SettingsFrame.java revision 16234:3b25414eb6af 
1/*
2 * Copyright (c) 2015, 2016, Oracle and/or its affiliates. All rights reserved.
3 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
4 *
5 * This code is free software; you can redistribute it and/or modify it
6 * under the terms of the GNU General Public License version 2 only, as
7 * published by the Free Software Foundation.  Oracle designates this
8 * particular file as subject to the "Classpath" exception as provided
9 * by Oracle in the LICENSE file that accompanied this code.
10 *
11 * This code is distributed in the hope that it will be useful, but WITHOUT
12 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
13 * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
14 * version 2 for more details (a copy is included in the LICENSE file that
15 * accompanied this code).
16 *
17 * You should have received a copy of the GNU General Public License version
18 * 2 along with this work; if not, write to the Free Software Foundation,
19 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
20 *
21 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
22 * or visit www.oracle.com if you need additional information or have any
23 * questions.
24 */
25
26package jdk.incubator.http.internal.frame;
27
28import java.nio.ByteBuffer;
29import java.util.Arrays;
30
31public class SettingsFrame extends Http2Frame {
32
33    private final int[] parameters;
34
35    public static final int TYPE = 0x4;
36
37    // Flags
38    public static final int ACK = 0x1;
39
40    @Override
41    public String flagAsString(int flag) {
42        switch (flag) {
43        case ACK:
44            return "ACK";
45        }
46        return super.flagAsString(flag);
47    }
48
49    @Override
50    public String toString() {
51        StringBuilder sb = new StringBuilder();
52        sb.append(super.toString())
53          .append(" Settings: ");
54
55        for (int i = 0; i < MAX_PARAM; i++) {
56            if (parameters[i] != -1) {
57                sb.append(name(i))
58                  .append("=")
59                  .append(Integer.toString(parameters[i]))
60                  .append(' ');
61            }
62        }
63        return sb.toString();
64    }
65
66    // Parameters
67    public static final int HEADER_TABLE_SIZE = 0x1;
68    public static final int ENABLE_PUSH = 0x2;
69    public static final int MAX_CONCURRENT_STREAMS = 0x3;
70    public static final int INITIAL_WINDOW_SIZE = 0x4;
71    public static final int MAX_FRAME_SIZE = 0x5;
72    public static final int MAX_HEADER_LIST_SIZE = 0x6;
73
74    private String name(int i) {
75        switch (i+1) {
76        case HEADER_TABLE_SIZE:
77            return "HEADER_TABLE_SIZE";
78        case ENABLE_PUSH:
79            return "ENABLE_PUSH";
80        case MAX_CONCURRENT_STREAMS:
81            return "MAX_CONCURRENT_STREAMS";
82        case INITIAL_WINDOW_SIZE:
83            return "INITIAL_WINDOW_SIZE";
84        case MAX_FRAME_SIZE:
85            return "MAX_FRAME_SIZE";
86        case MAX_HEADER_LIST_SIZE:
87            return "MAX_HEADER_LIST_SIZE";
88        }
89        return "unknown parameter";
90    }
91    public static final int MAX_PARAM = 0x6;
92
93    public SettingsFrame(int flags) {
94        super(0, flags);
95        parameters = new int [MAX_PARAM];
96        Arrays.fill(parameters, -1);
97    }
98
99    public SettingsFrame() {
100        this(0);
101    }
102
103    @Override
104    public int type() {
105        return TYPE;
106    }
107
108    public int getParameter(int paramID) {
109        if (paramID > MAX_PARAM) {
110            throw new IllegalArgumentException("illegal parameter");
111        }
112        return parameters[paramID-1];
113    }
114
115    public SettingsFrame setParameter(int paramID, int value) {
116        if (paramID > MAX_PARAM) {
117            throw new IllegalArgumentException("illegal parameter");
118        }
119        parameters[paramID-1] = value;
120        return this;
121    }
122
123    int length() {
124        int len = 0;
125        for (int i : parameters) {
126            if (i != -1) {
127                len  += 6;
128            }
129        }
130        return len;
131    }
132
133    void toByteBuffer(ByteBuffer buf) {
134        for (int i = 0; i < MAX_PARAM; i++) {
135            if (parameters[i] != -1) {
136                buf.putShort((short) (i + 1));
137                buf.putInt(parameters[i]);
138            }
139        }
140    }
141
142    public byte[] toByteArray() {
143        byte[] bytes = new byte[length()];
144        ByteBuffer buf = ByteBuffer.wrap(bytes);
145        toByteBuffer(buf);
146        return bytes;
147    }
148
149    private static final int K = 1024;
150
151    public static SettingsFrame getDefaultSettings() {
152        SettingsFrame f = new SettingsFrame();
153        // TODO: check these values
154        f.setParameter(ENABLE_PUSH, 1);
155        f.setParameter(HEADER_TABLE_SIZE, 4 * K);
156        f.setParameter(MAX_CONCURRENT_STREAMS, 35);
157        f.setParameter(INITIAL_WINDOW_SIZE, 64 * K - 1);
158        f.setParameter(MAX_FRAME_SIZE, 16 * K);
159        return f;
160    }
161}
162