content: /**
   * 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.apache.aurora.common.util;
  
  import java.io.InputStream;
  import java.util.Map;
  import java.util.Properties;
  
  import com.google.common.annotations.VisibleForTesting;
  import com.google.common.collect.ImmutableMap;
  import com.google.common.collect.Maps;
  
  import org.apache.aurora.common.base.MorePreconditions;
  import org.slf4j.Logger;
  import org.slf4j.LoggerFactory;
  
  import static java.util.Objects.requireNonNull;
  
  /**
   * Handles loading of a build properties file, and provides keys to look up known values in the
   * properties.
   */
  public class BuildInfo {
  
    private static final Logger LOG = LoggerFactory.getLogger(BuildInfo.class);
  
    private static final String DEFAULT_BUILD_PROPERTIES_PATH = "build.properties";
  
    private final String resourcePath;
  
    private Map<String, String> properties = ImmutableMap.of();
  
    /**
     * Creates a build info container that will use the default properties file path.
     */
    public BuildInfo() {
      this(DEFAULT_BUILD_PROPERTIES_PATH);
    }
  
    /**
     * Creates a build info container, reading from the given path.
     *
     * @param resourcePath The resource path to read build properties from.
     */
    public BuildInfo(String resourcePath) {
      this.resourcePath = MorePreconditions.checkNotBlank(resourcePath);
      fetchProperties();
    }
  
    @VisibleForTesting
    public BuildInfo(Map<String, String> properties) {
      this.resourcePath = null;
      this.properties = requireNonNull(properties);
    }
  
    private void fetchProperties() {
      LOG.info("Fetching build properties from " + resourcePath);
      InputStream in = ClassLoader.getSystemResourceAsStream(resourcePath);
      if (in == null) {
        LOG.warn("Failed to fetch build properties from " + resourcePath);
        return;
      }
  
      try {
        Properties buildProperties = new Properties();
        buildProperties.load(in);
        properties = Maps.fromProperties(buildProperties);
      } catch (Exception e) {
        LOG.warn("Failed to load properties file " + resourcePath, e);
      }
    }
  
    /**
     * Fetches the properties stored in the resource location.
     *
     * @return A map of the loaded properties, or an empty Map if there was a problem loading
     *    the specified properties resource.
     */
    public Map<String, String> getProperties() {
      return properties;
    }
  }
  