netbeans.apache.org/src/content/tutorials/nbm-google.asciidoc

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= NetBeans Platform Plugin Quick Start
:jbake-type: platform_tutorial
:jbake-tags: tutorials 
:jbake-status: published
:syntax: true
:source-highlighter: pygments
:toc: left
:toc-title:
:icons: font
:experimental:
:description: Apache NetBeans Platform Plugin Quick Start
:reviewed: 2020-12-01
:keywords: Apache NetBeans Platform, Platform Tutorials, NetBeans Platform Plugin Quick Start

Welcome to Apache NetBeans plugin development!

This tutorial provides a simple and quick introduction to the Apache NetBeans plugin development workflow by walking you through the creation of a new toolbar for any Apache NetBeans Platform application. Once you are done with this tutorial, you will know how to create, build, and install plugins for the Apache NetBeans Platform.

After you finish this tutorial, you can move on to the  link:https://netbeans.apache.org/kb/docs/platform.html[NetBeans Platform learning trail]. The learning trail provides comprehensive tutorials that highlight a wide range of Apache NetBeans APIs for a variety of application types. If you do not need to do a "Hello World" tutorial, you can skip the instructions that follow and jump straight to the learning trail.

The toolbar you create in this tutorial will look as follows:

image::images/nbm-googlebar/google-result.png[]

The concept is that the user enters some text, presses kbd:Enter, and the IDE's default browser opens and the text in the toolbar is sent to a Google search, with the results available in the open browser.

To create this toolbar, you will use the  link:https://bits.netbeans.org/dev/javadoc/[NetBeans APIs] to enhance the Apache NetBeans Platform's feature set. Specifically, you will create and register an action invoked by a button created by the NetBeans Platform in the toolbar. You will then create a  ``JPanel``  containing a  ``JLabel``  and  ``JTextField``  as GUI components. Finally, you will implement  link:https://bits.netbeans.org/dev/javadoc/org-openide-util/org/openide/util/actions/Presenter.Toolbar.html[ ``Presenter.Toolbar`` ] to return the  ``JPanel``  so that it displays in the toolbar, instead of the button.

If it would help you, do some background reading before diving into this tutorial. In particular, you might like to read the  link:https://bits.netbeans.org/dev/javadoc/org-openide-modules/org/openide/modules/doc-files/api.html[Modules API Reference] document, which explains what modules are and provides some context for this tutorial. Also note that there is an extensive Reference Material section on the  link:https://netbeans.apache.org/kb/docs/platform.html[NetBeans Platform Learning Trail]. Of course you can always go back to those later, or again, whenever you would like to.

The completed tutorial source code is also available as link:https://github.com/bradh/GoogleBar[a GitHub repository].

== Setting up the Module Project

We begin by creating the source structure common to all NetBeans Platform modules. Read the  link:https://bits.netbeans.org/dev/javadoc/org-openide-modules/org/openide/modules/doc-files/api.html[Modules API Reference] for details.


[start=1]
1. Choose menu:File[New Project] (kbd:[Ctrl+Shift+N]). Under Categories, expand Java with Ant, and select NetBeans Modules. Under Projects, select Module: 

image::images/nbm-googlebar/new-project-0.png[]

The difference between the 4 templates above is as follows:

* *NetBeans Platform Application.* A project that groups a set of module projects and library wrapper module projects that have dependencies on each other, and lets you deploy them together as a unit. Automatically included are a subset of the modules that make up the NetBeans Platform.
* *Module Suite.* Same as above, except that the pre-included modules are more than only those relating to the NetBeans Platform — in this case, all the modules that make up NetBeans IDE are included as well.
* *Library Wrapper Module.* A project that puts a library JAR file on its classpath and exports some or all of the JAR file's packages from the module as public packages.
* *Module.* A project for implementing the functionality, business logic, and user interface of a module or application built on the NetBeans Platform.

Click btn:[Next].

[start=2]
1. In the Name and Location panel:
* In the Project Name field, type  ``GoogleToolbar`` .
* In the Project Location field, change the value to any directory on your computer where the module will be stored.

It should look similar to this:

image::images/nbm-googlebar/new-project-1.png[] 

Click btn:[Next].

[start=3]
1. In the Basic Module Configuration panel:
* Type  ``org.myorg.googletoolbar``  in "Code Name Base", which defines the unique string identifying the module you are creating. The code name base is also used as the main package of the module, i.e., your main package will be "org.myorg.googletoolbar".
* Do not select the "Generate OSGi Bundle" checkbox, since we will be using the default NetBeans module system, rather than OSGi.

