com.hazelcast.nio.Packet Maven / Gradle / Ivy
/*
* Copyright (c) 2008-2017, Hazelcast, Inc. 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.hazelcast.nio;
import com.hazelcast.internal.serialization.impl.HeapData;
import com.hazelcast.spi.annotation.PrivateApi;
import java.nio.ByteBuffer;
import static com.hazelcast.nio.Bits.BYTE_SIZE_IN_BYTES;
import static com.hazelcast.nio.Bits.INT_SIZE_IN_BYTES;
import static com.hazelcast.nio.Bits.SHORT_SIZE_IN_BYTES;
/**
* A Packet is a piece of data sent over the wire. The Packet is used for member to member communication.
*
* The Packet extends HeapData instead of wrapping it. From a design point of view this is often
* not the preferred solution (prefer composition over inheritance), but in this case that
* would mean more object litter.
*
* Since the Packet isn't used throughout the system, this design choice is visible locally.
*/
@PrivateApi
// Declaration order suppressed due to private static int FLAG_TYPEx declarations
@SuppressWarnings("checkstyle:declarationorder")
public final class Packet extends HeapData implements OutboundFrame {
public static final byte VERSION = 4;
// PACKET HEADER FLAGS
//
// Flags are dispatched against in a cascade:
// 1. URGENT (bit 4)
// 2. Packet type (bits 0, 2, 5)
// 3. Flags specific to a given packet type (bits 1, 6)
// 1. URGENT flag
/** Marks the packet as Urgent */
public static final int FLAG_URGENT = 1 << 4;
// 2. Packet type flags, encode up to 7 packet types.
//
// When adding a new packet type, DO NOT ADD MORE TYPE FLAGS. Instead rename one of the
// Packet.Type.UNDEFINEDx members to represent the new type.
//
// Historically the first three packet types were encoded as separate, mutually exclusive flags.
// These are given below. The enum Packet.Type should be used to encode/decode the type from the
// header flags bitfield.
/** Packet type bit 0. Historically the OPERATION type flag. */
private static final int FLAG_TYPE0 = 1 << 0;
/** Packet type bit 1. Historically the EVENT type flag. */
private static final int FLAG_TYPE1 = 1 << 2;
/** Packet type bit 2. Historically the BIND type flag. */
private static final int FLAG_TYPE2 = 1 << 5;
// 3. Type-specific flags. Same bits can be reused within each type
// 3.a Operation packet flags
/** Marks an Operation packet as Response */
public static final int FLAG_OP_RESPONSE = 1 << 1;
/** Marks an Operation packet as Operation control (like invocation-heartbeats) */
public static final int FLAG_OP_CONTROL = 1 << 6;
// 3.b Jet packet flags
/** Marks a Jet packet as Flow control */
public static final int FLAG_JET_FLOW_CONTROL = 1 << 1;
// END OF HEADER FLAG SECTION
private static final int HEADER_SIZE = BYTE_SIZE_IN_BYTES + SHORT_SIZE_IN_BYTES + INT_SIZE_IN_BYTES + INT_SIZE_IN_BYTES;
// char is a 16-bit unsigned integer. Here we use it as a bitfield.
private char flags;
private int partitionId;
private transient Connection conn;
// These 3 fields are only used during read/write. Otherwise they have no meaning.
private int valueOffset;
private int size;
private boolean headerComplete;
public Packet() {
}
public Packet(byte[] payload) {
this(payload, -1);
}
public Packet(byte[] payload, int partitionId) {
super(payload);
this.partitionId = partitionId;
}
/**
* Gets the Connection this Packet was send with.
*
* @return the Connection. Could be null.
*/
public Connection getConn() {
return conn;
}
/**
* Sets the Connection this Packet is send with.
*
* This is done on the reading side of the Packet to make it possible to retrieve information about
* the sender of the Packet.
*
* @param conn the connection.
* @return {@code this} (for fluent interface)
*/
public Packet setConn(Connection conn) {
this.conn = conn;
return this;
}
public Type getPacketType() {
return Type.fromFlags(flags);
}
/**
* Sets the packet type by updating the packet type bits in the {@code flags} bitfield. Other bits
* are unaffected.
