What's NeXT? Archive

Behind the Scenes: NeXTSTEP Services

Last week we took a brief look at the NeXTSTEP Pasteboard and how it differs from the Mac OS Clipboard; this week we'll delve into the world of the NeXT Services menu. Keep in mind that this is not meant to be an all-inclusive guide; I'm not a programmer.

The concept of Services is really very simple. So simple, in fact, that it's surprising no other modern OS has anything that even resembles it. Even Microsoft has ignored this feature! Services opens up a whole new area of powerful, extensible functionality for NeXTSTEP users. But to understand Services, you should know how the pasteboard works (see last week's column).

Good Help is Hard to Find
When most people buy software, they are looking for applications that perform a specific task very well. They're not looking for a Word Processor that is also a Spreadsheet, HTML editor, Illustration program, and Page Layout program all in one. They choose the tools that fit their needs, then apply them to the task at hand. This is a guiding principle behind NeXTSTEP. By doing so, the user avoids the "Jack of All Trades, Master of None" approach described above, which is a common theme throughout all Microsoft applications. In NeXTSTEP, you have a suite of small applications working together on your document; the user merely switches back and forth from one to the other. Of course, this only works if the applications you're using communicate and cooperate with each other. Microsoft applications certainly don't work this way, and neither do some Macintosh programs. NeXTSTEP gets around this problem by letting the pasteboard handle the task of interapplication communication.

Having solved the communication problem, you now have an environment where it really is feasible to use multiple applications to get your job done. While you're thinking about how this works, questions start forming in your mind: Isn't it confusing to always be switching between applications? Isn't it a lot of extra work? Won't it be tedious and time-consuming? The simple answer is "Yes, yes and yes." But since NeXTSTEP's Services menu solves this problem, in the end the answer will be "No, no and no."

Most everyone who uses multiple applications today has to deal with the repetitive and tedious job of manually switching between applications. Usually we're copying data from one application, pasting into another to modify it, then copying it back to the original or another application entirely, possibly for further modification. In the end, you get what you want, but it's very time consuming. Mercifully, users of NeXTSTEP never have to deal with this, because Services are merely an extension of the pasteboard that allow the user to skip the whole process of cutting and pasting data back and forth between applications.

For example, using Services, the user could have a text document that they want to make a copy of for their friend using a Macintosh. The file format is incompatible with anything on the Mac, and character mappings are different, too. So the user has to convert the file to a Macintosh text-only document to give to their friend. With Services, the user just chooses the Services menu from the main menu, then "Convert Files" from the list of submenus, and finally what format they would like to make the converted document. Once the choice is made, the text from that document is copied to the converter application, converted to Macintosh text format, and saved on the hard disk. The original NeXTSTEP document is unchanged. This all takes place behind the scenes, while the user never has to leave the main application. NeXTSTEP automatically launches the converter application (if it isn't already running), copies the text from the original document, changes it to a different format, and saves a new file.

Since the pasteboard is used by Services for these tasks, one might naturally worry about having other data on the pasteboard being wiped out by using Services. Not to worry; as mentioned in the previous column about the pasteboard, NeXTSTEP has multiple pasteboards; the one used for cutting and pasting is different from the one used by Services, so your data is safe.

The Services menu also solves the problem of having different interfaces for each application that is being used. By having a simple, consistent approach to viewing and selecting a service, the user can stay in their main application, focused on getting their work done, without having to switch back and forth between different applications.

Service Nirvana
Before you can take advantage of Services, you first need to have applications that provide services to use. Many NeXTSTEP applications offer some services, especially those developed by the same company. Some applications are meant only to provide services to other off-the-shelf applications, and other services are built into NeXTSTEP.

For example, both PasteUp and WriteUp offer services between each other, while OmniImage Filter only offers services to other applications for using different image formats. NeXTSTEP itself provides several applications that act as services, including Dark Forest, Webster's Dictionary and Thesaurus, and NeXTmail, to name a few. There are also some parts of NeXTSTEP that you probably don't realize are actually services, such as the NeXT spelling checker, and the Print panel functions.

With so many services available, the Services menu can quickly become lengthy and difficult to sort through. Again, NeXTSTEP provides a way out of this mess. Using the Preferences application, the user can selectively turn off whichever services they don't need or don't use very often; they won't even appear in the Services menu, unless you turn them on again.

Only the Beginning
From the start, Services have been an important part of NeXTSTEP, providing a simple, consistent way of moving and transforming data between different applications. The ease of providing new services resulted in a new market for small developers to gain a foothold in the market and make money. With Rhapsody coming up for release next year, we should see a whole new wave of useful services. And perhaps some of the major application developers will see fit to "deconstruct" their monolithic programs and sell only the basic core, while allowing others to develop and sell add-on services to for more functionality.