org.licas.autonomic

Class MessageQueue

java.lang.Object

org.licas.autonomic.MessageQueue

public class MessageQueue
extends java.lang.Object

This class stores lists of messages for processing by the system. The messages can be accessed in an ordered manner or based on communication ID. When an autonomic component receives a message, it can put it onto a message queue if it is wrapped inside of an AutonomicManager. The Auto.messageReply(...) method will do this automatically. The manager then has full access to all messages and can use its control loop to process them and try to detect errors or faults.

Author:

Kieran Greer

Constructor Summary

Constructors

Constructor and Description
MessageQueue() Create a new instance of MessageQueue

Method Summary

Modifier and Type	Method and Description
void	addMessage(MessageInfo messageInfo) Add a new message to the list.
protected MessageInfo	copyConversationMessage(java.lang.String commID, int position) Get a copy of the specified message in the specified conversation.
protected java.util.ArrayList<MessageInfo>	copyMessageInterval(long startTime, long endTime) Get a copy of all messages time stamped between the two time intervals.
MessageInfo	getAndRemoveMessageAt(int index) Get the message at position index in the queue and remove the message from all queues.
MessageInfo	getAndRemoveNextMessage() Get the next message in the queue and remove the message from all queues.
MessageInfo	getAndRemoveNextMessageName(java.lang.String methodName) Get the next message in the queue relating to a particular method name.
MessageInfo	getAndRemoveNextMessageTime(long timeStamp) Get the next message in the queue relating to a particular time interval.
MessageInfo	getAndRemoveNextMessageTime(long startTimeStamp, long endTimeStamp) Get the next message in the queue relating to a particular time interval.
protected java.util.ArrayList<java.lang.String>	getCommIDs() Get the lit of current communication IDs.
protected int	getConversationLength(java.lang.String commID) Get the number of messages related to a particular communication ID.
MessageInfo	getMessageAt(int index) Get the message at position index in the queue, but keep the message in all queues.
MessageInfo	getNextMessage() Get the next message in the queue, but keep the message in all queues.
boolean	isEMpty() Return true if the message queue is empty, meaning no message in the queue.
int	queueSize() Get the size of the message queue.
void	removeAllMessages(java.lang.String commID) Remove all messages, from both lists, with the specified communication ID.
protected void	returnLastMessage(MessageInfo nextMessage) Return the message to the start of the message queue and update all other message lists.

Methods inherited from class java.lang.Object

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

Constructor Detail

MessageQueue

public MessageQueue()

Create a new instance of MessageQueue

Method Detail

getCommIDs

protected java.util.ArrayList<java.lang.String> getCommIDs()

Get the lit of current communication IDs.

Returns:

the key list for the messageComms structure.

addMessage

public void addMessage(MessageInfo messageInfo)

Add a new message to the list. The message is added to the end of the message queue and also the related conversation.

Parameters:

messageInfo - a full MessageInfo description. The unique communication ID is required.

isEMpty

public boolean isEMpty()

Return true if the message queue is empty, meaning no message in the queue.

Returns:

true if empty.

queueSize

public int queueSize()

Get the size of the message queue.

Returns:

the size of messageQueue.

getMessageAt

public MessageInfo getMessageAt(int index)

Get the message at position index in the queue, but keep the message in all queues.

Parameters:

index - index of the message to retrieve.

Returns:

the message at position index in the queue, or null if out of range.

getNextMessage

public MessageInfo getNextMessage()

Get the next message in the queue, but keep the message in all queues.

Returns:

the next message in the queue.

getAndRemoveMessageAt

public MessageInfo getAndRemoveMessageAt(int index)

Get the message at position index in the queue and remove the message from all queues.

Parameters:

index - index of the message to retrieve.

Returns:

the message at position index in the queue, or null if out of range.

getAndRemoveNextMessage

public MessageInfo getAndRemoveNextMessage()

Get the next message in the queue and remove the message from all queues.

Returns:

the next message in the queue.

getAndRemoveNextMessageTime

public MessageInfo getAndRemoveNextMessageTime(long startTimeStamp,
                                               long endTimeStamp)

Get the next message in the queue relating to a particular time interval. Return the first message that lies inside the time interval. This also automatically removes the message from all queues.

Parameters:

startTimeStamp - the start time interval for the message.

endTimeStamp - the end time interval for the message.

Returns:

the next message in the queue.

getAndRemoveNextMessageTime

public MessageInfo getAndRemoveNextMessageTime(long timeStamp)

Get the next message in the queue relating to a particular time interval. This is an exact time stamp, probably relating to only one message. This also automatically removes the message from all queues.

Parameters:

timeStamp - the exact timestamp for the message.

Returns:

the next message in the queue.

getAndRemoveNextMessageName

public MessageInfo getAndRemoveNextMessageName(java.lang.String methodName)

Get the next message in the queue relating to a particular method name. This must be a MethodInfo object and it also automatically removes the message from all queues.

Parameters:

methodName - the name of the method to retrieve.

Returns:

the next message in the queue with the specified name.

removeAllMessages

public void removeAllMessages(java.lang.String commID)

Remove all messages, from both lists, with the specified communication ID.

Parameters:

commID - the message communication ID.

returnLastMessage

protected void returnLastMessage(MessageInfo nextMessage)

Return the message to the start of the message queue and update all other message lists.

Parameters:

nextMessage - the message to add again.

getConversationLength

protected int getConversationLength(java.lang.String commID)

Get the number of messages related to a particular communication ID.

Parameters:

commID - the communication ID.

Returns:

the number of messages in the related message queue, or 0 if there are no messages.

copyConversationMessage

protected MessageInfo copyConversationMessage(java.lang.String commID,
                                              int position)

Get a copy of the specified message in the specified conversation. This returns a copy that does not change the original message queue, but the message itself can be changed by the calling program. Use getAndRemoveMessage to retrieve the message and also remove it from the queue.

Parameters:

commID - the communication ID.

position - the position of the message in the communication queue.

Returns:

a copy of the specified message.

copyMessageInterval

protected java.util.ArrayList<MessageInfo> copyMessageInterval(long startTime,
                                                               long endTime)

Get a copy of all messages time stamped between the two time intervals. This returns a copy that does not change the original message queue, but the message itself can be changed by the calling program. Use getAndRemoveMessage to retrieve the message and also remove it from the queue.

Parameters:

startTime - the start of the time interval.

endTime - the end of the time interval.

Returns:

a copy of the specified message.