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 <title>NetBeans Java Language Infrastructure Tutorial (Part 2) for NetBeans Platform 6.0</title>
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  content="A walk-through of the Retouche approach.">
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 <body>
 <h1>NetBeans Java Language Infrastructure Tutorial (Part 2)</h1>

 <p>In the <a href="nbm-copyfqn.html">previous tutorial</a>, you created a button in the toolbar which,
  when clicked, explicitly invoked the underlying Java language
  infrastructure. In this tutorial, you will make implicit calls
  to the same infrastructure, by registering factory classes
  in the META-INF/services folder. At the end of this tutorial,
  the Projects window will look as follows:

       <p align="left"><img border="1" src="../../images/tutorials/whichelement/projects-window-final.png" alt="Projects window">

       <p>After installation of the module, information about
           the <tt>Element</tt> under the caret is displayed
           in a read-only textfield in the IDE's status bar. For example,
           if a package is identified under the caret, the
       textfield shows the following information (look in the status bar
       at the bottom of the screenshot below):</p>

   <p align="left"><img border="1" src="../../images/tutorials/whichelement/package-found.png" alt="Package found">

         <p>However, if a field is under the caret, the textfield shows
         different content:</p>

         <p align="left"><img border="1" src="../../images/tutorials/whichelement/variable-found.png" alt="Variable found">

         <p>Similarly, if the caret is placed on a
         class declaration or a method, the underlying Java language infrastructure
         is called implicitly, i.e., without the user needing to do anything explicit,
         and the status bar displays information relevant to the current
         <tt>Element</tt>.

         <h3>Contents</h3>
      <table border="0" cellpadding="0" cellspacing="0" width="100%">
        <tbody><tr>
          <td align="left" valign="top">
 <ul>
             <li><a href="#installing-the-software">Installing the Software</a></li>
             <li><a href="#setting-up-the-module">Setting Up the Module</a></li>
             <li><a href="#creating-a-caret-aware-java-source-task-factory">Creating a Caret-Aware Java Source Task Factory</a></li>
             <li><a href="#identifying-java-source-files">Identifying Java Source Files</a></li>
             <li><a href="#determining-open-state">Determining Open State</a></li>
             <li><a href="#detecting-the-element-under-the-caret">Detecting the Element Under the Cursor</a></li>
             <li><a href="#doing-something-useful">Doing Something Useful</a></li>
         </ul></td>
          <td width="20"> </td>

            <td align="right" valign="top">
       <img src="../../images/articles/60/netbeans-stamp60-61.gif"
 alt="Content on this page applies to NetBeans IDE 6.0" title="Content on this page applies to the NetBeans
 IDE 6.0" border="0">
    </td>
        </tr>
      </tbody></table>

         <p>The following resources have been provided specifically to help you get acquainted with the Retouche APIs:

         <ul>
             <li><a href="http://wiki.netbeans.org/wiki/view/Java_DevelopersGuide">Java Infrastructure Developer's Guide</a>
             <li><a href="http://wiki.netbeans.org/wiki/view/RetoucheDeveloperFAQ">Retouche Developer FAQ</a>
         </ul>


         <p>For more information on creating NetBeans modules, see the <a href="https://platform.netbeans.org/index.html">
             NetBeans Development Project home</a> on the NetBeans website. If you have questions, visit the
             <a href="http://wiki.netbeans.org/wiki/view/NetBeansDeveloperFAQ">NetBeans Developer FAQ</a> or use the feedback link
         at the bottom of this page.</p>

         <br />


 <!-- ===================================================================================== -->

 <h2 class="tutorial"><a name="installing-the-software"></a>Installing the Software</h2>


       <p>Before you begin, you need to install the following software on your
         computer:</p>
 <ul>
     <li>The J2SE(TM) Development Kit (JDK), version 5.0 or compatible
     (<a href="http://java.sun.com/javase/downloads/index.jsp">download the
     most recent JDK</a>).</li>
         <li>NetBeans IDE 6.0 (<a href="http://download.netbeans.org/netbeans/6.0/final/">download</a>).
     </ul>


 <p><h2><a name="setting-up-the-module"></a>Setting Up the Module</h2>

      <p>In this section, we use wizards to create a module project and
          to set dependencies on relevant NetBeans modules.

