com.mischiefbox.pollserve
Class InputQueue

java.lang.Object
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  +--com.mischiefbox.pollserve.Queue
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        +--com.mischiefbox.pollserve.InputQueue

public class InputQueue

extends Queue

Input queue and manager. Accepts partial or complete messages. Holds partial messages until a complete message is composed, or discards messages beyond a hard-coded message size limit. Complete messages become a new Message object which are put onto the message handler queue. This class is a specialization of the generic Queue class. The queue is a linked list. New elements are added to the tail, available elements are removed from the front.

Version:

$Id$

Author:

Chris Jones

See Also:

Message, Queue

Field Summary

protected static byte[]	baMessageFooter Message footer byte signature.
protected static byte[]	baMessageHeader Message header byte signature.
protected Hashtable	htMessages The dictionary (Hashtable) of partial messages.
protected static int	MAX_MESSAGE_SIZE The maximum incomplete message size.

Constructor Summary

InputQueue()
Create a new InputQueue.

Method Summary

void	incomingMessage(String sConnectionId, byte[] baMessageContent) Convert partial messages into Message objects.
static int	scanByteArray(byte[] baContent, byte[] baSpec) Scan a byte array for a pattern.

Methods inherited from class com.mischiefbox.pollserve.Queue

dequeue, enqueue, getSize, peek

Methods inherited from class java.lang.Object

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

Field Detail

MAX_MESSAGE_SIZE

protected static final int MAX_MESSAGE_SIZE

The maximum incomplete message size.

htMessages

protected Hashtable htMessages

The dictionary (Hashtable) of partial messages. A Hashtable is used because the class is thread-safe (synchronized so that multiple connection handlers can work with it at once). Key is connection id, value is a byte array partial message.

baMessageHeader

protected static byte[] baMessageHeader

Message header byte signature. Used in partial-message matching.

baMessageFooter

protected static byte[] baMessageFooter

Message footer byte signature. Used in partial-message matching.

Constructor Detail

InputQueue

public InputQueue()

Create a new InputQueue. Do the housekeeping necessary to make the input queue usable.

Method Detail

incomingMessage

public void incomingMessage(String sConnectionId,
                            byte[] baMessageContent)
                     throws MessageTooLargeException

Convert partial messages into Message objects. Accepts a partial message and connection. Attempts to create a complete Message object from the partial message and previous partial messages. Inserts the completed message object onto the queue. Discards incomplete messages that are larger than the maximum message size. Partial messages are stored in a dictionary-type object (Hashtable, so multiple connection handlers can use this method).

Parameters:

sConnectionId - the incoming connection id.

baMessageContent - the incoming message content.

Throws:

MessageTooLargeException - on overly long messages.

scanByteArray

public static int scanByteArray(byte[] baContent,
                                byte[] baSpec)

Scan a byte array for a pattern. Arrays in Java may not be larger than int (32-bit), so it is safe to return int from this method.

Parameters:

baContent - the searched byte array.

baSpec - the specified byte array to find.

Returns:

the offset of the specified byte array inside the searched byte array, or -1 if not found.