/*
 * Licensed to the Apache Software Foundation (ASF) under one
 * or more contributor license agreements.  See the NOTICE file
 * distributed with this work for additional information
 * regarding copyright ownership.  The ASF licenses this file
 * to you 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.flink.runtime.registration;

import java.io.Serializable;

/**
 * Base class for responses given to registration attempts from {@link RetryingRegistration}.
 */
public abstract class RegistrationResponse implements Serializable {

	private static final long serialVersionUID = 1L;

	// ----------------------------------------------------------------------------
	
	/**
	 * Base class for a successful registration. Concrete registration implementations
	 * will typically extend this class to attach more information.
	 */
	public static class Success extends RegistrationResponse {
		private static final long serialVersionUID = 1L;
		
		@Override
		public String toString() {
			return "Registration Successful";
		}
	}

	// ----------------------------------------------------------------------------

	/**
	 * A rejected (declined) registration.
	 */
	public static final class Decline extends RegistrationResponse {
		private static final long serialVersionUID = 1L;

		/** the rejection reason */
		private final String reason;

		/**
		 * Creates a new rejection message.
		 * 
		 * @param reason The reason for the rejection.
		 */
		public Decline(String reason) {
			this.reason = reason != null ? reason : "(unknown)";
		}

		/**
		 * Gets the reason for the rejection.
		 */
		public String getReason() {
			return reason;
		}

		@Override
		public String toString() {
			return "Registration Declined (" + reason + ')';
		}
	}
}