package com.atlassian.scheduler.core.util;
   
   import com.atlassian.scheduler.JobRunner;
   import com.atlassian.scheduler.config.JobRunnerKey;
   import com.google.common.collect.ImmutableSet;
   
   import javax.annotation.Nonnull;
   import java.util.Set;
   import java.util.concurrent.ConcurrentHashMap;
  import java.util.concurrent.ConcurrentMap;
  
  import static com.atlassian.util.concurrent.Assertions.notNull;
  
  /**
   * Encapsulates the registration and retrieval of job runners.
   *
   * @since v1.0
   */
  public class JobRunnerRegistry {
      private final ConcurrentMap<JobRunnerKey, JobRunner> jobRunnerRegistry = new ConcurrentHashMap<JobRunnerKey, JobRunner>();
  
      public void registerJobRunner(final JobRunnerKey jobRunnerKey, final JobRunner jobRunner) {
          jobRunnerRegistry.put(notNull("jobRunnerKey", jobRunnerKey), notNull("jobRunner", jobRunner));
      }
  
      public void unregisterJobRunner(final JobRunnerKey jobRunnerKey) {
          jobRunnerRegistry.remove(notNull("jobRunnerKey", jobRunnerKey));
      }
  
      public JobRunner getJobRunner(final JobRunnerKey jobRunnerKey) {
          return jobRunnerRegistry.get(notNull("jobRunnerKey", jobRunnerKey));
      }
  
      @Nonnull
      public Set<JobRunnerKey> getRegisteredJobRunnerKeys() {
          return ImmutableSet.copyOf(jobRunnerRegistry.keySet());
      }
  }