Class HandlerInspector

java.lang.Object

io.fluxzero.common.handling.HandlerInspector

public class HandlerInspector
extends Object

Utility for inspecting and constructing handler components from annotated methods.

The HandlerInspector scans classes for methods that match handler criteria (e.g., @HandleCommand), and constructs Handler, HandlerMatcher, and HandlerInvoker instances based on those methods. It supports both stateless (singleton) and stateful handlers by accepting target suppliers and parameter resolvers.

This class is the core of the handler discovery and resolution mechanism in Fluxzero, bridging the gap between annotated user-defined classes and runtime message dispatch infrastructure.

Capabilities

• Detect handler methods on a class based on annotations and signatures
• Create Handler instances that provide lifecycle-aware invocation logic
• Build HandlerMatchers that analyze message applicability
• Support parameter resolution for dependency injection and message binding

See Also:

• Handler
• HandlerMatcher
• HandlerInvoker

Nested Class Summary

Nested Classes

Modifier and Type	Class	Description
static class	HandlerInspector.MethodHandlerMatcher<M>	A matcher that encapsulates metadata and resolution logic for a single handler method or constructor.
static class	HandlerInspector.ObjectHandlerMatcher<M>	A composite HandlerMatcher that delegates to a list of individual matchers.

Constructor Summary

Constructors

Constructor	Description
HandlerInspector()

Method Summary

Modifier and Type	Method	Description
static <M> Handler<M>	createHandler(Object target, Class<? extends Annotation> methodAnnotation)	Creates a Handler for the given target object and annotation type.
static <M> Handler<M>	createHandler(Object target, Class<? extends Annotation> methodAnnotation, List<ParameterResolver<? super M>> parameterResolvers)	Creates a Handler backed by a target supplier and parameter resolvers.
static <M> Handler<M>	createHandler(Object target, List<ParameterResolver<? super M>> parameterResolvers, HandlerConfiguration<? super M> config)	Creates a Handler backed by a target supplier and parameter resolvers.
static <M> Handler<M>	createHandler(Function<M,?> targetSupplier, Class<?> targetClass, List<ParameterResolver<? super M>> parameterResolvers, HandlerConfiguration<? super M> config)	Creates a Handler backed by a target supplier and parameter resolvers.
static boolean	hasHandlerMethods(Class<?> targetClass, HandlerConfiguration<?> handlerConfiguration)	Returns whether the given class contains at least one method or constructor that matches the handler configuration.
static <M> HandlerMatcher<Object,M>	inspect(Class<?> targetClass, List<ParameterResolver<? super M>> parameterResolvers, HandlerConfiguration<? super M> config)	Inspects the given class for methods matching the specified annotation and builds a HandlerMatcher.
static <M> HandlerMatcher<Object,M>	inspect(Class<?> targetClass, List<ParameterResolver<? super M>> parameterResolvers, Class<? extends Annotation> methodAnnotation)	Inspects the given class for methods matching the specified annotation and builds a HandlerMatcher.

Methods inherited from class Object

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

Constructor Details

HandlerInspector

public HandlerInspector()

Method Details

hasHandlerMethods

public static boolean hasHandlerMethods(Class<?> targetClass,
 HandlerConfiguration<?> handlerConfiguration)

Returns whether the given class contains at least one method or constructor that matches the handler configuration.

Parameters:

targetClass - the class to inspect

handlerConfiguration - the handler configuration to match against

Returns:

true if at least one method or constructor is a valid handler

createHandler

public static <M> Handler<M> createHandler(Object target,
 Class<? extends Annotation> methodAnnotation)

Creates a Handler for the given target object and annotation type. This variant uses a default no-op parameter resolver.

Type Parameters:

M - the message type

Parameters:

target - the handler instance

methodAnnotation - the annotation to detect handler methods (e.g. @HandleCommand)

Returns:

a new Handler instance

createHandler

public static <M> Handler<M> createHandler(Object target,
 Class<? extends Annotation> methodAnnotation,
 List<ParameterResolver<? super M>> parameterResolvers)

Creates a Handler backed by a target supplier and parameter resolvers. Suitable for stateful handlers where the instance depends on the message content.

Type Parameters:

M - the message type

Parameters:

target - the handler instance

methodAnnotation - the annotation to detect handler methods (e.g. @HandleCommand)

parameterResolvers - resolvers for handler method parameters

Returns:

a handler capable of resolving and invoking methods on the target

createHandler

public static <M> Handler<M> createHandler(Object target,
 List<ParameterResolver<? super M>> parameterResolvers,
 HandlerConfiguration<? super M> config)

Creates a Handler backed by a target supplier and parameter resolvers. Suitable for stateful handlers where the instance depends on the message content.

Type Parameters:

M - the message type

Parameters:

target - the handler instance

parameterResolvers - resolvers for handler method parameters

config - handler configuration settings

Returns:

a handler capable of resolving and invoking methods on the target

createHandler

public static <M> Handler<M> createHandler(Function<M,?> targetSupplier,
 Class<?> targetClass,
 List<ParameterResolver<? super M>> parameterResolvers,
 HandlerConfiguration<? super M> config)

Creates a Handler backed by a target supplier and parameter resolvers. Suitable for stateful handlers where the instance depends on the message content.

Type Parameters:

M - the message type

Parameters:

targetSupplier - provides the handler instance to use for a given message

targetClass - the class containing handler methods

parameterResolvers - resolvers for handler method parameters

config - handler configuration settings

Returns:

a handler capable of resolving and invoking methods on the target

inspect

public static <M> HandlerMatcher<Object,M> inspect(Class<?> targetClass,
 List<ParameterResolver<? super M>> parameterResolvers,
 Class<? extends Annotation> methodAnnotation)

Inspects the given class for methods matching the specified annotation and builds a HandlerMatcher.

This matcher can later be used to resolve a HandlerInvoker for a target object and message.

Parameters:

targetClass - the class containing handler methods

parameterResolvers - resolvers for handler method parameters

methodAnnotation - the annotation to detect handler methods (e.g. @HandleCommand)

inspect

public static <M> HandlerMatcher<Object,M> inspect(Class<?> targetClass,
 List<ParameterResolver<? super M>> parameterResolvers,
 HandlerConfiguration<? super M> config)

Inspects the given class for methods matching the specified annotation and builds a HandlerMatcher.

This matcher can later be used to resolve a HandlerInvoker for a target object and message.

Parameters:

targetClass - the class containing handler methods

parameterResolvers - resolvers for handler method parameters

config - handler configuration settings