Registry (Java SE 15 & JDK 15) (original) (raw)

All Superinterfaces:

[Remote](../Remote.html "interface in java.rmi")

public interface Registry extends Remote

Registry is a remote interface to a simple remote object registry that provides methods for storing and retrieving remote object references bound with arbitrary string names. Thebind, unbind, and rebind methods are used to alter the name bindings in the registry, and the lookup and list methods are used to query the current name bindings.

In its typical usage, a Registry enables RMI client bootstrapping: it provides a simple means for a client to obtain an initial reference to a remote object. Therefore, a registry's remote object implementation is typically exported with a well-known address, such as with a well-known ObjID and TCP port number (default is 1099).

The LocateRegistry class provides a programmatic API for constructing a bootstrap reference to a Registry at a remote address (see the static getRegistry methods) and for creating and exporting a Registry in the current VM on a particular local address (see the staticcreateRegistry methods).

A Registry implementation may choose to restrict access to some or all of its methods (for example, methods that mutate the registry's bindings may be restricted to calls originating from the local host). If a Registry method chooses to deny access for a given invocation, its implementation may throw AccessException, which (because it extends RemoteException) will be wrapped in a ServerException when caught by a remote client.

The names used for bindings in a Registry are pure strings, not parsed. A service which stores its remote reference in a Registry may wish to use a package name as a prefix in the name binding to reduce the likelihood of name collisions in the registry.

Since:

1.1

See Also:

LocateRegistry

• Field Summary

Fields

• Method Summary

• Field Details

  • REGISTRY_PORT

  static final int REGISTRY_PORT
  Well known port for registry.
  See Also:
  Constant Field Values

• Method Details

  • lookup

  Returns the remote reference bound to the specifiedname in this registry.
  Parameters:
  name - the name for the remote reference to look up
  Returns:
  a reference to a remote object
  Throws:
  [NotBoundException](../NotBoundException.html "class in java.rmi") - if name is not currently bound
  [RemoteException](../RemoteException.html "class in java.rmi") - if remote communication with the registry failed; if exception is a ServerException containing an AccessException, then the registry denies the caller access to perform this operation
  [AccessException](../AccessException.html "class in java.rmi") - if this registry is local and it denies the caller access to perform this operation
  [NullPointerException](../../../../java.base/java/lang/NullPointerException.html "class in java.lang") - if name is null

  • bind

  Binds a remote reference to the specified name in this registry.
  Parameters:
  name - the name to associate with the remote reference
  obj - a reference to a remote object (usually a stub)
  Throws:
  [AlreadyBoundException](../AlreadyBoundException.html "class in java.rmi") - if name is already bound
  [RemoteException](../RemoteException.html "class in java.rmi") - if remote communication with the registry failed; if exception is a ServerException containing an AccessException, then the registry denies the caller access to perform this operation (if originating from a non-local host, for example)
  [AccessException](../AccessException.html "class in java.rmi") - if this registry is local and it denies the caller access to perform this operation
  [NullPointerException](../../../../java.base/java/lang/NullPointerException.html "class in java.lang") - if name isnull, or if obj is null

  • unbind

  Removes the binding for the specified name in this registry.
  Parameters:
  name - the name of the binding to remove
  Throws:
  [NotBoundException](../NotBoundException.html "class in java.rmi") - if name is not currently bound
  [RemoteException](../RemoteException.html "class in java.rmi") - if remote communication with the registry failed; if exception is a ServerException containing an AccessException, then the registry denies the caller access to perform this operation (if originating from a non-local host, for example)
  [AccessException](../AccessException.html "class in java.rmi") - if this registry is local and it denies the caller access to perform this operation
  [NullPointerException](../../../../java.base/java/lang/NullPointerException.html "class in java.lang") - if name is null

  • rebind

  Replaces the binding for the specified name in this registry with the supplied remote reference. If there is an existing binding for the specified name, it is discarded.
  Parameters:
  name - the name to associate with the remote reference
  obj - a reference to a remote object (usually a stub)
  Throws:
  [RemoteException](../RemoteException.html "class in java.rmi") - if remote communication with the registry failed; if exception is a ServerException containing an AccessException, then the registry denies the caller access to perform this operation (if originating from a non-local host, for example)
  [AccessException](../AccessException.html "class in java.rmi") - if this registry is local and it denies the caller access to perform this operation
  [NullPointerException](../../../../java.base/java/lang/NullPointerException.html "class in java.lang") - if name isnull, or if obj is null

  • list

  Returns an array of the names bound in this registry. The array will contain a snapshot of the names bound in this registry at the time of the given invocation of this method.
  Returns:
  an array of the names bound in this registry
  Throws:
  [RemoteException](../RemoteException.html "class in java.rmi") - if remote communication with the registry failed; if exception is a ServerException containing an AccessException, then the registry denies the caller access to perform this operation
  [AccessException](../AccessException.html "class in java.rmi") - if this registry is local and it denies the caller access to perform this operation