Package com.mdfromhtml.core

Class MDfromHTMLIPCMessage

java.lang.Object

com.mdfromhtml.core.MDfromHTMLIPCMessage

All Implemented Interfaces:

IMDfromHTMLIPCMessage, Serializable

public class MDfromHTMLIPCMessage
extends Object
implements IMDfromHTMLIPCMessage, Serializable

Implementation of the MDfromHTML IPC Message to be sent (or received) across the MDfromHTML Interprocess Communications Infrastructure. Messages may carry JSONObject or byte[] content. Messages are identified by a topic (used for subscription), a type (used for identifying how a message should be parsed and interpreted), a create time, a sequence number where 0 implies the only message, 1 or greater implies a chunk of a larger message (where Integer.MAX_VALUE acks as a semaphore to signal the last of a sequence), and a flag describing if the message content is a JSONObject or byte[].

See Also:

Serialized Form

Field Summary

Fields

Modifier and Type	Field	Description
static int	IPC_MAX_MESSAGE_SIZE	Below overridden by a MDfromHTMLIPC.properties value

Constructor Summary

Constructors

Constructor	Description
MDfromHTMLIPCMessage(com.api.json.JSONObject message)
MDfromHTMLIPCMessage(String publisherName, MDfromHTMLID sessionID, MDfromHTMLIPCApplications appl, String topic, String type, MDfromHTMLIPCVerbs verb, MDfromHTMLID userID, byte[] message)	Constructor.
MDfromHTMLIPCMessage(String publisherName, MDfromHTMLID sessionID, MDfromHTMLIPCApplications appl, String topic, String type, MDfromHTMLIPCVerbs verb, MDfromHTMLID userID, com.api.json.JSONObject message)	Constructor.

Method Summary

Modifier and Type	Method	Description
static MDfromHTMLIPCMessage	fromByteArray(byte[] bytes)	Converts the message format sent across the wire into a MDfromHTMLIPCMessage object
MDfromHTMLIPCApplications	getApplication()
int	getApplicationValue()
static MDfromHTMLIPCMessage	getAssembledMessage(MDfromHTMLIPCMessage[] msgs)	Reassembles an array of sequenced messages into a single message
static int	getIPCMaxMessageSize()
static Properties	getMDfromHTMLIPCProps()
com.api.json.JSONObject	getMessage()
byte[]	getMessageBytes()
protected int	getMessageSize()	Retrieve the length (in bytes) of the message content.
String	getPublisherName()
int	getSequence()
MDfromHTMLIPCMessage[]	getSequencedMessages(int chunkSize)	Splits a single message into a sequence of smaller messages based on the chunkSize.
MDfromHTMLID	getSessionID()
long	getTime()
String	getTopic()
String	getType()
MDfromHTMLID	getUserID()	Retrieve the user identification associated with this message
MDfromHTMLIPCVerbs	getVerb()	Retrieve the enumerated value associated with this message
int	getVerbValue()	Retrieve the numeric identity of the verb
boolean	isJSON()
boolean	isLastMessage()
boolean	isOnlyMessage()
boolean	isSequence()
static void	main(String[] args)	Test rig for various methods
void	setMessage(com.api.json.JSONObject message)	Updates the message when disassembling or reassembling a chunked message
static byte[]	toByteArray(MDfromHTMLIPCMessage msg)	Transforms a message into the byte array used for transmission on the wire
String	toHdrString()
com.api.json.JSONObject	toJson()
String	toString()
String	toStringFull()
String	toStringFull(boolean formatJSON)
String	toStringHeader()

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, wait, wait, wait

Field Detail

IPC_MAX_MESSAGE_SIZE

public static int IPC_MAX_MESSAGE_SIZE

Below overridden by a MDfromHTMLIPC.properties value

Constructor Detail

MDfromHTMLIPCMessage

public MDfromHTMLIPCMessage(String publisherName,
                            MDfromHTMLID sessionID,
                            MDfromHTMLIPCApplications appl,
                            String topic,
                            String type,
                            MDfromHTMLIPCVerbs verb,
                            MDfromHTMLID userID,
                            byte[] message)

Constructor.

