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<h1>NetBeans Platform Porting Tutorial</h1>
<p>This tutorial demonstrates how to port a simple Swing application to the <a href="https://platform.netbeans.org/screenshots.html">NetBeans Platform</a>.
Though the scenario below is simple, the basic concepts of "porting" an application to the NetBeans
Platform will become clear. In the end, some general principles will be identified, based on the
steps taken in the tutorial. Hopefully, they will be useful to you when porting your own
Swing applications to the NetBeans Platform.</p>
<p><b>Contents</b></p>
<p><img src="../images/articles/69/netbeans-stamp69.png" class="stamp" width="114" height="114" alt="Content on this page applies to NetBeans IDE 6.5, 6.7, 6.8" title="Content on this page applies to NetBeans IDE 6.5, 6.7, 6.8"/></p>
<ul class="toc">
<li><a href="#intro">Introduction to Porting</a></li>
<li><a href="#getting">Getting the Anagram Game</a></li>
<li><a href="#compliance">Levels of Compliance</a>
<ul>
<li><a href="#creating">Creating the NetBeans Platform Application</a></li>
<li><a href="#porting0">Porting Level 0: Launchable</a></li>
<li><a href="#porting1">Porting Level 1: Integration</a></li>
<li><a href="#porting3">Porting Level 2: Use Case Support</a></li>
<li><a href="#porting4">Porting Level 3: Aligned</a></li>
</ul></li>
<li><a href="#tips">Porting Tips & Tricks</a></li>
</ul>
<p><b>To follow this tutorial, you need the software and resources listed in the following
table.</b></p>
<table>
<tbody>
<tr>
<th class="tblheader" scope="col">Software or Resource</th>
<th class="tblheader" scope="col">Version Required</th>
</tr>
<tr>
<td class="tbltd1">NetBeans IDE</td>
<td class="tbltd1">version 6.9 or above</td>
</tr>
<tr>
<td class="tbltd1">Java Developer Kit (JDK)</td>
<td class="tbltd1"><a href="http://java.sun.com/javase/downloads/index.jsp">version 6</a></td>
</tr>
<!-- <tr>
<td class="tbltd1"><a href="http://plugins.netbeans.org/PluginPortal/faces/PluginDetailPage.jsp?pluginid=2753">Download the Sample</a></td>
<td class="tbltd1"></td>
</tr>-->
</tbody>
</table>
<h2 class="tutorial"><a name="intro"></a>Introduction to Porting</h2>
<p>Before beginning this procedure, it makes sense to ask why one would want to do so in the
first place. A typical Swing application consists of a domain-specific layer on top of a
general framework. The general framework normally provides features dealing with an
application's infrastructure, such
as an application's menu bar, windowing system (also known as "docking framework"), and
lifecycle management. Typically this framework is very generic and is (or could be)
reused by many applications within the
same organization. The NetBeans Platform exists specifically to cater to these infrastructural
concerns. You do not need to create these on your own for your own Swing applications. You
can simply move the useful domain-specific parts of your application to the
NetBeans Platform and then,
from that point onwards, the NetBeans Platform will be the new underlying 'plumbing' layer
of your application. You can then focus on the more interesting parts of your application,
specifically, the domain-specific parts. This will speed up your development process and give you
a consistent basis for all your applications.</p>
<p>In this tutorial, we will begin with the Anagram Game, which is a standard Swing application
sample that is distributed with NetBeans IDE. We will, step by step, move it to the NetBeans
Platform and gradually see the advantages of doing so.</p>
<!-- ===================================================================================== -->
<h2 class="tutorial"><a name="getting"></a>Getting the Anagram Game</h2>
<p>We begin by getting the Anagram Game, which is one of the IDE's standard Java samples,
from the New Project wizard. Then we run it and analyze its parts.</p>
<ol>
<li><p>Choose File &gt; New Project (Ctrl-Shift-N). Under Categories, select Samples &gt; Java. Under Projects,
select Anagram Game. Click Next and Finish.</p>
<p>You should now see the Anagram Game application outlined in the Projects window, as shown here:</p>
<p><img alt="" src="../images/tutorials/porting/ag0.png"/></p>
<p>The application contains the following classes:</p>
<ul>
<li><b><tt>WordLibrary.java</tt></b>. Provides an abstract class, with
abstract methods like <code>getWord(int idx)</code>, <code>getScrambledWord(int idx)</code>,
and <code>isCorrect(int idx, String userGuess)</code>.</li>
<li><b><tt>StaticWordLibrary.java</tt></b>. Extends <code>WordLibrary.java</code>,
providing a list of scrambled words, as well
as their unscrambled equivalents, together with the getters and setters for accessing them
and for evaluating them.</li>
<li><b><tt>Anagrams.java</tt></b>. Provides the main user interface of the application,
principally consisting of a <code>JFrame</code> with
a <tt>JPanel</tt> containing labels and text fields. Also included
is a menu bar containing a File menu, with the menu items 'About' and 'Exit'.</li>
<li><b><tt>About.java</tt></b>. Provides the About box, accessed from the File menu.</li>
</ul></li>
<li><p>Run the application and you should see the following:</p>
<p><img alt="" src="../images/tutorials/porting/ag1.png"/></p></li>
<li><p>When you specify the correctly unscrambled word, you will see this:</p>
<p><img alt="" src="../images/tutorials/porting/ag2.png"/></p></li>
</ol>
<p>Before porting this application to the NetBeans Platform, we need to think
about <i>the stages in which we want to port our application</i>. In other
words, you do not need to port everything at once. And there are different
levels to which you can integrate your application, from a mostly superfical
level to a level that aligns your application completely with the paradigms
and purposes of the NetBeans Platform. The next section will show the levels
of compliance your application can have with the NetBeans Platform.</p>
<!-- ===================================================================================== -->
<h2 class="tutorial"><a name="compliance"></a>Levels of Compliance</h2>
<p>Converting an application to be fit for a framework such as the NetBeans Platform can be done
on various levels. The integration can be shallow and use just a few integration points or
it can be deeper, tightly following the paradigms of the NetBeans Platform.</p>
