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An open source implementation of the Distributed Interactive Simulation (DIS) IEEE-1278 protocol
package edu.nps.moves.dis;
import java.util.*;
import java.io.*;
import edu.nps.moves.disenum.*;
import edu.nps.moves.disutil.*;
// Jaxb and Hibernate annotations generally won't work on mobile devices. XML serialization uses jaxb, and
// javax.persistence uses the JPA JSR, aka hibernate. See the Hibernate site for details.
// To generate Java code without these, and without the annotations scattered through the
// see the XMLPG java code generator, and set the boolean useHibernateAnnotations and useJaxbAnnotions
// to false, and then regenerate the code
import javax.xml.bind.*; // Used for JAXB XML serialization
import javax.xml.bind.annotation.*; // Used for XML serialization annotations (the @ stuff)
import javax.persistence.*; // Used for JPA/Hibernate SQL persistence
/**
* The superclass for all PDUs. This incorporates the PduHeader record, section 5.2.29.
*
* Copyright (c) 2008-2010, 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
*/
@Entity // Hibernate
@Inheritance(strategy=InheritanceType.JOINED) // Hibernate
public class Pdu extends Object implements Serializable
{
/** Primary key for hibernate, not part of the DIS standard */
private long pk_Pdu;
/** 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;
/** Length, in bytes, of the PDU. Changed name from length to avoid use of Hibernate QL reserved word */
protected int pduLength;
/** zero-filled array of padding */
protected short padding = (short)0;
/** Constructor */
public Pdu()
{
}
@Transient
public int getLength()
{
return this.getMarshalledSize();
}
@Transient // Marked as transient to prevent hibernate from thinking this is a persistent property
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;
}
/** Primary key for hibernate, not part of the DIS standard */
@Id
@GeneratedValue(strategy=GenerationType.AUTO)
public long getPk_Pdu()
{
return pk_Pdu;
}
/** Hibernate primary key, not part of the DIS standard */
public void setPk_Pdu(long pKeyName)
{
this.pk_Pdu = pKeyName;
}
public void setProtocolVersion(short pProtocolVersion)
{ protocolVersion = pProtocolVersion;
}
@XmlAttribute // Jaxb
@Basic // Hibernate
public short getProtocolVersion()
{ return protocolVersion;
}
public void setExerciseID(short pExerciseID)
{ exerciseID = pExerciseID;
}
@XmlAttribute // Jaxb
@Basic // Hibernate
public short getExerciseID()
{ return exerciseID;
}
public void setPduType(short pPduType)
{ pduType = pPduType;
}
@XmlAttribute // Jaxb
@Basic // Hibernate
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
*/
@Transient
public PduType getPduTypeEnum() {
return PduType.lookup[pduType];
}
public void setProtocolFamily(short pProtocolFamily)
{ protocolFamily = pProtocolFamily;
}
@XmlAttribute // Jaxb
@Basic // Hibernate
public short getProtocolFamily()
{ return protocolFamily;
}
public void setTimestamp(long pTimestamp)
{ timestamp = pTimestamp;
}
@XmlAttribute // Jaxb
@Basic // Hibernate
public long getTimestamp()
{ return timestamp;
}
public void setPduLength(int pPduLength)
{ pduLength = pPduLength;
}
@XmlAttribute // Jaxb
@Basic // Hibernate
public int getPduLength()
{ return pduLength;
}
public void setPadding(short pPadding)
{ padding = pPadding;
}
@XmlAttribute // Jaxb
@Basic // Hibernate
public short getPadding()
{ return padding;
}
private long shiftBytes(int[] fourBytes)
{
long value = 0;
value = ((long) (fourBytes[0] << 24
| fourBytes[1] << 16
| fourBytes[2] << 8
| fourBytes[3]))
& 0xFFFFFFFFL;
return value;
}
public long readUnsignedInt(DataInputStream dis)
{
int fourBytes[] = new int[4];
try
{
fourBytes[0] = dis.readUnsignedByte();
fourBytes[1] = dis.readUnsignedByte();
fourBytes[2] = dis.readUnsignedByte();
fourBytes[3] = dis.readUnsignedByte();
}
catch(Exception e)
{
System.out.println(e);
}
return this.shiftBytes(fourBytes);
}
public long readUnsignedInt(java.nio.ByteBuffer buff)
{
int fourBytes[] = new int[4];
try
{
fourBytes[0] = ((int)buff.get()) & 0xff;
fourBytes[1] = ((int)buff.get()) & 0xff;
fourBytes[2] = ((int)buff.get()) & 0xff;
fourBytes[3] = ((int)buff.get()) & 0xff;
}
catch(Exception e)
{
System.out.println(e);
}
return this.shiftBytes(fourBytes);
}
public void marshal(DataOutputStream dos)
{
try
{
dos.writeByte( (byte)protocolVersion);
dos.writeByte( (byte)exerciseID);
dos.writeByte( (byte)pduType);
dos.writeByte( (byte)protocolFamily);
dos.writeInt( (int)timestamp);
dos.writeShort( this.getLength());
dos.writeShort( (short)padding);
} // end try
catch(Exception e)
{
System.out.println(e);}
} // end of marshal method
public void unmarshal(DataInputStream dis)
{
try
{
protocolVersion = (short)dis.readUnsignedByte();
exerciseID = (short)dis.readUnsignedByte();
pduType = (short)dis.readUnsignedByte();
protocolFamily = (short)dis.readUnsignedByte();
timestamp = dis.readInt();
pduLength = (int)dis.readUnsignedShort();
padding = dis.readShort();
} // end try
catch(Exception e)
{
System.out.println(e);
}
} // 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)(buff.get() & 0xFF);
exerciseID = (short)(buff.get() & 0xFF);
pduType = (short)(buff.get() & 0xFF);
protocolFamily = (short)(buff.get() & 0xFF);
timestamp = buff.getInt();
pduLength = (int)(buff.getShort() & 0xFFFF);
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( ! (pduLength == rhs.pduLength)) ivarsEqual = false;
if( ! (padding == rhs.padding)) ivarsEqual = false;
return ivarsEqual;
}
} // end of class