// Path: src/main/java/com/spotify/dns/statistics/DnsReporter.java
// public interface DnsReporter {
//   /**
//    * Report resolve timing.
//    * @return A new timing context.
//    */
//   DnsTimingContext resolveTimer();
// 
//   /**
//    * Report that an empty response has been received from a resolve.
//    */
//   void reportEmpty();
// 
//   /**
//    * Report that a resolve resulting in a failure.
//    * @param error The exception causing the failure.
//    */
//   void reportFailure(Throwable error);
// }
// 
// Path: src/main/java/com/spotify/dns/statistics/DnsTimingContext.java
// @FunctionalInterface
// public interface DnsTimingContext {
//   void stop();
// }


import static com.google.common.base.Throwables.throwIfUnchecked;
import static java.util.Objects.requireNonNull;
import com.spotify.dns.statistics.DnsReporter;
import com.spotify.dns.statistics.DnsTimingContext;
import java.util.List;
import java.util.concurrent.CompletionStage;
/*
 * Copyright (c) 2015 Spotify AB
 *
 * 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.spotify.dns;




/**
 * Tracks metrics for DnsSrvResolver calls.
 */
class MeteredDnsSrvResolver implements DnsSrvResolver {
  private final DnsSrvResolver delegate;
  private final DnsReporter reporter;

  MeteredDnsSrvResolver(DnsSrvResolver delegate, DnsReporter reporter) {
    this.delegate = requireNonNull(delegate, "delegate");
    this.reporter = requireNonNull(reporter, "reporter");
  }

    @Override
    public List<LookupResult> resolve(String fqdn) {
        // Only catch and report RuntimeException to avoid Error's since that would
        // most likely only aggravate any condition that causes them to be thrown.

        final DnsTimingContext resolveTimer = reporter.resolveTimer();

        final List<LookupResult> result;

        try {
            result = delegate.resolve(fqdn);
        } catch (RuntimeException error) {
            reporter.reportFailure(error);
            throw error;
        } finally {
            resolveTimer.stop();
        }

// Path: src/main/java/com/spotify/dns/statistics/DnsReporter.java
// public interface DnsReporter {
//   /**
//    * Report resolve timing.
//    * @return A new timing context.
//    */
//   DnsTimingContext resolveTimer();
// 
//   /**
//    * Report that an empty response has been received from a resolve.
//    */
//   void reportEmpty();
// 
//   /**
//    * Report that a resolve resulting in a failure.
//    * @param error The exception causing the failure.
//    */
//   void reportFailure(Throwable error);
// }
// 
// Path: src/main/java/com/spotify/dns/statistics/DnsTimingContext.java
// @FunctionalInterface
// public interface DnsTimingContext {
//   void stop();
// }


// Path: src/main/java/com/spotify/dns/MeteredDnsSrvResolver.java
import static com.google.common.base.Throwables.throwIfUnchecked;
import static java.util.Objects.requireNonNull;
import com.spotify.dns.statistics.DnsReporter;
import com.spotify.dns.statistics.DnsTimingContext;
import java.util.List;
import java.util.concurrent.CompletionStage;

/*
 * Copyright (c) 2015 Spotify AB
 *
 * 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.spotify.dns;




/**
 * Tracks metrics for DnsSrvResolver calls.
 */
class MeteredDnsSrvResolver implements DnsSrvResolver {
  private final DnsSrvResolver delegate;
  private final DnsReporter reporter;

  MeteredDnsSrvResolver(DnsSrvResolver delegate, DnsReporter reporter) {
    this.delegate = requireNonNull(delegate, "delegate");
    this.reporter = requireNonNull(reporter, "reporter");
  }

    @Override
    public List<LookupResult> resolve(String fqdn) {
        // Only catch and report RuntimeException to avoid Error's since that would
        // most likely only aggravate any condition that causes them to be thrown.

        final DnsTimingContext resolveTimer = reporter.resolveTimer();

        final List<LookupResult> result;

        try {
            result = delegate.resolve(fqdn);
        } catch (RuntimeException error) {
            reporter.reportFailure(error);
            throw error;
        } finally {
            resolveTimer.stop();
        }

        if (result.isEmpty()) {