          <ol>

          <li>Choose File &gt; New Project. In the New Project wizard,
          choose NetBeans Modules under Categories and Module
      under Projects. Click Next.

      <li>Type <tt>WhichElement</tt> in Project Name
      and set Project Location to an appropriate folder on your disk. If they
      are not selected, select
      Standalone Module and Set as Main Project. Click Next.

      <li>Type <tt>org.netbeans.modules.whichelement</tt> in Code Name Base
      and <tt>WhichElement</tt> in Module Display Name. Click Finish.

      <li>Right-click the project, choose Properties, click Libraries
      in the Project Properties dialog box and declare a dependency on the following APIs:

      <p><ul>
          <li>File System API
          <li>Javac API Wrapper
          <li>Java Source
          <li>UI Utilities API
          <li>Utilities API
      </ul>


      <p>Click OK.

  </ol>

  <p><h2><a name="creating-a-caret-aware-java-source-task-factory"></a>Creating a Caret-Aware Java Source Task Factory</h2>

       <p>In this section, we create a task factory
           for Java source files that is caret-aware. We then
           register it in the META-INF/services folder.

           <ol>
           <li>Right-click the module project, choose
           New &gt; Java Class. Click Next.

           <li>Type <tt>WhichElementJavaSourceTaskFactory</tt> in
           Class Name. Click Finish.

           <li>Change the default code to the following:

           <pre class="examplecode">public class WhichElementJavaSourceTaskFactory extends CaretAwareJavaSourceTaskFactory {

     public WhichElementJavaSourceTaskFactory() {
         super(Phase.RESOLVED, Priority.LOW);
     }

     public CancellableTask&lt;CompilationInfo&gt; createTask(FileObject fileObject) {
         return new WhichElementTask(this, fileObject);
     }

 }</pre>


 <li>Create a skeleton implementation of CancellableTask,
  which we will fill out later:

 <pre class="examplecode">public class WhichElementTask implements CancellableTask&lt;CompilationInfo&gt; {

     private WhichElementJavaSourceTaskFactory whichElementJavaSourceTaskFactory;
     private FileObject fileObject;

     WhichElementTask(WhichElementJavaSourceTaskFactory whichElementJavaSourceTaskFactory, FileObject fileObject) {
         this.whichElementJavaSourceTaskFactory = whichElementJavaSourceTaskFactory;
         this.fileObject = fileObject;
     }

     public void cancel() {
         throw new UnsupportedOperationException("Not supported yet.");
     }

     public void run(CompilationInfo compilationInfo) {
         String fileName = compilationInfo.getFileObject().getName();
         StatusDisplayer.getDefault().setStatusText("File name: " + fileName);
     }

 }</pre>

       <li>Register the factory in the META-INF/services folder. To
   do so, first find the "all services" node, in the Important Files
  node, shown below:</p>

       <p align="left"><img border="1" src="../../images/tutorials/whichelement/caretaware-metainf2.png" alt="caretaware-metainf2">

       <p>Expand it and look for the <tt>org.netbeans.api.java.source.JavaSourceTaskFactory</tt>. Then right-click it,
       as shown here:</p>

       <p align="left"><img border="1" src="../../images/tutorials/whichelement/caretaware-metainf1.png" alt="caretaware-metainf1">

       <p>Now you can browse to your factory class...

       <p align="left"><img border="1" src="../../images/tutorials/whichelement/caretaware-metainf3.png" alt="caretaware-metainf3">

       <p>...and once you click OK, new nodes are added to your project:

       <p align="left"><img border="1" src="../../images/tutorials/whichelement/caretaware-metainf4.png" alt="caretaware-metainf4">


      <li>Right-click the module and choose Install.</p>

      <p>Once the module is installed, open a Java file
       and notice that, automatically, the file name
       appears in the status bar, as shown below:</p>

       <p align="left"><img border="1" src="../../images/tutorials/whichelement/first-open.png" alt="first open">

  </ol>


  <p><h2><a name="identifying-java-source-files"></a>Creating a Status Element Provider</h2>

  <p>In this section...

