/**
* Copyright The Apache Software Foundation
*
* 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.hadoop.hbase.io.hfile.bucket;
import java.io.IOException;
import java.nio.ByteBuffer;
import org.apache.hadoop.hbase.classification.InterfaceAudience;
/**
* A class implementing IOEngine interface supports data services for
* {@link BucketCache}.
*/
@InterfaceAudience.Private
public interface IOEngine {
/**
* @return true if persistent storage is supported for the cache when shutdown
*/
boolean isPersistent();
/**
* Transfers data from IOEngine to the given byte buffer
* @param dstBuffer the given byte buffer into which bytes are to be written
* @param offset The offset in the IO engine where the first byte to be read
* @return number of bytes read
* @throws IOException
*/
int read(ByteBuffer dstBuffer, long offset) throws IOException;
/**
* Transfers data from the given byte buffer to IOEngine
* @param srcBuffer the given byte buffer from which bytes are to be read
* @param offset The offset in the IO engine where the first byte to be
* written
* @throws IOException
*/
void write(ByteBuffer srcBuffer, long offset) throws IOException;
/**
* Sync the data to IOEngine after writing
* @throws IOException
*/
void sync() throws IOException;
/**
* Shutdown the IOEngine
*/
void shutdown();
}