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        <h1>NetBeans Property Editor Tutorial</h1>

        <p>This tutorial shows techniques for using property editors in 
            NetBeans, including providing custom editors and custom inplace editors. Specifically,
            the following will be covered:</p>

        <ul>
            <li>Providing your own property editor for an individual Node</li>
            <li>Creating a custom editor</li>
            <li>Creating a custom inplace editor</li>
            <li>Registering a custom property editor globally</li>
        </ul>

        <p><strong class="notes">Note: </strong>This document uses NetBeans Platform 7.1 and
            NetBeans IDE 7.1. If you
            are using an earlier version, see <a href="71/nbm-nodesapi2.html">the previous version
                of this document</a>.</p>

        <p><b>Contents</b></p>
        <p><img src="../../images/articles/72/netbeans-stamp-71-72.gif" class="stamp" width="114" height="114" alt="Content on this page applies to NetBeans IDE 7.1" title="Content on this page applies to NetBeans IDE 7.1"/></p>
        <ul class="toc">
            <li><a href="#custom-editors">Introduction to Custom Property Editors</a></li>
            <li><a href="#creating-custom-editor">Creating a Property Editor</a></li>
            <li><a href="#customEditor">Creating a Custom Editor</a></li>
            <li><a href="#inplace-editor">Creating a Custom Inplace Editor</a></li>
            <li><a href="#registering">Registering DatePropertyEditor Globally</a></li>
            <li><a href="#propertypanel">Using PropertyPanel</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"><a href="https://netbeans.org/downloads/index.html">NetBeans IDE</a></td>
                    <td class="tbltd1">version 7.1 or above</td>
                </tr>
                <tr>
                    <td class="tbltd1"><a href="http://java.sun.com/javase/downloads/index.jsp">Java Developer Kit (JDK)</a></td>
                    <td class="tbltd1">version 6 or above</td>
                </tr>
            </tbody>
        </table>

        <p>Related community tutorials:</p>
        <ul>
            <li><a href="http://netbeans.dzone.com/nb-custom-float-propertyeditor">Custom Float Property Editor (1)</a></li>
            <li><a href="http://netbeans.dzone.com/nb-custom-float-propertyeditor-2">Custom Float Property Editor (2)</a></li>
        </ul>

        <!-- ===================================================================================== -->
        <h2><a name="custom-editors"></a>Introduction to Custom Property Editors</h2>
        <p>Often you may have a property for which either the standard property editor is not
            sufficient, or the property type is a class for which there is no standard 
            property editor.  NetBeans IDE contains classes for many common Java 
            types, but every possible need cannot be covered by a set of generic property
            editors.</p>


        <p>This tutorial is intended as a follow-on to these preceding tutorials, and its
            code is based on the code from them:</p>
        <ul>
            <li><a href="nbm-selection-1.html">Selection Management Tutorial I&#8212;Using a TopComponent's Lookup</a></li>
            <li><a href="nbm-selection-2.html">NetBeans Selection Management Tutorial II&#8212;Using Nodes</a></li>
            <li><a href="nbm-nodesapi2.html">Using the Nodes API</a></li>
        </ul>

        <p>
            You'll pick up where you left off in the previous tutorial, with the class <code>EventNode</code>,
            which wraps an <code>Event</code> object, and offers a read-only property for 
            its <code>index</code> property and a read/write one for its <code>date</code>
            property.</p>

        <h2><a name="creating-custom-editor"></a>Creating a Property Editor</h2>

        <p>The basics of creating a property editor are pretty simple.  The JavaBeans API
            offers a base class, <code>PropertyEditorSupport</code>, which covers most of 
            the basics, and can be used to create a simple property editor with little work.</p>

        <p>Property editors serve two purposes&#8212;converting values to and from strings
            for display in the property sheet, and validating new values when they are set.
            To start out, you will create a property editor which simply provides and accepts a differently
            formatted date.</p>

        <div class="indent">

            <ol>
                <li>Right click the <code>org.myorg.myeditor</code> package, and choose 
                    New &gt; Java Class.  In the wizard, name the class <code>DatePropertyEditor</code>.</li>
                <li>In the code editor, change the class signature to extend 
                    <code>PropertyEditorSupport</code>:
                    <pre class="examplecode">public class DatePropertyEditor extends PropertyEditorSupport {</pre>
                </li>
                <li>Implement <code>setAsText()</code> and <code>getAsText()</code> as follows:
                    <pre class="examplecode">@Override
public String getAsText() {
    Date d = (Date) getValue();
    if (d == null) {
        return "No Date Set";
    }
    return new SimpleDateFormat("MM/dd/yy HH:mm:ss").format(d);
}