      <ol>

      <li>Create a Java class called <tt>WhichElementStatusElementProvider</tt>,
      and fill it out as follows:

      <pre class="examplecode">public class WhichElementStatusElementProvider implements StatusLineElementProvider {

     private WhichElementPanel whichElementPanel;
     public WhichElementStatusElementProvider() {
         whichElementPanel = new WhichElementPanel();
     }

     public Component getStatusLineElement() {
         return whichElementPanel;
     }

     static class WhichElementPanel extends JPanel {
         private JLabel iconLabel;

         private JTextField whichElementTextField;

         WhichElementPanel() {
             super(new FlowLayout(FlowLayout.LEADING, 0,0));

             iconLabel = new JLabel(){
                 Point tooltipLocation;

                 <b>// Consider the font's size to compute the location of the
                 // tooltip:</b>
                 public void addNotify() {
                     super.addNotify();
                     tooltipLocation = new Point(0, -2 * getFont().getSize());
                 }

                 public Point getToolTipLocation(MouseEvent event) {
                     return tooltipLocation;
                 }
             };

             add(iconLabel, BorderLayout.WEST);

             <b>// Create the text field:</b>
             whichElementTextField = new JTextField(40) {
                 Point tooltipLocation;

                 <b>// Consider the font's size to compute the location of the
                 // tooltip:</b>
                 public void addNotify() {
                     super.addNotify();
                     tooltipLocation = new Point(0, -2 * getFont().getSize());
                 }

                 public Point getToolTipLocation(MouseEvent event) {
                     return tooltipLocation;
                 }
             };

             <b>// Set the text field to read-only:</b>
             whichElementTextField.setEditable(false);

             add(whichElementTextField, BorderLayout.CENTER);
         }

         void setIcon(Icon icon) {
             iconLabel.setIcon(icon);
         }

         void setIconToolTip(String text) {
             iconLabel.setToolTipText(text);
         }

         void setText(String text) {
             whichElementTextField.setText(text);
         }

         public void setToolTipText(String text) {
             whichElementTextField.setToolTipText(text);
         }
     }
 }</pre>

      <li>Check that your import statements are as follows:

      <pre class="examplecode">import java.awt.BorderLayout;
 import java.awt.Component;
 import java.awt.FlowLayout;
 import java.awt.Point;
 import java.awt.event.MouseEvent;
 import javax.swing.Icon;
 import javax.swing.JLabel;
 import javax.swing.JPanel;
 import javax.swing.JTextField;
 import org.openide.awt.StatusLineElementProvider;</pre>


      <li>As in the previous section, register your new class
      in the META-INF/services folder, this time in <tt>org.openide.awt.StatusDisplayer</tt>,
  as shown below:</p>

   <p align="left"><img border="1" src="../../images/tutorials/whichelement/caretaware-metainf5.png" alt="metainf">


   <li>Finally...

 <pre class="examplecode">public class WhichElementTask implements CancellableTask&lt;CompilationInfo&gt; {

     private WhichElementJavaSourceTaskFactory whichElementJavaSourceTaskFactory;
     private FileObject fileObject;
     private boolean canceled;
     WhichElementStatusElementProvider.WhichElementPanel whichElementPanel;

     WhichElementTask(WhichElementJavaSourceTaskFactory whichElementJavaSourceTaskFactory,FileObject fileObject) {
         this.whichElementJavaSourceTaskFactory = whichElementJavaSourceTaskFactory;
         this.fileObject = fileObject;
     }

     private static final Collection<Modifier> NO_MODIFIERS = Collections.<Modifier>emptySet();

     public void run(CompilationInfo compilationInfo) {
         <b>// Find the TreePath for the caret position:</b>
         TreePath tp =
                 compilationInfo.getTreeUtilities().pathFor(whichElementJavaSourceTaskFactory.getLastPosition(fileObject));