It should look similar to this:

image::images/nbm-googlebar/new-project-2.png[]

Click btn:[Finish].

The IDE creates the  ``GoogleToolbar``  project: 


image::images/nbm-googlebar/new-project-3.png[]

A "project" is a NetBeans IDE compilation/deployment unit. It contains a Build Script, as shown above, which on disk is named "build.xml" file. This is an Ant script for compiling and running the project. The project contains all of your sources. The project opens in the IDE. You can view its logical structure in the Projects window (Ctrl+1) and its file structure in the Files window (Ctrl+2).

If you expand the Important Files node, you can open the Module Manifest, shown above, which has this content:


[source,java]
----
Manifest-Version: 1.0
AutoUpdate-Show-In-Client: true
OpenIDE-Module: org.myorg.googletoolbar
OpenIDE-Module-Localizing-Bundle: org/myorg/googletoolbar/Bundle.properties
OpenIDE-Module-Specification-Version: 1.0
----

For details on these NetBeans-specific manifest keys, check the  link:http://bits.netbeans.org/dev/javadoc/org-openide-modules/org/openide/modules/doc-files/api.html[NetBeans Modules API] Javadoc description.



== Coding the Module

In order to create a Google toolbar, we will need to complete the following steps:

* <<creating-action,Create the Action>>
* <<creating-panel,Create the Toolbar>>


=== Creating the Action

In this section, you use the New Action wizard in NetBeans IDE to create a new Action. An Action is a piece of code invoked by the user to do something in the application. An Action can be invoked from a menu item, toolbar button, and keyboard shortcut in the application.

NOTE:  As you will see, the New Action wizard creates a Java class with annotations. At compile-time, the annotations are converted into XML elements in a file contributed to the virtual filesystem of the application, which is how an Action is registered in the application. For more information relating to the creation and registration of Actions in the NetBeans Platform, see  link:https://netbeans.apache.org/wiki/index.asciidoc#_actions:_how_to_add_things_to_files.2c_folders.2c_menus.2c_toolbars_and_more[Actions: How to add things to Files, Folders, Menus, Toolbars and more] in the  link:https://netbeans.apache.org/wiki/[NetBeans Platform Wiki].


[start=1]
1. Right-click the GoogleToolbar project node and choose New > Action:

image::images/nbm-googlebar/new-action-0.png[]

If Action is not displayed, access it by choosing Other, then in the New File wizard under Categories, select Module Development and then Action.

image::images/nbm-googlebar/new-action-1.png[]

Click btn:[Next].

[start=2]
1. In the Action Type panel: 
* Keep the default setting, which will let the Action be unconditionally enabled, as shown below.

image::images/nbm-googlebar/new-action-2.png[]

Click btn:[Next].

[start=3]
1. In the GUI Registration panel: 
* Select File from the Category drop-down list. The Category drop-down list controls where an action is shown in the Keyboard Shortcuts editor in the IDE.
* Deselect Global Menu Item because we will not need a menu item.
* Select Global Toolbar Button. In the Toolbar drop-down list, select File, then in the Position drop-down list, select the toolbar button's position within the toolbar as "Save All - HERE" as shown below.

image::images/nbm-googlebar/new-action-3.png[]

Click btn:[Next].

[start=4]
1. 
In the Name, Icon, and Location panel: 

* In the Class Name field, type  ``GoogleActionListener`` 
* In the Display Name field, type  ``Google`` 
* In the Icon field, browse to an icon that has a dimension of 16x16 pixels. 

If needed, here are two icons you can use:

* 16x16: 

image::images/nbm-googlebar/google.png[]

* 24x24: 

image::images/nbm-googlebar/google24.png[]

However, note that by the end of this tutorial you will not use the icon at all once you have created the toolbar. Instead, you will display the JPanel that you create in the next section.

The Name, Icon, and Location panel of the New Action wizard should now look like this:

image::images/nbm-googlebar/new-action-4.png[]

[start=5]
1. Click btn:[Finish]. The module source structure is now as follows: 

image::images/nbm-googlebar/new-action-5.png[]

Additional dependencies have been included in the Libraries section, and additional sources have been added.

