Add EventSubscriber (#31222)

infra/util/src/main/java/org/apache/shardingsphere/infra/util/eventbus/EventBusContext.java

@@ -33,12 +33,12 @@ public final class EventBusContext {
     }
 
     /**
-     * Register object.
+     * Register event subscriber.
      * 
-     * @param object object
+     * @param subscriber event subscriber
      */
-    public void register(final Object object) {
-        eventBus.register(object);
+    public void register(final EventSubscriber subscriber) {
+        eventBus.register(subscriber);
     }
 
     /**

infra/util/src/main/java/org/apache/shardingsphere/infra/util/eventbus/EventSubscriber.java

@@ -0,0 +1,24 @@
+/*
+ * Licensed to the Apache Software Foundation (ASF) under one or more
+ * contributor license agreements.  See the NOTICE file distributed with
+ * this work for additional information regarding copyright ownership.
+ * The ASF 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.apache.shardingsphere.infra.util.eventbus;
+
+/**
+ * Event subscriber.
+ */
+public interface EventSubscriber {
+}

infra/util/src/test/java/org/apache/shardingsphere/infra/util/eventbus/EventBusContextTest.java

@@ -17,7 +17,7 @@
 
 package org.apache.shardingsphere.infra.util.eventbus;
 
-import org.apache.shardingsphere.infra.util.eventbus.fixture.EventListenerFixture;
+import org.apache.shardingsphere.infra.util.eventbus.fixture.EventSubscriberFixture;
 import org.junit.jupiter.api.Test;
 
 import static org.hamcrest.CoreMatchers.is;
@@ -28,7 +28,7 @@ class EventBusContextTest {
     @Test
     void assertEventBusContextTest() {
         EventBusContext eventBusContext = new EventBusContext();
-        EventListenerFixture listener = new EventListenerFixture();
+        EventSubscriberFixture listener = new EventSubscriberFixture();
         eventBusContext.register(listener);
         eventBusContext.post("foo_event");
         assertThat(listener.getEvents().size(), is(1));

infra/util/src/test/java/org/apache/shardingsphere/infra/util/eventbus/fixture/EventListenerFixture.java → infra/util/src/test/java/org/apache/shardingsphere/infra/util/eventbus/fixture/EventSubscriberFixture.java

@@ -19,12 +19,13 @@
 
 import com.google.common.eventbus.Subscribe;
 import lombok.Getter;
+import org.apache.shardingsphere.infra.util.eventbus.EventSubscriber;
 
 import java.util.LinkedList;
 import java.util.List;
 
 @Getter
-public final class EventListenerFixture {
+public final class EventSubscriberFixture implements EventSubscriber {
 
     private final List<String> events = new LinkedList<>();
 

mode/core/src/main/java/org/apache/shardingsphere/mode/subsciber/RuleItemChangedSubscriber.java

@@ -23,14 +23,15 @@
 import org.apache.shardingsphere.infra.rule.event.rule.alter.AlterRuleItemEvent;
 import org.apache.shardingsphere.infra.rule.event.rule.drop.DropRuleItemEvent;
 import org.apache.shardingsphere.infra.spi.type.typed.TypedSPILoader;
+import org.apache.shardingsphere.infra.util.eventbus.EventSubscriber;
 import org.apache.shardingsphere.mode.manager.ContextManager;
 import org.apache.shardingsphere.mode.spi.RuleItemConfigurationChangedProcessor;
 
 /**
  * Rule item changed subscriber.
  */
 @RequiredArgsConstructor
-public final class RuleItemChangedSubscriber {
+public final class RuleItemChangedSubscriber implements EventSubscriber {
 
     private final ContextManager contextManager;
 

mode/type/cluster/core/src/main/java/org/apache/shardingsphere/mode/manager/cluster/coordinator/registry/metadata/subscriber/ShardingSphereSchemaDataRegistrySubscriber.java

@@ -19,14 +19,15 @@
 
 import com.google.common.eventbus.Subscribe;
 import org.apache.shardingsphere.infra.util.eventbus.EventBusContext;
+import org.apache.shardingsphere.infra.util.eventbus.EventSubscriber;
 import org.apache.shardingsphere.metadata.persist.data.ShardingSphereDataPersistService;
 import org.apache.shardingsphere.mode.manager.cluster.coordinator.registry.data.event.ShardingSphereSchemaDataAlteredEvent;
 import org.apache.shardingsphere.mode.repository.cluster.ClusterPersistRepository;
 
