If you have a reference to an object, for example, the object person of the type Person and need to see its methods, type person. Whenever Eclipse detects a problem, it will underline the problematic text in the editor. This functionality is called Quick Fix. Eclipse will suggest creating a field or local variable. Quick Fix is extremely powerful.
For example, it allows you to create new local variables and fields as well as new methods and new classes. It can also assign a statement to a variable and much more. Quick Fix also gives several options for code changes on code which does not contain errors, e. This section demonstrates the quick fix for converting anonymous inner classes to lambda expressions.
Eclipse has several possibilities to generate code for you. This can save significant time during development. For example, Eclipse can override methods from superclasses and generate the toString , hashcode and equals methods. It can also generate getter and setter methods for attributes of your Java class. To test the source generation, create the following class in your com. In this exercise you practice the usage of code generation and the usage of the Content Assists functionality.
Use the Source Generate Getter and Setter to create getters and setters for all fields. Use Eclipse to generate a toString method for the Todo class based on the id and summary field. Also generate a hashCode and equals method based on the id field. Create a new class called TodoProvider. Create the following static method in your TodoProvider class. Write another TodoProviderTest class with a public static void main String[] args method. In your main method call the createInitialModel method and validate that the returned number of items is 5.
If another number than 5 is returned, throw a RuntimeException. If the correct number is returned, write the String "Correct" to the Console view. Use Content assist to create the System.
While this exercise was about code generation and content assists, you might be interested in a potential solution for this exercise.
The following listing contains a potential solution. This section covers the refactoring facilities of Eclipse which allow you to improve the structure of your source code.
Refactoring is the process of restructuring the code without changing its behavior. For example, renaming a Java class or method is a refactoring activity.
For example, to use the Rename refactoring, you can right-click on your class in the editor or Package Explorer and select Refactor Rename to rename your class. Eclipse will make sure that all calls in your Workspace to your class or method are renamed.
The following screenshot shows how to call the Rename refactoring for a class. The cursor is positioned on the class and the context menu is activated via a right-click on the class. Gives magic numbers or hard-coded strings a descriptive constant name and replaces all occurences.
Eclipse has many more refactorings. The available options depend on the selection in the Java editor. In most cases you should get an idea of the performed action by the naming of the refactoring operation. A useful refactoring is to mark code and create a method from the selected code. Mark now the coding of the "for" loop, right click on the selection and select Refactoring Extract Method.
Use calculateSum as the name of the new method. You can also extract strings and create constants based on the strings. Mark for this example the "Hello Eclipse! Eclipse provides a lot of shortcuts to work efficiently with the IDE. For a list of the most important Eclipse shortcuts please see Eclipse Shortcuts. You can store JAR files directly in your project, and add them to the classpath which the Java compiler of Eclipse is using.
To manage the classpath for your Eclipse, right-click on your project and select Properties. Under Java Build Path Libraries you can review and change your current classpath as depicted in the following screenshot.
JAR files can be stored outside your project or inside. Select the Java library you want to import and select the folder, e. Alternatively, to the import approach via the menu, you can copy and paste the jar file into a folder. You can define in Eclipse that a project is dependent on another project. If you do this, you can use its classes in the project defining the dependency. To do this select your project, right-click on it and select Properties.
Select Java Build Path and the Projects tab. This only works within Eclipse, it allows you to develop several projects which will later be exported as JAR files together. Outside of Eclipse you need to create Java libraries for the projects and add them to the classpath. You can open any class by positioning the cursor on the class in an editor and pressing F3. This shows a dialog in which you can enter the class name to open it.
This happens, for example, if you open a class from a the standard Java library without attaching the source code to it. To see the source code of such a class, you can attach a source archive or source folder to a Java library. Afterwards, the editor shows the source instead of the bytecode. To open this page, right-click on a project and select Properties Java Build Path.
The following screenshot shows this setting for the standard Java library. The file is typically called src.
It is also possible to add Javadoc to a library which you use. For this you need to have the Javadoc somewhere in your filesystem.
Select Properties Java Build Path. The Eclipse IDE allows you to install and update software components. The Eclipse update functionality only downloads new or updated components.
Installable software components are located in update sites. Update sites can be located on a web server or on the file system.
If you are behind a network proxy, you have to configure your proxy via the Window Preferences General Network Connection preference setting. Otherwise, Eclipse may not able to reach the update sites. To update your Eclipse installation, select Help Check for Updates. The system searches for updates in the configured update sites for the installed software components.
If it finds updated components, it will ask you to approve the update. From the Work with list, select or enter a URL for the update site you want to use. And not categorized items are only displayed if the grouping is disabled. After an update or an installation of a new software component, you should restart Eclipse to make sure that the changes are applied.
Eclipse contains a client which allows installing software components from the Eclipse marketplace. The advantage of this client is that you can search for components, discover popular extensions and see descriptions and ratings. Compared to the update manager, you do not have to know the URL for the software site which contains the installable software components.
Most Eclipse distributions contain the Marketplace client by default. You may need to install the Marketplace client software component into Eclipse before you can use it.