@Override
public void setAsText(String s) {
    try {
        setValue (new SimpleDateFormat("MM/dd/yy HH:mm:ss").parse(s));
    } catch (ParseException pe) {
        IllegalArgumentException iae = new IllegalArgumentException ("Could not parse date");
        throw iae;
    }
}</pre>
                </li>
                <li>Open <code>EventNode</code> in the code editor.  Change the line that
                    declares <code>dateProperty</code> so that the variable is declared as
                    <code>PropertySupport.Reflection</code> rather than <code>Property</code>.
                    You will be calling a method specific to <code>PropertySupport.Reflection</code>:
                    <pre class="examplecode">PropertySupport.Reflection dateProp = new PropertySupport.Reflection(obj, Date.class, "date");</pre>
                </li>
                <li>Insert a new line after that line:
                    <pre class="examplecode">dateProp.setPropertyEditorClass(DatePropertyEditor.class);</pre>
                </li>
                <li><p>Run the Event Manager, use Window &gt; Open Editor to open your editor
                        component, and note the new format of the Date property, as shown here:</p>
                    <img alt="" src="../../images/tutorials/custom-editors/71/changed-date-71.png"/>

                </li>

            </ol>

        </div>

        <h2><a name="customEditor"></a>Creating a Custom Editor</h2>
        <p>Another basic feature of standard <code>java.beans.PropertyEditor</code>s is 
            the ability to have a &quot;custom editor&quot;, which usually appears in a 
            dialog when you click a &quot;...&quot; button beside the property in the 
            property sheet.</p>

        <p>Going into the details of implementing such an editor is out of scope for
            this tutorial, but here are the basics:</p>

        <div class="indent">

            <ol>
                <li>Implement the following two methods on <code>DatePropertyEditor</code>:
                    <pre class="examplecode">@Override
public Component getCustomEditor() {
    return new JLabel ("I want to be a custom editor");
}

@Override
public boolean supportsCustomEditor() {
    return true;
}
                    </pre> 
                </li>
                <li><p>Run the Event Manager, and now you have a &quot;...&quot; button beside the
                        property in the property sheet, as shown below:</p>
                    <p><img alt="" src="../../images/tutorials/custom-editors/71/custom-editor-71-1.png"/></p>
                    <p>Click it, and your JLabel appears:</p>
                    <p><img alt="" src="../../images/tutorials/custom-editors/71/custom-editor-71-2.png"/></p>

                    <p>If you were doing this for real, you would create a JPanel, and embed some
                        sort of calendar and/or clock component to make it easy to set the 
                        properties;  the code necessary to do it right would be a distraction here.</p></li>

                <li>Remove the above two methods before continuing.</li>

            </ol>

        </div>

        <h2><a name="inplace-editor"></a>Creating a Custom Inplace Editor</h2>
        <p>What would be really useful is to have a better date editor embedded in the
            property sheet itself.  NetBeans has an API that makes this possible.  It 
            involves a bit of code, but the result is worth it.</p>
        <p>
            Since the SwingX project includes a nice date picker component, you will simply reuse that.
            So the first thing you need to do is to get SwingX into the Event Manager. Since NetBeans
            IDE bundles SwingX, we will get the swingx.jar by browsing into the NetBeans IDE installation
            directory and creating a new module from the swingx.jar that we will find there.</p>

        <div class="indent">

            <ol>
                <li><p>Expand the Event Manager, right-click the Modules node, and choose Add New Library,
                        as shown here:</p>
                    <p>
                        <img alt="" src="../../images/tutorials/custom-editors/71/library-wrapper-71.png"/></p>
                </li>
                <li>Browse for <code>swingx-0.9.5.jar</code> (or whatever version of the JAR is available)
                    in "ide/modules/ext" in
                    the NetBeans IDE installation directory. Click Next.</li>
                <li>Click Next again, set the code name base to <tt>org.jdesktop.swingx</tt>,
                    and then click Finish.</li>
                <li>Right click the My Editor project node in the Projects tab in the 
                    main window, and choose Properties.</li>
                <li>In the Libraries page, click the Add Dependency button, and add a dependency
                    on your new "swingx" module.</li>
            </ol>

        </div>

        <p>Now you are ready to make use of the date picker.  This will involve implementing
            a couple of NetBeans-specific interfaces:</p>
        <ul>
            <li>ExPropertyEditor&#8212;a property editor interface through which the 
                property sheet can pass an &quot;environment&quot; (<code>PropertyEnv</code>)
                object that gives the editor access to the <code>Property</code> object it
                is editing and more.</li>
            <li>InplaceEditor.Factory&#8212;an interface for objects that own an 
                <code>InplaceEditor</code></li>
            <li>InplaceEditor&#8212;an interface that allows a custom component to be
                provided for display in the property sheet.</li>
        </ul>

        <p>You will implement <code>InplaceEditor.Factory</code> and <code>ExPropertyEditor</code>
            directly on <code>DatePropertyEditor</code>, and then create an <code>InplaceEditor</code>
            nested class:</p>

