Package org.eclipse.scanning.api.event.core

Interface IRequester<T extends IdBean>

Type Parameters:

T - You must override the merge(...) method in your type. This puts the reponder's information into your bean. In the case where there are multiple reponders (like a list of detectors) you must be additive in the merge method.

All Superinterfaces:

AutoCloseable, IConnection, IRequestResponseConnection, IURIConnection

public interface IRequester<T extends IdBean>
extends IRequestResponseConnection

A poster broadcasts a request of an object with a unique id. The server then fills in information about this object and broadcasts it back. The UUID must be set to determine which response belongs with whcih request.

This mimics web server functionality but uses the existing messaging system without requiring a web server configuration. An alternative to this might be to start a jetty server on the acquisition server and response to requests directly.

A use case for this is where a client would like to get a list of detectors. NOTE: Unlike a web server this paradigm allows multiple responders to reply on a topic. Therefore for instance if many malcolm devices are available on different ports, a post will be made asking for those devices and the response from many listeners of the post topic collated.

Nested Class Summary

Nested Classes

Modifier and Type	Interface	Description
static enum	IRequester.ResponseType

Field Summary

Fields

Modifier and Type	Field	Description
static final IRequester.ResponseType	DEFAULT_RESPONSE_TYPE
static final TimeUnit	DEFAULT_TIME_UNIT
static final long	DEFAULT_TIMEOUT

Method Summary

Modifier and Type	Method	Description
T	post(T request)	Requests a response from the request and returns it.
T	post(T request, long timeout, TimeUnit timeUnit)	As post(IdBean), but allowing the caller to specify a timeout to apply to this request only.
T	post(T request, IResponseWaiter waiter)	Same as post(IdBean) with an optional IResponseWaiter (may be null) which provides the ability to return true if the post should carry on waiting.
T	post(T request, IResponseWaiter waiter, long timeout, TimeUnit timeUnit)	As post(IdBean, IResponseWaiter), but allowing the caller to specify a timeout to apply to this request only.
void	setResponseType(IRequester.ResponseType responseType)	Set the IRequester.ResponseType required (see above)
void	setTimeout(long time, TimeUnit unit)	Set the timeout for the request

Methods inherited from interface org.eclipse.scanning.api.event.core.IConnection

close, disconnect, isConnected

Methods inherited from interface org.eclipse.scanning.api.event.core.IRequestResponseConnection

getRequestTopic, getResponseTopic, setRequestTopic, setResponseTopic

Methods inherited from interface org.eclipse.scanning.api.event.core.IURIConnection

getConnectorService, getUri

Field Details

DEFAULT_RESPONSE_TYPE

static final IRequester.ResponseType DEFAULT_RESPONSE_TYPE

DEFAULT_TIMEOUT

static final long DEFAULT_TIMEOUT

See Also:

• Constant Field Values

DEFAULT_TIME_UNIT

static final TimeUnit DEFAULT_TIME_UNIT

Method Details

setResponseType

void setResponseType(IRequester.ResponseType responseType)

Set the IRequester.ResponseType required (see above)

setTimeout

void setTimeout(long time,
 TimeUnit unit)

Set the timeout for the request

post

T post(T request)
throws EventException,
InterruptedException

Requests a response from the request and returns it. This method blocks until the response has been retrieved with the correct UUID.

Calls post and waits for the timeout until one or more reponses have come in (depending on the response configuration) then returns.

Parameters:

request - the request to be sent

Returns:

the response to the request

Throws:

EventException

InterruptedException

post

T post(T request,
 long timeout,
 TimeUnit timeUnit)
throws EventException,
InterruptedException

As post(IdBean), but allowing the caller to specify a timeout to apply to this request only.

Throws:

EventException

InterruptedException

post

T post(T request,
 IResponseWaiter waiter)
throws EventException,
InterruptedException

Same as post(IdBean) with an optional IResponseWaiter (may be null) which provides the ability to return true if the post should carry on waiting. This is useful for instance in the case where a scannable is setting position. It will have notified position recently and if the waiter thinks it is still alive there is not reason to timeout. This is useful in setPosition(...) calls for scannables that can take an indeterminate time but should still timeout if they go inactive.

Parameters:

request - the request to be sent

waiter - IResponseWaiter (can be null) which determines if the post should carry on waiting after an initial timeout

Returns:

the response to the request

Throws:

EventException

InterruptedException

post

T post(T request,
 IResponseWaiter waiter,
 long timeout,
 TimeUnit timeUnit)
throws EventException,
InterruptedException

As post(IdBean, IResponseWaiter), but allowing the caller to specify a timeout to apply to this request only.

Throws:

EventException

InterruptedException