Parameters:

publisherName - if null, the MDfromHTMLID.UNDEFINED_ID is used to create a unique name

sessionID - if null, the MDfromHTMLID.UNDEFINED_ID is used

appl - the application id, if null, the MDfromHTMLIPCApplications.UNDEFINED is used

topic - if null, the MDfromHTMLConstants.IPC_DEFAULT_TOPIC is used

type - if null, the MDfromHTMLConstants.UNDEFINED_String is used

verb - the verb id, if null, the MDfromHTMLIPCVerbs.UNDEFINED is used

userID - the user id within the session, if null, the MDfromHTMLID.UNDEFINED_ID is used

message - if null, an empty byte array is used

MDfromHTMLIPCMessage

public MDfromHTMLIPCMessage(String publisherName,
                            MDfromHTMLID sessionID,
                            MDfromHTMLIPCApplications appl,
                            String topic,
                            String type,
                            MDfromHTMLIPCVerbs verb,
                            MDfromHTMLID userID,
                            com.api.json.JSONObject message)

Constructor.

Parameters:

publisherName - if null, the MDfromHTMLID.UNDEFINED_ID is used to create a unique name

sessionID - if null, the MDfromHTMLID.UNDEFINED_ID is used

appl - the application id, if null, the MDfromHTMLIPCApplications.UNDEFINED is used

topic - if null, the MDfromHTMLConstants.IPC_DEFAULT_TOPIC is used

type - if null, the MDfromHTMLConstants.UNDEFINED_String is used

verb - the verb id, if null, the MDfromHTMLIPCVerbs.UNDEFINED is used

userID - the user id within the session, if null, the MDfromHTMLID.UNDEFINED_ID is used

message - if null, an empty JSONObject is sent. If for some reason the object can not be serialized, rather than throwing an exception, we are using the toString() method that sends a non-JSON String. This should never happen as we are always using a valid JSON object so throwing the exception and forcing people to catch it everywhere didn't make any sense

MDfromHTMLIPCMessage

public MDfromHTMLIPCMessage(com.api.json.JSONObject message)
                     throws Exception

Throws:

Exception

Method Detail

getIPCMaxMessageSize

public static int getIPCMaxMessageSize()

fromByteArray

public static MDfromHTMLIPCMessage fromByteArray(byte[] bytes)
                                          throws Exception

Converts the message format sent across the wire into a MDfromHTMLIPCMessage object

Parameters:

bytes - byte array carrying the message

Returns:

transformation of the passed byte array into a message

Throws:

Exception - (Exception) if the bytes are null or not a valid message format (ExceptionParse) if the message content can not be transformed into a JSONObject

getAssembledMessage

public static MDfromHTMLIPCMessage getAssembledMessage(MDfromHTMLIPCMessage[] msgs)
                                                throws Exception

Reassembles an array of sequenced messages into a single message

Parameters:

msgs - array of message chunks to be reassembled into a single message

Returns:

the single message built from the pieces passed

Throws:

Exception - if the message array is null or incomplete (e.g., missing a sequence number)

main

public static void main(String[] args)

Test rig for various methods

Parameters:

args - No arguments are required, but if a positive integer between 1 and 99 is passed, it is used to split up the default 100 character message into chunks.

toByteArray

public static byte[] toByteArray(MDfromHTMLIPCMessage msg)
                          throws Exception

Transforms a message into the byte array used for transmission on the wire

Parameters:

msg - the message to be transformed into a byte array

Returns:

the byte array representing the content of the passed message

Throws:

Exception - if the message is null

getMDfromHTMLIPCProps

public static Properties getMDfromHTMLIPCProps()
                                        throws Exception

Returns:

the properties file used to define MDfromHTML interprocess communications

Throws:

Exception

See Also:

MDfromHTMLUtils.loadMDfromHTMLProperties(String), MDfromHTMLConstants.MDfromHTML_IPC_PropertiesFileName

getApplication

public MDfromHTMLIPCApplications getApplication()

Specified by:

getApplication in interface IMDfromHTMLIPCMessage

Returns:

the enumerated value associated with this message

See Also:

MDfromHTMLIPCVerbs

getApplicationValue

public int getApplicationValue()

Specified by:

getApplicationValue in interface IMDfromHTMLIPCMessage

Returns:

the numeric identity of the application

getMessage

public com.api.json.JSONObject getMessage()
                                   throws Exception

Specified by:

getMessage in interface IMDfromHTMLIPCMessage

Returns:

the message content as a JSONObject

Throws:

Exception

getMessageBytes

public byte[] getMessageBytes()

Specified by:

getMessageBytes in interface IMDfromHTMLIPCMessage

Returns:

the message content as a byte[]

getMessageSize

protected int getMessageSize()

Retrieve the length (in bytes) of the message content.