You can use the Find box to search for components. Pressing the Install button starts the installation process. The marketplace client allows to install your favorite plug-ins directy. For this, go to the Eclipse Marketplace website and login with your Eclipse. Afterwards, select the Favorites tab in the Eclipse Marketplace client and login to be able to install your favorites.
Eclipse plug-ins are distributed as jar files. If you want to use an Eclipse plug-in directly or do not know the update site for it, you can place it in the dropins folder of your Eclipse installation directory.
Eclipse monitors this directory and during a re- start of your IDE, the Eclipse update manager installs and removes plug-in based on the files contained in this directory. You should not modify the content of the Eclipse plugins directory directly.
If you want to install plug-ins, put them into the dropins folder. If you want to remove it, delete the JAR from this folder. Plug-ins are typically distributed as jar files. To add a plug-in to your Eclipse installation, put the plug-in. Eclipse should detect the new plug-in and install it for you. If you remove plug-ins from the dropins folder and restart Eclipse, these plug-ins are automatically removed from your Eclipse installation.
Eclipse allows you to export a file which describes the installed Eclipse components. During the export the user can select which components should be included into this description file. Other users can import this description file into their Eclipse installation and install the components based on this file. Select the components which should be included in your description file.
To install the described components in another Eclipse installation, open the exported file with File Import Install Install Software Items from File and follow the wizard. The wizard allows you to specify the components which should be installed. The Eclipse update manager has a component called director which allows you to install new features via the command line. You need to start this command in the command line and it assumes that you are in a directory which contains your Eclipse installation in a folder called eclipse.
The feature names which you need for this operation can be seen on the second page of the standard installation dialog of the Eclipse update manager. The behavior of the Eclipse IDE can be controlled via key value pairs stores as preference settings.
Each Eclipse software component can define such perferences and use the values to configure itself. This allows you for example to configure how long the Eclipse waits before the code completion or if the import statements in your source code should be automatically adjusted if you save your source code.
Which preferences are key values stored on the file system, the Eclipse IDE allows the user to configure most of these values via the preference dialog.
Select Window Preferences to open the preference dialog. You can use the filter box to search for specific settings. Correctly configuring Eclipse to your needs can largely improve your productivity.
Most of these preference settings are specific to your workspace but some are also valid for all workspaces. In this file you enter default values for preference settings. For example, the following will setup a default type filter for the java. The following example eclipse. To identify a key for a certain preference setting you can export existing preference settings via the following approach.
The Eclipse IDE is relatively conservative configured to avoid surprises during development. Certain settings in the Eclipse IDE allow you to use it more efficiently. If you find a setting in this exercise not working for you, you can always skip that setting. There is not a single correct setting for everyone in the world. You can synchronize the currently selected Java editor with the selection in the Project Explorer or the Package Explorer view.
This gives you a clearer visibility which object you are currently editing. Eclipse can make typing more efficient by placing semicolons at the correct position in your source code. In the Preference setting select Java Editor Typing. In the Automatically insert at correct position selection enable the Semicolons checkbox. Afterwards, you can type a semicolon in the middle of your code and Eclipse positions it at the end of the current statement.
Eclipse allows you to escape text automatically if it is pasted into a String literal. Eclipse would escape the text automatically for you. Now you can paste text that should be escaped. The following code snippet shows an example for the resulting code if you paste HTML code containing a link into a string literal. You can configure Eclipse to highlight the matching brackets of a code block in the source code editor.
Before the change you would not see the enclosing brackets. Afterwards, they will be slightly highlighted. This helps to see in which block you are.
By default, Eclipse determines if the currently selected file is executable and try to start that. This is sometimes confusing. You can configure the Eclipse IDE to always start the last started program. If there are several alternatives, Eclipse suggests all available packages and the user has to select the right one. The Save Actions setting can automatically organize import statements. It adds import statements automatically if there is only one possible import and removes unused ones.
The following shows the available packages for the List class in the Organize Imports dialog. The setting in the following screenshot excludes the java. Please note that Eclipse shows in its default configuration only the packages that are used in the current workspace. If you want to exclude standard Java packages, you have to create at least one Java project.
Select that the source code should be formated and that the imports should be organized at every save action. Import statements are only automatically created if where is one valid import. If Eclipse determines more than one valid import, it will not add import statements automatically.
You can also define the additional actions which are performed during save. Eclipse can override existing method calls, in case you trigger a code completion in an existing statement.
Eclipse can also try to guess the correct actual parameters for a method call. Due to Bug this setting is not usable at the moment. The Eclipse IDE is configured to give you automatic code completion suggestion only after the. YOu can configure Eclipse to get code completion on every character. You can define how the Java compiler should react to certain common programming problems. For example, you can define that an assignment of a variable which has no effect, e. You can enable annotation-based null checks in Eclipse via the setting highlighted in the following screenshot.
After enabling this setting, you can use the NonNull annotation on method parameters or variable definitions to indicate that these are not allowed to be NULL. Eclipse has the option to perform cleanup actions on existing code. This includes the removal of trailing whitespace, the additional of missing annotations but also advanced cleanups like the conversion of code to Java 8 lambda expressions.
