org.springframework.integration.annotation

Annotation Type Gateway

@Target(value={METHOD,ANNOTATION_TYPE})
 @Retention(value=RUNTIME)
 @Documented
public @interface Gateway

Indicates that an interface method is capable of mapping its parameters to a message or message payload. These method-level annotations are detected by the GatewayProxyFactoryBean where the annotation attributes can override the default channel settings.

A method annotated with @Gateway may accept a single non-annotated parameter of type Message or of the intended Message payload type. Method parameters may be mapped to individual Message header values by using the @Header parameter annotation. Alternatively, to pass the entire Message headers map, a Map-typed parameter may be annotated with Headers.

Return values from the annotated method may be of any type. If the declared return value is not a Message, the reply Message's payload will be returned and any type conversion as supported by Spring's SimpleTypeConverter will be applied to the return value if necessary.

Note: unlike @Publisher, this annotation is for exposing a Messaging Endpoint based on a Proxy for the marked interface method. The method invocation causes messaging interaction using an AOP Advice. Method parameters become the part of sent message (payload, headers). The method return value is the result (payload) of the messaging flow invoked by the Proxy.

Author:

Mark Fisher, Gary Russell, Artem Bilan

See Also:

MessagingGateway

Optional Element Summary

Optional Elements

Modifier and Type	Optional Element and Description
GatewayHeader[]	headers Specify additional headers that will be added to the request message.
String	payloadExpression Specify a SpEL expression to determine the payload of the request message.
String	replyChannel Specify the channel from which reply messages will be received; overrides the encompassing gateway's default reply channel.
long	replyTimeout Specify the time (ms) that the thread sending the request will wait for a reply.
String	replyTimeoutExpression Specify a SpEL Expression to determine the the time (ms) that the thread sending the request will wait for a reply.
String	requestChannel Specify the channel to which messages will be sent; overrides the encompassing gateway's default request channel.
long	requestTimeout Specify the timeout (ms) when sending to the request channel - only applies if the send might block (such as a bounded QueueChannel that is currently full.
String	requestTimeoutExpression Specify a SpEL Expression to determine the timeout (ms) when sending to the request channel - only applies if the send might block (such as a bounded QueueChannel that is currently full.

Element Detail

requestChannel

public abstract String requestChannel

Specify the channel to which messages will be sent; overrides the encompassing gateway's default request channel.

Returns:

the channel name.

Default:

""

replyChannel

public abstract String replyChannel

Specify the channel from which reply messages will be received; overrides the encompassing gateway's default reply channel.

Returns:

the channel name.

Default:

""

requestTimeout

public abstract long requestTimeout

Specify the timeout (ms) when sending to the request channel - only applies if the send might block (such as a bounded QueueChannel that is currently full. Overrides the encompassing gateway's default request timeout.

Returns:

the timeout.

See Also:

requestTimeoutExpression()

Default:

-9223372036854775808L

requestTimeoutExpression

public abstract String requestTimeoutExpression

Specify a SpEL Expression to determine the timeout (ms) when sending to the request channel - only applies if the send might block (such as a bounded QueueChannel that is currently full. Overrides the encompassing gateway's default request timeout. Overrides requestTimeout().

Returns:

the timeout.

Since:

5.0

Default:

""

replyTimeout

public abstract long replyTimeout

Specify the time (ms) that the thread sending the request will wait for a reply. The timer starts when the thread returns to the gateway, not when the request message is sent. Overrides the encompassing gateway's default reply timeout.

Returns:

the timeout.

See Also:

replyTimeoutExpression()

Default:

-9223372036854775808L

replyTimeoutExpression

public abstract String replyTimeoutExpression

Specify a SpEL Expression to determine the the time (ms) that the thread sending the request will wait for a reply. The timer starts when the thread returns to the gateway, not when the request message is sent. Overrides the encompassing gateway's default reply timeout. Overrides replyTimeout().

Returns:

the timeout.

Since:

5.0

Default:

""

payloadExpression

public abstract String payloadExpression

Specify a SpEL expression to determine the payload of the request message.

Returns:

the expression.

Default:

""

headers

public abstract GatewayHeader[] headers

Specify additional headers that will be added to the request message.

Returns:

the headers.

Default:

{}