<p>The stages can be described as follows:</p>
<h4 id="section-LevelsOfCompliance-Level0Launchable">Level 0: Launchable</h4>
<p>One or more of the following can be done to make your application launchable with as
few changes as possible:</p>
<ul>
<li>Enhance your manifest with NetBeans key/value pairs so that your JAR is recognized as an
OSGi bundle or as a
NetBeans module.</li>
<li>Set dependencies between modules. In the manifest, with instances of plain Class-Path you can set dependencies
between modules.</li>
<li>Register a menu item in the declarative
layer file (<tt>layer.xml</tt>) of your module, to
invoke your original application. This file can be created automatically when you create a new
module project in NetBeans IDE, as you will see later.</li>
</ul>
<p>In this tutorial, we will do all of the above. We will enhance the manifest, which the module
project wizard will do for us. We will create a menu item that will
invoke our application. To do so, we will move our application's classes into a module source
structure. Then we will use the New Action wizard to create a new menu item, which will
automatically be registered for us, and a dependency will be set on the UI Utilities API, which
we will need to implement the Action. From that action, we will invoke our application.</p>
<h4 id="section-LevelsOfCompliance-Level1Integrated">Level 1: Integrated</h4>
<p>Here are some pointers for integrating the application more
tightly with the NetBeans Platform:</p>
<ul>
<li>Integrate visually to get the benefits of the NetBeans Window System, which is
its docking framework.</li>
<li>Use NetBeans Window System API and the Dialog APIs, primarily the <tt>TopComponent</tt> class and the
<tt>DialogDisplayer</tt> class.</li>
<li>Change initialization code of your application, use the <tt>ModuleInstall</tt>
class or declarative registrations, through the layer file or the META-INF/services folder.</li>
</ul>
<p>In this tutorial, we will move the relevant parts of the <tt>JPanel</tt>
from the <tt>JFrame</tt> to a new <tt>TopComponent</tt>. The <tt>TopComponent</tt> class
creates a window on the NetBeans Platform, which in our case will show our <tt>JPanel</tt>.</p>
<h4 id="section-LevelsOfCompliance-Level2UseCaseSupport">Level 2: Use Case Support</h4>
<p>This level of compliance with the NetBeans Platform is concerned with one or more of the following activities:</p>
<ul>
<li>Bind your application to other modules by inspecting existing functionality and trying to use it.</li>
<li>Simplify the workflow to fit into the NetBeans Platform paradigms.</li>
<li>Listen to the global selection to discover what other modules are doing and update your state accordingly.</li>
</ul>
<p>In this tutorial, we will listen for the existence of <tt><a href="http://bits.netbeans.org/dev/javadoc/org-openide-text/org/openide/cookies/EditorCookie.html">EditorCookie</a>s</tt>.
A cookie is a <i>capability</i>.
With a Java interface, your object's capabilities are fixed at compile time, while NetBeans Platform cookies
allow your object to behave dynamically because your object can expose capabilities, or
not, based on its state. An <tt>EditorCookie</tt>
defines an editor, with interfaces for common activities such as opening a document, closing the editor,
background loading of files, document saving, and modification notifications. We will listen for the
existence of such a cookie and then we will pass the content of the editor to the <tt>TopComponent</tt>, in the
form of words. By doing this, we are doing what the first item above outlines, i.e., inspecting existing
functionality and reusing it within the context of our ported application. This is a modest level of integration.
However, it pays off because you are reusing functionality provided by the NetBeans Platform.</p>
<h4 id="section-LevelsOfCompliance-Level3Aligned">Level 3: Aligned</h4>
<p>In this final stage of your porting activity, you are concerned with the following thoughts, first and foremost:</p>
<ul>
<li>Become a good citizen of the NetBeans Platform, by exposing your own state to other modules so that they know what you are doing.</li>
<li>Eliminate duplicated functionality, by
reusing the Navigator, Favorites window, Task List, Progress API, etc., instead of creating or maintaining your own.</li>
<li>Cooperate with other modules and adapt your application to the NetBeans Platform way of doing things.</li>
</ul>
<p>Towards the end of this tutorial, we will adopt this level of compliance by letting our <tt>TopComponent</tt>
expose a <tt>SaveCookie</tt> when changes are made to the "Guessed Word" text field. By doing this, we will
enable the Save menu item under the Tools menu. This kind of integration brings the full benefits of the
NetBeans Platform, however it also requires some effort to attain.</p>
<!-- ===================================================================================== -->
<h2 class="tutorial"><a name="creating"></a>Creating the NetBeans Platform Application</h2>
<p>First, let's create the basis of our application. We use a wizard to do so. This
is the typical first practical step of creating a new application
on top of the NetBeans Platform application.</p>
<ol>
<li><p>Choose File &gt; New Project (Ctrl-Shift-N). Under Categories, select NetBeans Modules.
Under Projects,
select NetBeans Platform Application, as shown below:</p>
<p><img alt="" src="../images/tutorials/porting/agp0.png"/></p>
<p>Click Next.</p></li>
<li><p>Name the application <code>AnagramApplication</code>, as shown below:</p>
<p><img alt="" src="../images/tutorials/porting/agp01.png"/></p>
<p>Click Finish</p>
<p>You now have a NetBeans Platform application. You can run it and
you will see an empty main window, with a menu bar and a tool bar. Look
under some of the menus, click a few toolbar buttons, and explore the
basis of your new application.</p>
<p>Next, we create our first custom module. We will name it
<code>AnagramUI</code> because, in the end, it will
only contain the user interface (UI) of the application.
In a subsequent tutorial, we
will add additional modules, which will provide an API and an
implementation of the business logic. But, for the moment, we
will port everything into the module that will ultimately provide
only the UI of the application.</p></li>
<li><p>Choose File &gt; New Project (Ctrl-Shift-N) again. Under Categories, select NetBeans Modules.
