Recent by Andre Guirard
Read Attachment Files without Writing to Disk
By Andre Guirard | 3/13/23 3:13 AM | Development - Notes / Domino | Added by Roberto Boccadoro
Someone sent me a link to this “domino idea” asking for the ability to read file data from attachments in Notes documents without “extracting the file” to disk, since ECLs might not always let you do that.
I never like to say there’s no way to do that, so the question prompted me to create an answer. This code uses DXL — it exports the document, then searches the exported data for the file data objects, which are encoded in base64. Fortunately it’s just the plain file data without CD record headers or the like, so it’s easy to convert to a NotesStream containing the raw data — or to interpret that data as text in a specified character set.
The Pront statement [sic]
By Andre Guirard | 2/3/23 4:18 AM | Development - Notes / Domino | Added by Roberto Boccadoro
The LotusScript debugger isn’t the simplest thing in the world to use, especially when debugging form event code, where the fact of the debugger grabbing focus may change what happens.
You can put Print statements in LotusScript to do a less impactful debug, but these are hard to read and you can’t tell which messages are new — or which are repeats of the last message.
For a project I’m working on now, I wanted something easier to use. So I present the Pront Console. This is an NSF you download and install on your client, with a bit to put in your applications to make the Pront statement available.
A new tool for creating rich text
By Andre Guirard | 1/26/23 7:32 AM | Development - Notes / Domino | Added by Roberto Boccadoro
I’ve used an earlier version of this in other applications, but now it’s greatly improved and expanded. This is an API for creating rich text, including all the variations of sections, tables, image backgrounds, links, borders…
This is an initial 0.1 release, so there will almost certainly be more changes coming, but I need y’all to drive this. Download it, try it out, respond here with questions and suggestions
More thoughts on Content Assist
By Andre Guirard | 1/24/23 3:34 AM | Development - Notes / Domino | Added by Roberto Boccadoro
Recently I write about best practices for commenting for content assist. I’ve been writing a lot of LotusScript recently (I’m making a present for you), and in trying to make the content assist as helpful as possible, I’ve had some additional thoughts.
Download: Simple App Starter
By Andre Guirard | 1/16/23 5:58 AM | Development - Notes / Domino | Added by Roberto Boccadoro
I was creating yet another HCL Notes demo client application recently and was hunting for an existing application I could copy the basic navigation features from without having too many unique things to get rid of. Strange hide formulas, Queryopen code, etc.
It occurred to me there should be a template for that. So I created it and here it is (also available on the Downloads page).
Best practice error trapping in LotusScript
By Andre Guirard | 1/13/23 10:31 AM | Development - Notes / Domino | Added by Roberto Boccadoro
The handling of unexpected errors is one of the headaches we have to deal with while coding. By their nature, you don’t have a specific strategy for handling that error, or it would be an expected error. But you don’t want to present the end user with the uninformative default error dialog.
Default type mismatch error dialog.What line, please? Also, end user, please DON’T click the link.
We’d hope the end user never sees the system error message, but if they do, we should at least have enough information for a developer to locate the code line that generated the error. That means we want a stack with line numbers, such as Java generates by default.
In this article, I discuss three “levels” of error handling. You can choose how far to take it based on your needs and the amount of effort you want to put in.
Users don't read your dialogs
By Andre Guirard | 1/12/23 3:02 AM | Development - Notes / Domino | Added by Roberto Boccadoro
You know how you open a dialog to ask for confirmation or additional information, or to warn them what’s about to happen? Yeah. People don’t read that stuff. The dialogbox is just an obstacle to completing their task. They may press Enter or do whatever it takes to get past it — especially if they routinely encounter other dialogs in the application.
This article discusses best practices and tooling to get people’s attention where it’s needed and to avoid negative consequences of inattention.
Close & Reopen Database, and Ad Hoc Stored Form
By Andre Guirard | 1/9/23 9:09 AM | Development - Notes / Domino | Added by Roberto Boccadoro
I’ve been working on a Notes client application recently where I ran into the problem that I needed to create a design element and then immediately use it. This ran afoul of the Notes client’s design element cache — it wouldn’t recognize the new design element until I closed the application and reopened it.
There’s no “close and reopen” command in any Notes scripting language, and if you close the current application completely, your code in that application stops running, so you can’t then execute a command to reopen it.
Here’s my solution. Someone will probably comment about some much simpler solution I’ve missed, such as a secret command to reload the design element cache, but this way works.
