org.fosstrak.capturingapp
Class ECReportsHandler

java.lang.Object
  org.fosstrak.capturingapp.ECReportsHandler

Direct Known Subclasses:

DefaultECReportHandler

public abstract class ECReportsHandler
extends java.lang.Object

An ECReportHandler receives a ECReport and generates a EPCIS document that can be sent to an EPCIS repository. If you would like to implement your own handler, you will find some guide-lines below. In addition you can get inspiration by the default reports handler DefaultECReportHandler.

Default Execution Sequence:

If you do not override the method LinkedList<EPCISDocumentType> handle(ECReports reports), the execution sequence of the handler is as following:

1. abstract loadRules(): load drools rules from disc.
2. checkErrors(): checks if errors in the rule-set. If there are errors, an exception is thrown.
3. registerKnowledgeBase(): Create a new knowledge-base kbase from the kbuilder.
4. createSession(): Creates a drools session. By default, a StatefulKnowledgeSession is created. Notice, that all subsequent generic methods are programmed in such a way, that they can handle both StatefulKnowledgeSession and StatelessKnowledgeSession.
5. prepareGlobalCollector(ksession): Registers a collector for the EPCIS documents. If you override the method handle make sure, to call this method before you execute the drools rules as otherwise third-party drools rules might crash.
6. executeSession(reports):: Execute the drools rules. In StatefulKnowledgeSession the ECReports are injected via insert, in StatelessKnowledgeSession the rules are executed via execute.
7. collectResults(): Retrieves the results from the global collector and submits them to the capture application for further delivery.

Methods to be implemented:

• loadRules(). It is required, that this method loads the drools rules from the file-system into kbuilder.
  Example:
  kbuilder.add(
ResourceFactory.newClassPathResource(
changeSet,
DefaultECReportHandler.class),
ResourceType.CHANGE_SET);

Author:

sawielan

Field Summary

protected java.lang.String	changeSet
static java.lang.String	DEFAULT_RULE_SET the default change-set to load with the drools rules.
protected java.util.ArrayList<java.lang.Object>	epcis array that will collect the results from the drools executions.
protected org.drools.KnowledgeBase	kbase the knowledge base.
protected org.drools.builder.KnowledgeBuilder	kbuilder the knowledge builder.
protected java.lang.Object	ksession the knowledge session. this is object to allow either state-full or state-less sessions.
static java.lang.String	RESULTS the name of the global variable for the drools results.

Constructor Summary

ECReportsHandler()
default constructor. sets the rule-set to 'changeset.xml'.

ECReportsHandler(java.lang.String changeSet)
create a new handler with a non default change set.

Method Summary

protected void	checkErrors() check the knowledge-builder for errors in the rules.
protected java.util.LinkedList<org.fosstrak.epcis.model.EPCISDocumentType>	collectResults() collect the results from the rules evaluation and put them into a nice typed linked list.
protected void	createSession() create a new knowledge session.
void	dispose() in case of a StatefullKnowledgeSession we have to call dispose at the end of execution.
void	executeSession(org.fosstrak.ale.xsd.ale.epcglobal.ECReports reports) executes the drools session.
java.lang.String	getChangeSet()
java.util.LinkedList<org.fosstrak.epcis.model.EPCISDocumentType>	handle(org.fosstrak.ale.xsd.ale.epcglobal.ECReports reports) this method is invoked from the capture application whenever a new ECReports is received.
abstract void	loadRules() // parse and compile the rule from file kbuilder.add(ResourceFactory.newClassPathResource( "HelloWorld.drl", HelloWorld.class), ResourceType.DRL);
protected void	prepareGlobalCollector(java.lang.Object ksession) prepare a global collector where the rules can store the results to.
protected void	registerKnowledgeBase() register the knowledge base from the rule builder in the knowledge base.

Methods inherited from class java.lang.Object

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

Field Detail

RESULTS

public static final java.lang.String RESULTS

the name of the global variable for the drools results.

See Also:

Constant Field Values

epcis

protected java.util.ArrayList<java.lang.Object> epcis

array that will collect the results from the drools executions.

kbuilder

protected final org.drools.builder.KnowledgeBuilder kbuilder

the knowledge builder.

kbase

protected org.drools.KnowledgeBase kbase

the knowledge base.

ksession

protected java.lang.Object ksession

the knowledge session. this is object to allow either state-full or state-less sessions.

DEFAULT_RULE_SET

public static final java.lang.String DEFAULT_RULE_SET

the default change-set to load with the drools rules.

See Also:

Constant Field Values

changeSet

protected final java.lang.String changeSet

Constructor Detail

ECReportsHandler

public ECReportsHandler()

default constructor. sets the rule-set to 'changeset.xml'.

ECReportsHandler

public ECReportsHandler(java.lang.String changeSet)

create a new handler with a non default change set.

Parameters:

changeSet -

Method Detail

getChangeSet

public final java.lang.String getChangeSet()

Returns:

the change set that is used with this handler.

handle

public java.util.LinkedList<org.fosstrak.epcis.model.EPCISDocumentType> handle(org.fosstrak.ale.xsd.ale.epcglobal.ECReports reports)
                                                                        throws java.lang.RuntimeException

this method is invoked from the capture application whenever a new ECReports is received. The resulting EPCIS document will be delivered automatically to the EPCIS repository. If you set the return value to null, then no report is generated.
NOTICE: If you override this method, make sure that you invoke the method prepareGlobalCollector(ksession) before you invoke the rule-set.

Parameters:

reports - the ECReports with the EPC data.

Returns:

an EPCIS document when this handler consumed the report, null otherwise.

Throws:

java.lang.RuntimeException - when the rule(s) could not be compiled.

executeSession

public void executeSession(org.fosstrak.ale.xsd.ale.epcglobal.ECReports reports)

executes the drools session. The method is aware of the two different knowledge-sessions StatelessKnowledgeSession and StatefulKnowledgeSession and invokes them respectively.

Parameters:

reports - the ECReports.

createSession

protected void createSession()

create a new knowledge session. By default a StatefulKnowledgeSession is generated.

registerKnowledgeBase

protected void registerKnowledgeBase()

register the knowledge base from the rule builder in the knowledge base.

checkErrors

protected void checkErrors()
                    throws java.lang.RuntimeException

check the knowledge-builder for errors in the rules.

Throws:

java.lang.RuntimeException - when there are errors in the rules.

prepareGlobalCollector

protected void prepareGlobalCollector(java.lang.Object ksession)

prepare a global collector where the rules can store the results to.

Parameters:

ksession - the session holding the collector.

collectResults

protected java.util.LinkedList<org.fosstrak.epcis.model.EPCISDocumentType> collectResults()

collect the results from the rules evaluation and put them into a nice typed linked list.

Returns:

a linked list holding the result set.

loadRules

public abstract void loadRules()

// parse and compile the rule from file
kbuilder.add(ResourceFactory.newClassPathResource(
"HelloWorld.drl", HelloWorld.class), ResourceType.DRL);


dispose

public void dispose()

in case of a StatefullKnowledgeSession we have to call dispose at the end of execution.