Under Projects,
select Module, as shown below:</p>
<p><img alt="" src="../images/tutorials/porting/agp1.png"/></p>
<p>Click Next.</p></li>
<li><p>Type <tt>AnagramGameUI</tt> in Project Name and choose somewhere
to store the module, as shown below:</p>
<p><img alt="" src="../images/tutorials/porting/agp2.png"/></p>
<p>Click Next.</p></li>
<li><p>Type a unique name in the Code Name Base field,
which provides the unique identifier for your module.
It could be anything, but here it is <tt>org.anagram.ui</tt>.</p>
<p><img alt="" src="../images/tutorials/porting/agp3.png"/></p>
<p><b>Note:</b> Optionally, check "Generate XML Layer". If you do
not select it, that's fine, because later in this tutorial
you will be shown how to create it manually and you will also
learn what it is
used for.</p></li>
<li><p>Click Finish.</p>
<p>Below the Anagram Game sample, you should now see the source structure of your
new module, as shown here:</p>
<p><img alt="" src="../images/tutorials/porting/agp4.png"/></p></li>
</ol>
<p>Above, we can see that we now have the original application,
together with the module to which it
will be ported. In the next sections, we will begin porting the application to
the module, using the porting levels described earlier.</p>
<!-- ===================================================================================== -->
<h2 class="tutorial"><a name="porting0"></a>Porting Level 0: Launchable</h2>
<p>At this stage, we simply want to be able to launch our application from
a module. To do that we will create a menu item that invokes the application.
We begin
by copying the application's sources into the module source structure.</p>
<ol>
<li><p>Copy the two packages from the Anagram Game into the module. Below,
the new packages and classes in the module are highlighted:</p>
<p><img alt="" src="../images/tutorials/porting/agport0.png"/></p></li>
<li><p>In the <code>org.anagram.ui</code> package, create a new Java
class named <code>OpenAnagramGameAction</code>, implementing
the standard JDK <code>ActionListener</code> as follows:</p>
<pre class="examplecode">import com.toy.anagrams.ui.Anagrams;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
public class OpenAnagramGameAction implements ActionListener {
@Override
public void actionPerformed(ActionEvent e) {
new Anagrams().setVisible(true);
}
}</pre>
<p>When the user
invokes the <code>OpenAnagramGameAction</code>, the
<code>JFrame</code> from the Anagram Game will open.</p>
</li>
<li><p>Next, we need to register the new <code>OpenAnagramGameAction</code> in
the NetBeans central registry, which is also known as the "System FileSystem".</p>
<p>If you do not have a file named <code>layer.xml</code> yet,
create one in the <code>org.anagram.ui</code> package,
with this content:</p>
<pre class="examplecode">&lt;?xml version="1.0" encoding="UTF-8"?&gt;
&lt;!DOCTYPE filesystem PUBLIC "-//NetBeans//DTD Filesystem 1.2//EN" "https://netbeans.org/dtds/filesystem-1_2.dtd"&gt;
&lt;filesystem&gt;
&lt;folder name="Actions"&gt;
&lt;folder name="Window"&gt;
&lt;file name="org-anagram-ui-OpenAnagramGameAction.instance"&gt;
&lt;attr name="delegate" newvalue="org.anagram.ui.OpenAnagramGameAction"/&gt;
&lt;attr name="instanceCreate" methodvalue="org.openide.awt.Actions.alwaysEnabled"/&gt;
&lt;attr name="displayName" bundlevalue="org.anagram.ui.Bundle#CTL_OpenAnagramGameAction"/&gt;
&lt;/file&gt;
&lt;/folder&gt;
&lt;/folder&gt;
&lt;folder name="Menu"&gt;
&lt;folder name="Window"&gt;
&lt;file name="OpenLibraryViewerWindowAction.shadow"&gt;
&lt;attr name="originalFile" stringvalue="Actions/Window/org-anagram-ui-OpenAnagramGameAction.instance"/&gt;
&lt;/file&gt;
&lt;/folder&gt;
&lt;/folder&gt;
&lt;/filesystem&gt;</pre>
<p>Each module in your application can have, at most, one
<code>layer.xml</code> file. The file is used to register
contributions to the NetBeans Platform application. For example,
new windows and new Actions are registered here, in folders
specifically dedicated to the contribution in question. Above, you
can see we are dealing with the "Actions" folder and the "Menu"
folder. Some notes on the elements and attributes above:</p>
<ul>
<li><p>Above, in the "delegate" attribute, you have registered the <code>OpenAnagramGameAction</code>
class. In the "instanceCreate" attribute, you have specified that the
NetBeans Platform method <code><a href="http://bits.netbeans.org/dev/javadoc/org-openide-awt/org/openide/awt/Actions.html#alwaysEnabled%28java.awt.event.ActionListener,%20java.lang.String,%20java.lang.String,%20boolean%29">org.openide.awt.Actions.alwaysEnabled</a></code>
will be called when the <code>OpenAnagramGameAction</code> is invoked. This
is a NetBeans Platform method that creates an Action that is always enabled,
regardless of the context of the application. Since you want the Anagram Game
to be able to be started at any time, it makes sense for the Action to
always be enabled.</p></li>
<li> <p>The "displayName" attribute above points to a key in the <code>Bundle.properties</code>
file, which is the central file for storing all the localizable strings
in the module.</p></li>
<li><p>While the "Actions" folder registers the Action, the "Menu" folder specifies
where the Action will be displayed. Above, you can see that the Action
will be displayed in the Window menu.</p></li>
</ul>
</li>
<li><p>In the <code>Bundle.properties</code> file, add the following key/value pair,
based on the "displayName" attribute above:</p>
<pre class="examplecode">CTL_OpenAnagramGameAction=Open Anagram Game</pre>
</li>
<li><p>In the Module Manifest, which you can find in the Important Files node
in the module, and which is <code>manifest.mf</code> on disk,
register the <code>layer.xml</code> file as follows:</p>
<pre class="examplecode">OpenIDE-Module-Layer: org/anagram/ui/layer.xml</pre>
</li>
<li><p>In the Projects window,
right-click the AnagramApplication project node
and choose Run. The application starts up, installing
all the modules provided by the application, which
includes our custom module.</p></li>
<li>Under the Window menu,
you should find the menu item "Open Anagram Game".