 /**
  * ShardingSphere schema data registry subscriber.
  */
-public final class ShardingSphereSchemaDataRegistrySubscriber {
+public final class ShardingSphereSchemaDataRegistrySubscriber implements EventSubscriber {
 
     private final ShardingSphereDataPersistService persistService;
 

mode/type/cluster/core/src/main/java/org/apache/shardingsphere/mode/manager/cluster/coordinator/registry/process/subscriber/ClusterProcessSubscriber.java

@@ -23,6 +23,7 @@
 import org.apache.shardingsphere.infra.executor.sql.process.yaml.swapper.YamlProcessListSwapper;
 import org.apache.shardingsphere.infra.instance.metadata.InstanceType;
 import org.apache.shardingsphere.infra.util.eventbus.EventBusContext;
+import org.apache.shardingsphere.infra.util.eventbus.EventSubscriber;
 import org.apache.shardingsphere.infra.util.yaml.YamlEngine;
 import org.apache.shardingsphere.metadata.persist.node.ComputeNode;
 import org.apache.shardingsphere.metadata.persist.node.ProcessNode;
@@ -41,7 +42,7 @@
 /**
  * Cluster process subscriber.
  */
-public final class ClusterProcessSubscriber implements ProcessSubscriber {
+public final class ClusterProcessSubscriber implements ProcessSubscriber, EventSubscriber {
 
     private final PersistRepository repository;
 

mode/type/cluster/core/src/main/java/org/apache/shardingsphere/mode/manager/cluster/coordinator/registry/process/subscriber/ProcessListChangedSubscriber.java

@@ -23,6 +23,7 @@
 import org.apache.shardingsphere.infra.executor.sql.process.ProcessRegistry;
 import org.apache.shardingsphere.infra.executor.sql.process.lock.ProcessOperationLockRegistry;
 import org.apache.shardingsphere.infra.executor.sql.process.yaml.swapper.YamlProcessListSwapper;
+import org.apache.shardingsphere.infra.util.eventbus.EventSubscriber;
 import org.apache.shardingsphere.infra.util.yaml.YamlEngine;
 import org.apache.shardingsphere.metadata.persist.node.ComputeNode;
 import org.apache.shardingsphere.metadata.persist.node.ProcessNode;
@@ -43,7 +44,7 @@
  */
 @SuppressWarnings("unused")
 @RequiredArgsConstructor
-public final class ProcessListChangedSubscriber {
+public final class ProcessListChangedSubscriber implements EventSubscriber {
 
     private final ContextManager contextManager;
 

mode/type/cluster/core/src/main/java/org/apache/shardingsphere/mode/manager/cluster/coordinator/registry/status/cluster/subscriber/ClusterStatusSubscriber.java

@@ -19,14 +19,15 @@
 
 import com.google.common.eventbus.Subscribe;
 import org.apache.shardingsphere.infra.util.eventbus.EventBusContext;
+import org.apache.shardingsphere.infra.util.eventbus.EventSubscriber;
 import org.apache.shardingsphere.metadata.persist.node.ComputeNode;
 import org.apache.shardingsphere.mode.manager.cluster.coordinator.registry.status.cluster.event.ClusterStatusChangedEvent;
 import org.apache.shardingsphere.mode.repository.cluster.ClusterPersistRepository;
 
 /**
  * Cluster status subscriber.
  */
-public final class ClusterStatusSubscriber {
+public final class ClusterStatusSubscriber implements EventSubscriber {
 
     private final ClusterPersistRepository repository;
 

mode/type/cluster/core/src/main/java/org/apache/shardingsphere/mode/manager/cluster/coordinator/registry/status/compute/subscriber/ComputeNodeStatusSubscriber.java

@@ -18,6 +18,7 @@
 package org.apache.shardingsphere.mode.manager.cluster.coordinator.registry.status.compute.subscriber;
 
 import com.google.common.eventbus.Subscribe;
+import org.apache.shardingsphere.infra.util.eventbus.EventSubscriber;
 import org.apache.shardingsphere.metadata.persist.node.ComputeNode;
 import org.apache.shardingsphere.mode.event.node.ComputeNodeStatusChangedEvent;
 import org.apache.shardingsphere.mode.manager.cluster.coordinator.RegistryCenter;
@@ -29,7 +30,7 @@
 /**
  * Compute node status subscriber.
  */
-public final class ComputeNodeStatusSubscriber {
+public final class ComputeNodeStatusSubscriber implements EventSubscriber {
 
     private final RegistryCenter registryCenter;
 

mode/type/cluster/core/src/main/java/org/apache/shardingsphere/mode/manager/cluster/coordinator/registry/status/storage/subscriber/QualifiedDataSourceStatusSubscriber.java