        <div class="indent">

            <ol>
                <li>Change the signature of <code>DatePropertyEditor</code> as follows:
                    <pre class="examplecode">public class DatePropertyEditor extends PropertyEditorSupport implements ExPropertyEditor, InplaceEditor.Factory {</pre>
                </li>
                <li><p>As in earlier examples, press Ctrl-Shift-I to Fix Imports and then
                        use the &quot;Implement All Abstract Methods&quot; to cause the missing methods to
                        be added.</p></li>
                <li>Add the following methods to <code>DatePropertyEditor</code>:
                    <pre class="examplecode">@Override
public void attachEnv(PropertyEnv env) {
    env.registerInplaceEditorFactory(this);
}

private InplaceEditor ed = null;

@Override
public InplaceEditor getInplaceEditor() {
    if (ed == null) {
        ed = new Inplace();
    }
    return ed;
}</pre>
                </li>
                <li>Now you need to implement the <code>InplaceEditor</code> itself.  This will be 
                    an object that owns a swingx <code>JXDatePicker</code> component, and some
                    plumbing methods to set up its value, and dispose of resources when it is no 
                    longer in use.
                    It requires a bit of code, but it's all quite straightforward.  Just 
                    create <code>Inplace</code> as
                    a static nested class inside <code>DatePropertyEditor</code>:
                    <pre class="examplecode">private static class Inplace implements InplaceEditor {

    private final JXDatePicker picker = new JXDatePicker();
    private PropertyEditor editor = null;

    @Override
    public void connect(PropertyEditor propertyEditor, PropertyEnv env) {
        editor = propertyEditor;
        reset();
    }

    @Override
    public JComponent getComponent() {
        return picker;
    }

    @Override
    public void clear() {
        //avoid memory leaks:
        editor = null;
        model = null;
    }

    @Override
    public Object getValue() {
        return picker.getDate();
    }

    @Override
    public void setValue(Object object) {
        picker.setDate((Date) object);
    }

    @Override
    public boolean supportsTextEntry() {
        return true;
    }

    @Override
    public void reset() {
        Date d = (Date) editor.getValue();
        if (d != null) {
            picker.setDate(d);
        }
    }

    @Override
    public KeyStroke[] getKeyStrokes() {
        return new KeyStroke[0];
    }

    @Override
    public PropertyEditor getPropertyEditor() {
        return editor;
    }

    @Override
    public PropertyModel getPropertyModel() {
        return model;
    }

    private PropertyModel model;

    @Override
    public void setPropertyModel(PropertyModel propertyModel) {
        this.model = propertyModel;
    }

    @Override
    public boolean isKnownComponent(Component component) {
        return component == picker || picker.isAncestorOf(component);
    }

    @Override
    public void addActionListener(ActionListener actionListener) {
        //do nothing - not needed for this component
    }

    @Override
    public void removeActionListener(ActionListener actionListener) {
        //do nothing - not needed for this component
    }

}</pre>
                </li>
                <li><p>If you haven't already, press Ctrl-Shift-I to Fix Imports.</p></li>
                <li><p>Run the Event Manager again, use Window &gt; Open Editor to open your
                        editor (really it's not much of an editor anymore), select an instance
                        of <code>EventNode</code> and click the value of the date property in
                        the property sheet.  Notice that the date picker popup appears, and
                        behaves exactly as it should, as shown below:</p>

                    <p>
                        <img alt="" src="../../images/tutorials/custom-editors/71/custom-editor-71-3.png"/></p>
                </li>

            </ol>

        </div>

        <h2><a name="registering"></a>Registering DatePropertyEditor Globally</h2>
        <p>Often it is useful to register a property editor to be used for all properties
            of a given type.  Indeed, your <code>DatePropertyEditor</code> is generally
            useful for any property of the type <code>java.util.Date</code>.  While usefulness
            is not the primary determinant of whether such a property editor should be 
            registered, if your application or module will regularly deal with Date properties,
            it might be useful to do so.</p>
        <p>Here is how to register <code>DatePropertyEditor</code>
            so that any property of the type <code>java.util.Date</code> will use <code>DatePropertyEditor</code>
            in the property sheet:</p>

        <div class="indent">

            <ol>
                <li>Right click the <code>org.myorg.myeditor</code> package in the My Editor
                    project and choose New &gt; Other.  Under the NetBeans Module Development
                    category, select Module Installer. Click Finish.  A
                    subclass of <code>org.openide.modules.ModuleInstall</code> will be created for
                    you&#8212;this class contains code that will run during startup.
                </li>
                <li>Implement the <code>restored()</code> method, which is run during startup,
                    as follows:
                    <pre class="examplecode">public void restored() {
    PropertyEditorManager.registerEditor(Date.class, DatePropertyEditor.class);
}</pre>
                    This code will register your custom <code>DatePropertyEditor</code> as the default editor
                    for all properties of the type <code>java.util.Date</code> throughout the system.
                </li>
                <li>Press Ctrl-Shift-I to Fix Imports.</li>
            