``GoogleActionListener.java`` , which you should see in the Projects window, has this content:


[source,java]
----
package org.myorg.googletoolbar;

import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import org.openide.awt.ActionID;
import org.openide.awt.ActionReference;
import org.openide.awt.ActionRegistration;
import org.openide.util.NbBundle.Messages;

@ActionID(
        category = "File",
        id = "org.myorg.googletoolbar.GoogleActionListener"
)
@ActionRegistration(
        iconBase = "org/myorg/googletoolbar/google.png",
        displayName = "#CTL_GoogleActionListener"
)
@ActionReference(path = "Toolbars/File", position = 500)
@Messages("CTL_GoogleActionListener=Google")
public final class GoogleActionListener implements ActionListener {

    @Override
    public void actionPerformed(ActionEvent e) {
        // TODO implement action body
    }
}
----

NOTE:  When you build the module, which is done automatically in the next step when you run the module, the class annotations that you see above will be converted to XML tags in a file that will be contributed to the virtual filesystem of the application. The XML file will be named "generated-layer.xml" and will be found in the "build\classes\META-INF" folder of your module, which you can see if the Files window (Ctrl-2) is open in the IDE. This file is created at compile-time and contains XML entries generated from the NetBeans annotations that you have defined in your Java classes. Together with the "layer.xml" file that your module can optionally provide, the "generated-layer.xml" file defines the contributions that the module makes to the virtual filesystem. Read about the virtual filesystem  link:https://netbeans.apache.org/wiki/DevFaqSystemFilesystem.asciidoc[here], in the  link:https://netbeans.apache.org/wiki/[NetBeans Platform Wiki]. Also see  link:https://blogs.oracle.com/geertjan/entry/messages[this article] for more information on the @Messages annotation.


[start=6]
1. In the Projects window, right-click the  ``GoogleToolbar``  project node and choose Run. The module is built and installed in a new instance of the IDE (which is currently set to be the target platform). By default, the default target platform is the version of the IDE you are currently working in. The target platform opens so that you can try out the new module. You should be able to see your button and click it: 

image::images/nbm-googlebar/result-1.png[]

Close the target platform instance:

image::images/nbm-googlebar/result-2.png[]

=== Creating the Toolbar

In this section, we will create a  ``JPanel``  that will replace the  ``JButton``  that the Action wizard created in the previous section.


[start=1]
1. Right-click the project node and choose New > Other.

image::images/nbm-googlebar/new-toolbar-0.png[]

Under Categories, select Swing GUI Forms. Under File Types, select JPanel Form: 

image::images/nbm-googlebar/new-toolbar-1.png[]

Click btn:[Next].

[start=2]
1. In the Name and Location panel, type  ``GooglePanel``  as the Class Name and select the package from the drop-down list: 

image::images/nbm-googlebar/new-toolbar-2.png[]

Click btn:[Finish].  

``GooglePanel.java``  is added to the package and is opened in the Design view in the Source Editor.


[start=3]
1. Place the cursor at the bottom right-hand corner of the JPanel, then select the JPanel and drag the cursor to resize it, so that its width and length resemble that of a toolbar, as shown below: 

image::images/nbm-googlebar/new-toolbar-3.png[]

[start=4]
1. Drag a  Label (``JLabel``) item and a Text Field (``JTextField``)  item from the Palette (Ctrl+Shift+8) directly into the  ``JPanel`` , then resize the  ``JPanel``  and the other two items so that they fit snugly together. Finally, press F2 on the  ``JLabel``  and change its text to  ``Google:`` , then delete the default text in the  ``JTextField`` . 

If you click F2 over the  ``JLabel``  and the  ``JTextField`` , their display text will become editable. You can also do this using the properties dialog.

Your  ``JPanel``  should now resemble the image shown below: 

image::images/nbm-googlebar/new-toolbar-4.png[]

You can set other UI properties as required.

[start=5]
1. Double-click on the JTextField (or right-click on it and choose Events > Action > actionPerformed). This generates a  ``jTextField1ActionPerformed()``  method in the  ``GooglePanel.java``  source code, which displays in the Source Editor. Fill out the  ``jTextField1ActionPerformed``  method as follows (inserted text shown in *bold*):

[source,java]
----
private void jTextField1ActionPerformed(java.awt.event.ActionEvent evt) {                                            
    try {
        String searchText = URLEncoder.encode(jTextField1.getText(), "UTF-8");
        URLDisplayer.getDefault().showURL(new URL("https://www.google.com/search?q=" + searchText));
    } catch (UnsupportedEncodingException | MalformedURLException eee) {
        //nothing much to do
    }
}
----

If you need to, right-click in the Source Editor and choose Format (Alt+Shift+F).


[start=6]
1. Right-click in the Source Editor and choose Fix Imports (Ctrl+Shift+I). The Fix All Imports dialog displays, listing suggested paths for unrecognized classes: 

image::images/nbm-googlebar/new-toolbar-5.png[]

Click btn:[OK].

