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Getting Started with the Eclipse Workbench : Page 2

If you think an open source product like the Eclipse Workbench is necessarily Spartan and unassuming, think again. With a collection of great UI features, Eclipse may be good enough to make you wrinkle your nose at your current IDE. Get a look at what you're missing.




Building the Right Environment to Support AI, Machine Learning and Deep Learning

A Tour of the Workbench UI
Eclipse is made up of components, and the fundamental component is the Eclipse Workbench. This is the main window that appears when you start Eclipse. The Workbench has one simple job: to allow you to work with projects. It doesn't know anything about editing, running, or debugging Java programs; it only knows how to navigate projects and resources (such as files and folders). Any tasks it can't handle, it delegates to other components, such as the Java Development Tools (JDT).

Perspectives, Views, and Editors
The Eclipse Workbench is a single application window that at any given time contains a number of different types of panes called views plus one special pane, the editor. In some cases, a single pane may contain a group of views in a tabbed notebook. Depending on the perspective, one pane might contain a console window while another might contain an outline of the currently selected project. The primary component of every perspective, however, is the editor.

Just as there are different types of documents, there are different types of editors. When you select (or create) a document in Eclipse, Eclipse does its best to open the document using the most appropriate editor. If it's a simple text document, the document will be opened using Eclipse's built-in text editor. If it's a Java source file, it will be opened using the JDT's Java editor, which has special features such as the ability to check syntax as code is typed. If it's a Microsoft Word document on a Windows computer and Word is installed, the document will be opened using Word inside Eclipse, by means of object linking and embedding (OLE).

You don't directly choose each of the different views in the Workbench or how they are arranged. Instead, Eclipse provides several preselected sets of views arranged in a predetermined way; they are called perspectives, and they can be customized to suit your needs.

Dragging one view on top of another will cause them to appear as a single tabbed notebook of views.
Every perspective is designed to perform a specific task, such as writing or debugging a Java program, and each of the views in the perspective is chosen to allow you to deal with different aspects of that task. For example, in a perspective for debugging, one view might show the source code, another might show the current values of the program's variables, and yet another might show the program's output.

The first time you start Eclipse, it will be in the Resource perspective (see Figure 1). You might think of this as the home perspective. It is a general-purpose perspective useful for creating, viewing, and managing all types of resources—whether a resource is a Java project or a set of word processing documents doesn't matter in this perspective, apart from which editor is used to open specific documents in the editor area.

The panel at upper left is called the Navigator view; it shows a hierarchical representation of your workspace and all the projects in it. At first this view will be empty, of course; but, as you'll see, it is the starting point for creating projects and working with Eclipse.

Figure 1. The Resource Perspective: The initial view is a general-purpose perspective for creating, viewing, and managing all types of resources.
Within the Workbench, as you work, you can choose among the different perspectives by selecting Window > Open Perspective. Eclipse will also change the perspective automatically, when appropriate—such as changing from the Java perspective to the Debug perspective when you choose to debug a program from the Eclipse menu.

Menus and Toolbars
In addition to perspective, views, and editors, several other features of the Workbench UI are worth mentioning: the main menu, the main toolbar, and the shortcut toolbar. Like the views and editors in a perspective, the Workbench's menu and toolbar can change depending on the tasks and features available in the current perspective.

The Eclipse main menu appears at the top of the Workbench window, below the title bar (unless you are using a Macintosh, in which case the menu appears, Mac style, at the top of the screen). You can invoke most actions in Eclipse from the main menu or its submenus. For example, if the document HelloWorld.java is currently being edited, you can save it by selecting File > Save HelloWorld.java from the main menu.

Below the main menu is a toolbar called the main toolbar, which contains buttons that provide convenient shortcuts for commonly performed actions. One, for example, is an icon representing a floppy disk, which saves the contents of the document that is currently being edited (like the File > Save menu selection). These tool buttons don't display labels to indicate what they do unless you position the mouse pointer over them; doing so causes a short text description to display as a hovering tool tip.

Along the left side of the screen is another toolbar called the shortcut toolbar. The buttons here provide a quick way to open a new perspective and switch between perspectives. The top button, Open a Perspective, is an alternative to the Window > Open Perspective selection in the main menu. Below it is a shortcut to the Resource perspective. As you open new perspectives, shortcuts to those perspectives appear here, as well.

You can optionally add another type of shortcut to the shortcut toolbar: a Fast View button. Fast Views provide a way to turn a view in a perspective into an icon—similar to the way you can minimize a window in many applications. For example, you may find that in the Resource perspective, you need to look at the Outline view only occasionally. To turn the Outline view into a Fast View icon, click on the Outline icon in the view's title bar and select Fast View from the menu that appears. The Outline view is closed, and its icon appears in the shortcut toolbar. Clicking on the icon alternately opens and closes the view. To restore the view in its previous place in the perspective, right-click on the Fast View icon and select Fast View.

In addition to the Workbench menu and toolbars, views can also have menus. Every view has a menu you can select by clicking on its icon. This menu lets you perform actions on the view's window, such as maximizing it or closing it. Generally this menu is not used for any other purpose. Views can also have a view-specific menu, which is represented in the view's title bar by a black triangle. In the Resource perspective, the Navigator view has a menu that lets you set sorting and filtering options.

Some views also have a toolbar. In the Resource perspective, the Outline view has tool buttons that let you toggle various display options on or off.

Changing Perspectives
As you work in the Eclipse Workbench, you'll occasionally find that the different views aren't quite the right size for the work you're doing—perhaps your source code is too wide for the editor area. The solution is to click on the left or right window border and drag it so the window is the right size.

Sometimes you may want to supersize a view temporarily by double-clicking on the title bar; this will maximize it within the Eclipse Workbench. Double-clicking on the title bar again will reduce it back to its regular size.

You can also move views around by dragging them using their title bars. Dragging one view on top of another will cause them to appear as a single tabbed notebook of views. Selecting a view in a notebook is like selecting a document in the editor pane: Click its tab at the top or bottom of the notebook. Dragging a view below, above, or beside another view will cause the views to dock—the space occupied by the stationary view will be redistributed between the stationary view and the view you are dragging into place. As you drag the window you want to move, the mouse pointer will become a black arrow whenever it is over a window boundary, indicating that docking is allowed. For example, if you want to make the editor area taller in the Resource perspective, drag the Task view below the Outline view so the Navigator, Outline, and Task views share a single column on the left side of the screen.

In addition to moving views around, you can remove a view from a perspective by selecting Close from the view's title bar menu. You can also add a new view to a perspective by selecting Window > Show View from the main Eclipse menu.

Eclipse will save the changes you make to perspectives as you move from perspective to perspective or close and open Eclipse. To restore the perspective to its default appearance, select Window > Reset Perspective.

If you find that your customized perspective is particularly useful, you can add it to Eclipse's repertoire of perspectives. From the Eclipse menu, select Window > Save Perspective As; you will be prompted to provide a name for your new perspective.

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