
+import org.slf4j.Logger;
+import org.slf4j.LoggerFactory;
+
+public class HelloWorldEntitlementPluginApi implements EntitlementPluginApi {
+
+    public static final Logger logger = LoggerFactory.getLogger(HelloWorldEntitlementPluginApi.class);
+
+    private final OSGIKillbillAPI killbillAPI;
+
+    public HelloWorldEntitlementPluginApi(final OSGIKillbillAPI killbillAPI) {
+        this.killbillAPI = killbillAPI;
+    }
+
+    @Override
+    public PriorEntitlementResult priorCall(final EntitlementContext context, final Iterable<PluginProperty> properties) throws EntitlementPluginApiException {
+        if (context.getOperationType() == OperationType.CREATE_SHOPPING_CART_SUBSCRIPTIONS || context.getOperationType() == OperationType.CREATE_SUBSCRIPTION || context.getOperationType() == OperationType.CREATE_SUBSCRIPTIONS_WITH_AO) {
+            Iterable<BaseEntitlementWithAddOnsSpecifier> baseEntList = context.getBaseEntitlementWithAddOnsSpecifiers();
+            String newplanName = baseEntList.iterator().next().getEntitlementSpecifier().iterator().next().getPlanPhaseSpecifier().getPlanName();
+            logger.info("New planName: {}", newplanName);
+            List<SubscriptionBundle> bundles = null;
+            try {
+                bundles = killbillAPI.getSubscriptionApi().getSubscriptionBundlesForAccountId(context.getAccountId(), context);
+                for (SubscriptionBundle bundle : bundles) {
+                    List<Subscription> subscriptions = bundle.getSubscriptions();
+                    for (Subscription subscription : subscriptions) {
+                        Plan plan = subscription.getLastActivePlan();
+                        logger.info("Plan is {}", plan.getName());
+                        if (plan.getName().equals(newplanName)) {
+                            logger.info("Subscription already exists, blocking operation");
+                            return new PriorEntitlementResultImp.Builder<>().withIsAborted(true).build();
+                        }
+                    }
+                }
+            } catch (SubscriptionApiException e) {
+                throw new RuntimeException(e);
+            }
+        }
+        return null;
+    }
+
+    @Override
+    public OnSuccessEntitlementResult onSuccessCall(final EntitlementContext context, final Iterable<PluginProperty> properties) throws EntitlementPluginApiException {
+        return null;
+    }
+
+    @Override
+    public OnFailureEntitlementResult onFailureCall(final EntitlementContext context, final Iterable<PluginProperty> properties) throws EntitlementPluginApiException {
+        return null;
+    }
+}