/*
 * Copyright 2017-2020 original authors
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 * https://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */
package io.micronaut.inject;

import io.micronaut.core.annotation.AnnotationMetadata;
import io.micronaut.core.annotation.AnnotationMetadataDelegate;
import io.micronaut.core.type.Argument;
import io.micronaut.core.type.ReturnType;

import edu.umd.cs.findbugs.annotations.NonNull;
import java.lang.reflect.Method;

Represents a handle to an executable object. Differs from Executable in that the first argument to invoke(Object...) is not the object instead the object is typically held within the handle itself.

Executable handles are also applicable to constructors and static methods
Author:
Graeme Rocher
Type parameters:
<T> – The target type
<R> – The result type
Since:
1.0/**
 * <p>Represents a handle to an executable object. Differs from {@link io.micronaut.core.type.Executable} in that the
 * first argument to {@link #invoke(Object...)} is not the object instead the object is typically held within the
 * handle itself.</p>
 * <p>
 * <p>Executable handles are also applicable to constructors and static methods</p>
 *
 * @param <T> The target type
 * @param <R> The result type
 * @author Graeme Rocher
 * @since 1.0
 */
public interface ExecutionHandle<T, R> extends AnnotationMetadataDelegate {

    
The target of the method invocation.
Returns:
The target object/**
     * The target of the method invocation.
     *
     * @return The target object
     */
    T getTarget();

    
Returns:
The declaring type/**
     * @return The declaring type
     */
    Class getDeclaringType();

    
Returns:
The required argument types./**
     * @return The required argument types.
     */
    Argument[] getArguments();

    
Invokes the method.
Params:
arguments – The arguments
Returns:
The result/**
     * Invokes the method.
     *
     * @param arguments The arguments
     * @return The result
     */
    R invoke(Object... arguments);

    
Creates an ExecutionHandle for the give bean and method. 
Params:
bean – The bean
method – The method
Type parameters:
<T2> – The bean type
<R2> – The method return type
Returns:
The execution handle/**
     * Creates an {@link ExecutionHandle} for the give bean and method.
     *
     * @param bean The bean
     * @param method The method
     * @param <T2> The bean type
     * @param <R2> The method return type
     * @return The execution handle
     */
    static <T2, R2> MethodExecutionHandle<T2, R2> of(T2 bean, ExecutableMethod<T2, R2> method) {
        return new MethodExecutionHandle<T2, R2>() {
            @NonNull
            @Override
            public ExecutableMethod<?, R2> getExecutableMethod() {
                return method;
            }

            @Override
            public T2 getTarget() {
                return bean;
            }

            @Override
            public Class getDeclaringType() {
                return bean.getClass();
            }

            @Override
            public String getMethodName() {
                return method.getMethodName();
            }

            @Override
            public Argument[] getArguments() {
                return method.getArguments();
            }

            @Override
            public Method getTargetMethod() {
                return method.getTargetMethod();
            }

            @Override
            public ReturnType getReturnType() {
                return method.getReturnType();
            }

            @Override
            public R2 invoke(Object... arguments) {
                return method.invoke(bean, arguments);
            }

            @Override
            public AnnotationMetadata getAnnotationMetadata() {
                return method.getAnnotationMetadata();
            }
        };
    }
}