/*
 * 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;

import java.util.concurrent.TimeUnit;

import org.aopalliance.intercept.MethodInterceptor;
import org.aopalliance.intercept.MethodInvocation;
import org.killbill.commons.metrics.api.Timer;

/**
 * A method interceptor which times the execution of the annotated method.
 */
class TimedInterceptor implements MethodInterceptor {

    private final Timer timer;

    TimedInterceptor(final Timer timer) {
        this.timer = timer;
    }

    @Override
    public Object invoke(final MethodInvocation invocation) throws Throwable {
        // Since these timers are always created via the default ctor (via MetricRegister#timer), they always use
        // nanoTime, so we can save an allocation here by not using Context.
        final long start = System.nanoTime();
        try {
            return invocation.proceed();
        } finally {
            timer.update(System.nanoTime() - start, TimeUnit.NANOSECONDS);
        }
    }
}
