/*
* The Alluxio Open Foundation licenses this work under the Apache License, version 2.0
* (the "License"). You may not use this work except in compliance with the License, which is
* available at www.apache.org/licenses/LICENSE-2.0
*
* This software is distributed on an "AS IS" basis, WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND,
* either express or implied, as more fully set forth in the License.
*
* See the NOTICE file distributed with this work for information regarding copyright ownership.
*/
package alluxio.client.keyvalue;
import alluxio.annotation.PublicApi;
import alluxio.exception.AlluxioException;
import java.io.Closeable;
import java.io.IOException;
import java.nio.ByteBuffer;
/**
* Interface for readers which accesses key-value stores in Alluxio.
*/
@PublicApi
public interface KeyValueStoreReader extends Closeable, KeyValueIterable {
/**
* Gets the value associated with {@code key}, returns null if not found. When getting large
* values (e.g., larger than 10KB), {@link #get(ByteBuffer)} might be more efficient by taking
* advantage from zero-copy.
*
* @param key key to get, cannot be null
* @return value associated with the given key, or null if not found
*/
byte[] get(byte[] key) throws IOException, AlluxioException;
/**
* Gets the value associated with {@code key}, returns null if not found.
*
* @param key key to get, cannot be null
* @return value associated with the given key, or null if not found
*/
ByteBuffer get(ByteBuffer key) throws IOException, AlluxioException;
/**
* @return the number of key-value pairs in the store
*/
int size() throws IOException, AlluxioException;
}