/*
 * Copyright (c) 2023 PANTHEON.tech, s.r.o. and others.  All rights reserved.
 *
 * This program and the accompanying materials are made available under the
 * terms of the Eclipse Public License v1.0 which accompanies this distribution,
 * and is available at http://www.eclipse.org/legal/epl-v10.html
 */
package org.opendaylight.mdsal.binding.api;

import com.google.common.annotations.Beta;
import org.eclipse.jdt.annotation.Nullable;
import org.opendaylight.yangtools.yang.binding.DataObject;

/**
 * Interface implemented by classes interested in receiving data changes.
 * It provides a comparison on before-value and after-value.
 */
@Beta
@FunctionalInterface
public interface DataChangeListener<T extends DataObject> {
    /**
     * Invoked when there was data change for the supplied path, which was used
     * to register the listener.
     *
     * <p>
     * Note: When invoking the method {@link DataTreeChangeListener#onInitialData} initial data == null, null.
     * @param previousValue data before.
     * @param currentValue data after.
     */
    void dataChanged(@Nullable T previousValue, @Nullable T currentValue);
}