         <b>// if cancelled, return:</b>
         if (isCancelled()) {
             return;
         }

         <b>// Get Element:</b>
         Element element = compilationInfo.getTrees().getElement(tp);

         <b>// if cancelled, return:</b>
         if (isCancelled()) {
             return;
         }

         String status = "";
         String iconToolTip = "";
         Icon icon = UiUtils.getElementIcon(ElementKind.PARAMETER, NO_MODIFIERS);

         if (element != null) {
             String modifiers = element.getModifiers().toString();
             if (modifiers.startsWith("[") && modifiers.endsWith("]")) {
                 modifiers = modifiers.substring(1, modifiers.length() -1).replaceAll(",", "").trim();
             }
             iconToolTip =  modifiers + (modifiers.length() > 0 ? " " : "");
             icon = UiUtils.getElementIcon(element.getKind(), element.getModifiers());

             if (element instanceof PackageElement) {
                 PackageElement packageElement = (PackageElement) element;
                 status = packageElement.toString();
                 iconToolTip += element.getKind().name().toLowerCase();
             } else if (element instanceof TypeElement) {
                 TypeElement typeElement = (TypeElement) element;
                 status = typeElement.getQualifiedName().toString();
                 iconToolTip += element.getKind().name().toLowerCase();
             } else if (element instanceof VariableElement) {
                 VariableElement variableElement = (VariableElement) element;
                 status = variableElement.toString() + ":" + variableElement.asType().toString();
                 iconToolTip += element.getKind().name().toLowerCase();
             } else if (element instanceof ExecutableElement) {
                 ExecutableElement executableElement = (ExecutableElement) element;
                 // Method
                 if (element.getKind() == ElementKind.METHOD) {
                     status = executableElement.getEnclosingElement().toString()
                             + "."
                             + executableElement.toString()
                             + ":"
                             + executableElement.getReturnType().toString();
                     iconToolTip += element.getKind().name().toLowerCase();
                 } else if (element.getKind() == ElementKind.CONSTRUCTOR) { // CTOR - use enclosing class name
                     status = executableElement.getEnclosingElement().toString()
                             + "."
                             + executableElement.toString();
                     iconToolTip += element.getKind().name().toLowerCase();
                 }
             }
         }

         WhichElementStatusElementProvider.WhichElementPanel localWhichElementPanel = getWhichElementPanel();

         <b>// Set the info:</b>
         if (localWhichElementPanel != null) {
             localWhichElementPanel.setIcon(icon);
             localWhichElementPanel.setIconToolTip(iconToolTip);
             localWhichElementPanel.setText(status);
             localWhichElementPanel.setToolTipText(status);
         }
     }

     private WhichElementStatusElementProvider.WhichElementPanel getWhichElementPanel() {
         if (whichElementPanel == null) {
             StatusLineElementProvider statusLineElementProvider = (StatusLineElementProvider) Lookup.getDefault().lookup(WhichElementStatusElementProvider.class);
             if (statusLineElementProvider != null) {
                 whichElementPanel = (WhichElementStatusElementProvider.WhichElementPanel) statusLineElementProvider.getStatusLineElement();
             }
         }
         return whichElementPanel;
     }

     <b>/**
      * After this method is called the task if running should exit the run
      * method immediately.
      */</b>
     public final synchronized void cancel() {
         canceled = true;
     }

     protected final synchronized boolean isCancelled() {
         return canceled;
     }
 }</pre>


      <li>Install the module again.


