Java Platform 1.2 API Specification: Class Request

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org.omg.CORBA
Class Request

java.lang.Object
  |
  +--org.omg.CORBA.Request

public abstract class Request
extends Object

An object containing the information necessary for invoking a method. This class is the cornerstone of the ORB Dynamic Invocation Interface (DII), which allows dynamic creation and invocation of requests. A server cannot tell the difference between a client invocation using a client stub and a request using the DII.

A Request object consists of:

the name of the operation to be invoked
an NVList containing arguments for the operation.
Each item in the list is a NamedValue object, which has three parts:
1. the name of the argument
2. the value of the argument (as an Any object)
3. the argument mode flag indicating whether the argument is for input, output, or both

Request objects may also contain additional information, depending on how an operation was defined in the original IDL interface definition. For example, where appropriate, they may contain a NamedValue object to hold the return value or exception, a context, a list of possible exceptions, and a list of context strings that need to be resolved.

New Request objects are created using one of the create_request methods in the Object class. In other words, a create_request method is performed on the object which is to be invoked.

See Also:: NamedValue

Constructor Summary
`Request()`

Method Summary
`abstract Any`	`add_in_arg()` Creates an input argument and adds it to this `Request` object.
`abstract Any`	`add_inout_arg()` Adds an input/output argument to this `Request` object.
`abstract Any`	`add_named_in_arg(String name)` Creates an input argument with the given name and adds it to this `Request` object.
`abstract Any`	`add_named_inout_arg(String name)` Adds an input/output argument with the given name to this `Request` object.
`abstract Any`	`add_named_out_arg(String name)` Adds an output argument with the given name to this `Request` object.
`abstract Any`	`add_out_arg()` Adds an output argument to this `Request` object.
`abstract NVList`	`arguments()` Retrieves the `NVList` object containing the arguments to the method being invoked.
`abstract ContextList`	`contexts()` Retrieves the `ContextList` object for this request.
`abstract Context`	`ctx()` Retrieves the `Context` object for this request.
`abstract void`	`ctx(Context c)` Sets this request's `Context` object to the one given.
`abstract Environment`	`env()` Retrieves the `Environment` object for this request.
`abstract ExceptionList`	`exceptions()` Retrieves the `ExceptionList` object for this request.
`abstract void`	`get_response()` Allows the user to access the response for the invocation triggered earlier with the `send_deferred` method.
`abstract void`	`invoke()` Makes a synchronous invocation using the information in the `Request` object.
`abstract String`	`operation()` Retrieves the name of the method to be invoked.
`abstract boolean`	`poll_response()` Allows the user to determine whether a response has been received for the invocation triggered earlier with the `send_deferred` method.
`abstract NamedValue`	`result()` Retrieves the `NamedValue` object containing the return value for the method.
`abstract Any`	`return_value()` Returns the `Any` object that contains the value for the result of the method.
`abstract void`	`send_deferred()` Makes an asynchronous invocation on the request.
`abstract void`	`send_oneway()` Makes a oneway invocation on the request.
`abstract void`	`set_return_type(TypeCode tc)` Sets the typecode for the return value of the method.
`abstract Object`	`target()` Retrieves the the target object reference.

Methods inherited from class java.lang.Object

clone, 
equals, 
finalize, 
getClass, 
hashCode, 
notify, 
notifyAll, 
toString, 
wait, 
wait, 
wait

Constructor Detail

Request

public Request()

Method Detail

target

public abstract Object target()

Retrieves the the target object reference.

Returns:: the object reference that points to the object implementation for the method to be invoked

operation

public abstract String operation()

Retrieves the name of the method to be invoked.

Returns:: the name of the method to be invoked

arguments

public abstract NVList arguments()

Retrieves the NVList object containing the arguments to the method being invoked. The elements in the list are NamedValue objects, with each one describing an argument to the method.

Returns:: the NVList object containing the arguments for the method

result

public abstract NamedValue result()

Retrieves the NamedValue object containing the return value for the method.

Returns:: the NamedValue object containing the result of the method

env

public abstract Environment env()

Retrieves the Environment object for this request. It contains the exception that the method being invoked has thrown (after the invocation returns).

Returns:: the Environment object for this request

exceptions

public abstract ExceptionList exceptions()

Retrieves the ExceptionList object for this request. This list contains TypeCode objects describing the exceptions that may be thrown by the method being invoked.

Returns:: the ExceptionList object describing the exceptions that may be thrown by the method being invoked

contexts

public abstract ContextList contexts()

Retrieves the ContextList object for this request. This list contains context Strings that need to be resolved and sent with the invocation.

Returns:: the list of context strings whose values need to be resolved and sent with the invocation.

ctx

public abstract Context ctx()

Retrieves the Context object for this request. This is a list of properties giving information about the client, the environment, or the circumstances of this request.

Returns:: the Context object that is to be used to resolve any context strings whose values need to be sent with the invocation

ctx

public abstract void ctx(Context c)

Sets this request's Context object to the one given.

Parameters:: c - the new Context object to be used for resolving context strings

add_in_arg

public abstract Any add_in_arg()

Creates an input argument and adds it to this Request object.

Returns:: an Any object that contains the value and typecode for the input argument added

add_named_in_arg

public abstract Any add_named_in_arg(String name)

Creates an input argument with the given name and adds it to this Request object.

Parameters:: name - the name of the argument being added
Returns:: an Any object that contains the value and typecode for the input argument added

add_inout_arg

public abstract Any add_inout_arg()

Adds an input/output argument to this Request object.

Returns:: an Any object that contains the value and typecode for the input/output argument added

add_named_inout_arg

public abstract Any add_named_inout_arg(String name)

Adds an input/output argument with the given name to this Request object.

Parameters:: name - the name of the argument being added
Returns:: an Any object that contains the value and typecode for the input/output argument added

add_out_arg

public abstract Any add_out_arg()

Adds an output argument to this Request object.

Returns:: an Any object that contains the value and typecode for the output argument added

add_named_out_arg

public abstract Any add_named_out_arg(String name)

Adds an output argument with the given name to this Request object.

Parameters:: name - the name of the argument being added
Returns:: an Any object that contains the value and typecode for the output argument added

set_return_type

public abstract void set_return_type(TypeCode tc)

Sets the typecode for the return value of the method.

Parameters:: tc - the TypeCode object containing type information for the return value

return_value

public abstract Any return_value()

Returns the Any object that contains the value for the result of the method.

Returns:: an Any object containing the value and typecode for the return value

invoke

public abstract void invoke()

Makes a synchronous invocation using the information in the Request object. Exception information is placed into the Request object's environment object.

send_oneway

public abstract void send_oneway()

Makes a oneway invocation on the request. In other words, it does not expect or wait for a response. Note that this can be used even if the operation was not declared as oneway in the IDL declaration. No response or exception information is returned.

send_deferred

public abstract void send_deferred()

Makes an asynchronous invocation on the request. In other words, it does not wait for a response before it returns to the user. The user can then later use the methods poll_response and get_response to get the result or exception information for the invocation.

poll_response

public abstract boolean poll_response()

Allows the user to determine whether a response has been received for the invocation triggered earlier with the send_deferred method.

Returns:: true if the method response has been received; false otherwise

get_response

public abstract void get_response()
                           throws WrongTransaction

Allows the user to access the response for the invocation triggered earlier with the send_deferred method.

Throws:: WrongTransaction - if the method get_response was invoked from a different transaction's scope than the one from which the request was originally sent. See the OMG Transaction Service specification for details.