/*
 * 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.aop;

import io.micronaut.context.annotation.DefaultScope;
import io.micronaut.context.annotation.Executable;
import io.micronaut.core.annotation.Internal;

import javax.inject.Singleton;
import java.lang.annotation.Documented;
import java.lang.annotation.ElementType;
import java.lang.annotation.Retention;
import java.lang.annotation.Target;

import static java.lang.annotation.RetentionPolicy.RUNTIME;

An Adapter is advice applicable to a method that will create an entirely new bean definition that delegates to the annotated method.
Typically used in conjunction with an interface or class that provides a "Single Abstract Method" (or SAM) type.
An example of usage could be to introduce a ApplicationEventListener:
For example:
 @Adapter(ApplicationEventListener) public void onStartup(StartupEvent startupEvent) { } 
The above example will create a new bean that delegates to the onStartup method that is an instance of ApplicationEventListener. The generic types are aligned and populated from the types defined in the method signature
This annotation can be used as a stereotype annotation. If for some reason the generated class cannot delegate to the method then a compilation error should occur.
Author:
graemerocher
Since:
1.0/**
 * <p>An {@link Adapter} is advice applicable to a method that will create an entirely new bean definition that delegates to the
 * annotated method.</p>
 *
 * <p>Typically used in conjunction with an interface or class that provides a "Single Abstract Method" (or SAM) type.</p>
 *
 * <p>An example of usage could be to introduce a {@link io.micronaut.context.event.ApplicationEventListener}:</p>
 *
 * <p>For example:</p>
 *
 * <pre><code>
 *  {@literal @}Adapter(ApplicationEventListener)
 *   public void onStartup(StartupEvent startupEvent) {
 *   }
 * </code></pre>
 *
 * <p>The above example will create a new bean that delegates to the {@code onStartup} method that is an instance of {@link io.micronaut.context.event.ApplicationEventListener}.
 * The generic types are aligned and populated from the types defined in the method signature</p>
 *
 * <p>This annotation can be used as a stereotype annotation. If for some reason the generated class cannot delegate to the method then a compilation error should occur.</p>
 *
 * @author graemerocher
 * @since 1.0
 */
@Documented
@Retention(RUNTIME)
@Target({ElementType.ANNOTATION_TYPE, ElementType.METHOD})
@DefaultScope(Singleton.class)
@Executable
public @interface Adapter {

    
The target interface to adapt.
Returns:
An interface to adapt/**
     * The target interface to adapt.
     *
     * @return An interface to adapt
     */
    Class<?> value();

    
Internal attributes for the adapter annotation.
/**
     * Internal attributes for the adapter annotation.
     */
    @Internal
    class InternalAttributes {
        public static final String ADAPTED_BEAN = "adaptedBean";
        public static final String ADAPTED_METHOD = "adaptedMethod";
        public static final String ADAPTED_ARGUMENT_TYPES = "adaptedArgumentTypes";
        public static final String ADAPTED_QUALIFIER = "adaptedQualifier";
    }
}