  </ol>


 <br>
 <div class="feedback-box"><a href="https://netbeans.org/about/contact_form.html?to=3&amp;subject=Feedback:%20Java%20Language%20Infrastructure%20Tutorial%20Part%202">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 Module, see the following resources:
   <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>

   <hr>

     <!-- ======================================================================================== -->

     </body>
 </html>
	<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Strict//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-strict.dtd">
	<html xmlns="http://www.w3.org/1999/xhtml">
	<head>
	<!-- -- xhtml -- -->
	<title>NetBeans Java Language Infrastructure Tutorial (Part 2) for NetBeans Platform 6.0</title>
	<link rel="stylesheet" type="text/css" href="https://netbeans.org/netbeans.css">
	<meta name="AUDIENCE" content="NBUSER">
	<meta name="TYPE" content="ARTICLE">
	<meta name="EXPIRES" content="N">
	<meta name="developer" content="geertjan.wielenga@sun.com">
	<meta name="indexed" content="y">
	<meta name="description"
	content="A walk-through of the Retouche approach.">
	<!-- Copyright (c) 2007 Sun Microsystems, Inc. All rights reserved. -->
	<!-- Use is subject to license terms.-->
	</head>
	<body>
	<h1>NetBeans Java Language Infrastructure Tutorial (Part 2)</h1>

	<p>In the <a href="nbm-copyfqn.html">previous tutorial</a>, you created a button in the toolbar which,
	when clicked, explicitly invoked the underlying Java language
	infrastructure. In this tutorial, you will make implicit calls
	to the same infrastructure, by registering factory classes
	in the META-INF/services folder. At the end of this tutorial,
	the Projects window will look as follows:

	<p align="left"><img border="1" src="../../images/tutorials/whichelement/projects-window-final.png" alt="Projects window">

	<p>After installation of the module, information about
	the <tt>Element</tt> under the caret is displayed
	in a read-only textfield in the IDE's status bar. For example,
	if a package is identified under the caret, the
	textfield shows the following information (look in the status bar
	at the bottom of the screenshot below):</p>

	<p align="left"><img border="1" src="../../images/tutorials/whichelement/package-found.png" alt="Package found">

	<p>However, if a field is under the caret, the textfield shows
	different content:</p>

	<p align="left"><img border="1" src="../../images/tutorials/whichelement/variable-found.png" alt="Variable found">

	<p>Similarly, if the caret is placed on a
	class declaration or a method, the underlying Java language infrastructure
	is called implicitly, i.e., without the user needing to do anything explicit,
	and the status bar displays information relevant to the current
	<tt>Element</tt>.

	<h3>Contents</h3>
	<table border="0" cellpadding="0" cellspacing="0" width="100%">
	<tbody><tr>
	<td align="left" valign="top">
	<ul>
	<li><a href="#installing-the-software">Installing the Software</a></li>
	<li><a href="#setting-up-the-module">Setting Up the Module</a></li>
	<li><a href="#creating-a-caret-aware-java-source-task-factory">Creating a Caret-Aware Java Source Task Factory</a></li>
	<li><a href="#identifying-java-source-files">Identifying Java Source Files</a></li>
	<li><a href="#determining-open-state">Determining Open State</a></li>
	<li><a href="#detecting-the-element-under-the-caret">Detecting the Element Under the Cursor</a></li>
	<li><a href="#doing-something-useful">Doing Something Useful</a></li>
	</ul></td>
	<td width="20"> </td>

	<td align="right" valign="top">
	<img src="../../images/articles/60/netbeans-stamp60-61.gif"
	alt="Content on this page applies to NetBeans IDE 6.0" title="Content on this page applies to the NetBeans
	IDE 6.0" border="0">
	</td>
	</tr>
	</tbody></table>

	<p>The following resources have been provided specifically to help you get acquainted with the Retouche APIs:

	<ul>
	<li><a href="http://wiki.netbeans.org/wiki/view/Java_DevelopersGuide">Java Infrastructure Developer's Guide</a>
	<li><a href="http://wiki.netbeans.org/wiki/view/RetoucheDeveloperFAQ">Retouche Developer FAQ</a>
	</ul>



	<p>For more information on creating NetBeans modules, see the <a href="https://platform.netbeans.org/index.html">
	NetBeans Development Project home</a> on the NetBeans website. If you have questions, visit the
	<a href="http://wiki.netbeans.org/wiki/view/NetBeansDeveloperFAQ">NetBeans Developer FAQ</a> or use the feedback link
	at the bottom of this page.</p>