Choose it and your application appears.</li>
</ol>
<p>The application is displayed, but note that it is not
well integrated with the NetBeans Platform. For example,
it is not modal and it is impossible to close the <code>JFrame</code>,
unless you close the entire application. The latter is because
the entire application now manages the lifecycle of the <code>JFrame</code>.
In the next section,
we will integrate
the Anagram Game more tightly with the NetBeans Platform.</p>
<p><b>Note:</b> In the section above, you manually created and registered a <code>layer.xml</code> file
and you manually created an <code>ActionListener</code> and you
manually registered the <code>ActionListener</code> in the <code>layer.xml</code> file.
Now that you know how and why and where these activities occur, you
can automate the process. Whenever you create a new module,
select the "Generate XML Layer" checkbox, which will let the IDE
automatically create the <code>layer.xml</code> file and the IDE
will also register it in the <code>manifest.mf</code> file for you.
In addition, you can automate the creation and registration of Actions
by using the "New Action" wizard, which is available in the New File dialog (Ctrl-N).
Also, whenever you use a wizard that registers something in the <code>layer.xml</code>
file, such as the New Action wizard does, and the <code>layer.xml</code> file does not
exist, the <code>layer.xml</code> file will automatically be created for you.</p>
<!-- ===================================================================================== -->
<h2 class="tutorial"><a name="porting1"></a>Porting Level 1: Integration</h2>
<p>In this section, we integrate the application
more tightly by creating a new window, so that we have a user
interface, that is.,
a window, to which we can move those contents of
the <tt>JFrame</tt> that are useful to our new application.</p>
<ol>
<li><p>Right-click the <code>org.anagram.ui</code> package in the Projects window and then
choose New &gt; Other. Under Categories, select Module Development. Under File Types,
select Window.</p>
<p><img alt="" src="../images/tutorials/porting/agport4.png"/></p>
<p>Click Next.</p>
</li>
<li><p>Choose the position where you would
like the window to appear. For purposes of this
tutorial choose "editor", which will place the
Anagram Game in the main part of the application:</p>
<p><img alt="" src="../images/tutorials/porting/agport5.png"/></p>
<p>Optionally, specify whether the window should
open automatically when the application starts up.</p>
<p>Click Next.</p>
</li>
<li><p>Type <tt>Anagram</tt> in Class Name
Prefix and select <tt>org.anagram.ui</tt>
in Package, as shown here:</p>
<p><img alt="" src="../images/tutorials/porting/agport6.png"/></p>
<p>Above, notice that the IDE shows the files it
will create and modify.</p></li>
<li><p>Click Finish.</p>
<p>Now you have a set of new Java and XML source
files, as shown here:</p>
<p><img alt="" src="../images/tutorials/porting/agport7.png"/></p></li>
<li><p>Open the <tt>Anagrams</tt> class in
the <code>com.toy.anagrams.ui</code> package. Also open
the <tt>AnagramTopComponent</tt>, which was created
in the previous step. When you click the mouse in the
Anagram class, notice that the labels and
text fields are in a Swing container, in
this case a <tt>JPanel</tt>, as shown here:</p>
<p><img alt="" style="border: 1px solid" src="../images/tutorials/porting/agport8.png"/></p>
<p><b>Tip:</b> If the Swing components were not within a container,
you could select them all with the mouse, then right-click and
choose "Enclose In", to let the IDE create a container within which
all the selected components would be enclosed.</p></li>
<li><p>Right-click the <tt>JPanel</tt> and copy it.
Paste it in the TopComponent and you should see
the old user interface in your new <code>TopComponent</code> class:</p>
<p><img alt="" style="border: 1px solid" src="../images/tutorials/porting/agport9.png"/></p></li>
<li><p>You have now ported the user interface of the Anagram Game.
A few variables need still to be moved from the <code>Anagrams</code>
class to the new <code>AnagramTopComponent</code> class. Declare these
two, which are in the <code>Anagrams</code> class, at the top of your
new <code>AnagramTopComponent</code> class.</p>
<pre class="examplecode">private int wordIdx = 0;
private WordLibrary wordLibrary;</pre>
<p>Next, look in the constructor of the <code>Anagrams</code> class. The first line
in the constructor is as follows:</p>
<pre class="examplecode">wordLibrary = WordLibrary.getDefault();</pre>
<p>Copy that statement. Paste it into the <code>TopComponent</code> class, making it
the new first statement in the constructor of the <code>TopComponent</code> class.</p></li>
<li><p>Next, open the <code>Bundle.properties</code> file. The content should be something
similar to this:</p>
<pre class="examplecode">CTL_AnagramAction=Anagram
CTL_AnagramTopComponent=Anagram Window
HINT_AnagramTopComponent=This is a Anagram window
OpenIDE-Module-Name=AnagramGameUI
CTL_OpenAnagramGameAction=Open Anagram Game
AnagramTopComponent.feedbackLabel.text=\
AnagramTopComponent.guessLabel.text=Your Guess:
AnagramTopComponent.scrambledLabel.text=Scrambled Word:
AnagramTopComponent.nextTrial.toolTipText=Fetch a new word.
AnagramTopComponent.nextTrial.text=New Word
AnagramTopComponent.guessButton.toolTipText=Guess the scrambled word.
AnagramTopComponent.guessButton.text=Guess</pre>
<p>Notice line 6 above. The IDE erroneously created a backslash
instead of a space in the key/value pair in line 6 above. If
you have a line where the value is set to be a backslash, simply
delete the backslash.</p>
<p>If you do not delete the backslash, when you run the application, in the
next step, you will see error messages such as these:</p>
<pre class="examplecode">--java.util.MissingResourceException: Can't find resource for bundle
org.openide.util.NbBundle$PBundle, key AnagramTopComponent.guessLabel.text
--java.lang.AssertionError: Component cannot be created for {component=null,
displayName=Anagram, instanceCreate=AlwaysEnabledAction[Anagram]}</pre>
<p>If you see the above error messages, open the <code>Bundle.properties</code>
file and remove the erroneously generated backslash. This is a known bug.</p></li>
<li><p>Run the application again. When the
application starts up, you should now see the Anagram Game window, which
you defined in this section. You will also find
a new menu item that opens the window, under the
Window menu. Also notice that the game works as before. You
need to click the "New Word" button once, to have the module
call up a new word, and then you can use it as
before:</p>
<p><img alt="" src="../images/tutorials/porting/agport10.png"/></p></li>
<li><p>As a final step in this section, you can simply delete
the <code>com.toy.anagrams.ui</code> package. That package
contains the two UI classes from the original Anagram Game.