@@ -19,14 +19,15 @@
 
 import com.google.common.eventbus.Subscribe;
 import org.apache.shardingsphere.infra.util.eventbus.EventBusContext;
+import org.apache.shardingsphere.infra.util.eventbus.EventSubscriber;
 import org.apache.shardingsphere.mode.event.node.QualifiedDataSourceDeletedEvent;
 import org.apache.shardingsphere.mode.repository.cluster.ClusterPersistRepository;
 import org.apache.shardingsphere.mode.storage.node.QualifiedDataSourceNode;
 
 /**
  * Qualified data source status subscriber.
  */
-public final class QualifiedDataSourceStatusSubscriber {
+public final class QualifiedDataSourceStatusSubscriber implements EventSubscriber {
 
     private final ClusterPersistRepository repository;
 

mode/type/cluster/core/src/main/java/org/apache/shardingsphere/mode/manager/cluster/coordinator/subscriber/CacheEvictedSubscriber.java

@@ -20,12 +20,13 @@
 import com.google.common.eventbus.Subscribe;
 import org.apache.shardingsphere.infra.rule.event.GovernanceEvent;
 import org.apache.shardingsphere.infra.spi.type.ordered.cache.OrderedServicesCache;
+import org.apache.shardingsphere.infra.util.eventbus.EventSubscriber;
 
 /**
  * Cache evicted subscriber.
  */
 @SuppressWarnings("unused")
-public final class CacheEvictedSubscriber {
+public final class CacheEvictedSubscriber implements EventSubscriber {
 
     /**
      * Callback of any {@link GovernanceEvent}.

mode/type/cluster/core/src/main/java/org/apache/shardingsphere/mode/manager/cluster/coordinator/subscriber/ConfigurationChangedSubscriber.java

@@ -19,6 +19,7 @@
 
 import com.google.common.eventbus.Subscribe;
 import lombok.RequiredArgsConstructor;
+import org.apache.shardingsphere.infra.util.eventbus.EventSubscriber;
 import org.apache.shardingsphere.mode.event.config.AlterGlobalRuleConfigurationEvent;
 import org.apache.shardingsphere.mode.event.config.AlterPropertiesEvent;
 import org.apache.shardingsphere.mode.event.datasource.unit.AlterStorageUnitEvent;
@@ -31,7 +32,7 @@
  */
 @RequiredArgsConstructor
 @SuppressWarnings("unused")
-public final class ConfigurationChangedSubscriber {
+public final class ConfigurationChangedSubscriber implements EventSubscriber {
 
     private final ContextManager contextManager;
 

mode/type/cluster/core/src/main/java/org/apache/shardingsphere/mode/manager/cluster/coordinator/subscriber/ContextManagerSubscriberRegister.java

@@ -18,6 +18,7 @@
 package org.apache.shardingsphere.mode.manager.cluster.coordinator.subscriber;
 
 import org.apache.shardingsphere.infra.util.eventbus.EventBusContext;
+import org.apache.shardingsphere.infra.util.eventbus.EventSubscriber;
 import org.apache.shardingsphere.mode.manager.ContextManager;
 import org.apache.shardingsphere.mode.manager.cluster.coordinator.RegistryCenter;
 import org.apache.shardingsphere.mode.manager.cluster.coordinator.registry.process.subscriber.ProcessListChangedSubscriber;
@@ -28,11 +29,11 @@
 /**
  * Context manager subscriber register.
  */
-public final class ContextManagerSubscriberRegister {
+public final class ContextManagerSubscriberRegister implements EventSubscriber {
 
     private final EventBusContext eventBusContext;
 
-    private final Collection<Object> subscribers;
+    private final Collection<EventSubscriber> subscribers;
 
     public ContextManagerSubscriberRegister(final RegistryCenter registryCenter, final ContextManager contextManager) {
         eventBusContext = contextManager.getInstanceContext().getEventBusContext();

mode/type/cluster/core/src/main/java/org/apache/shardingsphere/mode/manager/cluster/coordinator/subscriber/DatabaseChangedSubscriber.java

@@ -19,6 +19,7 @@
 
 import com.google.common.eventbus.Subscribe;
 import lombok.RequiredArgsConstructor;
+import org.apache.shardingsphere.infra.util.eventbus.EventSubscriber;
 import org.apache.shardingsphere.mode.manager.ContextManager;
 import org.apache.shardingsphere.mode.manager.cluster.coordinator.registry.data.event.DatabaseDataAddedEvent;
 import org.apache.shardingsphere.mode.manager.cluster.coordinator.registry.data.event.DatabaseDataDeletedEvent;
@@ -33,7 +34,7 @@
  */
 @RequiredArgsConstructor
 @SuppressWarnings("unused")
-public final class DatabaseChangedSubscriber {
+public final class DatabaseChangedSubscriber implements EventSubscriber {
 
     private final ContextManager contextManager;
 

mode/type/cluster/core/src/main/java/org/apache/shardingsphere/mode/manager/cluster/coordinator/subscriber/ResourceMetaDataChangedSubscriber.java