Returns:

the length (in bytes) of the message content.

getPublisherName

public String getPublisherName()

Specified by:

getPublisherName in interface IMDfromHTMLIPCMessage

Returns:

the publisher (creator) of this message

getSequence

public int getSequence()

Specified by:

getSequence in interface IMDfromHTMLIPCMessage

Returns:

the sequence number of this message. Note: zero implies the only message, non-zero implies a part of a chunked message, with 65768 signifying the last of the sequence of messages.

getSequencedMessages

public MDfromHTMLIPCMessage[] getSequencedMessages(int chunkSize)
                                            throws Exception

Splits a single message into a sequence of smaller messages based on the chunkSize. The original message's time is preserved, as is the isJSON status

Parameters:

chunkSize -

Returns:

array of messages based on the passed chunkSize

Throws:

Exception

getSessionID

public MDfromHTMLID getSessionID()

Specified by:

getSessionID in interface IMDfromHTMLIPCMessage

Returns:

the session id related to the message content. If the content is not associated with a particular session, the ID returned is MDfromHTMLID.UNDEFINED_ID and corresponds with the String value in MDfromHTMLConstants.UNDEFINED_ID

getTime

public long getTime()

Specified by:

getTime in interface IMDfromHTMLIPCMessage

Returns:

the original message creation time (not necessarily the same as the time it was published)

getTopic

public String getTopic()

Specified by:

getTopic in interface IMDfromHTMLIPCMessage

Returns:

the message topic

getType

public String getType()

Specified by:

getType in interface IMDfromHTMLIPCMessage

Returns:

the message type. If the original was undefined, the type will return the MDfromHTMLConstants.UNDEFINED_String

getVerb

public MDfromHTMLIPCVerbs getVerb()

Description copied from interface: IMDfromHTMLIPCMessage

Retrieve the enumerated value associated with this message

Specified by:

getVerb in interface IMDfromHTMLIPCMessage

Returns:

the enumerated value associated with this message

See Also:

MDfromHTMLIPCVerbs

getUserID

public MDfromHTMLID getUserID()

Description copied from interface: IMDfromHTMLIPCMessage

Retrieve the user identification associated with this message

Specified by:

getUserID in interface IMDfromHTMLIPCMessage

Returns:

the user identification associated with this message

getVerbValue

public int getVerbValue()

Description copied from interface: IMDfromHTMLIPCMessage

Retrieve the numeric identity of the verb

Specified by:

getVerbValue in interface IMDfromHTMLIPCMessage

Returns:

the numeric identity of the verb

isJSON

public boolean isJSON()

Specified by:

isJSON in interface IMDfromHTMLIPCMessage

Returns:

true if the original message was a String (as opposed to a byte[])

isLastMessage

public boolean isLastMessage()

Specified by:

isLastMessage in interface IMDfromHTMLIPCMessage

Returns:

true if the message sequence is Integer.MAX_VALUE signaling the end of a chunked sequence of messages

isOnlyMessage

public boolean isOnlyMessage()

Specified by:

isOnlyMessage in interface IMDfromHTMLIPCMessage

Returns:

true if the message sequence is zero signaling the message was not chunked

isSequence

public boolean isSequence()

Specified by:

isSequence in interface IMDfromHTMLIPCMessage

Returns:

true if the message sequence is not zero (for an "chunked" message).

setMessage

public void setMessage(com.api.json.JSONObject message)

Updates the message when disassembling or reassembling a chunked message

Parameters:

message - the payload of this message

toStringFull

public String toStringFull()

Specified by:

toStringFull in interface IMDfromHTMLIPCMessage

Returns:

formatted complete version of this message

See Also:

that is more useful for debugging

toStringFull

public String toStringFull(boolean formatJSON)

Specified by:

toStringFull in interface IMDfromHTMLIPCMessage

Parameters:

formatJSON - true if the message is to be formatted (if the message contains JSON), false if not.

Returns:

formatted complete version of this message

See Also:

that is more useful for debugging

toHdrString

public String toHdrString()

toStringHeader

public String toStringHeader()

toString

public String toString()

Specified by:

toString in interface IMDfromHTMLIPCMessage

Overrides:

toString in class Object

Returns:

an abbreviated formatted version of the message (contains only the first 100 bytes of the payload)

toJson

public com.api.json.JSONObject toJson()