*** This class provides Binary Compatibility only, not Source Compatibility ***

Package com.sas.services.discovery

Class JVMAttribute

java.lang.Object
com.sas.services.AbstractServiceAttribute
com.sas.services.discovery.IdAttribute
com.sas.services.discovery.JVMAttribute
All Implemented Interfaces:
ServiceAttributeInterface, Serializable
@SASScope("ALL") @BinaryCompatibilityOnly public final class JVMAttribute extends IdAttribute
A foundation service discovery attribute which may be used to locate a service which has been instantiated in the local JVM or the same JVM as another previously discovered service.

When a service is deployed, a JVMAttribute will be added to its service discovery configuration. This will enable one to find a service that is deployed in a particular JVM.

Examples

Examples are provided to find a service that was deployed in:

Example 1: Find a service that was deployed in this JVM

To find a service that was instantiated in this JVM, define a service template that specifies one or more interfaces that the desired service must implement and this attribute using its default constructor.

The following example shows how to define a service template that can be used to discover an Authentication service that was deployed in this JVM. 


import com.sas.services.discovery.DiscoveryService;
import com.sas.services.discovery.JVMAttribute;
import com.sas.services.discovery.ServiceAttributeInterface;
import com.sas.services.discovery.ServiceTemplate;
import com.sas.services.security.AuthenticationServiceInterface;

...

// specify the desired service type(s)
Class[] desiredServiceTypes = new Class[] {
   AuthenticationServiceInterface.class};

// specify the optional attributes to be used to qualify a discovery lookup
// to include only those services which were instantiated in this JVM
ServiceAttributeInterface[] serviceAttributes =
   new ServiceAttributeInterface[] {
      new JVMAttribute()};

// create a service lookup template specifying the required
// service interface(s) and a service attribute for a
// service that was instantiated in this JVM
ServiceTemplate serviceTemplate = new ServiceTemplate(
   desiredServiceTypes,
   serviceAttributes);

// discover a service satisfying the service template
AuthenticationServiceInterface authenticationService = (AuthenticationServiceInterface)
   DiscoveryService.defaultInstance().findService(serviceTemplate);

Example 2: Find a service that was deployed in the same JVM as another service

To find a service that was deployed in the same JVM as a previously discovered service, define a service template that specifies one or more interfaces that the desired service must implement and a JVMAttribute initialized with the desired ID which may be queried from a service's JVMAttribute stored in its service discovery configuration.

The following example shows how to define a service template that can be used to discover an Authentication Service that was instantiated in the same JVM as another service. 


import com.sas.services.ServiceConfigurationInterface;
import com.sas.services.discovery.DiscoveryService;
import com.sas.services.discovery.JVMAttribute;
import com.sas.services.discovery.ServiceAttributeInterface;
import com.sas.services.discovery.ServiceDiscoveryConfigurationInterface;
import com.sas.services.discovery.ServiceTemplate;
import com.sas.services.security.AuthenticationServiceInterface;
import com.sas.services.user.UserServiceInterface;

...

// specify the desired service type(s)
final Class[] desiredServiceTypes = new Class[] {
   AuthenticationServiceInterface.class};

// part 1: 
// find a foundation User service and determine its JVM ID 
// from its service discovery configuration, so that we
// can lookup another service that was instantiated in the same JVM

ServiceTemplate serviceTemplate = new ServiceTemplate(
   new Class[] {UserServiceInterface.class});
RemoteServiceInterface userService = 
   DiscoveryService.defaultInstance().findService(serviceTemplate);

ServiceDiscoveryConfigurationInterface serviceDiscoveryConfig = 
   (ServiceDiscoveryConfigurationInterface) userService.getServiceConfiguration(
      ServiceConfigurationInterface.CONFIGURATION_SERVICE_DISCOVERY);
String jvmId = serviceDiscoveryConfig.getJVMId();

if (jvmId != null) {
   // part 2:
   // find a Authentication service that was deployed in the same JVM as the
   // previously discovered User service

   // specify the optional attributes to be used to qualify a discovery lookup
   // to include only those services which are not accessible to remote clients
   ServiceAttributeInterface[] serviceAttributes =
      new ServiceAttributeInterface[] {
         new JVMAttribute(jvmId)}; // ID of the desired JVM

   // create a service lookup template specifying the required
   // service interface(s) and a service attribute for a
   // service that was instantiated in the same JVM as the previously
   // discovered User service
   ServiceTemplate serviceTemplate = new ServiceTemplate(
      desiredServiceTypes,
      serviceAttributes);

   // discover a service satisfying the service template
   AuthenticationServiceInterface authenticationService = (AuthenticationServiceInterface)
      DiscoveryService.defaultInstance().findService(serviceTemplate);
}
Since:
9.2
See Also:

  • Field Summary

    Fields
    Modifier and Type
    Field
    Description
    static final String
    JVM_ID
    Identifier unique to this JVM that can be used to determine whether another service was instantiated in the same JVM.

    Fields inherited from class com.sas.services.discovery.IdAttribute

    id, idType

  • Constructor Summary

    Constructors
    Constructor
    Description
    JVMAttribute()
    Constructs an instance of a service discovery attribute that is initialized with an identifier representing this JVM.
    JVMAttribute(String id)
    Constructs a service discovery attribute which may be used to lookup a service which has been instantiated in a JVM with the specified ID.

  • Method Summary

    Methods inherited from class com.sas.services.discovery.IdAttribute

    getFieldNameToValueMap

    Methods inherited from class com.sas.services.AbstractServiceAttribute

    equals, hashCode, toString

    Methods inherited from class java.lang.Object

    clone, finalize, getClass, notify, notifyAll, wait, wait, wait

  • Field Details

    • JVM_ID

      public static final String JVM_ID
      Identifier unique to this JVM that can be used to determine whether another service was instantiated in the same JVM.

  • Constructor Details

    • JVMAttribute

      public JVMAttribute()
      Constructs an instance of a service discovery attribute that is initialized with an identifier representing this JVM.

      Use this constructor to instantiate a service discovery attribute to be associated with a service that is being instantiated in this JVM.

      A discovery service consumer can use this constructor to create a service discovery attribute which may be used to locate a service that has been instantiated in the same JVM.

      This constructor initializes the value of the id to the value of this JVM's id.

    • JVMAttribute

      public JVMAttribute(String id)
      Constructs a service discovery attribute which may be used to lookup a service which has been instantiated in a JVM with the specified ID.
      Parameters:
      id - The ID of the JVM attribute.

      If you wish to locate a foundation service that has been started in the same JVM use the default constructor JVMAttribute() instead.