Package org.eclipse.jetty.websocket.core.internal.util

Class InvokerUtils

java.lang.Object

org.eclipse.jetty.websocket.core.internal.util.InvokerUtils

public class InvokerUtils
extends Object

Nested Class Summary

Nested Classes

Modifier and Type	Class	Description
static class	InvokerUtils.Arg
static interface	InvokerUtils.ParamIdentifier

Field Summary

Fields

Modifier and Type	Field	Description
static final InvokerUtils.ParamIdentifier	PARAM_IDENTITY

Constructor Summary

Constructors

Constructor	Description
InvokerUtils()

Method Summary

Modifier and Type	Method	Description
static MethodHandle	bindTo(MethodHandle methodHandle, Object... objs)	Bind optional arguments to provided method handle
static MethodHandle	mutatedInvoker(MethodHandles.Lookup lookup, Class<?> targetClass, Method method, InvokerUtils.Arg... callingArgs)	Build a MethodHandle that can call the method with the calling args provided.
static MethodHandle	mutatedInvoker(MethodHandles.Lookup lookup, Class<?> targetClass, Method method, InvokerUtils.ParamIdentifier paramIdentifier, String[] namedVariables, InvokerUtils.Arg... callingArgs)	Create a MethodHandle that performs the following layers MethodHandles.permuteArguments(MethodHandle, MethodType, int...) - moving calling Args around to fit actual actual method parameter arguments (in proper order), with remaining (unused) calling args afterwords MethodHandles.dropArguments(MethodHandle, int, Class[]) - to drop the unused calling args MethodHandle.invoke(Object...) - to call the specific method
static MethodHandle	optionalMutatedInvoker(MethodHandles.Lookup lookup, Class<?> targetClass, Method method, InvokerUtils.Arg... callingArgs)
static MethodHandle	optionalMutatedInvoker(MethodHandles.Lookup lookup, Class<?> targetClass, Method method, InvokerUtils.ParamIdentifier paramIdentifier, String[] namedVariables, InvokerUtils.Arg... callingArgs)	Create an optional MethodHandle that performs the following layers.

Methods inherited from class java.lang.Object

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

Field Details

PARAM_IDENTITY

public static final InvokerUtils.ParamIdentifier PARAM_IDENTITY

Constructor Details

InvokerUtils

public InvokerUtils()

Method Details

bindTo

public static MethodHandle bindTo(MethodHandle methodHandle,
 Object... objs)

Bind optional arguments to provided method handle

Parameters:

methodHandle - the method handle to bind to

objs - the list of optional objects to bind to.

Returns:

the bound MethodHandle, or null if the provided methodHandle was null.

mutatedInvoker

public static MethodHandle mutatedInvoker(MethodHandles.Lookup lookup,
 Class<?> targetClass,
 Method method,
 InvokerUtils.Arg... callingArgs)

Build a MethodHandle that can call the method with the calling args provided.

Might need to drop calling args and/or reorder the calling args to fit the actual method being called.

Parameters:

lookup - the MethodHandles.Lookup instance to use.

targetClass - the target class for invocations of the resulting MethodHandle (also known as parameter 0)

method - the method to invoke

callingArgs - the calling arguments. This is the array of arguments that will always be passed into the returned MethodHandle. They will be present in the MethodHandle.type() in the order specified in this array.

mutatedInvoker

public static MethodHandle mutatedInvoker(MethodHandles.Lookup lookup,
 Class<?> targetClass,
 Method method,
 InvokerUtils.ParamIdentifier paramIdentifier,
 String[] namedVariables,
 InvokerUtils.Arg... callingArgs)

Create a MethodHandle that performs the following layers

1. MethodHandles.permuteArguments(MethodHandle, MethodType, int...) - moving calling Args around to fit actual actual method parameter arguments (in proper order), with remaining (unused) calling args afterwords
2. MethodHandles.dropArguments(MethodHandle, int, Class[]) - to drop the unused calling args
3. MethodHandle.invoke(Object...) - to call the specific method

The returned MethodHandle.MethodHandle.type() assumes the following:

1. Return type will be what the provided Method has.
2. The first parameter is the type of class provided in the targetClass.
3. The next parameters are all of the found type's of the named arguments, or type String if not found in provided Method.
4. The next parameters are all of the provided callingArg types

Parameters:

lookup - the MethodHandles.Lookup instance to use.

targetClass - the target class for invocations of the resulting MethodHandle (also known as parameter 0)

method - the method to invoke

paramIdentifier - the mechanism to identify parameters in method

namedVariables - the array of named variables. This is the array of named arguments that the target method might have. The resulting MethodHandle will include all of these namedVariables as the first non-object arguments in the MethodType found on the returned MethodHandle.type()

callingArgs - the calling arguments. This is the array of arguments that will always be passed into the returned MethodHandle. They will be present in the MethodHandle.type() in the order specified in this array.

Returns:

the MethodHandle for this set of CallingArgs

Throws:

RuntimeException - when unable to fit Calling Args to Parameter Types

optionalMutatedInvoker

public static MethodHandle optionalMutatedInvoker(MethodHandles.Lookup lookup,
 Class<?> targetClass,
 Method method,
 InvokerUtils.ParamIdentifier paramIdentifier,
 String[] namedVariables,
 InvokerUtils.Arg... callingArgs)

Create an optional MethodHandle that performs the following layers.

1. MethodHandles.permuteArguments(MethodHandle, MethodType, int...) - moving calling Args around to fit actual actual method parameter arguments (in proper order), with remaining (unused) calling args afterwords
2. MethodHandles.dropArguments(MethodHandle, int, Class[]) - to drop the unused calling args
3. MethodHandle.invoke(Object...) - to call the specific method

Parameters:

lookup - the MethodHandles.Lookup instance to use.

targetClass - the target class for invocations of the resulting MethodHandle (also known as parameter 0)

method - the method to invoke

paramIdentifier - the mechanism to identify parameters in method

namedVariables - the array of named variables. This is the array of named arguments that the target method might have. The resulting MethodHandle will include all of these namedVariables as the first non-object arguments in the MethodType found on the returned MethodHandle.type()

callingArgs - the calling arguments. This is the array of arguments that will always be passed into the returned MethodHandle. They will be present in the MethodHandle.type() in the order specified in this array.

Returns:

the MethodHandle for this set of CallingArgs, or null if not possible to create MethodHandle with CallingArgs to provided method

optionalMutatedInvoker

public static MethodHandle optionalMutatedInvoker(MethodHandles.Lookup lookup,
 Class<?> targetClass,
 Method method,
 InvokerUtils.Arg... callingArgs)