Java tutorial
/* * Copyright (c) 2012-2015 Spotify AB * * 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.spotify.netty4.handler.codec.zmtp; import java.nio.ByteBuffer; import io.netty.buffer.ByteBuf; import static com.spotify.netty4.handler.codec.zmtp.ZMTPUtils.checkNotNull; import static java.lang.String.format; /** * Tools for reading and writing the ZMTP/2.0 wire format, greeting and message frames. */ class ZMTP20WireFormat implements ZMTPWireFormat { static final byte FINAL_FLAG = 0x0; static final byte LONG_FLAG = 0x02; static final byte MORE_FLAG = 0x1; @Override public int frameLength(final int content) { if (content < 256) { return 1 + 1 + content; } else { return 1 + 8 + content; } } @Override public Header header() { return new ZMTP20Header(); } /** * Read a ZMTP/2.0 greeting. * * @param in The buffer to read the greeting from. * @return A {@link com.spotify.netty4.handler.codec.zmtp.ZMTP20WireFormat.Greeting}. * @throws ZMTPParsingException If the greeting is malformed. * @throws IndexOutOfBoundsException If there is not enough readable bytes to read an entire * greeting. */ static Greeting readGreeting(ByteBuf in) throws ZMTPParsingException { if (in.readByte() != (byte) 0xff) { throw new ZMTPParsingException("Illegal ZMTP/2.0 greeting, first octet not 0xff"); } in.skipBytes(9); return readGreetingBody(in); } /** * Read a ZMTP/2.0 greeting body. * * @param in The buffer to read the greeting from. * @return A {@link com.spotify.netty4.handler.codec.zmtp.ZMTP20WireFormat.Greeting}. * @throws ZMTPParsingException If the greeting is malformed. * @throws IndexOutOfBoundsException If there is not enough readable bytes to read an entire * greeting. */ static Greeting readGreetingBody(final ByteBuf in) throws ZMTPParsingException { final int revision = in.readByte(); final ZMTPSocketType socketType = readSocketType(in); final int flags = in.readByte(); if (flags != 0x00) { throw new ZMTPParsingException( format("Malformed ZMTP/2.0 greeting. Flags (byte 13) expected to be 0x00, was 0x%02x", flags)); } final int len = in.readByte(); final byte[] identity = new byte[len]; in.readBytes(identity); return new Greeting(revision, socketType, ByteBuffer.wrap(identity)); } /** * Read a ZMTP/2.0 socket type. * * @param in The buffer to read the socket type from. * @return A {@link ZMTPSocketType}. * @throws ZMTPParsingException If the socket type is malformed. * @throws IndexOutOfBoundsException If there is not enough readable bytes to read an entire * socket type. */ static ZMTPSocketType readSocketType(final ByteBuf in) throws ZMTPParsingException { return socketType((int) in.readByte()); } /** * Translate a ZMTP/2.0 wire socket type representation to a {@link ZMTPSocketType}. * * @param socketType The ZMTP/2.0 wire socket type. * @return a {@link ZMTPSocketType} * @throws ZMTPParsingException If the socket type is invalid. */ static ZMTPSocketType socketType(final int socketType) throws ZMTPParsingException { switch (socketType) { case 0: return ZMTPSocketType.PAIR; case 1: return ZMTPSocketType.PUB; case 2: return ZMTPSocketType.SUB; case 3: return ZMTPSocketType.REQ; case 4: return ZMTPSocketType.REP; case 5: return ZMTPSocketType.DEALER; case 6: return ZMTPSocketType.ROUTER; case 7: return ZMTPSocketType.PULL; case 8: return ZMTPSocketType.PUSH; default: throw new ZMTPParsingException("Invalid socket type: " + socketType); } } /** * Write a ZMTP/2.0 socket type. * * @param out The buffer to write the socket type to. * @param socketType The socket type to write. */ static void writeSocketType(final ByteBuf out, final ZMTPSocketType socketType) { out.writeByte(socketType(socketType)); } /** * Translate a {@link ZMTPSocketType} to a ZMTP/2.0 wire representation. * * @param socketType The {@link ZMTPSocketType}. * @return The ZMTP/2.0 wire representation. */ static int socketType(final ZMTPSocketType socketType) { switch (socketType) { case PAIR: return 0; case PUB: return 1; case SUB: return 2; case REQ: return 3; case REP: return 4; case DEALER: return 5; case ROUTER: return 6; case PULL: return 7; case PUSH: return 8; default: throw new IllegalArgumentException("Unknown socket type: " + socketType); } } /** * Read enough bytes from buffer to deduce the remote protocol version in a backwards compatible * ZMTP handshake. * * @param in the buffer of data to determine version from. * @return The detected {@link ZMTPVersion}. * @throws IndexOutOfBoundsException if there is not enough data available in buffer. */ static ZMTPVersion detectProtocolVersion(final ByteBuf in) { if (in.readByte() != (byte) 0xff) { return ZMTPVersion.ZMTP10; } in.skipBytes(8); if ((in.readByte() & 0x01) == 0) { return ZMTPVersion.ZMTP10; } return ZMTPVersion.ZMTP20; } /** * Write a ZMTP/2.0 greeting. * * @param out The buffer to write the greeting to. * @param socketType The socket type. * @param identity The socket identity. */ static void writeGreeting(final ByteBuf out, final ZMTPSocketType socketType, final ByteBuffer identity) { writeSignature(out); writeGreetingBody(out, socketType, identity); } /** * Write a ZMTP/2.0 greeting signature. * * @param out The buffer to write the signature to. */ static void writeSignature(final ByteBuf out) { out.writeByte(0xff); out.writeLong(0x00); out.writeByte(0x7f); } /** * Write a ZMTP/2.0 greeting body. * * @param out The buffer to write the greeting body to. * @param socketType The socket type. * @param identity The socket identity. */ static void writeGreetingBody(final ByteBuf out, final ZMTPSocketType socketType, final ByteBuffer identity) { out.writeByte(0x01); // socket-type writeSocketType(out, socketType); // identity // the final-short flag octet out.writeByte(0x00); out.writeByte(identity.remaining()); out.writeBytes(identity.duplicate()); } /** * Write a backwards compatible ZMTP/2.0 greeting signature. * * @param out The buffer to write the signature to. * @param identity The socket identity. */ static void writeCompatSignature(final ByteBuf out, final ByteBuffer identity) { out.writeByte(0xFF); out.writeLong(identity.remaining() + 1); out.writeByte(0x7f); } static class ZMTP20Header implements Header { int maxLength; int length; boolean more; @Override public void set(final int maxLength, final int length, final boolean more) { this.maxLength = maxLength; this.length = length; this.more = more; } @Override public void write(final ByteBuf out) { final byte flags = more ? MORE_FLAG : FINAL_FLAG; if (maxLength < 256) { out.writeByte(flags); out.writeByte((byte) length); } else { out.writeByte(flags | LONG_FLAG); out.writeLong(length); } } @Override public boolean read(final ByteBuf in) { if (in.readableBytes() < 2) { return false; } int flags = in.readByte(); more = (flags & MORE_FLAG) == MORE_FLAG; if ((flags & LONG_FLAG) != LONG_FLAG) { length = in.readByte() & 0xff; return true; } if (in.readableBytes() < 8) { return false; } final long len = in.readLong(); length = (int) len; return true; } @Override public long length() { return length; } @Override public boolean more() { return more; } } /** * The ZMTP/2.0 greeting contents. */ static class Greeting { private final int revision; private final ZMTPSocketType socketType; private final ByteBuffer identity; Greeting(final int revision, final ZMTPSocketType socketType, final ByteBuffer identity) { this.revision = revision; this.socketType = checkNotNull(socketType, "socketType"); this.identity = checkNotNull(identity, "identity"); } int revision() { return revision; } ZMTPSocketType socketType() { return socketType; } ByteBuffer identity() { return identity.asReadOnlyBuffer(); } @Override public boolean equals(final Object o) { if (this == o) { return true; } if (o == null || getClass() != o.getClass()) { return false; } final Greeting that = (Greeting) o; if (revision != that.revision) { return false; } if (socketType != that.socketType) { return false; } return !(identity != null ? !identity.equals(that.identity) : that.identity != null); } @Override public int hashCode() { int result = revision; result = 31 * result + (socketType != null ? socketType.hashCode() : 0); result = 31 * result + (identity != null ? identity.hashCode() : 0); return result; } @Override public String toString() { return "Greeting{" + "revision=" + revision + ", socketType=" + socketType + ", identity=" + identity + '}'; } } }