package com.atlassian.messagequeue.internal.core;
   
   import com.atlassian.messagequeue.MessageRunnerKey;
   import com.atlassian.messagequeue.registry.MessageRunner;
   import com.atlassian.messagequeue.registry.MessageRunnerRegistryService;
   
   import javax.annotation.concurrent.ThreadSafe;
   import java.util.Optional;
   import java.util.concurrent.ConcurrentHashMap;
  import java.util.concurrent.ConcurrentMap;
  
  /**
   * A default message runner registry that stores registrations in memory in a concurrent data structure.
   */
  @ThreadSafe
  public class DefaultMessageRunnerRegistryService implements MessageRunnerRegistryService, MessageRunnerRegistryHelper {
      private final ConcurrentMap<MessageRunnerKey, MessageRunner> registry;
  
      public DefaultMessageRunnerRegistryService() {
          this.registry = new ConcurrentHashMap<>();
      }
  
      @Override
      public void registerMessageRunner(MessageRunnerKey messageRunnerKey, MessageRunner messageRunner) {
          registry.put(messageRunnerKey, messageRunner);
      }
  
      @Override
      public void unregisterMessageRunner(MessageRunnerKey messageRunnerKey) {
          registry.remove(messageRunnerKey);
      }
  
      @Override
      public Optional<MessageRunner> getMessageRunner(MessageRunnerKey messageRunnerKey) {
          return Optional.ofNullable(registry.get(messageRunnerKey));
      }
  }