View Javadoc

1   /**
2    * Licensed to the Apache Software Foundation (ASF) under one
3    * or more contributor license agreements.  See the NOTICE file
4    * distributed with this work for additional information
5    * regarding copyright ownership.  The ASF licenses this file
6    * to you under the Apache License, Version 2.0 (the
7    * "License"); you may not use this file except in compliance
8    * with the License.  You may obtain a copy of the License at
9    *
10   *     http://www.apache.org/licenses/LICENSE-2.0
11   *
12   * Unless required by applicable law or agreed to in writing, software
13   * distributed under the License is distributed on an "AS IS" BASIS,
14   * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
15   * See the License for the specific language governing permissions and
16   * limitations under the License.
17   */
18  package org.apache.hadoop.hbase.io.hfile;
19  
20  import java.io.IOException;
21  
22  import org.apache.hadoop.hbase.classification.InterfaceAudience;
23  import org.apache.hadoop.hbase.io.hfile.Cacheable.MemoryType;
24  import org.apache.hadoop.hbase.nio.ByteBuff;
25  
26  /**
27   * Interface for a deserializer. Throws an IOException if the serialized data is
28   * incomplete or wrong.
29   * */
30  @InterfaceAudience.Private
31  public interface CacheableDeserializer<T extends Cacheable> {
32    /**
33     * Returns the deserialized object.
34     *
35     * @return T the deserialized object.
36     */
37    T deserialize(ByteBuff b) throws IOException;
38  
39    /**
40     * @param b
41     * @param reuse true if Cacheable object can use the given buffer as its
42     *          content
43     * @param memType the {@link MemoryType} of the buffer
44     * @return T the deserialized object.
45     * @throws IOException
46     */
47    T deserialize(ByteBuff b, boolean reuse, MemoryType memType) throws IOException;
48  
49    /**
50     * Get the identifier of this deserialiser. Identifier is unique for each
51     * deserializer and generated by {@link CacheableDeserializerIdManager}
52     * @return identifier number of this cacheable deserializer
53     */
54    int getDeserialiserIdentifier();
55  }