	<br />



	<!-- ===================================================================================== -->

	<h2 class="tutorial"><a name="installing-the-software"></a>Installing the Software</h2>


	<p>Before you begin, you need to install the following software on your
	computer:</p>
	<ul>
	<li>The J2SE(TM) Development Kit (JDK), version 5.0 or compatible
	(<a href="http://java.sun.com/javase/downloads/index.jsp">download the
	most recent JDK</a>).</li>
	<li>NetBeans IDE 6.0 (<a href="http://download.netbeans.org/netbeans/6.0/final/">download</a>).
	</ul>


	<p><h2><a name="setting-up-the-module"></a>Setting Up the Module</h2>

	<p>In this section, we use wizards to create a module project and
	to set dependencies on relevant NetBeans modules.

	<ol>

	<li>Choose File > New Project. In the New Project wizard,
	choose NetBeans Modules under Categories and Module
	under Projects. Click Next.

	<li>Type <tt>WhichElement</tt> in Project Name
	and set Project Location to an appropriate folder on your disk. If they
	are not selected, select
	Standalone Module and Set as Main Project. Click Next.

	<li>Type <tt>org.netbeans.modules.whichelement</tt> in Code Name Base
	and <tt>WhichElement</tt> in Module Display Name. Click Finish.

	<li>Right-click the project, choose Properties, click Libraries
	in the Project Properties dialog box and declare a dependency on the following APIs:

	<p><ul>
	<li>File System API
	<li>Javac API Wrapper
	<li>Java Source
	<li>UI Utilities API
	<li>Utilities API
	</ul>


	<p>Click OK.

	</ol>

	<p><h2><a name="creating-a-caret-aware-java-source-task-factory"></a>Creating a Caret-Aware Java Source Task Factory</h2>

	<p>In this section, we create a task factory
	for Java source files that is caret-aware. We then
	register it in the META-INF/services folder.

	<ol>
	<li>Right-click the module project, choose
	New > Java Class. Click Next.

	<li>Type <tt>WhichElementJavaSourceTaskFactory</tt> in
	Class Name. Click Finish.

	<li>Change the default code to the following:

	<pre class="examplecode">public class WhichElementJavaSourceTaskFactory extends CaretAwareJavaSourceTaskFactory {

	public WhichElementJavaSourceTaskFactory() {
	super(Phase.RESOLVED, Priority.LOW);
	}

	public CancellableTask<CompilationInfo> createTask(FileObject fileObject) {
	return new WhichElementTask(this, fileObject);
	}

	}</pre>


	<li>Create a skeleton implementation of CancellableTask,
	which we will fill out later:

	<pre class="examplecode">public class WhichElementTask implements CancellableTask<CompilationInfo> {

	private WhichElementJavaSourceTaskFactory whichElementJavaSourceTaskFactory;
	private FileObject fileObject;

	WhichElementTask(WhichElementJavaSourceTaskFactory whichElementJavaSourceTaskFactory, FileObject fileObject) {
	this.whichElementJavaSourceTaskFactory = whichElementJavaSourceTaskFactory;
	this.fileObject = fileObject;
	}

	public void cancel() {
	throw new UnsupportedOperationException("Not supported yet.");
	}

	public void run(CompilationInfo compilationInfo) {
	String fileName = compilationInfo.getFileObject().getName();
	StatusDisplayer.getDefault().setStatusText("File name: " + fileName);
	}

	}</pre>

	<li>Register the factory in the META-INF/services folder. To
	do so, first find the "all services" node, in the Important Files
	node, shown below:</p>

	<p align="left"><img border="1" src="../../images/tutorials/whichelement/caretaware-metainf2.png" alt="caretaware-metainf2">

	<p>Expand it and look for the <tt>org.netbeans.api.java.source.JavaSourceTaskFactory</tt>. Then right-click it,
	as shown here:</p>

	<p align="left"><img border="1" src="../../images/tutorials/whichelement/caretaware-metainf1.png" alt="caretaware-metainf1">

	<p>Now you can browse to your factory class...

