summaryrefslogtreecommitdiff
path: root/src/main/java/com/amazon/carbonado/layout/LayoutOptions.java
blob: 40d18512ddb9f6a9a50e37569f737b3d43997269 (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
/*
 * Copyright 2009-2012 Amazon Technologies, Inc. or its affiliates.
 * Amazon, Amazon.com and Carbonado are trademarks or registered trademarks
 * of Amazon Technologies, Inc. or its affiliates.  All rights reserved.
 *
 * Licensed 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 com.amazon.carbonado.layout;

import java.io.ByteArrayInputStream;
import java.io.ByteArrayOutputStream;
import java.io.DataInputStream;
import java.io.DataOutputStream;
import java.io.IOException;

import java.util.HashMap;
import java.util.Map;

/**
 * Extra options encoded with a Storable layout.
 *
 * @author Brian S O'Neill
 */
public class LayoutOptions {
    /**
     * Data is compression algorithm name, encoded by DataOutput.writeUTF.
     */
    static final byte COMPRESSION_TYPE = 1;

    private final Map<Byte, Object> mData;

    private boolean mReadOnly;

    public LayoutOptions() {
        mData = new HashMap<Byte, Object>(1);
    }

    /**
     * @return null if not compressed
     */
    public synchronized String getCompressionType() {
        return (String) mData.get(COMPRESSION_TYPE);
    }

    /**
     * @param type null if not compressed
     */
    public void setCompressionType(String type) {
        put(COMPRESSION_TYPE, type);
    }

    private synchronized void put(byte op, Object value) {
        if (mReadOnly) {
            throw new IllegalStateException("Options are read only");
        }
        if (value == null) {
            mData.remove(op);
        } else {
            mData.put(op, value);
        }
    }

    synchronized void readOnly() {
        mReadOnly = true;
    }

    /**
     * @return null if empty
     */
    public synchronized byte[] encode() {
        if (mData.isEmpty()) {
            return null;
        }

        try {
            ByteArrayOutputStream bout = new ByteArrayOutputStream();
            DataOutputStream dout = new DataOutputStream(bout);

            for (Map.Entry<Byte, Object> entry : mData.entrySet()) {
                switch (entry.getKey()) {
                default:
                    break;
                case COMPRESSION_TYPE:
                    dout.write(COMPRESSION_TYPE);
                    dout.writeUTF((String) entry.getValue());
                }
            }

            dout.close();
            return bout.toByteArray();
        } catch (IOException e) {
            throw new AssertionError(e);
        }
    }

    /**
     * @param source can be null if empty
     */
    public synchronized void decode(byte[] source) throws IOException {
        mData.clear();

        if (source == null || source.length == 0) {
            return;
        }

        ByteArrayInputStream bin = new ByteArrayInputStream(source);
        DataInputStream din = new DataInputStream(bin);

        while (bin.available() > 0) {
            byte op = din.readByte();
            switch (op) {
            default:
                throw new IOException("Unknown extra data type: " + op);
            case COMPRESSION_TYPE:
                mData.put(COMPRESSION_TYPE, din.readUTF());
                break;
            }
        }
    }
}