Interface ExtensionHandler

All Known Subinterfaces:

Handler

Functional Interface:

This is a functional interface and can therefore be used as the assignment target for a lambda expression or method reference.

@FunctionalInterface
@Alpha
public interface ExtensionHandler

Provides functionality for a single method on an extension object. Each extension handler can either call another piece of code to return the result (e.g. the method on the underlying object) or return the result itself.

Since:

3.38.0

Field Summary

Fields

Modifier and Type	Field	Description
static final ExtensionHandler	EQUALS_HANDLER	Implementation for the Object.equals(Object) method.
static final ExtensionHandler	HASHCODE_HANDLER	Implementation for the Object.hashCode() method.
static final ExtensionHandler	NULL_HANDLER	Handler that only returns null independent of any input parameters.

Method Summary

Modifier and Type	Method	Description
static ExtensionHandler	createForMethod(Method method)	Create an extension handler and bind it to a method that will be called on the target object when invoked.
static ExtensionHandler	createForMethodHandle(MethodHandle methodHandle)	Create an extension handler and bind it to a MethodHandle instance.
static ExtensionHandler	createForSpecialMethod(Method method)	Create an extension handler and bind it to a special method that will be called on the target object when invoked.
Object	invoke(HandleSupplier handleSupplier, Object target, Object... args)	Gets invoked to return a value for the method that this handler was bound to.
static ExtensionHandler	missingExtensionHandler(Method method)	Returns a default handler for missing functionality.
default void	warm(ConfigRegistry config)	Called after the method handler is constructed to pre-initialize any important configuration data structures.

Field Details

EQUALS_HANDLER

static final ExtensionHandler EQUALS_HANDLER

Implementation for the Object.equals(Object) method. Each object using this handler is only equal to itself.

HASHCODE_HANDLER

static final ExtensionHandler HASHCODE_HANDLER

Implementation for the Object.hashCode() method.

NULL_HANDLER

static final ExtensionHandler NULL_HANDLER

Handler that only returns null independent of any input parameters.

Method Details

invoke

Object invoke(HandleSupplier handleSupplier,
 Object target,
 Object... args)
       throws Exception

Gets invoked to return a value for the method that this handler was bound to.

Parameters:

handleSupplier - A HandleSupplier instance for accessing the handle and its related objects

target - The target object on which the handler should operate

args - Optional arguments for the handler

Returns:

The return value for the method that was bound to the extension handler. Can be null

Throws:

Exception - Any exception from the underlying code

warm

@Beta
default void warm(ConfigRegistry config)

Called after the method handler is constructed to pre-initialize any important configuration data structures.

Parameters:

config - the method configuration to use for warming up

missingExtensionHandler

static ExtensionHandler missingExtensionHandler(Method method)

Returns a default handler for missing functionality. The handler will throw an exception when invoked.

Parameters:

method - The method to which this specific handler instance is bound

Returns:

An ExtensionHandler instance

createForMethod

static ExtensionHandler createForMethod(Method method)
                                 throws IllegalAccessException

Create an extension handler and bind it to a method that will be called on the target object when invoked.

Parameters:

method - The Method to bind to

Returns:

An ExtensionHandler

Throws:

IllegalAccessException - If the method could not be unreflected

createForSpecialMethod

static ExtensionHandler createForSpecialMethod(Method method)
                                        throws IllegalAccessException

Create an extension handler and bind it to a special method that will be called on the target object when invoked. This is needed e.g. for interface default methods.

Parameters:

method - The Method to bind to

Returns:

An ExtensionHandler

Throws:

IllegalAccessException - If the method could not be unreflected

createForMethodHandle

static ExtensionHandler createForMethodHandle(MethodHandle methodHandle)

Create an extension handler and bind it to a MethodHandle instance.

Parameters:

methodHandle - The MethodHandle to bind to

Returns:

An ExtensionHandler