The IDE creates the following import statements at the top of the class:

[source,java]
----
import java.io.UnsupportedEncodingException;
import java.net.MalformedURLException;
import java.net.URL;
import java.net.URLEncoder;
import org.openide.awt.HtmlBrowser.URLDisplayer;
----

Also notice that all errors disappear from the Source Editor.

[start=7]
1. 
Because the  ``JPanel``  you have created is the component that will be rendered in the toolbar, you need to implement  `` link:https://bits.netbeans.org/dev/javadoc/org-openide-util-ui/org/openide/util/actions/Presenter.Toolbar.html[Presenter.Toolbar]``  in the  ``ActionListener``  you created earlier, in order to display the  ``JPanel``  in the toolbar.

Change the signature of Open  ``GoogleActionListener.java`` . so that  `` link:https://bits.netbeans.org/dev/javadoc/org-openide-util-ui/org/openide/util/actions/Presenter.Toolbar.html[Presenter.Toolbar]``  is implemented. When using  ``Presenter.Toolbar`` , you need to extend  ``AbstractAction`` , instead of implementing  ``ActionListener`` . Also, you can delete the "iconBase" attribute (as well as the icons from the source tree) because you no longer need an icon in this scenario.

The result of these changes is as follows:


[source,java]
----
package org.myorg.googletoolbar;

import java.awt.Component;
import java.awt.event.ActionEvent;
import javax.swing.AbstractAction;
import org.openide.awt.ActionID;
import org.openide.awt.ActionReference;
import org.openide.awt.ActionRegistration;
import org.openide.util.NbBundle.Messages;
import org.openide.util.actions.Presenter;

@ActionID(
        category = "File",
        id = "org.myorg.googletoolbar.GoogleActionListener"
)
@ActionRegistration(
        lazy = false,
        displayName = "NOT-USED"
)
@ActionReference(path = "Toolbars/File", position = 500)
@Messages("CTL_GoogleActionListener=Google")
public final class GoogleActionListener extends AbstractAction implements Presenter.Toolbar {

    @Override
    public void actionPerformed(ActionEvent e) {
        // delegated to toolbar
    }

    @Override
    public Component getToolbarPresenter() {
        return new GooglePanel();
    }
}
----

``Presenter.Toolbar`` is provided in the Utilities library, which we need to add.

[start=8]
1. Click near to the relevant `import` statement, and select Search Module Dependency for org.openide.util.actions.Presenter:

image::images/nbm-googlebar/new-toolbar-6.png[]

The matching dependency is shown:

image::images/nbm-googlebar/new-toolbar-6.png[]

Click menu:[OK] to add the library module, which appears in the Project view.

[start=8]
1. Run the module again. This time, instead of a  ``JButton`` , you should see your  ``JPanel`` . Type a search string in the text field: 


image::images/nbm-googlebar/result-3.png[]

Press Enter. The IDE's default browser starts up, if you have set one in the Options window. The Google URL and your search string are sent to the browser and a search is performed. When the search results are returned, you can view them in the browser.

In this section, you have created a  ``JPanel``  that displays a  ``JTextField``  and a  ``JLabel`` . You have presented it in the NetBeans toolbar, thanks to the  ``Presenter.Toolbar``  class. When the user presses Enter in the  ``JTextField`` , its content is sent to a Google search. The HTML browser opens and you see the result of the Google search. The  ``ActionListener``  is used to integrate the  ``JPanel``  within the application's toolbar, as registered via the annotations in the  ``ActionListener`` . 

link:https://netbeans.apache.org/community/mailing-lists.html[ Send Us Your Feedback]



== See Also

This concludes the NetBeans Plugin Quick Start. This document has described how to create a plugin that adds a Google Search toolbar to the IDE. For more information about creating and developing plugins, see the following resources:

*  link:https://netbeans.apache.org/kb/docs/platform.html[NetBeans Platform Learning Trail]
*  link:https://bits.netbeans.org/dev/javadoc/[NetBeans API Javadoc]
* NetBeans API classes used in this tutorial:
*  `` link:https://bits.netbeans.org/dev/javadoc/org-openide-awt/org/openide/awt/HtmlBrowser.URLDisplayer.html[HtmlBrowser.URLDisplayer]`` 
*  `` link:https://bits.netbeans.org/dev/javadoc/org-openide-util/org/openide/util/actions/Presenter.Toolbar.html[Presenter.Toolbar]``