org.licas.autonomic.script

Class AutoEngine

java.lang.Object

org.licas.autonomic.script.AutoEngine

public class AutoEngine
extends java.lang.Object

This is a default implementation of an engine that can be used to interpret and execute the provided default script, possibly for the autonomic manager or one of its modules, or for an autonomous service in general. The script can be made up of a number of AutoEngineInfo objects that get processed in order. Evaluation takes place through the process method, where the MessageInfo object should pass a ArrayList of parameter values to pass to the evaluation method. This is partially dynamic, where a parameter list be specified as a KeyValue set, where the key can be the actual variable name in the method or class itself. This can then be matched to the auto engine method script that defines what parameters are required. It can include the parameter or variable name that should be used, where AiConst.QUERY is reserved for the input variable of this class and REPLY is reserved for the evaluator reply. If any name is missing, then it does not have to be added.

So a specific list of variable names will use only those variables and can include or omit anything specified/not specified. If a list of objects is passed, they are used in that order. If the list is replaced by a single object, then only that single value gets added.

Author:

Kieran Greer

Field Summary

Fields

Modifier and Type	Field and Description
protected org.dcs.query_process.Script_Engine	engine The engine to return the script elements in order.
protected ObjectsMap	objectsMap List of all named entities in the script, referenced by their unique public id.
protected org.dcs.query_process.model.Script_Process	process The process model to execute.

Constructor Summary

Constructors

Constructor and Description
AutoEngine(Service thisParent, PasswordHandler thisPasswordHandler) Create a new instance of AutoEngine.

Method Summary

Modifier and Type	Method and Description
protected AutoOut	executeScriptElement(AutoEngineInfo rootInfo) Execute the script element if appropriate and then return the result.
protected MessageInfo	getAutoQueueMessage(org.dcs.query_process.model.activity.Script_Auto scriptAuto) Get the first message in the auto manager's queue, retrieved using the specified function.
protected PasswordHandler	getPasswordHandler() Get the password handler.
org.dcs.query_process.Script_Engine	getScriptEngine() Get the script engine that processes and returns script elements in order.
boolean	hasProcess() Return true if the engine has a process script loaded, false otherwise.
AutoOut	invokeMethod(AutoEngineInfo rootInfo, java.util.ArrayList<KeyValue> paramList) Invoke the method in the autoInfo object, making variable replacements first.
boolean	isFinished() Return true if there are no further script elements to process.
java.util.ArrayList<KeyValue>	process(MessageInfo messageInfo) Process the script data and return the result.
void	resetEventRuleAction() Reset the already created event-rule-action script part so that it can be run again.
void	setEventRuleAction(org.licas_xml.abs.Element policyElem) Parse the event-rule-action script part and create the related objects.
void	setParent(Service thisParent) Set the parent service.

Methods inherited from class java.lang.Object

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

Field Detail

engine

protected org.dcs.query_process.Script_Engine engine

The engine to return the script elements in order.

process

protected org.dcs.query_process.model.Script_Process process

The process model to execute.

objectsMap

protected ObjectsMap objectsMap

List of all named entities in the script, referenced by their unique public id. Key is the id and value is the script element converted into its object instance.

Constructor Detail

AutoEngine

public AutoEngine(Service thisParent,
                  PasswordHandler thisPasswordHandler)

Create a new instance of AutoEngine. Parameters can be null if not used.

Parameters:

thisParent - the parent service. This is required if the this keyword is used.

thisPasswordHandler - the parent password handler.

Method Detail

hasProcess

public boolean hasProcess()

Return true if the engine has a process script loaded, false otherwise.

Returns:

true if process is not null, false otherwise.

isFinished

public boolean isFinished()
                   throws java.lang.Exception

Return true if there are no further script elements to process.

Returns:

true if at the end of the process stack. If the loop stack still has elements, then these would normally be processed.

Throws:

java.lang.Exception - any error.

setEventRuleAction

public void setEventRuleAction(org.licas_xml.abs.Element policyElem)
                        throws java.lang.Exception

Parse the event-rule-action script part and create the related objects.

Parameters:

policyElem - the policy section of the script.

Throws:

java.lang.Exception - any error.

resetEventRuleAction

public void resetEventRuleAction()
                          throws java.lang.Exception

Reset the already created event-rule-action script part so that it can be run again.

Throws:

java.lang.Exception - any error.

process

public java.util.ArrayList<KeyValue> process(MessageInfo messageInfo)
                                      throws java.lang.Exception

Process the script data and return the result. This default version will evaluate the message and execute any method using invocation. It will also replace named or tagged variables with actual instances from the parameter list included in the input messageInfo object. A BPEL-like script is used, but it is limited.

Parameters:

messageInfo - the message to evaluate. In this case it should be a ArrayList of parameter values (as KeyValue) as the message (messageInfo.getMessage()) that then update the method parameters. It can be null if there are no additional parameter values.

Returns:

the result of the monitoring. Note that this should not change the input message and is a list of actions to carry out in sequence, as KeyValue pairs.

Throws:

java.lang.Exception - any error.

executeScriptElement

protected AutoOut executeScriptElement(AutoEngineInfo rootInfo)

Execute the script element if appropriate and then return the result. This is probably the saved effector actions list, as AutoEngineInfo objects.

Parameters:

rootInfo - the root info object for execution.

Returns:

the value of effOutput.

invokeMethod

public AutoOut invokeMethod(AutoEngineInfo rootInfo,
                            java.util.ArrayList<KeyValue> paramList)
                     throws LicasException,
                            java.lang.Exception

Invoke the method in the autoInfo object, making variable replacements first. From that object, the evaluator is used to execute the method. The evaluation can be compared to the function. The input can be used to replace a tagged Const.QUERY parameter and so should be an XML element. If the reply is OK, the autoInfo effOutput is returned as the next set of actions.

Parameters:

rootInfo - the root process script for execution.

paramList - an external set of KeyValue objects that can replace named or tagged fields in the method parameter lists. If empty or no match, then nothing gets changed.

Returns:

the result of the evaluation. This is the effector list of the input parameter if the evaluation is true, or an empty list if it is false. Evaluating to true can include matching exactly to an XML description, or just have any result, for example, by using a checkReply method.

Throws:

LicasException - for a licas-specific mapping problem.

java.lang.Exception - any error.

getAutoQueueMessage

protected MessageInfo getAutoQueueMessage(org.dcs.query_process.model.activity.Script_Auto scriptAuto)

Get the first message in the auto manager's queue, retrieved using the specified function.

Parameters:

scriptAuto - description of the message to retrieve.

Returns:

the message if it exists, or null if there are none, or there is no parent service or queue.

setParent

public void setParent(Service thisParent)

Set the parent service.

Parameters:

thisParent - the parent service.

getScriptEngine

public org.dcs.query_process.Script_Engine getScriptEngine()

Get the script engine that processes and returns script elements in order.

Returns:

the value of engine.

getPasswordHandler

protected PasswordHandler getPasswordHandler()

Get the password handler.

Returns:

the value of passwordHandler.