/*
 * Copyright 2015-2016 Norbert Potocki (norbert.potocki@nort.pl)
 *
 * 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 org.cfg4j.source.metered;

import static java.util.Objects.requireNonNull;

import com.codahale.metrics.MetricRegistry;
import com.codahale.metrics.Timer;
import org.cfg4j.source.ConfigurationSource;
import org.cfg4j.source.context.environment.Environment;

import java.util.Properties;

/**
 * Decorator for {@link ConfigurationSource} that emits execution metrics. It emits the following metrics (each of those prefixed
 * with a string passed at construction time):
 * <ul>
 * <li>source.getConfiguration</li>
 * <li>source.init</li>
 * <li>source.reload</li>
 * </ul>
 * Each of those metrics is of {@link Timer} type (i.e. includes execution time percentiles, execution count, etc.)
 */
public class MeteredConfigurationSource implements ConfigurationSource {

  private final ConfigurationSource delegate;

  private final Timer getConfigurationTimer;
  private final Timer initTimer;
  private final Timer reloadTimer;

  /**
   * Create decorator for given {@code delegate} and using {@code metricRegistry} for constructing metrics. Each metric will
   * be prefixed with {@code metricPrefix}.
   *
   * @param metricRegistry metric registry to hold execution metrics
   * @param metricPrefix   prefix for metric names (trailing dot will be added to it)
   * @param delegate       configuration provider to monitor
   */
  public MeteredConfigurationSource(MetricRegistry metricRegistry, String metricPrefix, ConfigurationSource delegate) {
    requireNonNull(metricRegistry);
    requireNonNull(metricPrefix);
    this.delegate = requireNonNull(delegate);

    getConfigurationTimer = metricRegistry.timer(metricPrefix + "source.getConfiguration");
    initTimer = metricRegistry.timer(metricPrefix + "source.init");
    reloadTimer = metricRegistry.timer(metricPrefix + "source.reload");
  }

  @Override
  public Properties getConfiguration(Environment environment) {
    Timer.Context context = getConfigurationTimer.time();

    try {
      return delegate.getConfiguration(environment);
    } finally {
      context.stop();
    }
  }

  @Override
  public void init() {
    Timer.Context context = initTimer.time();

    try {
      delegate.init();
    } finally {
      context.stop();
    }
  }
}

@@ -1169,34 +1169,8 @@
 li%3E%0A
- * %3Cli%3Esource.reload%3C/li%3E%0A
  * %3C
@@ -1496,43 +1496,8 @@
 mer;
-%0A  private final Timer reloadTimer;
 %0A%0A  
@@ -2297,80 +2297,8 @@
 %22);%0A
-    reloadTimer = metricRegistry.timer(metricPrefix + %22source.reload%22);%0A
   %7D%0A

clean up MeteredConfigurationSource