What is the concept of an object reference in a distributed system?

We consider here the means of providing access to an object; an information that fulfills this function is called an object reference. Figure 5.5: Object references. Recall that an object may only be accessed through its interface. Therefore an object reference must also refer to the object’s interface.

Why is a remote object passed as a reference and not as a copy in Java RMI?

Non-remote arguments to, and results from, a remote method invocation are passed by copy rather than by reference. This is because references to objects are only useful within a single virtual machine. A remote object is passed by reference, not by copying the actual remote implementation.

What is remote object invocation explain in distributed system?

In a distributed computing environment, remote method invocation (RMI) refers to calling a method on a remote object. It is analogous to a remote procedure call. The main role is to allow objects to access data and invoke methods on remote objects (objects residing in non-local memory space).

What is meant by object model describe how distributed objects are related to distributed system?

A distributed object is an object that can be accessed remotely. This means that a distributed object can be used like a regular object, but from anywhere on the network. An object is typically considered to encapsulate data and behavior. A distributed object might provide its user with a set of related capabilities.

What is the role of remote object reference?

A remote object reference can be stored using the URL-based methods of the class java. For a client to invoke a method on a remote object, that client must first obtain a reference to the object. A reference to a remote object is usually obtained as a parameter or return value in a method call.

What is meant by remote object reference and remote reference?

Two fundamental concepts of the distributed object model : Remote object reference: Other objects can invoke the methods of a remote object if they have access to its remote object reference. Remote interface: Every remote object has a remote interface that specifies which of its methods can be invoked remotely.

When you pass a remote object to or from a remote method what is really passed?

A serialized copy of the object is shipped to the Remote object. Client invokes trainPet(myDog) on the stub, passing a copy of the reference to the Dog object. The stub makes a serialized copy of the object and sends that copy over the wire to the skeleton.

What is remote interface?

In RMI, a remote interface is an interface that declares a set of methods that may be invoked from a remote Java virtual machine. A remote interface must satisfy the following requirements: A remote interface must at least extend, either directly or indirectly, the interface java.

What is the difference between remote objects and distributed objects?

– in a distributed object system, an object’s data should be accessible only via its methods; – objects can be accessed via object references; – remote object reference; – remote interface: specifies which methods can be invoked remotely; – CORBA IDL can be used to define the interface of a class.

What is a remote reference?

The remote reference layer is responsible for carrying out the semantics of the invocation. For example, the remote reference layer is responsible for determining whether the server is a single object or is a replicated object requiring communications with multiple locations.

What is responsible for translating between local and remote object references?

– a remote reference module (RRM) is responsible for translating between local and remote object references (ROR) and for creating remote object references; – Dispatcher: a server has one dispatcher and skeleton for each class representing a remote object.

What is distributed object model in Java?

Two fundamental concepts of the distributed object model : Remote object reference: Other objects can invoke the methods of a remote object if they have access to it s remote object reference. Remote interface: Every remote object has a remote interface that specifies which of its methods can be invoked remotely.

How to ensure that a remote object reference is unique?

There are several ways to ensure that a remote object reference is unique. One way is to construct a remote object reference by concatenating the Internet address of its computer and port number of the process that created it with the time of its creation and a local object number.

How do you create a remote object in Linux?

One way is to construct a remote object reference by concatenating the Internet address of its computer and port number of the process that created it with the time of its creation and a local object number. The local object number is incremented each time an object is created in that process.

What is remote interface in Salesforce?

Remote interface: Every remote object has a remote interface that specifies which of its methods can be invoked remotely. Retry request message: whether to retransmit the request message until either a reply is received or the server is assumed to have failed.