            </ol>    

        </div>

        <p>Remember, you should only do this if you really need to&#8212;<code>ModuleInstall</code>
            classes slow down application startup, because they mean more code has to run
            during startup.  So where possible they should be avoided.  If you do need to 
            register a lot of property editors, though, it may make sense to aggregate them
            in a single module that registers them during startup.</p>  
        <p>If the type you want to provide a property editor for is in your module, it may
            be preferable to place the registration code in a static block that will be 
            invoked when that class is loaded, e.g.</p>
        <pre class="examplecode">public class Foo {

    static {
         PropertyEditorManager.registerEditor(Foo.class, FooEditor.class);
    }
    //...</pre>
        <blockquote>
            <p><font color="red"><b>Caveat:</b> If you are not sure your property editor
                    will be used during a typical session, a better technique may be to use 
                    <code>PropertyEditorManager.setEditorSearchPath()</code>, adding your package
                    to the array of packages returned by 
                    <code>PropertyEditorManager.getEditorSearchPath()</code>.  The above code will
                    cause <code>FooEditor.class</code> to be loaded into memory&#8212;this is paying
                    a price of about 1K of memory for something that will not be used.  For one
                    or two property editors, this is probably acceptable;  for more, it is preferable
                    to aggregate all of your property editors into one package, name the classes
                    appropriately and register that package is being on the search path.  For 
                    more information on registering property editors, see the javadoc for 
                    <code><a href="http://java.sun.com/j2se/1.4.2/docs/api/java/beans/PropertyEditorManager.html">PropertyEditorManager</a></code>.

                </font></p>
        </blockquote>

        <h2><a name="propertypanel"></a>Using PropertyPanel</h2>

        <p>While you won't cover it in great detail, it is worth mentioning that the property
            sheet is not the only place that <code>Node.Property</code> objects are useful;
            there is also a convenient UI class in the <code>org.openide.explorer.PropertySheet</code>
            class called <code>PropertyPanel</code>.  It's function is to display one property,
            much as it is displayed in the property sheet, providing an editor field and a
            custom editor button, or you have called 
            <code>somePropertyPanel.setPreferences(PropertyPanel.PREF_CUSTOM_EDITOR)</code>,
            it will display the custom editor for a <code>Property</code>.  It is useful as
            a convenient way to get an appropriate UI component for editing any getter/setter
            pair for which there is a property editor.</p>

        <!--
        <h2><a name="propertypanel"></a>Using PropertyPanel</h2>
        The property sheet is not the only place <code>Node.Property</code>s are 
        useful:  There is also a convenient UI class in the <code>org.openide.explorer.PropertySheet</code>
        class called <code>PropertyPanel</code>.  It's function is to display one property,
        much as it is displayed in the property sheet, providing an editor field and a
        custom editor button.  So for the final exercise, you will modify the <code>MyViewer</code>
        component (which is now nearly superfluous, since the property sheet now does
        everything it did) to use <code>PropertyPanel</code> to show one property of
        the currently selected <code>EventNode</code>.
        
        <ol>
            <li>Right-click the My Viewer project and choose Properties from the popup
            menu</li>
            <li>On the Libraries page, click the Add button.  In the resulting dialog,
            type PropertyPanel.  The dialog should auto-select &quot;Explorer and Property Sheet API&quot;.
            When it does, press Enter or click OK to add the dependency.  The My Viewer
            module can now refer to classes in the property sheet API.
            </li>
            <li>Click the Add button once more, and type &quot;AbstractNode&quot; and
            add a dependency on the Nodes API from My Viewer&#8212;you will be needing 
            that momentarily</li>
            <li>Open <code>MyViewerTopComponent</code> in Matisse, the form editor.</li>
            <li>Select all of the components in <code>MyViewerTopComponent</code> and 
            delete them</li>
            <li>In the Component Inspector, right-click the node labeled &quot;TopComponent&quot;
            and choose Set Layout &gt; FlowLayout from the popup menu.</li>
            <li>Press the Code button in the editor toolbar to switch to the code editor</li>
            <li>Add the following line to the head of the class definition, so it appears thusly:
            <pre class=examplecode>
        public final class MyViewerTopComponent extends TopComponent implements LookupListener {
            private final PropertyPanel pnl;
            </pre>
            </li>
            <li>Add the following line at the end of the constructor:
            <pre class=examplecode>
                add (pnl = new PropertyPanel());
            </pre>
            </li>
        -->
        <!--</ol>-->

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