Creating random names for test data
By Andre Guirard | 1/9/23 9:07 AM | Development - Notes / Domino | Added by Roberto Boccadoro
Notes/Domino applications don’t just have code — they also store data, often a lot of it. But it can take years for them to accumulate enough documents for any performance issues to start seriously impacting users.
When designing an application, especially a brand new one, it’s important to performance test it with an unreasonable amount of sample data so any performance issues become evident immediately.
Coding for translatability in Domino
By Andre Guirard | 1/5/23 3:13 AM | Development - Notes / Domino | Added by Roberto Boccadoro
This is partly for organization which, like HCL, use Domino Global Workbench to do translations of their Notes/Domino applications. But also, even if you do translations manually, or even if you don’t do them at all, it makes sense to learn good habits for creating applications in a way that makes translations simple, because it’s not that hard and you never know.
Workstation-specific user application settings
By Andre Guirard | 1/3/23 6:23 AM | Development - Notes / Domino | Added by Roberto Boccadoro
For a couple of applications, I’ve needed a way to store values specific to the combination of a user and workstation. These are personal settings, in other words, but the same person may need different settings if they use the application on a different workstation.
This would mostly be local filepaths, things like the last folder the user selected for a particular file-open prompt, or the path of an external tool the user has to launch in a given situation. A list of recently accessed files. These would be different on different workstations.
Lazy code
By Andre Guirard | 1/2/23 4:12 AM | Development - Notes / Domino | Added by Roberto Boccadoro
You may be familiar with “lazy loading” on webpages. That’s where the browser doesn’t request images from the server until the page is scrolled to the point where they would be visible.
The general principle is to not do work until you have to, both to speed up initial loading and because who knows, you might not have to do it at all.
The same principle can be applied to writing code. For best performance of your code, try to avoid time-consuming operations altogether. In the LotusScript context, an example would be that you sometimes need to look things up in a view, but sometimes not. You don’t open the view and create a NotesView object until it’s first needed, and then once you have opened it, you don’t discard the object until you know you’re done with it. You can create your own cache.
Wonderful List datatype in LotusScript
By Andre Guirard | 12/29/22 2:55 AM | Development - Notes / Domino | Added by Roberto Boccadoro
The general term for it is “associative array” — a collection of values indexed by a string rather than a numeric index. You might be thinking you already know about the List datatype in LotusScript, but there are a few tricks you might not have thought of.
NotesStream performance
By Andre Guirard | 12/27/22 1:19 AM | Development - Notes / Domino | Added by Roberto Boccadoro
Lars Berntrop-Bos posted a comment concerning the LotusScript NotesStream class and his practice of reading as large a block as he possibly could to optimize performance. I decided to run a test to see how much difference that made. The results are as follows:
By Value, By Reference
By Andre Guirard | 12/27/22 1:17 AM | Development - Notes / Domino | Added by Roberto Boccadoro
This is about how function and subroutine parameters are passed in LotusScript, and how to use that intentionally in consideration of code maintainability and performance.
Best Practices: Commenting for content assist
By Andre Guirard | 12/19/22 8:16 AM | Development - Notes / Domino | Added by Roberto Boccadoro
When coding in LotusScript, please pay attention to your comments so the information needed by a developer making calls to your code, is available in the editor popups.
Consistent “to do” flagging
It’s easy, in the midst of writing code, to think you’ll come back and document something later, then forget to do it. To help me remember, I have one consistent string to flag all the locations I need to follow up on. Something I can put in my comment templates in the editor, and also short enough to type manually in comments within a module.
LotusScript Linked List data structure
By Andre Guirard | 12/19/22 8:15 AM | Development - Notes / Domino | Added by Roberto Boccadoro
I previously published two linked list data structures for objects in the LotusScript Gold Collection. These are in script libraries ObjectList and ObjectListLite. They’re actually — despite the “lite” — both a more complex implementation than you need for most purposes. Here I present a new, simpler class that does only the basics of a doubly-linked list.
The Queue class I wrote about previously is a variant of the linked list, but a list with limited functionality.
New download: Domino error list
By Andre Guirard | 12/16/22 2:26 AM | Development - Notes / Domino | Added by Roberto Boccadoro
Rhis is a Notes database containing a list of Notes/Domino error messages and their corresponding number codes and symbolic names, and other string resources ditto, compiled from scanning the header files in the Notes/Domino source pack.
LotusScript Stack data structure
By Andre Guirard | 12/15/22 3:36 AM | Development - Notes / Domino | Added by Roberto Boccadoro
The stack data structure is a collection of items that supports “last in, first out” access. You have two operations: “Push” an item onto the stack, and “Pop” to retrieve and remove the most recently added item. It’s like the stack of plates in a buffet restaurant, where unless you’re a rule-breaking savage, you can only take the plate on top, which was added last.
