content: /*
   * The Alluxio Open Foundation licenses this work under the Apache License, version 2.0
   * (the "License"). You may not use this work except in compliance with the License, which is
   * available at www.apache.org/licenses/LICENSE-2.0
   *
   * This software is distributed on an "AS IS" basis, WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND,
   * either express or implied, as more fully set forth in the License.
   *
   * See the NOTICE file distributed with this work for information regarding copyright ownership.
   */
  
  package alluxio;
  
  import alluxio.conf.InstancedConfiguration;
  import alluxio.conf.PropertyKey;
  
  import java.util.HashMap;
  import java.util.Map;
  
  /**
   * A rule for modifying Alluxio configuration during a test suite.
   */
  public final class ConfigurationRule extends AbstractResourceRule {
    private final Map<PropertyKey, Object> mKeyValuePairs;
    private final Map<PropertyKey, Object> mStashedProperties = new HashMap<>();
    private final InstancedConfiguration mConfiguration;
  
    /**
     * @param keyValuePairs map from configuration keys to the values to set them to
     * @param conf base configuration
     */
    public ConfigurationRule(Map<PropertyKey, Object> keyValuePairs, InstancedConfiguration conf) {
      mKeyValuePairs = keyValuePairs;
      mConfiguration = conf;
    }
  
    /**
     * @param key the key of the configuration property to set
     * @param value the value to set it to, can be null to unset this key
     * @param conf base configuration
     */
    public ConfigurationRule(final PropertyKey key, final Object value, InstancedConfiguration conf) {
      // ImmutableMap does not support nullable value, create a map literals
      this(new HashMap<PropertyKey, Object>() {
        {
          put(key, value);
        }
      }, conf);
    }
  
    /**
     * Set a specific PropertyKey of the global configuration,
     * change is only visible in the scope of the calling method.
     *
     * @param key the key of the configuration property to set
     * @param value the value to set it to, can be null to unset
     */
    public ConfigurationRule set(final PropertyKey key, final Object value) {
      if (!mStashedProperties.containsKey(key)) {
        if (mConfiguration.isSet(key)) {
          mStashedProperties.put(key, mConfiguration.get(key));
        } else {
          mStashedProperties.put(key, null);
        }
      }
  
      if (value != null) {
        mConfiguration.set(key, value);
      } else {
        mConfiguration.unset(key);
      }
  
      return this;
    }
  
    @Override
    public void before() {
      for (Map.Entry<PropertyKey, Object> entry : mKeyValuePairs.entrySet()) {
        PropertyKey key = entry.getKey();
        Object value = entry.getValue();
        if (mConfiguration.isSet(key)) {
          mStashedProperties.put(key, mConfiguration.get(key));
        } else {
          mStashedProperties.put(key, null);
        }
        if (value != null) {
          mConfiguration.set(key, value);
        } else {
          mConfiguration.unset(key);
        }
      }
    }
  
    @Override
    public void after() {
      for (Map.Entry<PropertyKey, Object> entry : mStashedProperties.entrySet()) {
        Object value = entry.getValue();
        if (value != null) {
          mConfiguration.set(entry.getKey(), value);
        } else {
          mConfiguration.unset(entry.getKey());
        }
      }
    }
  }
  