artemis-quorum-api/src/main/java/org/apache/activemq/artemis/quorum/MutableLong.java

/*
 * 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.activemq.artemis.quorum;

public interface MutableLong extends AutoCloseable {

   String getMutableLongId();

   long get() throws UnavailableStateException;

   void set(long value) throws UnavailableStateException;

   /**
    * This is not meant to be atomic; it's semantically equivalent to:
    * <pre>
    *    long oldValue = mutableLong.get();
    *    if (mutableLong.oldValue != expectedValue) {
    *       return false;
    *    }
    *    mutableLong.set(newValue);
    *    return true;
    * </pre>
    */
   default boolean compareAndSet(long expectedValue, long newValue) throws UnavailableStateException {
      final long oldValue = get();
      if (oldValue != expectedValue) {
         return false;
      }
      set(newValue);
      return true;
   }

   @Override
   void close();
}