1 /**
2 * Copyright 2009 The Apache Software Foundation
3 *
4 * Licensed to the Apache Software Foundation (ASF) under one
5 * or more contributor license agreements. See the NOTICE file
6 * distributed with this work for additional information
7 * regarding copyright ownership. The ASF licenses this file
8 * to you under the Apache License, Version 2.0 (the
9 * "License"); you may not use this file except in compliance
10 * with the License. You may obtain a copy of the License at
11 *
12 * http://www.apache.org/licenses/LICENSE-2.0
13 *
14 * Unless required by applicable law or agreed to in writing, software
15 * distributed under the License is distributed on an "AS IS" BASIS,
16 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
17 * See the License for the specific language governing permissions and
18 * limitations under the License.
19 */
20
21 package org.apache.hadoop.hbase.io;
22
23 import java.util.*;
24
25 /**
26 * A Static Interface.
27 * Instead of having this code in the the HbaseMapWritable code, where it
28 * blocks the possibility of altering the variables and changing their types,
29 * it is put here in this static interface where the static final Maps are
30 * loaded one time. Only byte[] and Cell are supported at this time.
31 */
32 public interface CodeToClassAndBack {
33 /**
34 * Static map that contains mapping from code to class
35 */
36 public static final Map<Byte, Class<?>> CODE_TO_CLASS =
37 new HashMap<Byte, Class<?>>();
38
39 /**
40 * Static map that contains mapping from class to code
41 */
42 public static final Map<Class<?>, Byte> CLASS_TO_CODE =
43 new HashMap<Class<?>, Byte>();
44
45 /**
46 * Class list for supported classes
47 */
48 public Class<?>[] classList = {byte[].class};
49
50 /**
51 * The static loader that is used instead of the static constructor in
52 * HbaseMapWritable.
53 */
54 public InternalStaticLoader sl =
55 new InternalStaticLoader(classList, CODE_TO_CLASS, CLASS_TO_CODE);
56
57 /**
58 * Class that loads the static maps with their values.
59 */
60 public class InternalStaticLoader{
61 InternalStaticLoader(Class<?>[] classList,
62 Map<Byte,Class<?>> CODE_TO_CLASS, Map<Class<?>, Byte> CLASS_TO_CODE){
63 byte code = 1;
64 for(int i=0; i<classList.length; i++){
65 CLASS_TO_CODE.put(classList[i], code);
66 CODE_TO_CLASS.put(code, classList[i]);
67 code++;
68 }
69 }
70 }
71 }