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Java example source code file (SpdyFrameEncoder.java)

This example Java source code file (SpdyFrameEncoder.java) is included in the alvinalexander.com "Java Source Code Warehouse" project. The intent of this project is to help you "Learn Java by Example" TM.

Learn more about this Java project at its project page.

Java - Java tags/keywords

bytebuf, integer, nio, nullpointerexception, spdy_flag_fin, spdy_goaway_frame, spdy_rst_stream_frame, spdy_settings_clear, spdy_settings_frame, spdy_settings_persist_value, spdy_settings_persisted, spdy_syn_reply_frame, spdy_syn_stream_frame, spdy_window_update_frame, spdyframeencoder, util

The SpdyFrameEncoder.java Java example source code

/*
 * Copyright 2014 The Netty Project
 *
 * The Netty Project licenses this file to you 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 io.netty.handler.codec.spdy;

import io.netty.buffer.ByteBuf;
import io.netty.buffer.ByteBufAllocator;

import java.nio.ByteOrder;
import java.util.Set;

import static io.netty.handler.codec.spdy.SpdyCodecUtil.*;

/**
 * Encodes a SPDY Frame into a {@link ByteBuf}.
 */
public class SpdyFrameEncoder {

    private final int version;

    /**
     * Creates a new instance with the specified {@code spdyVersion}.
     */
    public SpdyFrameEncoder(SpdyVersion spdyVersion) {
        if (spdyVersion == null) {
            throw new NullPointerException("spdyVersion");
        }
        version = spdyVersion.getVersion();
    }

    private void writeControlFrameHeader(ByteBuf buffer, int type, byte flags, int length) {
        buffer.writeShort(version | 0x8000);
        buffer.writeShort(type);
        buffer.writeByte(flags);
        buffer.writeMedium(length);
    }

    public ByteBuf encodeDataFrame(ByteBufAllocator allocator, int streamId, boolean last, ByteBuf data) {
        byte flags = last ? SPDY_DATA_FLAG_FIN : 0;
        int length = data.readableBytes();
        ByteBuf frame = allocator.ioBuffer(SPDY_HEADER_SIZE + length).order(ByteOrder.BIG_ENDIAN);
        frame.writeInt(streamId & 0x7FFFFFFF);
        frame.writeByte(flags);
        frame.writeMedium(length);
        frame.writeBytes(data, data.readerIndex(), length);
        return frame;
    }

    public ByteBuf encodeSynStreamFrame(ByteBufAllocator allocator,  int streamId, int associatedToStreamId,
            byte priority, boolean last, boolean unidirectional, ByteBuf headerBlock) {
        int headerBlockLength = headerBlock.readableBytes();
        byte flags = last ? SPDY_FLAG_FIN : 0;
        if (unidirectional) {
            flags |= SPDY_FLAG_UNIDIRECTIONAL;
        }
        int length = 10 + headerBlockLength;
        ByteBuf frame = allocator.ioBuffer(SPDY_HEADER_SIZE + length).order(ByteOrder.BIG_ENDIAN);
        writeControlFrameHeader(frame, SPDY_SYN_STREAM_FRAME, flags, length);
        frame.writeInt(streamId);
        frame.writeInt(associatedToStreamId);
        frame.writeShort((priority & 0xFF) << 13);
        frame.writeBytes(headerBlock, headerBlock.readerIndex(), headerBlockLength);
        return frame;
    }

    public ByteBuf encodeSynReplyFrame(ByteBufAllocator allocator, int streamId, boolean last, ByteBuf headerBlock) {
        int headerBlockLength = headerBlock.readableBytes();
        byte flags = last ? SPDY_FLAG_FIN : 0;
        int length = 4 + headerBlockLength;
        ByteBuf frame = allocator.ioBuffer(SPDY_HEADER_SIZE + length).order(ByteOrder.BIG_ENDIAN);
        writeControlFrameHeader(frame, SPDY_SYN_REPLY_FRAME, flags, length);
        frame.writeInt(streamId);
        frame.writeBytes(headerBlock, headerBlock.readerIndex(), headerBlockLength);
        return frame;
    }

