# javax.management.relation

***

**1. Creating and Registering a Relation Service**

```java
import javax.management.relation.RelationService;
import javax.management.relation.RelationSupport;
import javax.management.ObjectName;

ObjectName relationServiceName = new ObjectName("example:type=RelationService");
RelationService relationService = new RelationSupport();
server.registerMBean(relationService, relationServiceName);
```

**2. Creating a Relation**

```java
import javax.management.relation.Relation;
import javax.management.relation.RelationSupport;

Relation relation = new RelationSupport("example", "relationType");
relation.set("key1", obj1);
relation.set("key2", obj2);
```

**3. Registering a Relation**

```java
import javax.management.relation.Relation;
import javax.management.ObjectName;

relationService.registerRelation("example:name=testRelation", relation);
```

**4. Getting a Relation**

```java
import javax.management.relation.RelationService;
import javax.management.relation.Relation;
import javax.management.ObjectName;

Relation relation = relationService.getRelation("example:name=testRelation");
```

**5. Removing a Relation**

```java
import javax.management.relation.RelationService;
import javax.management.ObjectName;

relationService.unregisterRelation("example:name=testRelation");
```

**6. Querying Relations**

```java
import javax.management.relation.RelationService;
import javax.management.relation.RelationQueryExp;
import javax.management.relation.Role;
import javax.management.relation.RelationType;
import javax.management.ObjectName;

ObjectName relationServiceName = new ObjectName("example:type=RelationService");
RelationService relationService = (RelationService) MBeanServer.getObjectInstance(relationServiceName);

Role role = new Role("role1");
RelationType type = new RelationType("relationType");
RelationQueryExp query = new RelationQueryExp("example:name=testRelation", role, type);
Set<ObjectName> relationNames = relationService.queryRelations(query);
```

**7. Creating a Relation Notification Emitter**

```java
import javax.management.relation.RelationNotificationEmitter;
import javax.management.relation.RelationNotificationListener;

RelationNotificationEmitter emitter = new RelationNotificationEmitter(ObjectName.getInstance("example:service=ChatService"));
emitter.addRelationNotificationListener(listener);
```

**8. Handling Relation Notifications**

```java
import javax.management.relation.RelationNotification;
import javax.management.notification.NotificationListener;

public class RelationNotificationListener implements NotificationListener {

  @Override
  public void handleNotification(Notification notification, Object handback) {
    if (notification instanceof RelationNotification) {
      // Handle relation notification
    }
  }
}
```

**9. Creating a Relation Type**

```java
import javax.management.relation.RelationType;
import javax.management.relation.RoleInfo;
import javax.management.relation.RoleInfo.Cardinality;

RoleInfo role1 = new RoleInfo("role1", Cardinality.ONE);
RoleInfo role2 = new RoleInfo("role2", Cardinality.MANY);
RelationType relationType = new RelationType("relationType", "relationDescription", role1, role2);
```

**10. Registering a Relation Type**

```java
import javax.management.relation.RelationType;
import javax.management.ObjectName;

ObjectName relationServiceName = new ObjectName("example:type=RelationService");
RelationService relationService = (RelationService) MBeanServer.getObjectInstance(relationServiceName);
relationService.registerRelationType("example:relationType", relationType);
```

**11. Getting a Relation Type**

```java
import javax.management.relation.RelationService;
import javax.management.ObjectName;

ObjectName relationServiceName = new ObjectName("example:type=RelationService");
RelationService relationService = (RelationService) MBeanServer.getObjectInstance(relationServiceName);
RelationType relationType = relationService.getRelationType("example:relationType");
```

**12. Removing a Relation Type**

```java
import javax.management.relation.RelationService;
import javax.management.ObjectName;

ObjectName relationServiceName = new ObjectName("example:type=RelationService");
RelationService relationService = (RelationService) MBeanServer.getObjectInstance(relationServiceName);
relationService.unregisterRelationType("example:relationType");
```

**13. Creating a Relation Type Registry**

```java
import javax.management.relation.RelationTypeRegistry;
import javax.management.relation.RelationTypeSupport;
import javax.management.relation.RoleInfo;
import javax.management.relation.RoleInfo.Cardinality;

RelationTypeRegistry registry = new RelationTypeRegistry();
RoleInfo role1 = new RoleInfo("role1", Cardinality.ONE);
RoleInfo role2 = new RoleInfo("role2", Cardinality.MANY);
RelationTypeSupport relationType = new RelationTypeSupport("relationType", "relationDescription", role1, role2);
registry.registerRelationType(relationType);
```

**14. Getting a Relation Type from a Registry**

```java
import javax.management.relation.RelationTypeRegistry;

RelationTypeRegistry registry = new RelationTypeRegistry();
RelationType relationType = registry.getRelationType("relationType");
```

**15. Removing a Relation Type from a Registry**

```java
import javax.management.relation.RelationTypeRegistry;

RelationTypeRegistry registry = new RelationTypeRegistry();
registry.unregisterRelationType("relationType");
```

**16. Creating a Relation Query Expression**

```java
import javax.management.relation.RelationQueryExp;
import javax.management.ObjectName;

ObjectName relationServiceName = new ObjectName("example:type=RelationService");
RelationQueryExp query = new RelationQueryExp("example:name=testRelation", relationServiceName);
```

**17. Creating a Role**

```java
import javax.management.relation.Role;

Role role = new Role("role1");
```

**18. Getting a Role Name**

```java
import javax.management.relation.Role;

Role role = new Role("role1");
String roleName = role.getRoleName();
```

\*\*19. Getting a Role Cardina