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

com.sas.services.discovery
Class HostAttribute

com.sas.services.discovery.HostAttribute

All Implemented Interfaces:

ServiceAttributeInterface, java.io.Serializable

public final class HostAttribute

A foundation service discovery attribute which may be used to locate a service which has been deployed on a particular host by using the host's name and/or IP address.

When a service is deployed, a HostAttribute will be added to its service discovery configuration for each InetAddress associated with its host. This will enable one to find a service that is deployed on a particular host.

Examples

Examples are provided to find a foundation service deployed on:

• this host
• a host using the host's name
• a host using its IP address

Example 1: Find a service that was deployed on this host

This example shows how to define a service template that can be used to discover an Authentication Service that was deployed on this host.

To find a service that was deployed on this host, define a service template that specifies one or more interfaces that the desired service must satisfy and a HostAttribute initialized to the desired host by specifying either the host's name and/or its IP address.

import java.net.InetAddress;

import com.sas.services.discovery.DiscoveryService;
import com.sas.services.discovery.HostAttribute;
import com.sas.services.discovery.ServiceTemplate;
import com.sas.services.security.AuthenticationServiceInterface;

...

// define a service template that can be used to 
// lookup an Authentication Service
Class[] desiredServiceInterface = new Class[] {
   AuthenticationServiceInterface.class};

// get this host's InetAddress
// note: a host may have multiple addresses
InetAddress inetAddress = getInetAddress();

ServiceAttributeInterface serviceAttributes = new ServiceAttributeInterface[] {
   new HostAttribute(inetAddress)};

// create a service lookup template specifying the required
// service interface(s) and a service attribute for a
// service that was deployed on this host
ServiceTemplate serviceTemplate = new ServiceTemplate(
   desiredServiceInterface,
   serviceAttributes);

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

...

// Utility method used to determine the host's InetAddress:

import java.net.InetAddress;
import java.net.NetworkInterface;
import java.util.Enumeration;

import com.sas.services.deployment.RMIConfiguration;

...

// get this host's InetAddress discarding the "localhost" address
InetAddress getInetAddress () {

   InetAddress theInetAddress = null;

   try {
      final Enumeration netInterfaces = NetworkInterface.getNetworkInterfaces();
      NetworkInterface networkInterface = null;
      InetAddress inetAddress = null;
      Enumeration inetAddresses = null;
      while (netInterfaces.hasMoreElements()) {
              networkInterface= (NetworkInterface) netInterfaces.nextElement();            
              inetAddresses = networkInterface.getInetAddresses();
              while (inetAddresses.hasMoreElements()) {
                 inetAddress = (InetAddress) inetAddresses.nextElement();
             if (!RMIConfiguration.LOCALHOST.equals(inetAddress.getHostName())) { 
                theInetAddress = inetAddress;
                break;
             }
          } 
       }
    }
    catch (ClassCastException e) {
       // handle exception
    }

    return theInetAddress;

}
 

Example 2: Find a service that was deployed on a host using its name

This example shows how to define a service template that can be used to discover a foundation Authentication service that was deployed on a host named "xxx.acme.com".

To find a service that was deployed on this host, define a service template that specifies one or more interfaces that the desired service must satisfy and a HostAttribute initialized using the host's name.

import com.sas.services.discovery.DiscoveryService;
import com.sas.services.discovery.HostAttribute;
import com.sas.services.discovery.ServiceTemplate;
import com.sas.services.security.AuthenticationServiceInterface;

...

// define a service template that can be used to 
// lookup an Authentication Service
Class[] desiredServiceInterface = new Class[] {
   AuthenticationServiceInterface.class};

// the name of the desired host on which a service was deployed
String hostName = "xxx.acme.com";

// find a service on for a given host name
ServiceAttributeInterface serviceAttributes = new ServiceAttributeInterface[] {
   new HostAttribute(
      hostName,
      null)};//don't care about the host's address

// create a service lookup template specifying the required
// service interface(s) and a service attribute for a
// service that was deployed on the specified host
ServiceTemplate serviceTemplate = new ServiceTemplate(
   desiredServiceInterface,
   serviceAttributes);

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

 

Example 3: Find a service that was deployed on a host using its address

This example shows how to define a service template that can be used to discover a foundation Authentication service that was deployed on a host whose IP address is "99.99.99.99".