	<p align="left"><img border="1" src="../../images/tutorials/whichelement/caretaware-metainf3.png" alt="caretaware-metainf3">

	<p>...and once you click OK, new nodes are added to your project:

	<p align="left"><img border="1" src="../../images/tutorials/whichelement/caretaware-metainf4.png" alt="caretaware-metainf4">


	<li>Right-click the module and choose Install.</p>

	<p>Once the module is installed, open a Java file
	and notice that, automatically, the file name
	appears in the status bar, as shown below:</p>

	<p align="left"><img border="1" src="../../images/tutorials/whichelement/first-open.png" alt="first open">

	</ol>


	<p><h2><a name="identifying-java-source-files"></a>Creating a Status Element Provider</h2>

	<p>In this section...

	<ol>

	<li>Create a Java class called <tt>WhichElementStatusElementProvider</tt>,
	and fill it out as follows:

	<pre class="examplecode">public class WhichElementStatusElementProvider implements StatusLineElementProvider {

	private WhichElementPanel whichElementPanel;
	public WhichElementStatusElementProvider() {
	whichElementPanel = new WhichElementPanel();
	}

	public Component getStatusLineElement() {
	return whichElementPanel;
	}

	static class WhichElementPanel extends JPanel {
	private JLabel iconLabel;

	private JTextField whichElementTextField;

	WhichElementPanel() {
	super(new FlowLayout(FlowLayout.LEADING, 0,0));

	iconLabel = new JLabel(){
	Point tooltipLocation;

	<b>// Consider the font's size to compute the location of the
	// tooltip:</b>
	public void addNotify() {
	super.addNotify();
	tooltipLocation = new Point(0, -2 * getFont().getSize());
	}

	public Point getToolTipLocation(MouseEvent event) {
	return tooltipLocation;
	}
	};

	add(iconLabel, BorderLayout.WEST);

	<b>// Create the text field:</b>
	whichElementTextField = new JTextField(40) {
	Point tooltipLocation;

	<b>// Consider the font's size to compute the location of the
	// tooltip:</b>
	public void addNotify() {
	super.addNotify();
	tooltipLocation = new Point(0, -2 * getFont().getSize());
	}

	public Point getToolTipLocation(MouseEvent event) {
	return tooltipLocation;
	}
	};

	<b>// Set the text field to read-only:</b>
	whichElementTextField.setEditable(false);

	add(whichElementTextField, BorderLayout.CENTER);
	}

	void setIcon(Icon icon) {
	iconLabel.setIcon(icon);
	}

	void setIconToolTip(String text) {
	iconLabel.setToolTipText(text);
	}

	void setText(String text) {
	whichElementTextField.setText(text);
	}

	public void setToolTipText(String text) {
	whichElementTextField.setToolTipText(text);
	}
	}
	}</pre>

	<li>Check that your import statements are as follows:

	<pre class="examplecode">import java.awt.BorderLayout;
	import java.awt.Component;
	import java.awt.FlowLayout;
	import java.awt.Point;
	import java.awt.event.MouseEvent;
	import javax.swing.Icon;
	import javax.swing.JLabel;
	import javax.swing.JPanel;
	import javax.swing.JTextField;
	import org.openide.awt.StatusLineElementProvider;</pre>


	<li>As in the previous section, register your new class
	in the META-INF/services folder, this time in <tt>org.openide.awt.StatusDisplayer</tt>,
	as shown below:</p>

	<p align="left"><img border="1" src="../../images/tutorials/whichelement/caretaware-metainf5.png" alt="metainf">


	<li>Finally...