After finishing the configuration, press OK and the Next button in the cleanup wizard to get a preview of the changes. In this exercise you first configure the Java save actions to cleanup your code during save. Afterwards you learn how you can perform a mass cleanup of your code basis. Careful here, ensure you have committed the latest version of your code so that you can revert any automatic change you dislike.
You can improve this with type filters in the preference. Type filter allow you to ignore certain packages. Eclipse has the option to perform batch cleanup on existing code. This includes simple thinks like the removal of trailing whitespace, the additional of missing annotations but also advanced cleanups like the conversion of code to Java lambda expressions. The cleanups contain also lots of options to improve the performance of your code. This chapter lists other useful Eclipse settings which are not directly related to Java development.
It also explains how to export and import your preference settings from one workspace to another. The Default button in this preference dialog allows you to set the default editor for a certain file extension. This edit is used by default, if you open a new file with this extension. The other configured editors can be selected if you right-click on a file and by selecting Open With. In the sub-menu you see the available editors.
The available editors depend on your Eclipse installation. Eclipse remembers the last editor used to open a file. It uses this editor again the next time you open the file. You can export your preference settings from one workspace via File Export General Preferences. Eclipse does allow you to export some preference settings separately, but for most of them you have to select the Export all flag.
Similarly, you can import them again into another workspace via File Import General Preferences. You can also configure certain preference settings on a per project basis.
To do this, select your project, right-click on it and select Properties. For example, on the Java Editor Save Actions you can select the Enable project specific settings checkbox to configure the save action for the current project only. This creates a. You can add this folder to your version control system to ensure that every developer uses the same setting.
You could define a template which creates the method body for you. Eclipse allows you also to specify the settings for formatting the source code. These rules are used by Eclipse if you automatically format your source code.
Press the New button to create a new set of formatting rules or press the Edit button to adjust an existing profile. You can set the code formatter specific for a project via Right-click on the project Properties. This way you can ensure that everyone is using the same formatter while working on this project. Eclipse can generate source code automatically. In several cases comments are added to the source code. In the code tree you have the templates.
Select, for example, menu:Code [Method Body] and press the Edit button to edit this template and to remove the "todo" comment. Your Eclipse installation contains a file called eclipse. For example, the -Xmx parameter can be used to define how large the Java heap size can get. The following listing shows an example eclipse. Views are defined via the extension point "org. Views must implement the createPartControl and setFocus methods. This composite has by default a FillLayout layout manager assigned to it.
This layout manager assigns the same space to all components equally. A Perspective describes a certain configuration of Views and Editors. A Perspective is defined via "org. The WorkbenchParts which are part of a Perspective are either defined via a Java class defined in the extension point "org. You can also add placeholders for views via the layout. This methods accepts wildcards and a View with a matching ID would open in this area.
For example if you want to open all views in a specific place you could use the layout. You can also group view via a IFolderLayout which can be created via layout.
The following will explain how to add views to your application. We will continue to use the RCP project "de.
Add the extension "org. Select " plugin. Right mouse-click on your new view extension and select New View. Maintain the id "de. MyView" and the class "de. Create the class "MyView" by clicking on the "class" hyperlink and maintain the following code. Afterwards, your view is ready to be used. You have to add the view to your perspective. Maintain your view id de.
Make the view relative to org. I personally prefer extension points over code. But instead of using the extension point "org. For this modify "Perspective. Create a new RCP project called "de. Use the "RCP application with a view" as a template. In plugin.
Give the perspective with the id "de. Change the class name to "de. The createInitialLayout method in your new class is responsible for creating the new perspective.
We reuse the existing view in the coding. After this step the perspective is defined but not yet reachable via the application. After defining your perspective you also need to enable your application so that the user can select this perspective. You can activate the switch between perspectives the ApplicationWorkbenchWindowAdvisor in method preWindowOpen with configurer. In addition you could reuse the Eclipse command "org.
The following add an icon for the RCP application to the system tray and adds a menu to this icon. We add the functionality that if the window is minimized then the program is not visible in the taskpane only via the tray icon. Create a new project "de.
Use the "Hello RCP" as a template. Open the class "ApplicationWorkbenchWindowAdvisor" and maintain the following code. Run your application and see that you have a system tray icon. Test the menu and the minimized behavior. If the application is minimized it should not be visible in the taskbar but only in the system tray.
Forexampleyoucanaccesstheactiveeditororviewandopenor closeViewsandEditors. Aneditorprovidesthesameaccessvia getEditorSite. The followingdemonstrateshowtofirstcloseallviewsintherunning applicationandhowtoopenaViewwithaspecificID. YoucanalsoaddaPartListenertothepageandlistenfor changeinViewandEditors.
Hereisanexamplehowtoaddsucha listenerinApplicationWorkbenchWindowAdvisor. Eclipse has a pre-defined command to reset the perspective. See the Eclipse Commands tutorial. The status line in an RCP application can be used to give the user some information about the running application.
The shared message area can be used by all parts of the application to write messages to this area. The whole RCP application has access to the information in the shared status line therefore the information in the shared status line might be overwritten. In the file plugin. Of course you should only define the required plugins here. Eclipse RCP applications save configuration files in the folder ".
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