/*
 * Copyright 2020-2022 Equinix, Inc
 * Copyright 2014-2022 The Billing Project, LLC
 *
 * The Billing Project licenses this file to you 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 org.killbill.commons.metrics.guice.annotation;

import java.lang.annotation.Annotation;
import java.lang.reflect.Method;
import java.util.ArrayList;
import java.util.List;

import javax.annotation.Nonnull;
import javax.annotation.Nullable;

/**
 * Delegates to the provided list of resolvers, applying each resolver in turn.
 */
public class ListAnnotationResolver implements AnnotationResolver {

    private final List<AnnotationResolver> resolvers;

    public ListAnnotationResolver(final List<AnnotationResolver> resolvers) {
        this.resolvers = new ArrayList<>(resolvers);
    }

    @Nullable
    @Override
    public <T extends Annotation> T findAnnotation(@Nonnull final Class<T> annotationClass, @Nonnull final Method method) {
        for (final AnnotationResolver resolver : resolvers) {
            final T result = resolver.findAnnotation(annotationClass, method);
            if (result != null) {
                return result;
            }
        }

        return null;
    }
}
