package com.atlassian.messagequeue;
   
   import com.atlassian.annotations.PublicApi;
   
   import javax.annotation.Nullable;
   import java.io.Serializable;
   
   import static java.util.Objects.requireNonNull;
   
  /**
   * Message validator key
   * @since 1.0.6
   */
  @PublicApi
  public final class MessageValidatorKey implements Serializable, Comparable<MessageValidatorKey> {
      private static final long serialVersionUID = 1L;
  
      private final String key;
  
      private MessageValidatorKey(final String key) {
          this.key = requireNonNull(key, "key");
      }
  
      /**
       * Wraps the provided string as a {@code MessageValidatorKey}.
       * <p>
       * Although it is not necessary for correctness, it will usually make sense to create a single instance of
       * the {@code MessageValidatorKey} and reuse it as a constant, as in:
       * </p>
       * <pre>
       * {@code
       *     private static final MessageValidatorKey <strong>MY_MESSAGE_VALIDATOR</strong> = MessageValidatorKey.of("com.example.plugin.MyMessageValidator");
       *
       *     // ...
       *
       *     private void registerMessageValidator()
       *     {
       *         messageValidatorRegistryService.registerMessageValidator(MY_MESSAGE_VALIDATOR, new MyMessageValidatorImpl();
       *     }
       * }
       * </pre>
       *
       * @param key the message validator key, as a string
       * @return the wrapped message validator key
       */
      public static MessageValidatorKey of(String key) {
          return new MessageValidatorKey(key);
      }
  
      @Override
      @SuppressWarnings("SimplifiableIfStatement")
      public boolean equals(@Nullable final Object o) {
          if (this == o) {
              return true;
          }
          return o != null
                  && o.getClass() == getClass()
                  && ((MessageValidatorKey) o).key.equals(key);
      }
  
      @Override
      public int compareTo(final MessageValidatorKey o) {
          return key.compareTo(o.key);
      }
  
      @Override
      public int hashCode() {
          return key.hashCode();
      }
  
      @Override
      public String toString() {
          return key;
      }
  }