You do not need either of these two classes anymore. Simply
delete the package that contains them, since you have ported everything of interest
to the NetBeans Platform.</p>
<p>Then also delete the <code>OpenAnagramGameAction</code> class, as well
as the registration entries you manually added to the <code>layer.xml</code>
file earlier in this tutorial. Be careful when you delete these
entries, since others have been added to the <code>layer.xml</code>
file in the meantime and you do not want to delete entries that
do not relate to this specific Action that you are deleting!</p>
</li>
</ol>
<!-- ===================================================================================== -->
<h2 class="tutorial"><a name="porting3"></a>Porting Level 2: Use Case Support</h2>
<p>In this section, we are concerned with listening to the global selection and making use
of data we find there. The global selection is the registry for
global singletons and instances of objects which have been registered in the system by modules.
Here we query the lookup for <tt><a href="http://bits.netbeans.org/dev/javadoc/org-openide-text/org/openide/cookies/EditorCookie.html">EditorCookie</a></tt>s and make use of the <tt>EditorCookie</tt>'s
document to fill the string array that defines the scrambled words displayed in
the <tt>TopComponent</tt>. </p>
<p>A cookie is a capability. With a Java interface, your object's capabilities are
fixed at compile time, while NetBeans Platform cookies allow your object to behave dynamically
because your object can expose capabilities, or not, based on its state. An <code>EditorCookie</code>
defines an editor, with interfaces for common activities such as opening a document, closing the
editor, background loading of files, document saving, and modification notifications. We will
listen for the existence of such a cookie and then we will pass the content of the editor
to the TopComponent, in the form of words. By doing this, we are inspecting existing functionality
and reusing it within the context of our ported application. This is a modest level of
integration. However, it pays off because you are reusing functionality provided by the NetBeans Platform.</p>
<ol>
<li>We begin by tweaking the <tt>StaticWordLibrary</tt> class. We do this so that
we can set its list of words externally. The sample provides a hardcoded list,
but we want to be able to set that list ourselves, via an external action. Therefore,
add this method to <tt>StaticWordLibrary</tt>:
<pre class="examplecode">public static void setScrambledWordList(String[] inScrambledWordList) {
SCRAMBLED_WORD_LIST = inScrambledWordList;
}</pre>
<p>Importantly, change the class signature of <tt>StaticWordLibrary</tt>
to <code>public class</code> and remove the <code>final</code>
from the signature of <code>SCRAMBLED_WORD_LIST</code></p>
<p>Next, we will create an action that will obtain the content of a Manifest file,
break the content down into words, and fill the <tt>SCRAMBLED_WORD_LIST</tt> string array
with these words.</p>
</li>
<li>Right-click the module, choose Properties, and then open the Libraries
tab in the Project Properties dialog. Click "Add Dependency" and
then set dependencies on the Text API and the Nodes API.</li>
<li>In the Source Editor, create a Java class
named <code>SetScrambledAnagramsAction</code>
and define it as follows:
<pre class="examplecode">public final class SetScrambledAnagramsAction implements ActionListener {
private final EditorCookie context;
public SetScrambledAnagramsAction(EditorCookie context) {
this.context = context;
}
@Override
public void actionPerformed(ActionEvent ev) {
try {
//Get the EditorCookie's document:
StyledDocument doc = context.getDocument();
//Get the complete textual content:
String all = doc.getText(0, doc.getLength());
//Make words from the content:
String[] tokens = all.split(" ");
//Pass the words to the WordLibrary class:
StaticWordLibrary.setScrambledWordList(tokens);
//Open the TopComponent:
TopComponent win = AnagramTopComponent.findInstance();
win.open();
win.requestActive();
} catch (BadLocationException ex) {
Exceptions.printStackTrace(ex);
}
}
}</pre></li>
<li><p>Register the Action above in the layer file. Unlike the previous Action,
the Action above should not always be enabled. It should be available
for Manifest files only, since that is the file type we happen to be
interested in. Furthermore, the Action should only be enabled if
an <code>EditorCookie</code> is present. The result of these requirements
is a registration with this content:</p>
<pre class="examplecode">&lt;folder name="Actions"&gt;
&lt;folder name="Window"&gt;
&lt;file name="org-anagram-ui-SetScrambledAnagramsAction.instance"&gt;
&lt;attr name="delegate" methodvalue="org.openide.awt.Actions.inject"/&gt;
&lt;attr name="displayName" bundlevalue="org.anagram.ui.Bundle#CTL_SetScrambledAnagramsAction"/&gt;
&lt;attr name="injectable" stringvalue="org.anagram.ui.SetScrambledAnagramsAction"/&gt;
&lt;attr name="instanceCreate" methodvalue="org.openide.awt.Actions.context"/&gt;
&lt;attr name="noIconInMenu" boolvalue="false"/&gt;
&lt;attr name="selectionType" stringvalue="EXACTLY_ONE"/&gt;
&lt;attr name="type" stringvalue="org.openide.cookies.EditorCookie"/&gt;
&lt;/file&gt;
&lt;/folder&gt;
&lt;/folder&gt;
&lt;folder name="Editors"&gt;
&lt;folder name="text"&gt;
&lt;folder name="x-manifest"&gt;
&lt;folder name="Popup"&gt;
&lt;file name="org-anagram-ui-SetScrambledAnagramsAction.shadow"&gt;
&lt;attr name="originalFile" stringvalue="Actions/Window/org-anagram-ui-SetScrambledAnagramsAction.instance"/&gt;
&lt;attr name="position" intvalue="900"/&gt;
&lt;/file&gt;
&lt;/folder&gt;
&lt;/folder&gt;
&lt;/folder&gt;
&lt;/folder&gt;</pre>
<p>Many of the attributes above you have used previously. For example, the "displayName"
attribute points to a key in the <code>Bundle.properties</code> file. This key does not
exist yet. Create it now, in the <code>Bundle.properties</code> file, as follows:</p>
<pre class="examplecode">CTL_SetScrambledAnagramsAction=Set Scrambled Words</pre>
<p>The <code>instanceCreate</code> attribute specifies that
