MessageContext (sdn-apidoc 2.6.8 API)

All Known Implementing Classes:

MessageContextAdapter, TestMessageContext
```
public interface MessageContext
```
Provides a context when processing a specific OpenFlow PacketIn message. The source message event, (available via srcEvent()), contains the PacketIn message. The PacketSequencer will decode the packet to determine the protocols used. The decoded packet model is available via decodedPacket().
When the context is created, a mutable PacketOut message is also constructed and kept in the context. Note that the protocol version, transaction ID (xid), ingress port, and buffer ID of the PacketIn message are copied to the PacketOut message. SequencedPacketListeners can manipulate the PacketOut message via the PacketOut API.
Packet listeners (in the ADVISOR role) may add Hints to the message context to help listeners further downstream make decisions.
Once a packet listener (in the DIRECTOR role) has determined that the PacketOut message is ready to send back to the datapath, it indicates this to the PacketSequencer by calling send() on the PacketOut API. The sequencer will then forward the PacketOut message to the controller for sending.
Packet listeners downstream of the DIRECTOR that caused the PacketOut to be sent, still get to see the message context, and can therefore observe what transpired.

Author:

Simon Hunt, Scott Simes, Thomas Vachuska

Method Summary

Methods
Modifier and Type	Method and Description
`MessageContext`	`addHint(Hint hint)` Adds a hint to the context.
`Packet`	`decodedPacket()` Returns the decoded packet data generated by the Network Packet Library facility.
`boolean`	`failedToSend()` This flag is set in the unlikely event that the packet sequencer failed to send the PacketOut message via the controller.
`OfmPacketOut`	`getCompletedPacketOut()` Returns the PacketOut message that was sent back to the source datapath.
`List<Hint>`	`getHints()` Returns the hints contained in this context, in the order they were added by the Advisors.
`OfmPacketIn`	`getPacketIn()` Convenience method that returns the PacketIn message from the message event.
`List<ProtocolId>`	`getProtocols()` Returns an ordered list of `protocols` decoded from the packet.
`ProtocolVersion`	`getVersion()` Returns the protocol version of the associated PacketIn message event.
`boolean`	`isBlocked()` Returns true if response (packet-out message) to the associated message event has been blocked.
`boolean`	`isHandled()` Returns true if the associated message event has already been handled.
`boolean`	`isSent()` Returns true if response (packet-out message) to the associated message event has been sent.
`boolean`	`isTestPacket()` Returns true if the associated packet has been determined to be a diagnostic test packet.
`PacketOut`	`packetOut()` Returns the API for manipulating the PacketOut message.
`boolean`	`requiresProcessing()` Returns true if the associated packet is not a test packet, and has not yet been blocked or sent and thus continues to require processing.
`MessageEvent`	`srcEvent()` Returns the associated PacketIn message event.
`String`	`toDebugString()` Returns a multi-line string representation of this message context, suitable for debugging.

- Method Detail
  - srcEvent
```
MessageEvent srcEvent()
```
    Returns the associated PacketIn message event.
    
    Returns:
    the PacketIn message event
  - getVersion
```
ProtocolVersion getVersion()
```
    Returns the protocol version of the associated PacketIn message event.
    
    Returns:
    the protocol version
  - getPacketIn
```
OfmPacketIn getPacketIn()
```
    Convenience method that returns the PacketIn message from the message event.
    
    Returns:
    the PacketIn message
  - decodedPacket
```
Packet decodedPacket()
```
    Returns the decoded packet data generated by the Network Packet Library facility. This will be null if there is no packet data associated with the PacketIn message.
    
    Returns:
    the decoded packet data
  - getProtocols
```
List<ProtocolId> getProtocols()
```
    Returns an ordered list of protocols decoded from the packet. The protocols are ordered from outermost to innermost layer. This will be null if there is no packet data associated with the PacketIn message.
    
    Returns:
    the list of protocols
  - packetOut
```
PacketOut packetOut()
```
    Returns the API for manipulating the PacketOut message.
    
    Returns:
    the packet out API
  - getCompletedPacketOut
```
OfmPacketOut getCompletedPacketOut()
```
    Returns the PacketOut message that was sent back to the source datapath. Note that this method will return null if the PacketOut message has not yet been sent.
    
    Returns:
    the PacketOut message
  - addHint
```
MessageContext addHint(Hint hint)
```
    Adds a hint to the context.
    
    Parameters:
    hint - the hint to be added
    
    Returns:
    self, for chaining
    
    Throws:
    
    NullPointerException - if hint is null
  - getHints
```
List<Hint> getHints()
```
    Returns the hints contained in this context, in the order they were added by the Advisors.
    
    Returns:
    the hints
  - isHandled
```
boolean isHandled()
```
    Returns true if the associated message event has already been handled. That is, either blocked or sent.
    
    Returns:
    true if handled; false otherwise
  - isBlocked
```
boolean isBlocked()
```
    Returns true if response (packet-out message) to the associated message event has been blocked.
    
    Returns:
    true if blocked; false otherwise
  - isSent
```
boolean isSent()
```
    Returns true if response (packet-out message) to the associated message event has been sent.
    
    Returns:
    true if sent; false otherwise
  - isTestPacket
```
boolean isTestPacket()
```
    Returns true if the associated packet has been determined to be a diagnostic test packet.
    
    Returns:
    true if a diagnostic test packet; false otherwise
  - requiresProcessing
```
boolean requiresProcessing()
```
    Returns true if the associated packet is not a test packet, and has not yet been blocked or sent and thus continues to require processing.
    
    Returns:
    true if not a test packet, not blocked, and not sent
  - failedToSend
```
boolean failedToSend()
```
    This flag is set in the unlikely event that the packet sequencer failed to send the PacketOut message via the controller.
    
    Returns:
    true if an error occurred during send
  - toDebugString
```
String toDebugString()
```
    Returns a multi-line string representation of this message context, suitable for debugging.
    
    Returns:
    a multi-line string representation

Interface MessageContext

Method Summary

Method Detail

srcEvent

getVersion

getPacketIn

decodedPacket

getProtocols

packetOut

getCompletedPacketOut

addHint

getHints

isHandled

isBlocked

isSent

isTestPacket

requiresProcessing

failedToSend

toDebugString