/*
 * 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.ignite.internal.hlc;

/**
 * Used to track updates of a {@link HybridClock}: it gets notified each time {@link HybridClock#update(HybridTimestamp)},
 * is invoked.
 */
@FunctionalInterface
public interface ClockUpdateListener {
    /**
     * Called when the clock's current time advances due to a call to {@link HybridClock#update(HybridTimestamp)}.
     *
     * <p>This does NOT get called when the clock current time gets advanced by a call to
     * {@link HybridClock#now()}/{@link HybridClock#nowLong()}.
     *
     * <p>This method must NOT do any I/O operations or block. If such operations are needed, it should schedule them
     * on a thread pool.
     *
     * @param newTs New timestamp on the clock (represented as a long value, see {@link HybridTimestamp#longValue()}.
     */
    void onUpdate(long newTs);
}
