Sheets Release Notes

Virtual Machines & Compilers

Sheets was developed on Windows under JDK1.1 VMs from Sun. It should run quite well on most JDK1.1 versions, especially JDK1.1.6. It does not currently work under JDK1.2. We hope to rectify this limitation in the near future.

It will run under Microsoft SDK2.0 or SDK3.0, but has some problems with pop-up menus. It has not yet been tested with Microsoft's Java SDK 3.1, but the release was compiled successfully with it.

Sheets has been tested under Linux (VM unknown) and performed adequately. The only known problems are that bitmaps are not displayed properly and that checkboxes in pop-up menus fail.

Sheets should run on most other VMs, since it attempts to rely only on the core "pure" Java libraries. (The one exception is the use of the "sun.audio" library for sound.)

Sheets should be able to use any Java 1.1 compiler. We have made extensive use of both Sun's "javac" and Microsoft's "jvc". We tend to recommend the latter simply because it executes much more quickly.

Limitations & Gotchas

There remain a few known problems with this version of Sheets.

Global undo will reliably update the database, but it may scramble the screen image of a sheet. The current solution is to close the Sheet window and reopen it.
Some queries do not set constraints when they create sheets.
It is not possible to display a graph with multiple roots.
Documentation headers are displayed in fixed width rather than variable width fonts.
You cannot place hyperlinks in documentation headers.
Empty links do not display properly ...call to function thing. displays as ...call to function.
Unix Makefiles have not been rewritten. The current files are Windows (nmake) based.
There is a Reload .sheetsrc option on under the File menu for sheet frames. Unfortunately, it doesn't work all that well. The biggest problem is that if you change the keybindings inside the .sheetsrc file, existing windows will not notice the change and will continue to use the old keybindings. There may be similar problems changing .sheetsrc variables on the fly.
The persistence mechanism uses usernames to create unique object ids for components (ie, nkramer:1, rgs:32, etc). This means that if a single user creates two dump files and merges them together, there may be multiple objects with the same object id. The easiest way to avoid problems is to only have one "real" copy of the dump file at any one time, and treat all other copies of the dump file as temporary and disposable. A second solution is to create additional user names, like "rgs2".
The "summarization" capability of the "ShowImportDialog" command may report errors when importing some packages, including the JDK1.1.6 libraries. This is due to the inclusion of "//" comments in method headers. These errors will not break Sheets, but you can correct them by performing a query on "Incorrect fragments" and manually editing the fragments.

Parser notes

The parser we use is not fully compliant with Java 1.1 (Java with inner classes). The biggest fault is that we don't handle the ".class" construct when applied to a primitive type: "Vector.class" is ok, but "int.class" is not.

There are also several illegal constructs that Sheets will happily parse. Most of these are errors that are defined in Java as syntax errors, but which we prefer to think of as semantic errors. These include:

Illegal modifiers (like declaring a field "synchronized")
Naming parameters or local variables "this" or "super"
Explicit constructor invocations are allowed in places they don't belong
Interfaces are treated exactly like classes
"primitive constructors" are allowed -- `new int("twelve")' will be accepted by our parser.

In the future, we may generate warning messages when these illegal programs are parsed.

We also don't parse "foo instanceof bar instanceof baz", which is syntactically legal, but seldom semantically correct. (This behavior came from the JavaCC grammar we used for our parser, and we haven't yet fixed it)

We don't parse "int[].class". (It's unclear whether this is legal java, but it is accepted by javac.)

[Go back to index]