001/**
002 * Licensed to the Apache Software Foundation (ASF) under one
003 * or more contributor license agreements.  See the NOTICE file
004 * distributed with this work for additional information
005 * regarding copyright ownership.  The ASF licenses this file
006 * to you under the Apache License, Version 2.0 (the
007 * "License"); you may not use this file except in compliance
008 * with the License.  You may obtain a copy of the License at
009 *
010 *     http://www.apache.org/licenses/LICENSE-2.0
011 *
012 * Unless required by applicable law or agreed to in writing, software
013 * distributed under the License is distributed on an "AS IS" BASIS,
014 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
015 * See the License for the specific language governing permissions and
016 * limitations under the License.
017 */
018package org.apache.hadoop.hbase.io.hfile;
019
020import java.io.IOException;
021
022import org.apache.yetus.audience.InterfaceAudience;
023import org.apache.hadoop.hbase.io.hfile.Cacheable.MemoryType;
024import org.apache.hadoop.hbase.nio.ByteBuff;
025
026/**
027 * Interface for a deserializer. Throws an IOException if the serialized data is
028 * incomplete or wrong.
029 * */
030@InterfaceAudience.Private
031public interface CacheableDeserializer<T extends Cacheable> {
032  /**
033   * Returns the deserialized object.
034   *
035   * @return T the deserialized object.
036   */
037  T deserialize(ByteBuff b) throws IOException;
038
039  /**
040   * @param b
041   * @param reuse true if Cacheable object can use the given buffer as its
042   *          content
043   * @param memType the {@link MemoryType} of the buffer
044   * @return T the deserialized object.
045   * @throws IOException
046   */
047  T deserialize(ByteBuff b, boolean reuse, MemoryType memType) throws IOException;
048
049  /**
050   * Get the identifier of this deserialiser. Identifier is unique for each
051   * deserializer and generated by {@link CacheableDeserializerIdManager}
052   * @return identifier number of this cacheable deserializer
053   */
054  int getDeserialiserIdentifier();
055}