/*
 * Copyright (c) 2019, 2020 Oracle and/or its affiliates. All rights reserved.
 *
 * 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
 *
 *     http://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 com.fnproject.fn.api;

import java.lang.annotation.*;

/**
 * Annotation to be used in user function classes to enable runtime-wide feature.
 *
 * Runtime features are initialized at the point that the function class is loaded but prior to the call chain.
 */
@Retention(RetentionPolicy.RUNTIME)
@Target(ElementType.TYPE)
@Repeatable(FnFeatures.class)
public @interface FnFeature {
    /**
     * The feature class to load this must have a zero-arg public constructor
     * @return feature class
     */
    Class<? extends  RuntimeFeature> value();
}