the <a href="http://bits.netbeans.org/dev/javadoc/org-openide-awt/org/openide/awt/Actions.html#context%28java.lang.Class,%20boolean,%20boolean,%20org.openide.util.ContextAwareAction,%20java.lang.String,%20java.lang.String,%20java.lang.String,%20boolean%29">org.openide.awt.Actions.context</a>
method handles the Action.</p>
<p><b>Note:</b> Above, you manually created an Action class and registered it in the <code>layer.xml</code>
file. Now that you know how to do this, feel free to use the New Action wizard (in the New File dialog,
Ctrl-N) instead to
create context-sensitive Actions from now onwards.</p>
</li>
<li><p>As discussed above, when we run the application we want to be able to right-click
within a Manifest file, choose a menu item, and invoke our Action. Right now,
however, the NetBeans Platform is unable to distinguish Manifest files
from any other file. Therefore, we need to enable Manifest support in our
application.</p>
<p>For demonstration purposes, we will enable ALL the modules in the NetBeans Platform,
as well as those provided by NetBeans IDE. As a result, when we run the
application, a new instance of NetBeans IDE will start up, together with
our custom module.</p>
<p>To achieve the above, expand the Important Files node, then open
the NetBeans Platform Config file, which on disk
is named <code>platform.properties</code>. Notice that many modules have
been disabled. You can enable them via the Project Properties dialog
of the NetBeans Platform application. Since we are simply going to enable
ALL of them, we need only change the content of the <code>platform.properties</code>
file to the following:</p>
<pre class="examplecode">cluster.path=\
${nbplatform.active.dir}/apisupport:\
${nbplatform.active.dir}/harness:\
${nbplatform.active.dir}/ide:\
${nbplatform.active.dir}/java:\
${nbplatform.active.dir}/nb:\
${nbplatform.active.dir}/platform:\
${nbplatform.active.dir}/profiler:\
${nbplatform.active.dir}/websvccommon
disabled.modules=
nbplatform.active=default</pre>
<p>In the next step, when we run the application, all the groups
of modules (called "clusters") will be enabled, nothing will
be excluded, and you will see NetBeans IDE started up.</p></li>
<li><p>Run the application. Go to the Window menu and choose
Favorites. In the Favorites window, browse to a Manifest
file. Open the file. Inside the file, i.e., in the Manifest
Editor, right-click, and invoke the Set Scrambled Words
action via the menu item.</p>
<p><img alt="" src="../images/tutorials/porting/ageditorcookie3.png"/></p>
<p>The <code>AnagramTopComponent</code> is displayed and,
when you click the Next Word button, you will see that
the scrambled words all come from the selected Manifest file.</p>
<p><img alt="" src="../images/tutorials/porting/ageditorcookie4.png"/></p>
</li>
</ol>
<p>The result of this exercise is that you now see the content of the Manifest
file in the Scrambled Word text field.
Of course, these words are not really scrambled and you cannot
really unscramble them. However, your module is
making use of the content of a file that is supported by a
different set of modules altogether, that is, the Manifest support
modules, as well as related editor modules.</p>
<p>Optionally, before continuing, you can now remove all the groups of
modules (known as "clusters") provided by NetBeans IDE, which
may not be relevant for your own application. To do so, right-click
the <code>AnagramApplication</code> node in the Projects window,
choose Properties, go to the Libraries tab, and uncheck all the
checkboxes, except for <code>harness</code> and <code>platform</code>.
Run the application again and you will see that all the project-related
and editor-related features of the application have now been removed.</p>
<!-- ===================================================================================== -->
<h2 class="tutorial"><a name="porting4"></a>Porting Level 3: Aligned</h2>
<p>In this section, we are concerned with becoming a "good citizen" of the
NetBeans Platform. We are going to expose the state of the TopComponent to
the other modules, so that we can cooperate with them.</p>
<p>As an example of this, we
will modify the TopComponent to offer a <tt>SaveCookie</tt>, which gives
the user a way to store the text typed in the text field. By offering the
<tt>SaveCookie</tt> when changes are made in the text field, the Save button
and the Save menu item under the File menu will become enabled. That is because
the NetBeans Platform provides a context-sensitive Action called <code>SaveAction</code>.
The <code>SaveAction</code> becomes enabled whenever the capability of being saved,
in other words, the <code>SaveCookie</code>, is available. In this case,
we will make the <code>SaveCookie</code> available whenever the user types
something in the <code>guessedWord</code> text field. Then the <code>SaveAction</code>
will automatically become enabled.</p>
<p>When the user
selects the enabled button or menu item, a dialog will be displayed and the button
and menu item will become disabled, until the next time that a change is made
to the text field.</p>
<ol>
<li>Begin by setting a dependency on the Dialogs API.
Do this by right-clicking
the project node in the Projects window, choosing Properties, and
then using the Libraries tab to add the Dialogs API as
a dependency of the module.</li>
<li>Next, we define an implementation of the <code>SaveCookie</code>, somewhere
within the <code>AnagramTopComponent</code> class:
<pre class="examplecode">private class SaveCookieImpl implements SaveCookie {
@Override
public void save() throws IOException {
Confirmation msg = new NotifyDescriptor.Confirmation("Do you want to save \""
+ guessedWord.getText() + "\"?", NotifyDescriptor.OK_CANCEL_OPTION,
NotifyDescriptor.QUESTION_MESSAGE);
Object result = DialogDisplayer.getDefault().notify(msg);
//When user clicks "Yes", indicating they really want to save,
//we need to disable the Save button and Save menu item,
//so that it will only be usable when the next change is made
//to the text field:
if (NotifyDescriptor.YES_OPTION.equals(result)) {
fire(false);
//Implement your save functionality here.
