| /* |
| * 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.metastorage.client; |
| |
| import org.apache.ignite.lang.ByteArray; |
| import org.jetbrains.annotations.NotNull; |
| import org.jetbrains.annotations.Nullable; |
| |
| /** |
| * Represents a storage unit as entry with key, value and revision, where |
| * <ul> |
| * <li>key - an unique entry's key. Keys are comparable in lexicographic manner.</li> |
| * <li>value - a data which is associated with a key and represented as an array of bytes.</li> |
| * <li>revision - a number which denotes a version of whole meta storage. Each change increments the revision.</li> |
| * </ul> |
| */ |
| public interface Entry { |
| /** |
| * Returns a key. |
| * |
| * @return The key. |
| */ |
| @NotNull ByteArray key(); |
| |
| /** |
| * Returns a value. Could be {@code null} for empty entry. |
| * |
| * @return Value. |
| */ |
| @Nullable byte[] value(); |
| |
| /** |
| * Returns a revision. |
| * |
| * @return Revision. |
| */ |
| long revision(); |
| |
| /** |
| * Returns an update counter. |
| * |
| * @return Update counter. |
| */ |
| long updateCounter(); |
| |
| /** |
| * Returns value which denotes whether entry is empty or not. |
| * |
| * @return {@code True} if entry is empty, otherwise - {@code false}. |
| */ |
| boolean empty(); |
| |
| /** |
| * Returns value which denotes whether entry is tombstone or not. |
| * |
| * @return {@code True} if entry is tombstone, otherwise - {@code false}. |
| */ |
| boolean tombstone(); |
| } |