| /* |
| * 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.configuration.notifications; |
| |
| import org.apache.ignite.configuration.ConfigurationProperty; |
| import org.jetbrains.annotations.Nullable; |
| |
| /** |
| * Event object propagated on configuration change. Passed to listeners after configuration changes are applied. |
| * |
| * @param <VIEWT> Type of the subtree or the value that has been changed. |
| * @see ConfigurationProperty#listen(ConfigurationListener) |
| * @see ConfigurationListener |
| */ |
| public interface ConfigurationNotificationEvent<VIEWT> { |
| /** |
| * Returns the previous value of the updated configuration. |
| * |
| * <p>NOTE: For a new configuration/property will be {@code null}. |
| */ |
| @Nullable VIEWT oldValue(); |
| |
| /** |
| * Returns updated value of the configuration. |
| */ |
| @Nullable VIEWT newValue(); |
| |
| /** |
| * Returns monotonously increasing counter, linked to the specific storage for current configuration values. Gives a unique change |
| * identifier inside a specific configuration storage. |
| * |
| * @return Counter value. |
| */ |
| long storageRevision(); |
| |
| /** |
| * Returns the parent (any from the root) or current configuration. |
| * |
| * <p>For example, if we changed the child configuration, then we can get both the parent and the current child configuration. |
| * |
| * @param configClass Configuration interface, for example {@code RootConfiguration}. |
| * @param <T> Configuration type. |
| */ |
| @Nullable <T extends ConfigurationProperty> T config(Class<T> configClass); |
| |
| /** |
| * Returns the key of a named list item for the parent (any from the root) or current configuration. |
| * |
| * <p>For example, if a column of a table has changed, then we can get the name of the table and columns for which the changes have |
| * occurred. |
| * |
| * @param configClass Configuration interface, for example {@code TableConfiguration}. |
| */ |
| @Nullable String name(Class<? extends ConfigurationProperty> configClass); |
| } |