@@ -21,6 +21,7 @@
 import lombok.RequiredArgsConstructor;
 import org.apache.shardingsphere.infra.metadata.database.schema.model.ShardingSphereTable;
 import org.apache.shardingsphere.infra.metadata.database.schema.model.ShardingSphereView;
+import org.apache.shardingsphere.infra.util.eventbus.EventSubscriber;
 import org.apache.shardingsphere.mode.event.schema.table.CreateOrAlterTableEvent;
 import org.apache.shardingsphere.mode.event.schema.table.DropTableEvent;
 import org.apache.shardingsphere.mode.event.schema.view.CreateOrAlterViewEvent;
@@ -38,7 +39,7 @@
  */
 @RequiredArgsConstructor
 @SuppressWarnings("unused")
-public final class ResourceMetaDataChangedSubscriber {
+public final class ResourceMetaDataChangedSubscriber implements EventSubscriber {
 
     private final ContextManager contextManager;
 

mode/type/cluster/core/src/main/java/org/apache/shardingsphere/mode/manager/cluster/coordinator/subscriber/StateChangedSubscriber.java

@@ -25,6 +25,7 @@
 import org.apache.shardingsphere.infra.rule.attribute.datasource.StaticDataSourceRuleAttribute;
 import org.apache.shardingsphere.infra.state.datasource.DataSourceState;
 import org.apache.shardingsphere.infra.state.datasource.DataSourceStateManager;
+import org.apache.shardingsphere.infra.util.eventbus.EventSubscriber;
 import org.apache.shardingsphere.mode.manager.ContextManager;
 import org.apache.shardingsphere.mode.manager.cluster.coordinator.RegistryCenter;
 import org.apache.shardingsphere.mode.manager.cluster.coordinator.registry.status.cluster.event.ClusterLockDeletedEvent;
@@ -42,7 +43,7 @@
  */
 @RequiredArgsConstructor
 @SuppressWarnings("unused")
-public final class StateChangedSubscriber {
+public final class StateChangedSubscriber implements EventSubscriber {
 
     private final ContextManager contextManager;
 

mode/type/standalone/core/src/main/java/org/apache/shardingsphere/mode/manager/standalone/subscriber/StandaloneProcessSubscriber.java

@@ -21,6 +21,7 @@
 import org.apache.shardingsphere.infra.executor.sql.process.Process;
 import org.apache.shardingsphere.infra.executor.sql.process.ProcessRegistry;
 import org.apache.shardingsphere.infra.util.eventbus.EventBusContext;
+import org.apache.shardingsphere.infra.util.eventbus.EventSubscriber;
 import org.apache.shardingsphere.mode.process.ProcessSubscriber;
 import org.apache.shardingsphere.mode.process.event.KillProcessRequestEvent;
 import org.apache.shardingsphere.mode.process.event.ShowProcessListRequestEvent;
@@ -32,7 +33,7 @@
 /**
  * Standalone process subscriber.
  */
-public final class StandaloneProcessSubscriber implements ProcessSubscriber {
+public final class StandaloneProcessSubscriber implements ProcessSubscriber, EventSubscriber {
 
     private final EventBusContext eventBusContext;
 

proxy/backend/type/mysql/src/main/java/org/apache/shardingsphere/proxy/backend/mysql/handler/admin/executor/ShowProcessListExecutor.java

@@ -28,6 +28,7 @@
 import org.apache.shardingsphere.infra.executor.sql.process.Process;
 import org.apache.shardingsphere.infra.merge.result.MergedResult;
 import org.apache.shardingsphere.infra.merge.result.impl.transparent.TransparentMergedResult;
+import org.apache.shardingsphere.infra.util.eventbus.EventSubscriber;
 import org.apache.shardingsphere.mode.process.event.ShowProcessListRequestEvent;
 import org.apache.shardingsphere.mode.process.event.ShowProcessListResponseEvent;
 import org.apache.shardingsphere.proxy.backend.context.ProxyContext;
@@ -45,7 +46,7 @@
 /**
  * Show process list executor.
  */
-public final class ShowProcessListExecutor implements DatabaseAdminQueryExecutor {
+public final class ShowProcessListExecutor implements DatabaseAdminQueryExecutor, EventSubscriber {
 
     private final boolean showFullProcesslist;