edu.nps.moves.dis.Pdu Maven / Gradle / Ivy
package edu.nps.moves.dis;
import java.io.*;
import edu.nps.moves.disenum.*;
import edu.nps.moves.disutil.*;
import java.nio.ByteBuffer;
import java.util.logging.Level;
import java.util.logging.Logger;
/**
* The superclass for all PDUs. This incorporates the PduHeader record, section
* 5.2.29.
*
* Copyright (c) 2008-2016, MOVES Institute, Naval Postgraduate School. All
* rights reserved. This work is licensed under the BSD open source license,
* available at https://www.movesinstitute.org/licenses/bsd.html
*
* @author DMcG
*/
public class Pdu extends Object implements Serializable {
/**
* The version of the protocol. 5=DIS-1995, 6=DIS-1998.
*/
protected short protocolVersion = (short) 6;
/**
* Exercise ID
*/
protected short exerciseID = (short) 0;
/**
* Type of pdu, unique for each PDU class
*/
protected short pduType;
/**
* value that refers to the protocol family, eg SimulationManagement, et
*/
protected short protocolFamily;
/**
* Timestamp value
*/
protected long timestamp;
/**
* zero-filled array of padding
*/
protected short padding = (short) 0;
/**
* Constructor
*/
public Pdu() {
}
public int getLength() {
return this.getMarshalledSize();
}
public int getMarshalledSize() {
int marshalSize = 0;
marshalSize = marshalSize + 1; // protocolVersion
marshalSize = marshalSize + 1; // exerciseID
marshalSize = marshalSize + 1; // pduType
marshalSize = marshalSize + 1; // protocolFamily
marshalSize = marshalSize + 4; // timestamp
marshalSize = marshalSize + 2; // pduLength
marshalSize = marshalSize + 2; // padding
return marshalSize;
}
public void setProtocolVersion(short pProtocolVersion) {
protocolVersion = pProtocolVersion;
}
public short getProtocolVersion() {
return protocolVersion;
}
public void setExerciseID(short pExerciseID) {
exerciseID = pExerciseID;
}
public short getExerciseID() {
return exerciseID;
}
public void setPduType(short pPduType) {
pduType = pPduType;
}
public short getPduType() {
return pduType;
}
/**
* Returns the PduType, an enumeration from the disenum jar file. This is an
* enumerated java type, rather than a simple short integer. This should NOT
* be marshalled to DIS or XML.
*
* @return this Pdu's type enumeration
*/
public PduType getPduTypeEnum() {
return PduType.lookup[pduType];
}
public void setProtocolFamily(short pProtocolFamily) {
protocolFamily = pProtocolFamily;
}
public short getProtocolFamily() {
return protocolFamily;
}
public void setTimestamp(long pTimestamp) {
timestamp = pTimestamp;
}
public long getTimestamp() {
return timestamp;
}
/**
* @deprecated PDU length is determined by the PDU type and content and
* cannot be set directly
*/
@Deprecated
public void setPduLength(int pPduLength) {
}
/**
* @deprecated Use {@link #getMarshalledSize()}
*/
@Deprecated
public int getPduLength() {
return getMarshalledSize();
}
public void setPadding(short pPadding) {
padding = pPadding;
}
public short getPadding() {
return padding;
}
private static long shiftBytes(int[] fourBytes) {
long value = 0;
value = ((long) (fourBytes[0] << 24
| fourBytes[1] << 16
| fourBytes[2] << 8
| fourBytes[3]))
& 0xFFFFFFFFL;
return value;
}
public static long readUnsignedInt(java.nio.ByteBuffer buff) {
int fourBytes[] = new int[4];
fourBytes[0] = toUnsignedInt(buff.get());
fourBytes[1] = toUnsignedInt(buff.get());
fourBytes[2] = toUnsignedInt(buff.get());
fourBytes[3] = toUnsignedInt(buff.get());
return shiftBytes(fourBytes);
}
// TODO: replace with Byte#toUnsignedInt once Java 8 is new baseline.
public static int toUnsignedInt(byte b) {
return b & 0xff;
}
// TODO: replace with Short#toUnsignedInt once Java 8 is new baseline.
public static int toUnsignedInt(short s) {
return s & 0xffff;
}
public void marshal(DataOutputStream dos) {
try {
dos.write(marshal());
} catch (IOException ex) {
Logger.getLogger(Pdu.class.getName()).log(Level.SEVERE, null, ex);
}
}
public void unmarshal(DataInputStream dis) {
try {
// Read the pdu header to determine the pdu length
byte[] header = new byte[12];
dis.mark(header.length);
dis.read(header, 0, header.length);
int pduLength = ByteBuffer.wrap(header).getShort(8);
setPduLength(pduLength);
dis.reset();
// Now allocate enough space for full pdu
byte[] pdu = new byte[pduLength];
dis.read(pdu, 0, pduLength);
unmarshal(ByteBuffer.wrap(pdu));
} catch (IOException ex) {
Logger.getLogger(EntityStatePdu.class.getName()).log(Level.SEVERE, null, ex);
}
} // end of unmarshal method
/**
* Packs a Pdu into the ByteBuffer.
*
* @throws java.nio.BufferOverflowException if buff is too small
* @throws java.nio.ReadOnlyBufferException if buff is read only
* @see java.nio.ByteBuffer
* @param buff The ByteBuffer at the position to begin writing
* @since ??
*/
public void marshal(java.nio.ByteBuffer buff) {
buff.put((byte) protocolVersion);
buff.put((byte) exerciseID);
buff.put((byte) pduType);
buff.put((byte) protocolFamily);
buff.putInt((int) timestamp);
buff.putShort((short) this.getLength());
buff.putShort((short) padding);
} // end of marshal method
/**
* Unpacks a Pdu from the underlying data.