}
}
}</pre>
<p>We have not defined the <code>fire</code> method yet, so the related
statement above will be underlined in red until we do so.</p>
</li>
<li><p>In the constructor, call the as-yet-undefined <code>fire</code> method,
passing in true this time, whenever a change is detected in the
<code>guessedWord</code> text field:</p>
<pre class="examplecode">guessedWord.getDocument().addDocumentListener(new DocumentListener() {
@Override
public void insertUpdate(DocumentEvent arg0) {
fire(true);
}
public void removeUpdate(DocumentEvent arg0) {
fire(true);
}
public void changedUpdate(DocumentEvent arg0) {
fire(true);
}
});</pre></li>
<li><p>Now we declare an <code><a href="http://bits.netbeans.org/dev/javadoc/org-openide-util-lookup/org/openide/util/lookup/InstanceContent.html">InstanceContent</a></code> at the top of the class. The
<code>InstanceContent</code> class is a very powerful class in the NetBeans Platform,
enabling you to update the Lookup on the fly, at runtime. We also declare
the implementation of our <code>SaveCookie</code>:</p>
<pre class="examplecode">InstanceContent ic;
SaveCookieImpl impl;</pre></li>
<li><p>Next, at the end of the constructor, we instantiate the <code>SaveCookie</code> and the <code>InstanceContent</code>,
while adding the <code>InstanceContent</code> to the <code>Lookup</code>
of the <code>AnagramTopComponent</code>:</p>
<pre class="examplecode">impl = new SaveCookieImpl();
ic = new InstanceContent();
associateLookup(new AbstractLookup(ic));</pre></li>
<li><p>Now we can add the <code>fire</code> method, which
dynamically adds and removes the <code>SaveCookie</code>
from the <code>InstanceContent</code>:</p>
<pre class="examplecode">public void fire(boolean modified) {
if (modified) {
//If the text is modified,
//we add the SaveCookie implementation
//to the InstanceContent, which
//is in the Lookup of the TopComponent:
ic.add(impl);
} else {
//Otherwise, we remove the SaveCookie
//from the InstanceContent:
ic.remove(impl);
}
}</pre></li>
<li>By default, you have a Save menu item under the File menu, but no Save button
in the toolbar. For testing purposes, that is, to simplify
checking whether the <code>SaveAction</code> is enabled,
you may want a Save button in the toolbar.
For this purpose, add the following to the layer:
<pre class="examplecode">&lt;folder name="Toolbars"&gt;
&lt;folder name="File"&gt;
&lt;file name="org-openide-actions-SaveAction.shadow"&gt;
&lt;attr name="originalFile" stringvalue="Actions/System/org-openide-actions-SaveAction.instance"/&gt;
&lt;attr name="position" intvalue="444"/&gt;
&lt;/file&gt;
&lt;/folder&gt;
&lt;/folder&gt;</pre></li>
<li><p>Run the application again. Make a change in the "Guessed Word" text field and
notice that the Save button
and the Save menu item become enabled:</p>
<p><img alt="" src="../images/tutorials/porting/ageditorcookie2.png"/></p>
<p>Select either the button or the menu item,
click the "OK" button in the
dialog...</p>
<p><img alt="" src="../images/tutorials/porting/ageditorcookie5.png"/></p>
<p>...and notice that the Save functionality is disabled afterwards.</p>
</li>
</ol>
<p>Congratulations! Now that your application is making use of existing NetBeans Platform functionality,
you have taken
one further step
in successfully aligning it with the NetBeans Platform. Other modules can be now be
plugged into the NetBeans Platform to take advantage of, or even extend, features added by your
application. Hence, not only can your application benefit from what the NetBeans Platform provides,
but you can create features that other modules can use as well.</p>
<!--
<p>You need to continue finding ways
to further align your original application with the functionality offered by the NetBeans Platform,
in order to make it even more of a good "good citizen" and useful member of the community of modules
within the application.</p>
<p>For example, you can write a new node, with child nodes for each
word defined in the class:</p>
<pre class="examplecode">public class WordListNode extends AbstractNode {
private int index;
private final WordLibrary wordLibrary;
public WordListNode() {
this(WordLibrary.getDefault());
}
private WordListNode(WordLibrary w) {
super(new WordListChildren(w));
wordLibrary = w;
}
WordListNode(int index, WordLibrary w) {
super(Children.LEAF);
this.index = index;
this.wordLibrary = w;
setName("Index: " + index);
setDisplayName(wordLibrary.getWord(index));
}
@Override
public String getHtmlDisplayName() {
return "&lt;b&gt;" + wordLibrary.getWord(index) + "&lt;/b&gt; (&lt;i&gt;" + wordLibrary.getScrambledWord(index) + "&lt;/i&gt;)";
}
private static class WordListChildren extends Children.Keys&lt;Integer&gt; {
private final WordLibrary wordLibrary;
public WordListChildren(WordLibrary wordLibrary) {
this.wordLibrary = wordLibrary;
}
@Override
protected void addNotify() {
List&lt;Integer&gt; arr = new ArrayList&lt;Integer&gt;();
for (int i = 0; i &lt; wordLibrary.getSize(); i++) {
arr.add(i);
}
setKeys(arr);
}
@Override
protected void removeNotify() {
setKeys(Collections.&lt;Integer&gt;emptyList());
}
@Override
protected Node[] createNodes(Integer index) {
WordListNode node = new WordListNode(index, wordLibrary);
return new Node[] { node };
}
}
}</pre>
<p>In return, the lifecycle of the original application is now handled by the NetBeans Platform
and you can leverage as much of the existing modules' functionality as is reasonable for your module. In fact,
your original application is now no longer an application, but an integral part of a larger application.</p>
-->
<!-- ===================================================================================== -->
<h2 class="tutorial"><a name="tips"></a>Porting Tips & Tricks</h2>
<p>There are several next steps one can take at this point, aside from further aligning
the application with the NetBeans Platform, as outlined above:</p>
<ul>
<li><b>Attain a thorough understanding of what the NetBeans Platform provides.</b>
As you port your application, you will learn more and more about the
various features that the NetBeans Platform makes available. A central
problem is that the NetBeans Platform is quite large and attaining a thorough
overview of all that it offers can be a lengthy process. A quick shortcut
is to download and print out the <a href="http://refcardz.dzone.com/refcardz/essential-netbeans-platform">Essential NetBeans Platform Refcard</a>,
which is a free DZone document that highlights all the NetBeans Platform
benefits, features, APIs, and many tips and tricks in an easy
to digest format.</li>
<li><b>Become aware of the differences between standard Swing applications
and the NetBeans Platform.</b> For the most part, the standard Swing approach to
creating a user interface will continue to work for your NetBeans Platform
application. However, the NetBeans Platform approach is better, easier, or both
in some cases. One example is that of the NetBeans Dialogs API. The standard Swing approach,
via, for example, the <tt>JOptionsPane</tt>, works OK, but using the NetBeans Dialogs API is easier,
because it automatically centers your dialog in the application and allows you to dismiss it
with the ESC key. Using the Dialogs API also lets you plug in a different DialogDisplayer,
which can make it easier to customize or test your application.
