MVC in NetBeans
and other modular applications
Jaroslav Tulach

Agenda
MVC
DCI
NetBeans APIs
Towards Future
Q/A

MVC

DCI

NetBeans APIs

Towards Future

Q/A

MVC
Architecture Pattern
Separating Application
Model knows nothing about the rest
Better maintenance
Separate Input/Output
Mainframes
Web
Controller
knows it all
http://zdrojak.root.cz/clanky/prezentacni-vzory-zrodiny-mvc/

Architecture Pattern

Separating Application

Model knows nothing about the rest

Better maintenance

Separate Input/Output

Mainframes

Web

Controller

knows it all

Model/View/Presenter
Variation of MVC
Merged Input/Output
GUI
AJAX & co.
Presenter
business
logic
http://zdrojak.root.cz/clanky/prezentacni-vzory-zrodiny-mvc/

Variation of MVC

Merged Input/Output

GUI

AJAX & co.

Presenter

business

logic

Dialogs & Wizards API
Descriptor is model
Notify, Dialog, Wizard descriptors
DialogDisplayer
presenter
Wizards
Iterator, Panel
Internal view
No modularity

Descriptor is model

Notify, Dialog, Wizard descriptors

DialogDisplayer

presenter

Wizards

Iterator, Panel

Internal view

No modularity

Actions
Action is view
enables/disables
updates name
Editor is model
text
selection
history
Action tight to editor
works with the only model

Action is view

enables/disables

updates name

Editor is model

text

selection

history

Action tight to editor

works with the only model

Actions in NetBeans
Single action
knows nothing about components
slightly different meaning in each
Multiple Components
from various modules
Not really MVC

Single action

knows nothing about components

slightly different meaning in each

Multiple Components

from various modules

Not really MVC

Critique of MVC
OOP good for data modeling
Where to put operations?
BankAccount & money transfer
operation on account?
asymmetric
all or nothing
transactions
Projection of user mind

OOP good for data modeling

Where to put operations?

BankAccount & money transfer

operation on account?

asymmetric

all or nothing

transactions

Projection of user mind

DCI
Scandinavian
as different as Simula or Beta
Interactions
specify required context
Data
morphed
fed to the context
manipulated by
operations
http://www.artima.com/articles/dci_vision.html

Scandinavian

as different as Simula or Beta

Interactions

specify required context

Data

morphed

fed to the context

manipulated by

operations

DCI Actions in NetBeans
Action seeks in context
usually some specific interface
enables/disables on its presence
operates on it
TopComponents provide own context
morph themselves to specific interfaces
Selection
system builds Menu, Toolbar
binds actions to selected TopComponent's context

Action seeks in context

usually some specific interface

enables/disables on its presence

operates on it

TopComponents provide own context

morph themselves to specific interfaces

Selection

system builds Menu, Toolbar

binds actions to selected TopComponent's context

DCI in NetBeans
Action
Selection
Morphs Selection
to Action's model
Editor
Explorer
Image
viewer

Lookup
“Magical Bag”
a place to “fish” for an interface
Adaptable Pattern
an object can “morph” to something else
Supports changes
“swim in and out”
listeners
Type safe

“Magical Bag”

a place to “fish” for an interface

Adaptable Pattern

an object can “morph” to something else

Supports changes

“swim in and out”

listeners

Type safe

Exposing Window State
class MyWindow
extends org.openide.windows.TopComponent {
private JEditorPane pane;
public org.openide.util.Lookup getLookup() {
return Lookups.singleton(pane.getDocument());
}
}

Querying
import org.openide.util.Utilities;
class MyInsertAction extends AbstractAction {
public void actionPerformed (ActionEvent ev) {
Lookup lkp = Utilities.actionGlobalContext();
Document doc = lkp.lookup (Document.class);
if (doc != null) {
doc.insertString ("Hello world!", null, 0);
}
}
}

import org.openide.util.Utilities;

class MyInsertAction extends AbstractAction {

public void actionPerformed (ActionEvent ev) {

Lookup lkp = Utilities.actionGlobalContext();

Document doc = lkp.lookup (Document.class);

if (doc != null) {

doc.insertString ("Hello world!", null, 0);

}

}

}

Listening
Lookup.Result<SomeClass> res;
res = someLookup.lookupResult(SomeClass.class);
res.allItems(); // initialize
res.addLookupListener (new LookupListener() {
public void resultChanged (LookupEvent e) {
for (SomeClass : res.allInstances()) {
//handler code here
}
});

