org.axonframework.common.annotation

Class ParameterResolverFactory

java.lang.Object

org.axonframework.common.annotation.ParameterResolverFactory

Direct Known Subclasses:

CurrentUnitOfWorkParameterResolverFactory, DefaultParameterResolverFactory, FixtureResourceParameterResolverFactory, SimpleResourceParameterResolverFactory, SpringBeanParameterResolverFactory, TimestampParameterResolverFactory

public abstract class ParameterResolverFactory
extends Object

Abstract Factory that provides access to all ParameterResolverFactory implementations.

Application developers may provide custom ParameterResolverFactory implementations using the ServiceLoader mechanism. To do so, place a file called org.axonframework.common.annotation.ParameterResolverFactory in the META-INF/services folder. In this file, place the fully qualified class names of all available implementations.

The factory implementations must be public, non-abstract, have a default public constructor and extend the ParameterResolverFactory class.

Since:

2.0

Author:

Allard Buijze

See Also:

ServiceLoader, ServiceLoader.load(Class)

Constructor Summary

Constructors

Constructor and Description
ParameterResolverFactory()

Method Summary

Methods

Modifier and Type	Method and Description
protected abstract ParameterResolver	createInstance(Annotation[] memberAnnotations, Class<?> parameterType, Annotation[] parameterAnnotations) If available, creates a ParameterResolver instance that can provide a parameter of type parameterType for a given message.
static ParameterResolver	createPayloadResolver(Class<?> parameterType) Creates a ParameterResolver that resolves the payload of a given message when it is assignable to the given parameterType.
static ParameterResolver	findParameterResolver(Annotation[] memberAnnotations, Class<?> parameterType, Annotation[] parameterAnnotations, boolean isPayloadParameter) Iterates over all known ParameterResolverFactory implementations to create a ParameterResolver instance for the given parameters.
static void	registerChangeListener(org.axonframework.common.annotation.ParameterResolverFactory.ChangeListener listener) Registers a listener that is notified when the ParameterResolverFactory instances are registered or unregistered.
static void	registerFactory(ParameterResolverFactory factory) Registers a ParameterResolverFactory at runtime.
abstract boolean	supportsPayloadResolution() Indicates whether this resolver may be used to resolve the payload parameter of an annotated handler method.
static void	unregisterFactory(ParameterResolverFactory factory) Unregisters a ParameterResolverFactory at runtime.

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Constructor Detail

ParameterResolverFactory

public ParameterResolverFactory()

Method Detail

registerFactory

public static void registerFactory(ParameterResolverFactory factory)

Registers a ParameterResolverFactory at runtime. Annotated handlers that have already been inspected *may* not be able to use the newly added factory.

All registered ChangeListeners are notified of the registration

Parameters:

factory - The factory to register

unregisterFactory

public static void unregisterFactory(ParameterResolverFactory factory)

Unregisters a ParameterResolverFactory at runtime. Annotated handlers that have already been inspected *may* not be affected by the removal of the parameter resolver.

All registered ChangeListeners are notified of the registration if the given factory was registered prior to this method invocation.

Parameters:

factory - The factory to unregister

findParameterResolver

public static ParameterResolver findParameterResolver(Annotation[] memberAnnotations,
                                      Class<?> parameterType,
                                      Annotation[] parameterAnnotations,
                                      boolean isPayloadParameter)

Iterates over all known ParameterResolverFactory implementations to create a ParameterResolver instance for the given parameters. The ParameterResolverFactories invoked in the order they are found on the classpath. The first to provide a suitable resolver will be used. The DefaultParameterResolverFactory is always the last one to be inspected.

Parameters:

memberAnnotations - annotations placed on the member (e.g. method)

parameterType - the parameter type to find a resolver for

parameterAnnotations - annotations places on the parameter

isPayloadParameter - whether the parameter to resolve represents a payload parameter

Returns:

a suitable ParameterResolver, or null if none is found

createPayloadResolver

public static ParameterResolver createPayloadResolver(Class<?> parameterType)

Creates a ParameterResolver that resolves the payload of a given message when it is assignable to the given parameterType.

Parameters:

parameterType - The type of parameter to create a resolver for

Returns:

a ParameterResolver that resolves the payload of a given message

supportsPayloadResolution

public abstract boolean supportsPayloadResolution()

Indicates whether this resolver may be used to resolve the payload parameter of an annotated handler method.

Returns:

whether this factory provides Parameter Resolvers that support payload parameters

createInstance

protected abstract ParameterResolver createInstance(Annotation[] memberAnnotations,
                               Class<?> parameterType,
                               Annotation[] parameterAnnotations)

If available, creates a ParameterResolver instance that can provide a parameter of type parameterType for a given message.

If the ParameterResolverFactory cannot provide a suitable ParameterResolver, returns null.

Parameters:

memberAnnotations - annotations placed on the member (e.g. method)

parameterType - the parameter type to find a resolver for

parameterAnnotations - annotations places on the parameter

Returns:

a suitable ParameterResolver, or null if none is found

registerChangeListener

public static void registerChangeListener(org.axonframework.common.annotation.ParameterResolverFactory.ChangeListener listener)

Registers a listener that is notified when the ParameterResolverFactory instances are registered or unregistered. Generally, when caching the results of the ParameterResolverFactories, the component managing the cache should listen to changes to invalidate the cache.

Parameters:

listener - The listener to notify when state has changed