org.scijava
Interface Gateway

All Superinterfaces:

Comparable<Prioritized>, Contextual, HasPluginInfo, Prioritized, RichPlugin, SciJavaPlugin

All Known Implementing Classes:

AbstractGateway, SciJava

public interface Gateway
extends RichPlugin

Interface for convenience classes that wrap a Context to provide one-line access to a suite of Services.

The get(java.lang.Class) methods provide consistent Service instantiation, while throwing NoSuchServiceException if the requested Service is not found.

Sample implementation

Let's say we have a Kraken service and a Cow service. Using the Context directly, the code would look like:

 Context context = new Context();
 context.getService(Cow.class).feedToKraken();
 context.getService(Kraken.class).burp();

To perform these actions, you have to know a priori to ask for a Cow and a Kraken; i.e., your IDE's code completion will not give you a hint. Further, if either service is unavailable, a NullPointerException is thrown.

But if we create a Gateway class called Animals with the following signatures:

 public Cow cow() { return get(Cow.class); }
 public Kraken kraken() { return get(Kraken.class); }

We can now access our services through the new Animals gateway:

 Animals animals = new Animals();
 animals.cow().feedToKraken();
 animals.kraken().burp();

This provides succinct yet explicit access to the Cow and Kraken services; it is a simple two-layer access to functionality, which an IDE can auto-complete. And if one of the services is not available, a NoSuchServiceException is thrown, which facilitates appropriate (but optional) handling of missing services.

Gateways discoverable at runtime must implement this interface and be annotated with @Gateway with attribute Plugin.type() = Gateway.class. While it possible to create a gateway merely by implementing this interface, it is encouraged to instead extend AbstractGateway, for convenience.

Author:

Mark Hiner, Curtis Rueden

See Also:

Context

Method Summary

AppService	app()
EventService	event()
EventHistory	eventHistory()
<S extends Service> S	get(Class<S> serviceClass) Returns an implementation of the requested Service, if it exists in the underlying Context.
Service	get(String serviceClassName) Returns an implementation of the Service with the given class name, if it exists in the underlying Context.
App	getApp()
String	getInfo(boolean mem)
String	getTitle()
String	getVersion()
LogService	log()
ObjectService	object()
PluginService	plugin()
StatusService	status()
ThreadService	thread()

Methods inherited from interface org.scijava.Contextual

context, getContext, setContext

Methods inherited from interface org.scijava.Prioritized

getPriority, setPriority

Methods inherited from interface java.lang.Comparable

compareTo

Methods inherited from interface org.scijava.plugin.HasPluginInfo

getInfo, setInfo

Method Detail

get

<S extends Service> S get(Class<S> serviceClass)

Returns an implementation of the requested Service, if it exists in the underlying Context.

Parameters:

serviceClass - the requested Service

Returns:

The singleton instance of the given class

Throws:

NullContextException - if the application context is not set.

NoSuchServiceException - if there is no service of the given class.

get

Service get(String serviceClassName)

Returns an implementation of the Service with the given class name, if it exists in the underlying Context.

Parameters:

serviceClassName - name of the requested Service

Returns:

The singleton instance of the requested Service

Throws:

NullContextException - if the application context is not set.

NoSuchServiceException - if there is no service matching serviceClassName.

app

AppService app()

eventHistory

EventHistory eventHistory()

event

EventService event()

log

LogService log()

object

ObjectService object()

plugin

PluginService plugin()

status

StatusService status()

thread

ThreadService thread()

getApp

App getApp()

See Also:

AppService

getTitle

String getTitle()

See Also:

App.getTitle()

getVersion

String getVersion()

See Also:

App.getVersion()

getInfo

String getInfo(boolean mem)

See Also:

App.getInfo(boolean)