	<pre class="examplecode">public class WhichElementTask implements CancellableTask<CompilationInfo> {

	private WhichElementJavaSourceTaskFactory whichElementJavaSourceTaskFactory;
	private FileObject fileObject;
	private boolean canceled;
	WhichElementStatusElementProvider.WhichElementPanel whichElementPanel;

	WhichElementTask(WhichElementJavaSourceTaskFactory whichElementJavaSourceTaskFactory,FileObject fileObject) {
	this.whichElementJavaSourceTaskFactory = whichElementJavaSourceTaskFactory;
	this.fileObject = fileObject;
	}

	private static final Collection<Modifier> NO_MODIFIERS = Collections.<Modifier>emptySet();

	public void run(CompilationInfo compilationInfo) {
	<b>// Find the TreePath for the caret position:</b>
	TreePath tp =
	compilationInfo.getTreeUtilities().pathFor(whichElementJavaSourceTaskFactory.getLastPosition(fileObject));

	<b>// if cancelled, return:</b>
	if (isCancelled()) {
	return;
	}

	<b>// Get Element:</b>
	Element element = compilationInfo.getTrees().getElement(tp);

	<b>// if cancelled, return:</b>
	if (isCancelled()) {
	return;
	}

	String status = "";
	String iconToolTip = "";
	Icon icon = UiUtils.getElementIcon(ElementKind.PARAMETER, NO_MODIFIERS);

	if (element != null) {
	String modifiers = element.getModifiers().toString();
	if (modifiers.startsWith("[") && modifiers.endsWith("]")) {
	modifiers = modifiers.substring(1, modifiers.length() -1).replaceAll(",", "").trim();
	}
	iconToolTip = modifiers + (modifiers.length() > 0 ? " " : "");
	icon = UiUtils.getElementIcon(element.getKind(), element.getModifiers());

	if (element instanceof PackageElement) {
	PackageElement packageElement = (PackageElement) element;
	status = packageElement.toString();
	iconToolTip += element.getKind().name().toLowerCase();
	} else if (element instanceof TypeElement) {
	TypeElement typeElement = (TypeElement) element;
	status = typeElement.getQualifiedName().toString();
	iconToolTip += element.getKind().name().toLowerCase();
	} else if (element instanceof VariableElement) {
	VariableElement variableElement = (VariableElement) element;
	status = variableElement.toString() + ":" + variableElement.asType().toString();
	iconToolTip += element.getKind().name().toLowerCase();
	} else if (element instanceof ExecutableElement) {
	ExecutableElement executableElement = (ExecutableElement) element;
	// Method
	if (element.getKind() == ElementKind.METHOD) {
	status = executableElement.getEnclosingElement().toString()
	+ "."
	+ executableElement.toString()
	+ ":"
	+ executableElement.getReturnType().toString();
	iconToolTip += element.getKind().name().toLowerCase();
	} else if (element.getKind() == ElementKind.CONSTRUCTOR) { // CTOR - use enclosing class name
	status = executableElement.getEnclosingElement().toString()
	+ "."
	+ executableElement.toString();
	iconToolTip += element.getKind().name().toLowerCase();
	}
	}
	}

	WhichElementStatusElementProvider.WhichElementPanel localWhichElementPanel = getWhichElementPanel();

	<b>// Set the info:</b>
	if (localWhichElementPanel != null) {
	localWhichElementPanel.setIcon(icon);
	localWhichElementPanel.setIconToolTip(iconToolTip);
	localWhichElementPanel.setText(status);
	localWhichElementPanel.setToolTipText(status);
	}
	}

	private WhichElementStatusElementProvider.WhichElementPanel getWhichElementPanel() {
	if (whichElementPanel == null) {
	StatusLineElementProvider statusLineElementProvider = (StatusLineElementProvider) Lookup.getDefault().lookup(WhichElementStatusElementProvider.class);
	if (statusLineElementProvider != null) {
	whichElementPanel = (WhichElementStatusElementProvider.WhichElementPanel) statusLineElementProvider.getStatusLineElement();
	}
	}
	return whichElementPanel;
	}

	<b>/**
	* After this method is called the task if running should exit the run
	* method immediately.
	*/</b>
	public final synchronized void cancel() {
	canceled = true;
	}

	protected final synchronized boolean isCancelled() {
	return canceled;
	}
	}</pre>


	<li>Install the module again.


	</ol>


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