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JdwpPacket

public final class JdwpPacket
extends Object

java.lang.Object
↳	com.android.tradefed.device.server.jdwp.chunkhandler.JdwpPacket

A JDWP packet, sitting at the start of a ByteBuffer somewhere.

This allows us to wrap a "pointer" to the data with the results of decoding the packet.

None of the operations here are synchronized. If multiple threads will be accessing the same ByteBuffers, external sync will be required.

Use the constructor to create an empty packet, or "findPacket()" to wrap a JdwpPacket around existing data.

Summary

Constants
`int`	`JDWP_HEADER_LEN`

Public constructors
`JdwpPacket(ByteBuffer buf)` Create a new, empty packet, in "buf".

Public methods
`void`	`consume()` Consume the JDWP packet.
`void`	`copy(ByteBuffer into)` Helper function to copy the packet into a new buffer.
`static JdwpPacket`	`findPacket(ByteBuffer buf)`
`static JdwpPacket`	`findPacketHeader(ByteBuffer buf)`
`void`	`finishPacket(int cmdSet, int cmd, int payloadLength)` Finish a packet created with newPacket().
`int`	`getId()` Return the packet's ID.
`int`	`getLength()` Return the length of a packet.
`static int`	`getPacketLength(ByteBuffer buf)` When the "buf" contains JdwpPackets the first 4 bytes are the length of the packet.
`ByteBuffer`	`getPayload()` Return a slice of the byte buffer, positioned past the JDWP header to the start of the chunk header.
`boolean`	`is(int cmdSet, int cmd)`
`boolean`	`isEmpty()` Returns "true" if this JDWP packet has no data.
`boolean`	`isError()` Returns "true" if this JDWP packet is a reply with a nonzero error code.
`boolean`	`isReply()` Returns "true" if this JDWP packet is tagged as a reply.
`void`	`log(String action)`
`void`	`move(ByteBuffer buf)` "Move" the packet data out of the buffer we're sitting on and into buf at the current position.
`void`	`setPayload(ByteBuffer buf)` Replace the payload of the package with a buffer.
`String`	`toString()`
`void`	`write(SocketChannel chan)` Write our packet to "chan".

Constants

JDWP_HEADER_LEN

public static final int JDWP_HEADER_LEN

Constant Value: 11 (0x0000000b)

Public constructors

JdwpPacket

public JdwpPacket (ByteBuffer buf)

Create a new, empty packet, in "buf".

Parameters
`buf`	`ByteBuffer`

Public methods

consume

public void consume ()

Consume the JDWP packet.

On entry and exit, "position" is at the end of data in buffer.

copy

public void copy (ByteBuffer into)

Helper function to copy the packet into a new buffer.

Parameters
`into`	`ByteBuffer`

findPacket

public static JdwpPacket findPacket (ByteBuffer buf)

Parameters
`buf`	`ByteBuffer`

Returns
`JdwpPacket`

findPacketHeader

public static JdwpPacket findPacketHeader (ByteBuffer buf)

Parameters
`buf`	`ByteBuffer`

Returns
`JdwpPacket`

finishPacket

public void finishPacket (int cmdSet, 
                int cmd, 
                int payloadLength)

Finish a packet created with newPacket().

This always creates a command packet, with the next serial number in sequence.

We have to take "payloadLength" as an argument because we can't see the position in the "slice" returned by getPayload(). We could fish it out of the chunk header, but it's legal for there to be more than one chunk in a JDWP packet.

On exit, "position" points to the end of the data.

Parameters
`cmdSet`	`int`
`cmd`	`int`
`payloadLength`	`int`

getId

public int getId ()

Return the packet's ID. For a reply packet, this allows us to match the reply with the original request.

Returns
`int`

getLength

public int getLength ()

Return the length of a packet. This includes the header, so an empty packet is 11 bytes long.

Returns
`int`

getPacketLength

public static int getPacketLength (ByteBuffer buf)

When the "buf" contains JdwpPackets the first 4 bytes are the length of the packet. This helper function reads the first 4 bytes and validates that the length is at least the size of the JDWP header.

Parameters
`buf`	`ByteBuffer`: a buffer assumed to contain a jdwp packet.

Returns
`int`	-1 if the length is invalid, otherwise the length of the packet.

getPayload

public ByteBuffer getPayload ()

Return a slice of the byte buffer, positioned past the JDWP header to the start of the chunk header. The buffer's limit will be set to the size of the payload if the size is known; if this is a packet under construction the limit will be set to the end of the buffer.

Doesn't examine the packet at all -- works on empty buffers.

Returns
`ByteBuffer`

is

public boolean is (int cmdSet, 
                int cmd)

Parameters
`cmdSet`	`int`
`cmd`	`int`

Returns
`boolean`

isEmpty

public boolean isEmpty ()

Returns "true" if this JDWP packet has no data.

Returns
`boolean`

isError

public boolean isError ()

Returns "true" if this JDWP packet is a reply with a nonzero error code.

Returns
`boolean`

isReply

public boolean isReply ()

Returns "true" if this JDWP packet is tagged as a reply.

Returns
`boolean`

log

public void log (String action)

Parameters
`action`	`String`

move

public void move (ByteBuffer buf)

"Move" the packet data out of the buffer we're sitting on and into buf at the current position.

Parameters
`buf`	`ByteBuffer`

setPayload

public void setPayload (ByteBuffer buf)

Replace the payload of the package with a buffer. The current position is unchanged.

Parameters
`buf`	`ByteBuffer`

toString

public String toString ()

Returns
`String`

write

public void write (SocketChannel chan)

Write our packet to "chan".

The JDWP packet starts at offset 0 and ends at mBuffer.position().

Parameters
`chan`	`SocketChannel`