| /** |
| * |
| * 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.bookkeeper.bookie.storage.ldb; |
| |
| import java.io.Closeable; |
| import java.io.IOException; |
| import java.util.Map.Entry; |
| |
| /** |
| * Abstraction of a generic key-value local database. |
| */ |
| public interface KeyValueStorage extends Closeable { |
| |
| void put(byte[] key, byte[] value) throws IOException; |
| |
| /** |
| * Get the value associated with the given key. |
| * |
| * @param key |
| * the key to lookup |
| * @return the value or null if the key was not found |
| */ |
| byte[] get(byte[] key) throws IOException; |
| |
| /** |
| * Get the value associated with the given key. |
| * |
| * <p>This method will use the provided array store the value |
| * |
| * @param key |
| * the key to lookup |
| * @param value |
| * an array where to store the result |
| * @return -1 if the entry was not found or the length of the value |
| * @throws IOException |
| * if the value array could not hold the result |
| */ |
| int get(byte[] key, byte[] value) throws IOException; |
| |
| /** |
| * Get the entry whose key is the biggest and it's lesser than the supplied key. |
| * |
| * <p>For example if the db contains : |
| * |
| * <pre> |
| * { |
| * 1 : 'a', |
| * 2 : 'b', |
| * 3 : 'c' |
| * } |
| * </pre> |
| * |
| * <p>Then: |
| * |
| * <pre> |
| * getFloor(3) --> (2, 'b') |
| * </pre> |
| * |
| * @param key |
| * the non-inclusive upper limit key |
| * @return the entry before or null if there's no entry before key |
| */ |
| Entry<byte[], byte[]> getFloor(byte[] key) throws IOException; |
| |
| /** |
| * Get the entry whose key is bigger or equal the supplied key. |
| * |
| * @param key |
| * @return |
| * @throws IOException |
| */ |
| Entry<byte[], byte[]> getCeil(byte[] key) throws IOException; |
| |
| /** |
| * |
| * @param key |
| * @throws IOException |
| */ |
| void delete(byte[] key) throws IOException; |
| |
| /** |
| * Get an iterator over to scan sequentially through all the keys in the |
| * database. |
| * |
| * @return |
| */ |
| CloseableIterator<byte[]> keys(); |
| |
| /** |
| * Get an iterator over to scan sequentially through all the keys within a |
| * specified range. |
| * |
| * @param firstKey |
| * the first key in the range (included) |
| * @param lastKey |
| * the lastKey in the range (not included) |
| * |
| */ |
| CloseableIterator<byte[]> keys(byte[] firstKey, byte[] lastKey); |
| |
| /** |
| * Return an iterator object that can be used to sequentially scan through all |
| * the entries in the database. |
| */ |
| CloseableIterator<Entry<byte[], byte[]>> iterator(); |
| |
| /** |
| * Commit all pending write to durable storage. |
| */ |
| void sync() throws IOException; |
| |
| /** |
| * @return the number of keys. |
| */ |
| long count() throws IOException; |
| |
| /** |
| * Iterator interface. |
| * |
| * @param <T> |
| */ |
| interface CloseableIterator<T> extends Closeable { |
| boolean hasNext() throws IOException; |
| |
| T next() throws IOException; |
| } |
| |
| Batch newBatch(); |
| |
| /** |
| * Interface for a batch to be written in the storage. |
| */ |
| public interface Batch extends Closeable { |
| void put(byte[] key, byte[] value) throws IOException; |
| |
| void remove(byte[] key) throws IOException; |
| |
| void deleteRange(byte[] beginKey, byte[] endKey) throws IOException; |
| |
| void clear(); |
| |
| void flush() throws IOException; |
| } |
| } |