org.javagen.agile.core.visitor
Class TypeLookupVisitor

java.lang.Object
  org.javagen.agile.core.visitor.DefaultVisitor
      org.javagen.agile.core.visitor.TypeLookupVisitor

All Implemented Interfaces:

Generator, Visit, Visitor

Direct Known Subclasses:

IdAssignerVisitor

public class TypeLookupVisitor
extends DefaultVisitor

Defines a generic, extensible visitor pattern based on registering a Visit instance for each Model type.

The biggest problem with the traditional visitor pattern is that it binds you to a fixed set of node types witch is not good in an open-ended framework like JavaGen-Agile. This visitor pattern avoids that by allowing any number of Visit methods to be registered by Model type.

Arbitrary model hierarchies can be combined as this example illustrates:

 Visitor visitor = new TypeLookupVisitor( new OOLookupVisitor(), new DBLookupVisitor() );
 visitor.visit( combinedModelTree );
 

Author:

Richard Easterling

Field Summary

protected Visit	defualtVisit
protected Map<Class,Visit>	visitInstances

Fields inherited from class org.javagen.agile.core.visitor.DefaultVisitor

itinerary

Constructor Summary

TypeLookupVisitor()

TypeLookupVisitor(TypeLookupVisitor[] lookupVisitorDelegates)

Method Summary

void	addVisitInstances(Map<Class,Visit> visitInstances)
Visit	get(Class clazz)
Visit	getDefualtVisit()
Map<Class,Visit>	getVisitInstances()
void	put(Class clazz, Visit visit)
void	setDefualtVisit(Visit defualtVisit)
void	setVisitInstances(Map<Class,Visit> visitInstances)
void	visit(Model model) Lookup Visit instance for this model type and invoke visit method.

Methods inherited from class org.javagen.agile.core.visitor.DefaultVisitor

gen, getItinerary, itinerary, setItinerary

Methods inherited from class java.lang.Object

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

Field Detail

visitInstances

protected Map<Class,Visit> visitInstances

defualtVisit

protected Visit defualtVisit

Constructor Detail

TypeLookupVisitor

public TypeLookupVisitor()

TypeLookupVisitor

public TypeLookupVisitor(TypeLookupVisitor[] lookupVisitorDelegates)

Method Detail

visit

public void visit(Model model)

Lookup Visit instance for this model type and invoke visit method. If no Visit instance is registered for a given type, the defaultVisit method will be invoked if one has been specified.

Note: this method is only called if there is either no itinerary or the itinerary includes this modelType.

Specified by:

visit in interface Visit

Specified by:

visit in interface Visitor

Overrides:

visit in class DefaultVisitor

Parameters:

model - instance to visit.

addVisitInstances

public void addVisitInstances(Map<Class,Visit> visitInstances)

put

public void put(Class clazz,
                Visit visit)

get

public Visit get(Class clazz)

getVisitInstances

public Map<Class,Visit> getVisitInstances()

setVisitInstances

public void setVisitInstances(Map<Class,Visit> visitInstances)

getDefualtVisit

public Visit getDefualtVisit()

setDefualtVisit

public void setDefualtVisit(Visit defualtVisit)