*
* @param type the type to set
* @return {@code this} (for fluent interface)
*/
public Packet setPacketType(Packet.Type type) {
int nonTypeFlags = flags & (~FLAG_TYPE0 & ~FLAG_TYPE1 & ~FLAG_TYPE2);
resetFlagsTo(type.headerEncoding | nonTypeFlags);
return this;
}
/**
* Raises all the flags raised in the argument. Does not lower any flags.
*
* @param flagsToRaise the flags to raise
* @return {@code this} (for fluent interface)
*/
public Packet raiseFlags(int flagsToRaise) {
flags |= flagsToRaise;
return this;
}
/**
* Resets the entire {@code flags} bitfield to the supplied value. This also affects the packet type bits.
*
* @param flagsToSet the flags. Only the least significant two bytes of the argument are used.
* @return {@code this} (for fluent interface)
*/
public Packet resetFlagsTo(int flagsToSet) {
flags = (char) flagsToSet;
return this;
}
/**
* Returns {@code true} if any of the flags supplied in the argument are set.
*
* @param flagsToCheck the flags to check
* @return {@code true} if any of the flags is set, {@code false} otherwise.
*/
public boolean isFlagRaised(int flagsToCheck) {
return isFlagRaised(flags, flagsToCheck);
}
private static boolean isFlagRaised(char flags, int flagsToCheck) {
return (flags & flagsToCheck) != 0;
}
/**
* @return the complete flags bitfield as a {@code char}.
*/
public char getFlags() {
return flags;
}
/**
* Returns the partition id of this packet. If this packet is not for a particular partition, -1 is returned.
*
* @return the partition id.
*/
public int getPartitionId() {
return partitionId;
}
@Override
public boolean isUrgent() {
return isFlagRaised(FLAG_URGENT);
}
/**
* The methods {@link #readFrom(ByteBuffer)} and {@link #writeTo(ByteBuffer)} do not complete their I/O operation
* within a single call, and between calls there is some progress state to keep within this instance.
* Calling this method resets the state back to "no bytes read/written yet".
*/
public void reset() {
headerComplete = false;
valueOffset = 0;
}
/**
* Writes the packet data to the supplied {@code ByteBuffer}, up to the buffer's limit. If it returns {@code false},
* it should be called again to write the remaining data.
* @param dst the destination byte buffer
* @return {@code true} if all the packet's data is now written out; {@code false} otherwise.
*/
public boolean writeTo(ByteBuffer dst) {
if (!headerComplete) {
if (dst.remaining() < HEADER_SIZE) {
return false;
}
dst.put(VERSION);
dst.putChar(flags);
dst.putInt(partitionId);
size = totalSize();
dst.putInt(size);
headerComplete = true;
}
return writeValue(dst);
}
/**
* Reads the packet data from the supplied {@code ByteBuffer}. The buffer may not contain the complete packet.
* If this method returns {@code false}, it should be called again to read more packet data.
* @param src the source byte buffer
* @return {@code true} if all the packet's data is now read; {@code false} otherwise.
*/
public boolean readFrom(ByteBuffer src) {
if (!headerComplete) {
if (src.remaining() < HEADER_SIZE) {
return false;
}
byte version = src.get();
if (VERSION != version) {
throw new IllegalArgumentException("Packet versions are not matching! Expected -> "
+ VERSION + ", Incoming -> " + version);
}
flags = src.getChar();
partitionId = src.getInt();
size = src.getInt();
headerComplete = true;
}
return readValue(src);
}
// ========================= value =================================================
private boolean readValue(ByteBuffer src) {
if (payload == null) {
payload = new byte[size];
}
if (size > 0) {
int bytesReadable = src.remaining();
int bytesNeeded = size - valueOffset;
boolean done;
int bytesRead;
if (bytesReadable >= bytesNeeded) {
bytesRead = bytesNeeded;
done = true;
} else {
bytesRead = bytesReadable;
done = false;
}
// read the data from the byte-buffer into the bytes-array.
