Package org.axonframework.migration

Class MigrateCommandGatewayInEventHandler

java.lang.Object

org.openrewrite.Recipe

org.axonframework.migration.MigrateCommandGatewayInEventHandler

All Implemented Interfaces:

Cloneable

public class MigrateCommandGatewayInEventHandler
extends org.openrewrite.Recipe

Migrates an Axon Framework 4 event-handling component that dispatches commands via a class-level CommandGateway field to the AF5 in-handler pattern: a method-parameter CommandDispatcher.

Decision rule from CommandDispatcher's Javadoc — gateway for top-of-chain entry points (controllers, runners), dispatcher inside another message handler. Inside an @EventHandler the active ProcessingContext makes CommandDispatcher the right tool, and AF5's dispatcher is auto-injected into handler methods by the CommandDispatcherParameterResolverFactory. This recipe automates that mechanical part of the migration:

1. Inside every @EventHandler method that calls <field>.send(...) or <field>.sendAndWait(...) on a class field of type CommandGateway, the call is rewritten to commandDispatcher.send(...) (the AndWait suffix is dropped — AF5's dispatcher only exposes the async send family).
2. A CommandDispatcher commandDispatcher parameter is appended to the method signature when the method does not already declare one.
3. For methods whose return type is void and whose body matches one of two supported shapes — a single dispatch expression statement, or a single try/catch where each branch ends in a dispatch expression statement — the return type is widened to CompletableFuture<?>, the dispatch expression is converted to return ... .getResultMessage();, and java.util.concurrent.CompletableFuture is imported. Methods with non-void return types (e.g. Mono<?>, custom types) are left alone — the call rewrite still applies, but the surrounding adaptation is left to the human.
4. Once every @EventHandler in the class has been visited, the recipe checks whether the CommandGateway field is still referenced anywhere. If it is not, the field declaration, the corresponding constructor parameter, and any matching this.field = field; assignment are removed — and the now-unused CommandGateway import is dropped.

The recipe matches AF5 fully-qualified type names because it is intended to run after the Axon4ToAxon5Messaging package renames in the same composite. Anything that does not match the supported shapes (loops, multi-dispatch branches, conditional dispatch, reactive return types) is left untouched: the build will still surface those call sites as compile errors so the human can address them.

Since:

5.1.1

Author:

Mateusz Nowak

Nested Class Summary

Nested classes/interfaces inherited from class org.openrewrite.Recipe

org.openrewrite.Recipe.Builder, org.openrewrite.Recipe.DelegatingRecipe

Field Summary

Fields inherited from class org.openrewrite.Recipe

contributors, examples, PANIC

Constructor Summary

Constructors

Constructor	Description
MigrateCommandGatewayInEventHandler()

Method Summary

Modifier and Type	Method	Description
String	getDescription()
String	getDisplayName()
org.openrewrite.TreeVisitor<?,org.openrewrite.ExecutionContext>	getVisitor()

Methods inherited from class org.openrewrite.Recipe

addDataTable, builder, buildRecipeList, causesAnotherCycle, clone, createRecipeDescriptor, equals, getContributors, getDataTableDescriptors, getDescriptor, getEstimatedEffortPerOccurrence, getExamples, getInstanceName, getInstanceNameSuffix, getJacksonPolymorphicTypeTag, getMaintainers, getName, getRecipeList, getTags, hashCode, maxCycles, noop, onComplete, run, run, run, setContributors, setExamples, validate, validate, validateAll, validateAll, withOptions

Methods inherited from class java.lang.Object

finalize, getClass, notify, notifyAll, toString, wait, wait, wait

Constructor Details

MigrateCommandGatewayInEventHandler

public MigrateCommandGatewayInEventHandler()

Method Details

getDisplayName

public String getDisplayName()

Specified by:

getDisplayName in class org.openrewrite.Recipe

getDescription

public String getDescription()

Specified by:

getDescription in class org.openrewrite.Recipe

getVisitor

public org.openrewrite.TreeVisitor<?,org.openrewrite.ExecutionContext> getVisitor()

Overrides:

getVisitor in class org.openrewrite.Recipe