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doc: improve doc example of javadsl Extension (#28100)

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Patrik Nordwall 2019-11-08 16:27:52 +01:00 • committed by Johan Andrén
parent a47886c4f5
commit 0eddbe3589
2 changed files with 31 additions and 29 deletions
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52
akka-actor-typed-tests/src/test/java/jdocs/akka/typed/extensions/ExtensionDocTest.java
View file

@ -9,16 +9,14 @@ import akka.actor.typed.Behavior;
import akka.actor.typed.Extension;
import akka.actor.typed.ExtensionId;
import akka.actor.typed.javadsl.Behaviors;
import com.typesafe.config.ConfigFactory;
import docs.akka.typed.extensions.DatabasePool;
import docs.akka.typed.extensions.ExtensionDocSpec;
import java.util.concurrent.CompletionStage;
public class ExtensionDocTest {
interface ExtensionDocTest {
// #shared-resource
public static class ExpensiveDatabaseConnection {
public class ExpensiveDatabaseConnection {
public CompletionStage<Object> executeQuery(String query) {
throw new RuntimeException("I should do a database query");
}
@ -27,10 +25,31 @@ public class ExtensionDocTest {
// #shared-resource
// #extension
public static class DatabaseConnectionPool implements Extension {
public class DatabaseConnectionPool implements Extension {
// #extension
// #extension-id
public static class Id extends ExtensionId<DatabaseConnectionPool> {
private static final Id instance = new Id();
private Id() {}
// called once per ActorSystem
@Override
public DatabaseConnectionPool createExtension(ActorSystem<?> system) {
return new DatabaseConnectionPool(system);
}
public static DatabaseConnectionPool get(ActorSystem<?> system) {
return instance.apply(system);
}
}
// #extension-id
// #extension
private final ExpensiveDatabaseConnection _connection;
public DatabaseConnectionPool(ActorSystem<?> system) {
private DatabaseConnectionPool(ActorSystem<?> system) {
// database configuration can be loaded from config
// from the actor system
_connection = new ExpensiveDatabaseConnection();
@ -42,25 +61,6 @@ public class ExtensionDocTest {
}
// #extension
// #extension-id
public static class DatabaseConnectionPoolId extends ExtensionId<DatabaseConnectionPool> {
private static final DatabaseConnectionPoolId instance = new DatabaseConnectionPoolId();
private DatabaseConnectionPoolId() {}
// called once per ActorSystem
@Override
public DatabaseConnectionPool createExtension(ActorSystem system) {
return new DatabaseConnectionPool(system);
}
public static DatabaseConnectionPool get(ActorSystem<?> system) {
return instance.apply(system);
}
}
// #extension-id
public static Behavior<Object> initialBehavior() {
return null;
}
@ -69,7 +69,7 @@ public class ExtensionDocTest {
// #usage
Behaviors.setup(
(context) -> {
DatabaseConnectionPoolId.get(context.getSystem())
DatabaseConnectionPool.Id.get(context.getSystem())
.connection()
.executeQuery("insert into...");
return initialBehavior();

8
akka-docs/src/main/paradox/typed/extending.md
View file

@ -35,10 +35,10 @@ Scala
Java
: @@snip [ExtensionDocTest.java](/akka-actor-typed-tests/src/test/java/jdocs/akka/typed/extensions/ExtensionDocTest.java) { #extension }
This is the public API of your extension. Internally in this example we instantiate our expensive database connection.
The `DatabaseConnectionPool` can be looked up this way any number of times and it will return the same instance.
This is the public API of your extension. Internally in this example we instantiate our expensive database connection.
Then create an @apidoc[akka.actor.typed.ExtensionId] to identify the extension.
@scala[A good convention is to let the companion object of the `Extension` be the `ExtensionId`.]@java[A good convention is to define the `ExtensionId` as a static inner class of the `Extension`.]
Scala
: @@snip [ExtensionDocSpec.scala](/akka-actor-typed-tests/src/test/scala/docs/akka/typed/extensions/ExtensionDocSpec.scala) { #extension-id }
@ -54,6 +54,8 @@ Scala
Java
: @@snip [ExtensionDocTest.java](/akka-actor-typed-tests/src/test/java/jdocs/akka/typed/extensions/ExtensionDocTest.java) { #usage }
The `DatabaseConnectionPool` can be looked up in this way any number of times and it will return the same instance.
<a id="loading"></a>
## Loading from configuration
@ -66,7 +68,7 @@ Scala
Java
: ```ruby
akka.actor.typed {
extensions = ["jdocs.akka.extensions.ExtensionDocTest$DatabaseConnectionPoolId"]
extensions = ["jdocs.akka.extensions.ExtensionDocTest$DatabaseConnectionPool$Id"]
}
```