com.sun.squawk.debugger
Class Packet

java.lang.Object
  com.sun.squawk.debugger.Packet

Direct Known Subclasses:

CommandPacket, ReplyPacket

public abstract class Packet
extends Object

A Packet encapsulates a JDWP command or reply packet.

Field Summary

static short	FLAG_NEEDS_REPLY Indicates a packet for which no reply is expected.
static short	FLAG_REPLY The flag bit value indicating a reply packet.

Constructor Summary

Packet(int id)
Creates a Packet for a new JDWP request.

Packet(int id, int dataLength, DataInputStream data)
Creates a Packet to encapsulate a received JDWP packet.

Method Summary

protected void	appendData(StringBuffer buf) Appends a textualized form of this packet's data to a given StringBuffer.
abstract int	getFlags() Gets the value for the 'flags' field in the header of this packet.
int	getID() Gets the ID that is used to pair this packet with its associated command or reply packet (if any).
PacketInputStream	getInputStream() Gets a DataInputStream to read the data in this packet.
PacketOutputStream	getOutputStream() Gets a PacketOutputStream to write some data to this packet.
int	getSize() Gets the size (in bytes) of the entire packet.
abstract String	toString() Returns a string representation of the object.
void	write(DataOutputStream dos) Writes this packet to a given output stream.
protected abstract void	writeFields(DataOutputStream dos) Hook for sublasses to write their specific fields to a packet being sent.

Methods inherited from class java.lang.Object

equals, getClass, hashCode, notify, notifyAll, wait, wait, wait

Field Detail

FLAG_REPLY

public static final short FLAG_REPLY

The flag bit value indicating a reply packet.

See Also:

Constant Field Values

FLAG_NEEDS_REPLY

public static final short FLAG_NEEDS_REPLY

Indicates a packet for which no reply is expected.

See Also:

Constant Field Values

Constructor Detail

Packet

public Packet(int id)

Creates a Packet for a new JDWP request.

Parameters:

id - the identifier of the new packet

Packet

public Packet(int id,
              int dataLength,
              DataInputStream data)
       throws IOException

Creates a Packet to encapsulate a received JDWP packet.

Parameters:

owner - the JDWPListener that received the packet

id - the identifier in the packet

dataLength - the length of the data to read from data

data - the contents of the data field of the packet

Throws:

IOException

Method Detail

getInputStream

public PacketInputStream getInputStream()

Gets a DataInputStream to read the data in this packet.

Returns:

a DataInputStream to read the data in this packet

getOutputStream

public PacketOutputStream getOutputStream()

Gets a PacketOutputStream to write some data to this packet. This cannot be called on a packet that was initialized with some received data.

Returns:

a PacketOutputStream to write the data in this packet

getID

public final int getID()

Gets the ID that is used to pair this packet with its associated command or reply packet (if any).

Returns:

the ID that is unique to this command and reply packet pair this packet belongs to (if any)

toString

public abstract String toString()

Returns a string representation of the object. In general, the toString method returns a string that "textually represents" this object. The result should be a concise but informative representation that is easy for a person to read. It is recommended that all subclasses override this method.

The toString method for class Object returns a string consisting of the name of the class of which the object is an instance, the at-sign character `@', and the unsigned hexadecimal representation of the hash code of the object. In other words, this method returns a string equal to the value of:

 getClass().getName() + '@' + Integer.toHexString(hashCode())
 

Overrides:

toString in class Object

Returns:

a string representation of the object.

appendData

protected void appendData(StringBuffer buf)

Appends a textualized form of this packet's data to a given StringBuffer.

Parameters:

buf - the buffer to extend

getFlags

public abstract int getFlags()

Gets the value for the 'flags' field in the header of this packet.

writeFields

protected abstract void writeFields(DataOutputStream dos)
                             throws IOException

Hook for sublasses to write their specific fields to a packet being sent.

Parameters:

dos - the stream to write the fields to

Throws:

IOException - if an IO error occurs

getSize

public final int getSize()

Gets the size (in bytes) of the entire packet. This value may change if there is currently an output stream adding data to the packet.

Returns:

the size (in bytes) of the packets (include the header fields)

write

public final void write(DataOutputStream dos)
                 throws IOException

Writes this packet to a given output stream. No further data can be added to this packet once this operation is completed.

Parameters:

dos - where to write the packet

Throws:

IOException - if an IO error occurs