Compare to a queue, where when you get a value from it, you’re getting the oldest thing it contains.
Posted presentation on CompareDBs
By Andre Guirard | 12/14/22 2:16 AM | Infrastructure - Notes / Domino | Added by Roberto Boccadoro
I gave a presentation about CompareDBs, the new template in 12.0.1 Domino server, for a recent OpenNTF webinar. The slides for that — with their attached notes — are a reasonably good summary of what the tool is good for, so I decided to post them here.
Larger arrays in LotusScript
By Andre Guirard | 12/12/22 2:30 AM | Development - Notes / Domino | Added by Roberto Boccadoro
The array datatype in LotusScript supports arrays containing up to 216 elements (215 if you don’t use negative index values). This is fine for most purposes, but what if you need a larger indexed collection?
In this first of a series of posts about different specific data structures in LotusScript, I show how to create super large arrays via custom classes
LotusScript Data Structures Basics
By Andre Guirard | 12/8/22 6:39 AM | Development - Notes / Domino | Added by Roberto Boccadoro
What are these data structures of which you speak?
In computer science, the term “data structure” refers to a way of organizing data into an arrangement you can navigate in specific ways, depending on the needs of your application.
There are LotusScript implementations of the basic data structures in the LotusScript Gold Collection project on openntf.org. You can just take those and use them. But as noted above, often you need to modify the “classic” data structures for your specific requirements, or even create entirely new, specialized stuff. So I want to discuss the basic principles.
The forgotten logical operators
By Andre Guirard | 12/5/22 3:08 AM | Development - Notes / Domino | Added by Roberto Boccadoro
Here’s something I notice in a lot of other people’s code I look at, which has always bothered me. This isn’t language-specific — I see it everywhere.
Programmers create logical expressions with the boolean operators And, Or, and Not. It seems to require a sort of sideways view of things to apply the additional operators that work with boolean values, Eqv and Xor (or to use their non-bitwise counterparts which more people might recognize offhand, = and != (<> in LotusScript).
Overhead of error trapping in LotusScript
By Andre Guirard | 12/1/22 6:22 AM | Development - Notes / Domino | Added by Roberto Boccadoro
Having a little fun with the performance monitoring code from a previous post. Okay I have a warped idea of fun.
I’m always interested in performance, so I decided to analyze the overhead of using an error trap (On Error statement) to handle edge cases as opposed to an “if” statement or other branch.
The lsconst expedient
By Andre Guirard | 11/28/22 10:12 AM | Infrastructure - Notes / Domino | Added by Roberto Boccadoro
There are a lot of handy constants included in the LotusScript file lsconst.lss, which you can include in your scripts via the statement:
%Include "lsconst.lss"
It contains many “Const” definitions for symbolic names needed for calling built-in functions, such as this constant useful when calling Messagebox function:
Public Const MB_OK = 0
None of these constants is necessary since you can also hardcode the constant value when you make your call. But it makes your code easier to read and maintain if you use the symbolic names, so this is a best practice.
String Functions Performance Considerations
By Andre Guirard | 11/25/22 12:20 PM | Development - Notes / Domino | Added by Roberto Boccadoro
I’ve been doing some tests and I see Instr$ in LotusScript is still a lot slower when you start searching in the middle of the string. I wrote an SPR about this sometime back.
The same is true of Mid$ – I wrote a timing test that uses Mid$ to get the 1st character of a string as opposed to the 27000th. The latter takes much longer, and I don’t understand why. According to the help docs it’s two bytes per character, so it should be trivial to determine the location of a character from its number position.
XPages best practice: computed selection lists
By Andre Guirard | 5/27/13 12:25 AM | - | Added by Niklas Heidloff
XPages lets you write code to calculate the values for selection lists. The value your code returns may either be an array of strings, using the pipe symbol ("|") as a delimiter between display value and stored value, or it may be an array of javax.faces.model.SelectItem objects, which each contain a display and stored value as separate data items.
Beware script tags in XPages
By Andre Guirard | 5/15/13 11:57 PM | - | Added by Niklas Heidloff
I may be stating the obvious, but I wasn't the only one on my team caught out by this, so I thought I'd best mention it.
Searching for design elements 100 times faster
By Andre Guirard | 1/8/13 11:52 PM | - | Added by Niklas Heidloff
Often, entries in this blog are in reaction to questions I get, or someone else's code I've run across. One of the reasons things have been so quiet here is that my job has changed so that's not happening as often.