src.get(payload, valueOffset, bytesRead);
valueOffset += bytesRead;
if (!done) {
return false;
}
}
return true;
}
private boolean writeValue(ByteBuffer dst) {
if (size > 0) {
// the number of bytes that can be written to the bb.
int bytesWritable = dst.remaining();
// the number of bytes that need to be written.
int bytesNeeded = size - valueOffset;
int bytesWrite;
boolean done;
if (bytesWritable >= bytesNeeded) {
// All bytes for the value are available.
bytesWrite = bytesNeeded;
done = true;
} else {
// Not all bytes for the value are available. So lets write as much as is available.
bytesWrite = bytesWritable;
done = false;
}
byte[] byteArray = toByteArray();
dst.put(byteArray, valueOffset, bytesWrite);
valueOffset += bytesWrite;
if (!done) {
return false;
}
}
return true;
}
/**
* Returns an estimation of the packet, including its payload, in bytes.
*
* @return the size of the packet.
*/
public int packetSize() {
return (payload != null ? totalSize() : 0) + HEADER_SIZE;
}
@Override
public boolean equals(Object o) {
if (this == o) {
return true;
}
if (!(o instanceof Packet)) {
return false;
}
Packet packet = (Packet) o;
if (!super.equals(packet)) {
return false;
}
if (flags != packet.flags) {
return false;
}
return partitionId == packet.partitionId;
}
@Override
public int hashCode() {
int result = super.hashCode();
result = 31 * result + (int) flags;
result = 31 * result + partitionId;
return result;
}
@Override
public String toString() {
final Type type = getPacketType();
return "Packet{"
+ "partitionId=" + partitionId
+ ", conn=" + conn
+ ", rawFlags=" + Integer.toBinaryString(flags)
+ ", isUrgent=" + isUrgent()
+ ", packetType=" + type.name()
+ ", typeSpecificFlags=" + type.describeFlags(flags)
+ '}';
}
public enum Type {
/**
* Represents "missing packet type", consists of all zeros. A zeroed-out packet header would
* resolve to this type.
*
* {@code ordinal = 0}
*/
NULL,
/**
* The type of an Operation packet.
*
* {@code ordinal = 1}
*/
OPERATION {
@Override
public String describeFlags(char flags) {
return "[isResponse=" + isFlagRaised(flags, FLAG_OP_RESPONSE)
+ ", isOpControl=" + isFlagRaised(flags, FLAG_OP_CONTROL) + ']';
}
},
/**
* The type of an Event packet.
*
* {@code ordinal = 2}
*/
EVENT,
/**
* The type of a Jet packet.
*
* {@code ordinal = 3}
*/
JET {
@Override
public String describeFlags(char flags) {
return "[isFlowControl=" + isFlagRaised(flags, FLAG_JET_FLOW_CONTROL) + ']';
}
},
/**
* The type of a Bind Message packet.
*
* {@code ordinal = 4}
*/
BIND,
/**
* Unused packet type. Available for future use.
*
* {@code ordinal = 5}
*/
UNDEFINED5,
/**
* Unused packet type. Available for future use.
*
* {@code ordinal = 6}
*/
UNDEFINED6,
/**
* Unused packet type. Available for future use.
*
* {@code ordinal = 7}
*/
UNDEFINED7;
final char headerEncoding;
Type() {
headerEncoding = (char) encodeOrdinal();
}
public static Type fromFlags(int flags) {
return values()[headerDecode(flags)];
}
public String describeFlags(char flags) {
return "";
}
@SuppressWarnings("checkstyle:booleanexpressioncomplexity")
private int encodeOrdinal() {
final int ordinal = ordinal();
assert ordinal < 8 : "Ordinal out of range for member " + name() + ": " + ordinal;
return (ordinal & 0x01)
| (ordinal & 0x02) << 1
| (ordinal & 0x04) << 3;
}
@SuppressWarnings("checkstyle:booleanexpressioncomplexity")
private static int headerDecode(int flags) {
return (flags & FLAG_TYPE0)
| (flags & FLAG_TYPE1) >> 1
| (flags & FLAG_TYPE2) >> 3;
}
}
}