*
* @throws java.nio.BufferUnderflowException if buff is too small
* @see java.nio.ByteBuffer
* @param buff The ByteBuffer at the position to begin reading
* @since ??
*/
public void unmarshal(java.nio.ByteBuffer buff) {
protocolVersion = (short) (toUnsignedInt(buff.get()));
exerciseID = (short) (toUnsignedInt(buff.get()));
pduType = (short) (toUnsignedInt(buff.get()));
protocolFamily = (short) (toUnsignedInt(buff.get()));
timestamp = buff.getInt();
int pduLength = toUnsignedInt(buff.getShort());
setPduLength(pduLength);
padding = buff.getShort();
} // end of unmarshal method
/**
* A convenience method for marshalling to a byte array. This is not as
* efficient as reusing a ByteBuffer, but it is easy.
*
* @return a byte array with the marshalled {@link Pdu}
* @since ??
*/
public byte[] marshal() {
byte[] data = new byte[getMarshalledSize()];
java.nio.ByteBuffer buff = java.nio.ByteBuffer.wrap(data);
marshal(buff);
return data;
}
/**
* A convieneince method to marshal to a byte array with the timestamp set
* to the DIS standard for absolute timestamps (which works only if the host
* is slaved to NTP). This means the timestamp will roll over every hour.
*
* @return IEEE format byte array, with the timestamp set to the current DIS
* time
*/
public byte[] marshalWithDisAbsoluteTimestamp() {
DisTime disTime = DisTime.getInstance();
this.setTimestamp(disTime.getDisAbsoluteTimestamp());
return this.marshal();
}
public void marshalWithDisAbsoluteTimestamp(java.nio.ByteBuffer buff) {
DisTime disTime = DisTime.getInstance();
this.setTimestamp(disTime.getDisAbsoluteTimestamp());
this.marshal(buff);
}
/**
* A convieneince method to marshal to a byte array with the timestamp set
* to the DIS standard for relative timestamps. The timestamp will roll over
* every hour
*
* @return IEEE format byte array, with the timestamp set to relative DIS
* time
*/
public byte[] marshalWithDisRelativeTimestamp() {
DisTime disTime = DisTime.getInstance();
this.setTimestamp(disTime.getDisRelativeTimestamp());
return this.marshal();
}
public void marshalWithDisRelativeTimestamp(java.nio.ByteBuffer buff) {
DisTime disTime = DisTime.getInstance();
this.setTimestamp(disTime.getDisRelativeTimestamp());
this.marshal(buff);
}
/**
* A convienience method to marshal a PDU using the NPS-specific format for
* timestamps, which is hundredths of a second since the start of the year.
* This effectively eliminates the rollover issues from a practical
* standpoint.
*
* @return IEEE format byte array, with the timestamp set to hundredths of a
* second since the start of the year
*/
public byte[] marshalWithNpsTimestamp() {
DisTime disTime = DisTime.getInstance();
this.setTimestamp(disTime.getNpsTimestamp());
return this.marshal();
}
public void marshalWithNpsTimestamp(java.nio.ByteBuffer buff) {
DisTime disTime = DisTime.getInstance();
this.setTimestamp(disTime.getNpsTimestamp());
this.marshal(buff);
}
/**
* Another option for marshalling with the timestamp field set
* automatically. The UNIX time is conventionally seconds since January 1,
* 1970. UTC time is used, and leap seconds are excluded. This approach is
* popular in the wild, but the time resolution is not very good for high
* frequency updates, such as aircraft. An entity updating at 30 PDUs/second
* would see 30 PDUs sent out with the same timestamp, and have 29 of them
* discarded as duplicate packets.
*
* Note that there are other "Unix times", such milliseconds since 1/1/1970,
* saved in a long. This cannot be used, since the value is saved in a long.
* Java's System.getCurrentTimeMillis() uses this value.
*
* @return IEEE format byte array, with the timetamp set to seconds since
* 1970
*/
public byte[] marshalWithUnixTimestamp() {
DisTime disTime = DisTime.getInstance();
this.setTimestamp(disTime.getUnixTimestamp());
return this.marshal();
}
public void marshalWithUnixTimestamp(java.nio.ByteBuffer buff) {
DisTime disTime = DisTime.getInstance();
this.setTimestamp(disTime.getUnixTimestamp());
this.marshal(buff);
}
/*
* The equals method doesn't always work--mostly it works only on classes that consist only of primitives. Be careful.
*/
@Override
public boolean equals(Object obj) {
if (this == obj) {
return true;
}
if (obj == null) {
return false;
}
if (getClass() != obj.getClass()) {
return false;
}
return equalsImpl(obj);
}
/**
* Compare all fields that contribute to the state, ignoring transient and
* static fields, for this and the supplied object
*
* @param obj the object to compare to
* @return true if the objects are equal, false otherwise.
*/
public boolean equalsImpl(Object obj) {
boolean ivarsEqual = true;
if (!(obj instanceof Pdu)) {
return false;
}
final Pdu rhs = (Pdu) obj;
if (!(protocolVersion == rhs.protocolVersion)) {
ivarsEqual = false;
}
if (!(exerciseID == rhs.exerciseID)) {
ivarsEqual = false;
}
if (!(pduType == rhs.pduType)) {
ivarsEqual = false;
}
if (!(protocolFamily == rhs.protocolFamily)) {
ivarsEqual = false;
}
if (!(timestamp == rhs.timestamp)) {
ivarsEqual = false;
}
if (!(getMarshalledSize() == rhs.getMarshalledSize())) {
ivarsEqual = false;
}
if (!(padding == rhs.padding)) {
ivarsEqual = false;
}
return ivarsEqual;
}
} // end of class
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