    public ByteBuf encodeRstStreamFrame(ByteBufAllocator allocator, int streamId, int statusCode) {
        byte flags = 0;
        int length = 8;
        ByteBuf frame = allocator.ioBuffer(SPDY_HEADER_SIZE + length).order(ByteOrder.BIG_ENDIAN);
        writeControlFrameHeader(frame, SPDY_RST_STREAM_FRAME, flags, length);
        frame.writeInt(streamId);
        frame.writeInt(statusCode);
        return frame;
    }

    public ByteBuf encodeSettingsFrame(ByteBufAllocator allocator, SpdySettingsFrame spdySettingsFrame) {
        Set<Integer> ids = spdySettingsFrame.ids();
        int numSettings = ids.size();

        byte flags = spdySettingsFrame.clearPreviouslyPersistedSettings() ?
                SPDY_SETTINGS_CLEAR : 0;
        int length = 4 + 8 * numSettings;
        ByteBuf frame = allocator.ioBuffer(SPDY_HEADER_SIZE + length).order(ByteOrder.BIG_ENDIAN);
        writeControlFrameHeader(frame, SPDY_SETTINGS_FRAME, flags, length);
        frame.writeInt(numSettings);
        for (Integer id : ids) {
            flags = 0;
            if (spdySettingsFrame.isPersistValue(id)) {
                flags |= SPDY_SETTINGS_PERSIST_VALUE;
            }
            if (spdySettingsFrame.isPersisted(id)) {
                flags |= SPDY_SETTINGS_PERSISTED;
            }
            frame.writeByte(flags);
            frame.writeMedium(id);
            frame.writeInt(spdySettingsFrame.getValue(id));
        }
        return frame;
    }

    public ByteBuf encodePingFrame(ByteBufAllocator allocator, int id) {
        byte flags = 0;
        int length = 4;
        ByteBuf frame = allocator.ioBuffer(SPDY_HEADER_SIZE + length).order(ByteOrder.BIG_ENDIAN);
        writeControlFrameHeader(frame, SPDY_PING_FRAME, flags, length);
        frame.writeInt(id);
        return frame;
    }

    public ByteBuf encodeGoAwayFrame(ByteBufAllocator allocator, int lastGoodStreamId, int statusCode) {
        byte flags = 0;
        int length = 8;
        ByteBuf frame = allocator.ioBuffer(SPDY_HEADER_SIZE + length).order(ByteOrder.BIG_ENDIAN);
        writeControlFrameHeader(frame, SPDY_GOAWAY_FRAME, flags, length);
        frame.writeInt(lastGoodStreamId);
        frame.writeInt(statusCode);
        return frame;
    }

    public ByteBuf encodeHeadersFrame(ByteBufAllocator allocator, int streamId, boolean last, ByteBuf headerBlock) {
        int headerBlockLength = headerBlock.readableBytes();
        byte flags = last ? SPDY_FLAG_FIN : 0;
        int length = 4 + headerBlockLength;
        ByteBuf frame = allocator.ioBuffer(SPDY_HEADER_SIZE + length).order(ByteOrder.BIG_ENDIAN);
        writeControlFrameHeader(frame, SPDY_HEADERS_FRAME, flags, length);
        frame.writeInt(streamId);
        frame.writeBytes(headerBlock, headerBlock.readerIndex(), headerBlockLength);
        return frame;
    }

    public ByteBuf encodeWindowUpdateFrame(ByteBufAllocator allocator, int streamId, int deltaWindowSize) {
        byte flags = 0;
        int length = 8;
        ByteBuf frame = allocator.ioBuffer(SPDY_HEADER_SIZE + length).order(ByteOrder.BIG_ENDIAN);
        writeControlFrameHeader(frame, SPDY_WINDOW_UPDATE_FRAME, flags, length);
        frame.writeInt(streamId);
        frame.writeInt(deltaWindowSize);
        return frame;
    }
}

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