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.scheduler.base;
  
  import java.util.Objects;
  
  import com.google.common.base.Preconditions;
  
  import org.apache.aurora.gen.InstanceKey;
  import org.apache.aurora.scheduler.storage.entities.IInstanceKey;
  import org.apache.aurora.scheduler.storage.entities.IJobKey;
  
  /**
   * Utility function for {@link IInstanceKey instance keys}.
   */
  public final class InstanceKeys {
    private InstanceKeys() {
      // Utility class.
    }
  
    /**
     * Creates an instance key from a job and instance ID.
     *
     * @param job Job key.
     * @param instanceId Instance id.
     * @return Instance ID.
     */
    public static IInstanceKey from(IJobKey job, int instanceId) {
      Objects.requireNonNull(job);
      Preconditions.checkArgument(instanceId >= 0);
      return IInstanceKey.build(new InstanceKey(job.newBuilder(), instanceId));
    }
  
    /**
     * Creates a human-friendly string for an instance key.
     *
     * @param instance Instance key.
     * @return String representation of the instance key.
     */
    public static String toString(IInstanceKey instance) {
      return JobKeys.canonicalString(instance.getJobKey()) + "/" + instance.getInstanceId();
    }
  
    /**
     * Creates a human-friendly string for an instance key.
     *
     * @param job Job key.
     * @param instanceId Instance id.
     * @return String representation of the instance key.
     */
    public static String toString(IJobKey job, int instanceId) {
      return toString(from(job, instanceId));
    }
  }
  