49. Broadcasting Your Own Events
The Bus can carry any event of type RemoteApplicationEvent
. The default transport is JSON, and the deserializer needs to know which types are going to be used ahead of time. To register a new type, you must put it in a subpackage of org.springframework.cloud.bus.event
.
To customise the event name, you can use @JsonTypeName
on your custom class or rely on the default strategy, which is to use the simple name of the class.
Note | |
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Both the producer and the consumer need access to the class definition. |
If you cannot or do not want to use a subpackage of org.springframework.cloud.bus.event
for your custom events, you must specify which packages to scan for events of type RemoteApplicationEvent
by using the @RemoteApplicationEventScan
annotation. Packages specified with @RemoteApplicationEventScan
include subpackages.
For example, consider the following custom event, called MyEvent
:
package com.acme; public class MyEvent extends RemoteApplicationEvent { ... }
You can register that event with the deserializer in the following way:
package com.acme; @Configuration @RemoteApplicationEventScan public class BusConfiguration { ... }
Without specifying a value, the package of the class where @RemoteApplicationEventScan
is used is registered. In this example, com.acme
is registered by using the package of BusConfiguration
.
You can also explicitly specify the packages to scan by using the value
, basePackages
or basePackageClasses
properties on @RemoteApplicationEventScan
, as shown in the following example:
package com.acme; @Configuration //@RemoteApplicationEventScan({"com.acme", "foo.bar"}) //@RemoteApplicationEventScan(basePackages = {"com.acme", "foo.bar", "fizz.buzz"}) @RemoteApplicationEventScan(basePackageClasses = BusConfiguration.class) public class BusConfiguration { ... }
All of the preceding examples of @RemoteApplicationEventScan
are equivalent, in that the com.acme
package is registered by explicitly specifying the packages on @RemoteApplicationEventScan
.
Note | |
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You can specify multiple base packages to scan. |