To find a service that was deployed on this host, define a service template that specifies one or more interfaces that the desired service must satisfy and a HostAttribute initialized using the host's address.

import com.sas.services.discovery.DiscoveryService;
import com.sas.services.discovery.HostAttribute;
import com.sas.services.discovery.ServiceTemplate;
import com.sas.services.security.AuthenticationServiceInterface;

...

// define a service template that can be used to 
// lookup an Authentication Service
Class[] desiredServiceInterface = new Class[] {
   AuthenticationServiceInterface.class};

// the IP address of the desired host on which a service was deployed
String hostAddress = "99.99.99.99";

// find a service on for a given host name
ServiceAttributeInterface serviceAttributes = new ServiceAttributeInterface[] {
   new HostAttribute(
      null,//don't care about the host's name
      hostAddress)};

// create a service lookup template specifying the required
// service interface(s) and a service attribute for a
// service that was deployed on the specified host
ServiceTemplate serviceTemplate = new ServiceTemplate(
   desiredServiceInterface,
   serviceAttributes);

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

 

Since:

9.2

See Also:

Serialized Form

Field Summary

java.lang.String	address The host's IP address.
java.lang.String	host The host's name.

Constructor Summary

HostAttribute()
Constructs a service discovery attribute representing a host with its name and address to null.

HostAttribute(java.net.InetAddress inetAddress)
Constructs a service discovery attribute representing a host by initializing the host's name and address using values obtained from InetAddress.getHostName() and InetAddress.getHostAddress().

HostAttribute(java.lang.String hostName)
Constructs an attribute which may be used to locate a remotely accessible foundation service which was deployed on a particular host.

HostAttribute(java.lang.String hostName, java.lang.String hostAddress)
Constructs a service discovery attribute representing a host using the specified name and address.

Method Summary

java.util.Map

getFieldNameToValueMap() Gets a map of this attribute's fields and their values.

Methods inherited from class com.sas.services.AbstractServiceAttribute

equals, hashCode, toString

Field Detail

host

public java.lang.String host

The host's name.

address

public java.lang.String address

The host's IP address.

Constructor Detail

HostAttribute

public HostAttribute()

Constructs a service discovery attribute representing a host with its name and address to null.

HostAttribute

public HostAttribute(java.net.InetAddress inetAddress)

Constructs a service discovery attribute representing a host by initializing the host's name and address using values obtained from InetAddress.getHostName() and InetAddress.getHostAddress().

Since this attribute initializes both the name and address, a client can locate a foundation service deployed on a particular host by matching the host's name and/or address.

One may also use HostAttribute(String, String) to construct an instance using string values for the host's name and address.

Parameters:

inetAddress - An address representing the host on which a foundation service has been deployed.

Throws:

java.lang.IllegalArgumentException - if a null parameter is specified.

HostAttribute

public HostAttribute(java.lang.String hostName)

Constructs an attribute which may be used to locate a remotely accessible foundation service which was deployed on a particular host.

Parameters:

hostName - Internet host name.

HostAttribute

public HostAttribute(java.lang.String hostName,
                     java.lang.String hostAddress)

Constructs a service discovery attribute representing a host using the specified name and address.

A convenience constructor HostAttribute(InetAddress) is also provided if one would prefer to initialize this attribute using a host name and address obtained from an InetAddress.

Parameters:

hostName - Internet host name.

hostAddress - Internet host address.

Method Detail

getFieldNameToValueMap

public java.util.Map getFieldNameToValueMap()

Gets a map of this attribute's fields and their values.

• host
• address

Overrides:

getFieldNameToValueMap in class AbstractServiceAttribute

Returns:

String summarizing the state of this attribute.

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