DistributeMe Registry

What is DistributeMe Registry

Why does DistributeMe need a Registry

In the DistributeMe world a server is just a java process, running on a machine somewhere. A client, which is another process, or webserver, or just a class started from eclipse doesn't know where the server is running. To find out the location of the service you need a third player, someone known to both. This is the registry. The server registers itself at the registry (bind) and the client ask the registry about the whereabouts of the service (lookup). This way the client can dynamically lookup a service without a need for hardwired configuration.
The CORBA analogy is the NameService.

Registry format

If you call your registry you will get something like this:

<services>
<service serviceId="org_distributeme_test_echo_EchoService" host="192.168.200.107" port="9250" protocol="rmi" instanceId="awodzrtvcp" globalId="rmi://org_distributeme_test_echo_EchoService" registrationString="rmi://org_distributeme_test_echo_EchoService.awodzrtvcp@192.168.200.107:9250"/>
</services>

You will find a service entry for each registered service. The values are explained in following table:

Value

Explanation

Example

serviceId

The id of the service which is derived from source interface

org_distributeme_test_echo_EchoService

host

host on which the service is running. This is typically the first entry in the /etc/hosts

192.168.200.107

port

tcp port on which embedded rmiregistry is listening

Default range is 9250 - 9299

protocol

protocol that the service is speaking

rmi, corba or webservice

instanceId

unique instance id which changes on each restart

awodzrtvcp - 10 digits generated literal string

globalId

used by the client to obtain a service instance

rmi://org_distributeme_test_echo_EchoService

registrationString

complete service definition which is sent by the server instance to the registry for registration. Uniquely describes a service instance

rmi://org_distributeme_test_echo_EchoService.awodzrtvcp@192.168.200.107:9250

  • No labels