<p>Below is a list of the principle differences between the typical Swing approach
and that of the NetBeans Platform:</p>
<ul>
<li>Loading of images</li>
<li>Loading of resource bundles and localized string</li>
<li>Assigning of mnemonics to labels and buttons</li>
<li>Showing dialogs</li>
</ul>
<p>For details on all of the above items, read
this FAQ: <a href="http://wiki.netbeans.org/wiki/view/DevFaqNbIdeosyncracies">Common calls that should be done slightly differently in NetBeans than standard Swing apps (loading images, localized strings, showing dialogs)</a>.</p>
<p>In addition, note that, since the NetBeans Platform now handles the lifecycle of your module, since it is
now part of the whole application, you can no longer use <tt>System.exit</tt>. Instead, you need to use <tt>LifecycleManager</tt>. To
run code on start up, which should only be done when absolutely necessary, you need to use the NetBeans <tt>ModuleInstall</tt> class and,
specifically, its <tt>restored</tt> method. A useful reference in this context is <a href="http://www.ociweb.com/jnb/jnbOct2005.html#porting">Porting a Java Swing Application to the NetBeans Platform</a>,
by Tom Wheeler, in <a href="http://www.ociweb.com/jnb/jnbOct2005.html#porting">Building A Complete NetBeans Platform Application</a>.</p></li>
<li><p><b>Create a module project for each distinct part of your application.</b> The
NetBeans Platform provides a modular architecture out of the box. Break your
application into one or more modules. Doing so requires some analysis of your
original application and an assessment of which parts could best fit within
a new module and how to communicate between them. Since the example in this
tutorial was simple, we only needed one module. A next step might be to put the
<tt>WordLibrary</tt> class in a separate module and expose it as a public API.
The <tt>StaticWordLibrary</tt> would be put into another module, providing
an implementation of the <tt>WordLibrary</tt> API. Doing so would let other modules
provide user interfaces on top of the API provided by the first module, without
depending in any way on the implementations.</p>
<p>As shown above, you need to put the modules in a module suite. Then set
a dependency in the plugin module on the API module, using the Libraries
panel in the plugin module's Project Properties dialog box. The size of each module, i.e.,
when one should create a new module or continue developing within an existing one, is a
question of debate. Smaller is better, in general.</p></li>
<li><b>Always keep reevaluating what you really need to port.</b> Look at the NetBeans Platform and
decide where there is overlap with your own application. Where there is overlap,
such as the menu bar and About box, decide what you want to do. Typically, you
want to leverage as much as possible from the NetBeans Platform. Therefore, you
would port as little as possible from your own application, while keeping as much
of it as is useful to you.</li>
<li><b>Move distinct parts of your user interface to one or more TopComponents.</b> On the NetBeans
Platform, the <tt>TopComponent</tt> class provides the top level Swing container. In effect,
it is a window. Move the user interface from your original application to one or
more of these windows and discard your original <tt>JFrame</tt>s.</li>
<li><b>Copy the Java classes that do not provide user interface elements.</b> We simply
copied the original <tt>WordLibrary.java</tt> class. You can do the same with the model
of your own Swing applications. You might need to tweak some code to smoothen the transition
between the old Swing application and the new NetBeans Platform application, but (as
in the case shown in this tutorial) this might not even be necessary.</li>
<li><b>Learn from others.</b> Aside from joining the dev@platform.netbeans.org mailing list,
also read the following two crucial articles:
<ul>
<li><a href="http://netbeans.dzone.com/10-tips-4-porting-2-netbeans">Top 10 Tips for Porting to the NetBeans Platform</a></li>
<li><a href="http://java.dzone.com/news/how-to-split-into-modules">How to Split an Application into Modules?</a></li>
</ul>
</li>
<li><b>Watch the Top 10 NetBeans APIs Screencast.</b> The <a href="https://platform.netbeans.org/tutorials/nbm-10-top-apis.html">screencast series</a>
gives a good overview of the NetBeans Platform, with many useful code snippets and coding patterns.</li>
</ul>
<div class="feedback-box"><a href="https://netbeans.org/about/contact_form.html?to=3&amp;subject=Feedback:%20NetBeans%20Platform%20Porting%20Tutorial">Send Us Your Feedback</a></div>
<br style="clear:both;" />
<!-- ======================================================================================== -->
<h2><a name="nextsteps"></a>Next Steps</h2>
<p>For more information about creating and developing NetBeans modules, see the following resources:</p>
<ul>
<li><a href="https://netbeans.org/kb/trails/platform.html">Other Related Tutorials</a></li>
<li><a href="https://netbeans.org/download/dev/javadoc/">NetBeans API Javadoc</a></li>
</ul>
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