Lookup.Result<SomeClass> res;

res = someLookup.lookupResult(SomeClass.class);

res.allItems(); // initialize

res.addLookupListener (new LookupListener() {

public void resultChanged (LookupEvent e) {

for (SomeClass : res.allInstances()) {

//handler code here

}

});

Create Own Lookup
AbstractLookup + InstanceContent
Lookup whose contents you can manage
Lookups.singleton( Object ) - one item Lookup
Lookups.fixed( Object... ) - unchanging Lookup
Lookups.exclude ( Lookup, Class[] );
ProxyLookup ( Lookup[] otherLookups ) - compose multiple lookups

AbstractLookup + InstanceContent

Lookup whose contents you can manage

Lookups.singleton( Object ) - one item Lookup

Lookups.fixed( Object... ) - unchanging Lookup

Lookups.exclude ( Lookup, Class[] );

ProxyLookup ( Lookup[] otherLookups ) - compose multiple lookups

Morphing
class MyLazyLookup extends AbstractLookup {
MyTopComponent tc;
protected <T> void beforeLookup (Template<T> t) {
if (t.getType() == OpenCookie.class) {
ic.add(new MorphAsOpenCookie(tc));
}
}
}
class MorphAsOpenCookie implements OpenCookie {
public void open() {
// implement “open” on MyTopComponent
}
}

class MyLazyLookup extends AbstractLookup {

MyTopComponent tc;

protected <T> void beforeLookup (Template<T> t) {

if (t.getType() == OpenCookie.class) {

ic.add(new MorphAsOpenCookie(tc));

}

}

}

class MorphAsOpenCookie implements OpenCookie {

public void open() {

// implement “open” on MyTopComponent

}

}

Actions MVC and Modularity
Defined together as MVP
TopComponent1
module A
An Action
Common
Interface
TopComponent2
module B

Context Actions
http://wiki.netbeans.org/wiki/view/DevFaqActionContextSensitive
public class FooAction extends AbstractAction implements LookupListener, ContextAwareAction {
private Lookup context;
Lookup.Result lkpInfo;
public FooAction() {
this( Utilities.actionsGlobalContext() );
}
private FooAction(Lookup context) {
this.context = context;
}
void init() {
Lookup.Template tpl = new Lookup.Template( Whatever.class );
lkpInfo = context.lookup (tpl); lkpInfo.addLookupListener(this); resultChanged(null);
}
public boolean isEnabled() {
init(); return super.isEnabled();
}
public Action createContextAwareInstance(Lookup context) {
return new FooAction(context);
}
}

http://wiki.netbeans.org/wiki/view/DevFaqActionContextSensitive

Into the Future
@ActionRegistration (
displayName=”Open Action”,
iconBase=”org/.../Open.png”
)
public class MyAction extends ActionListener {
private OpenCookie oc;
public MyAction(OpenCookie oc) {
// or other ways to do dependency injection
this.oc = oc;
}
public void actionPerformed(ActionEvent ev) {
oc.open();
}
}

@ActionRegistration (

displayName=”Open Action”,

iconBase=”org/.../Open.png”

)

public class MyAction extends ActionListener {

private OpenCookie oc;

public MyAction(OpenCookie oc) {

// or other ways to do dependency injection

this.oc = oc;

}

public void actionPerformed(ActionEvent ev) {

oc.open();

}

}

Into the Future II
@ActionRegistration (
displayName=”Find Action”,
iconBase=”org/.../Open.png”,
key=”find”
)
public class MyAction extends ActionListener {
}
“key” to complete control
any TopComponent can provide own action
system will delegate, if found
tc. getActionMap(). put ( “find” , new MyOwnAction());

@ActionRegistration (

displayName=”Find Action”,

iconBase=”org/.../Open.png”,

key=”find”

)

public class MyAction extends ActionListener {

}

“key” to complete control

any TopComponent can provide own action

system will delegate, if found

tc. getActionMap(). put ( “find” , new MyOwnAction());

Conclusion
MVC
view and controller tied to model
DCI
morphing & adaptation
Lookup
the way to morph in NetBeans
Actions
define control interfaces
Future is in @annotations

MVC

view and controller tied to model

DCI

morphing & adaptation

Lookup

the way to morph in NetBeans

Actions

define control interfaces

Future is in @annotations

Q&A