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@ -30,31 +30,34 @@ import org.springframework.core.annotation.AliasFor;
@@ -30,31 +30,34 @@ import org.springframework.core.annotation.AliasFor;
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* |
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* <p>If an annotated method supports a single event type, the method may |
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* declare a single parameter that reflects the event type to listen to. |
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* If an annotated method supports multiple event types, this annotation may |
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* refer to one or more supported event types using the {@code classes} |
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* attribute. See {@link #classes} for further details. |
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* If an annotated method supports multiple event types, this annotation |
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* may refer to one or more supported event types using the {@code classes} |
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* attribute. See the {@link #classes} javadoc for further details. |
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* |
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* <p>Events can be {@link ApplicationEvent} instances as well as arbitrary |
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* objects. |
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* |
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* <p>Processing of {@code @EventListener} annotations is performed via the |
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* {@link EventListenerMethodProcessor} which is registered automatically |
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* when using Java config or manually via the {@code <context:annotation-driven/>} |
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* <p>Processing of {@code @EventListener} annotations is performed via |
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* the internal {@link EventListenerMethodProcessor} bean which gets |
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* registered automatically when using Java config or manually via the |
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* {@code <context:annotation-config/>} or {@code <context:component-scan/>} |
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* element when using XML config. |
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* |
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* <p>Annotated methods may have a non-{@code void} return type. When they do, |
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* the result of the method invocation is sent as a new event. If the return type |
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* is either an array or a collection, each element is sent as a new event. |
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* <p>Annotated methods may have a non-{@code void} return type. When they |
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* do, the result of the method invocation is sent as a new event. If the |
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* return type is either an array or a collection, each element is sent |
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* as a new individual event. |
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* |
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* <p>It is also possible to define the order in which listeners for a certain |
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* event are invoked. To do so, add Spring's common |
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* <p>It is also possible to define the order in which listeners for a |
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* certain event are to be invoked. To do so, add Spring's common |
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* {@link org.springframework.core.annotation.Order @Order} annotation |
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* alongside this annotation. |
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* alongside this event listener annotation. |
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* |
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* <p>While it is possible for an event listener to declare that it throws arbitrary |
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* exception types, any checked exceptions thrown from an event listener will be |
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* wrapped in an {@link java.lang.reflect.UndeclaredThrowableException} since |
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* the caller can only handle runtime exceptions. |
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* <p>While it is possible for an event listener to declare that it |
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* throws arbitrary exception types, any checked exceptions thrown |
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* from an event listener will be wrapped in an |
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* {@link java.lang.reflect.UndeclaredThrowableException} |
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* since the event publisher can only handle runtime exceptions. |
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* |
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* @author Stephane Nicoll |
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* @since 4.2 |
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@ -73,17 +76,17 @@ public @interface EventListener {
@@ -73,17 +76,17 @@ public @interface EventListener {
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/** |
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* The event classes that this listener handles. |
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* <p>If this attribute is specified with a single value, the annotated |
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* method may optionally accept a single parameter. However, if this |
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* attribute is specified with multiple values, the annotated method |
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* must <em>not</em> declare any parameters. |
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* <p>If this attribute is specified with a single value, the |
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* annotated method may optionally accept a single parameter. |
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* However, if this attribute is specified with multiple values, |
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* the annotated method must <em>not</em> declare any parameters. |
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*/ |
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@AliasFor("value") |
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Class<?>[] classes() default {}; |
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/** |
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* Spring Expression Language (SpEL) attribute used for making the event |
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* handling conditional. |
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* Spring Expression Language (SpEL) attribute used for making the |
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* event handling conditional. |
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* <p>Default is "", meaning the event is always handled. |
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*/ |
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String condition() default ""; |
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