• Added an option to republish records to different connections.
• Added actions to export and import records to a binary file format (the records are stored in a ZIP based file, they are stored as wire format messages with some additional metadata).
• Added an action to remove connections from the list; also, added some options to the connection list context menu to access the recent connections list.
• Added a dialog to allow the user to configure different record types. The underlying code to support this was present in the 1.5 release, but there was no way to access it short of editing the saved project file by hand.
• The build system no longer strips out unused classes from the included libraries. This increases the size of the download but in some cases the licenses of included libraries require this, and it simplifies the build process, which is a Good Thing.
• Started to use the Commons Lang and Commons IO libraries from Apache instead of the utility classes that I had written myself. The next step is to start using Commons Logging instead of my own custom logger.

A full list of features can be found in the plan file in the RvSnoop Subversion repository, but some of the big ones that will impact the overall architecture of RvSnoop are…

Pluggable Persistence Mechanism

I’m going to migrate the record ledger to being persistent, there are a couple of options here as to how this will be handled: flat files, a combination of flat files and Lucene based indexes, or some kind of JDBC backed store.

One option would be to make the persistence mechanism plug-able, this would also ease the use of an all-in-memory storage system, like the one that is currently used (which is useful when you just want to use RvSnoop as a graphical replacement for tibrvlisten).

Able to Run Headless

I’d like to add the ability to run RvSnoop without the UI, this would be based on loading a pre-configured project. Combining this feature with a JDBC backed store this could be really useful for auditing and logging messages.

EMS Support

I registered the emssnoop.org domain at the same time as rvsnoop.org, and there has been a project on SourceForge for a while, even if it hasn’t had anything checked in to it yet! An open question is whether to try for generic JMS support or just work with EMS directly.

User Written Plug-ins

It would be nice to be able to cleanly extend RvSnoop if required, without going back and modifying the main code base.

So, What About 2.0?

All (well, most) of these features point to a need for an extensible plug-in system, Eclipse has shown that a good way of architecting a desktop application (or any application, for that matter) is to build it entirely from plug-ins wrapped around a small core.

So, the upshot of this is that I’m planning on migrating to a managed runtime, probably OSGi, for the 2.0 release. I’ll talk about this more in another post. In particular, what’s the cost/benefit ratio of using this type of runtime; and which runtimes are good?

Changes from the last development build include:

• Added support for republishing on different connections.
• Added column to ledger to display wire size of messages.
• Fixed bug that caused republished messages to be filtered incorrectly from the subject hierarchy.
• Fixed bug with ledger renderer which caused striping to break when columns were added/removed from the view.
• Minor code clean-ups and removal of a couple of unused methods.
• Updated the FAQs page with correct details of timestamp formatting in ledger (this hasn’t been pushed out to the public site yet).

The only things left to do now (assuming no new bugs are found) are some additional testing and documentation updates.

• Saving and restoring messages between sessions.
• Remove Connection as a context sensitive menu option.
• Improved drag and drop support.

And also fixes some bugs involving the screen menu on Mac OS X. The save and restore messages option writes the selected records from the ledger to a ZIP based binary file format (it’s the same format that is used internally by the copy and paste mechanism). The format has also been enhanced to include subject information for the messages, as this is stripped out by the raw Rendezvous library calls.

Not that there’s any real comparison in functionality between the two of course!

Playing Well With Others

At the same time, I’ve taken the opportunity to include some of the Apache Commons libraries in the build. There were (well, still are) a number of small utility classes scattered around which I’m planning on replacing with the versions from Apache.

One side effect of this is that the build is increasing in size, to help control this I’m going to remove the Berkeley DB dependency from the build. I was origiannly planning to use this for the on disk message store but I’ve changed my mind here. My current thinking is to just write the messages out to files but to have a set of indexes (probably built using Lucene) as well for searching and sorting.

There should be another (alpha) release out later this week with the Commons and Berkeley DB changes complete, and a release next week with the new project structure.

However, I’ll start posting to this blog a little about what I’m working on and what my current plans are, and also try to start making more frequent releases.

I’ll rearrange the distributables slightly as well, given the speed of most connections these days I no longer see the point of keeping a binary only download so I’m just goint to include the compressed source and API docs will all of the releases, this will be labelled as the RvSnoop Stable release.

I’ll make more frequent releases of the code that I am working on as a RvSnoop Development release. But first, a little explanation of what you can expect from these unstable releases. I’ll post later about my plans for the upcoming releases.

It’s All Greek To Me

Projects use diffferent terminology for there release schedules, here’s how I’m using the terms.

Alpha

If a release is labelled alpha then it means that I am still adding new features and working on major known bugs. Once the release is feature complete and all of the major bugs have been squashed I’ll go through and clean up all of the strings, finally I’ll spend some time cleaning up any glaring UI problems.

Once this is complete I’ll relabel the release beta.

Beta

Moving forward one of the main points about the beta release is that it will be considered to be a string freeze release. I’m aiming for release 1.7 to be fully prepared for internationalization and hopefully some of the people who have been using RvSnoop will help out with translations.

Also at this point the UI will be basically finished, so the beta releases are for testing and minor bug fixing. Also during this phase I will run all of the analysis tasks (currently only PMD, but more are planned) and clean up whatever they reveal.

It turns out that this is pretty easy to achieve in Java, just use the following class:

public class DateCellRenderer extends DefaultTableCellRenderer {
    // Or load these from a user preference...
    private static final DateFormat[] dateFormats = {
    new SimpleDateFormat("yyyy-MM-dd HH:mm:ss.SSS"),
    new SimpleDateFormat("yy-MM-dd HH:mm:ss.SSS"),
    new SimpleDateFormat("MM/dd HH:mm:ss.SSS"),
    new SimpleDateFormat("HH:mm:ss.SSS"),
    new SimpleDateFormat("HH:mm:ss.SS"),
    new SimpleDateFormat("HH:mm:ss.S"),
    new SimpleDateFormat("HH:mm:ss"),
    new SimpleDateFormat("HH:mm") };
    private int currentWidth;
    private Font currentFont;
    private DateFormat currentFormat;
    private final Date date = new Date();
    public Component getTableCellRendererComponent(JTable table, Object value,
    boolean isSelected, boolean hasFocus, int row, int col) {
        DateFormat format = getFormat(table.getColumnModel().getColumn(col).getWidth(), table);
        String displayed = value != null ? format.format((Date) value) : "";
        return super.getTableCellRendererComponent(table, displayed, isSelected, hasFocus, row, col);
    }
    private DateFormat getFormat(int width, JTable table) {
        Font font = table.getFont();
        if (currentWidth == width && currentFormat != null && font.equals(currentFont)) {
            return currentFormat;
        }
        currentWidth = width;
        currentFont = font;
        FontMetrics metrics = table.getFontMetrics(font);
        date.setTime(System.currentTimeMillis())
        for (DateFormat df : dateFormats) {
            if (metrics.stringWidth(df.format(date)) < width) {
                currentFormat = df;
                return df;
                }
            }
        }
        currentFormat = dateFormats[dateFormats.length - 1];
        return currentFormat;
    }
}

You will need to register it with your JTable via myTable.getColumnModel().getColumn(0).setCellRenderer(myRenderer); and away you go. You can have more or less format options by altering the static array in the class.

• A graphical widget to display messages instead of the text field.
• More import/export formats for messages.
• General user interface clean-up.
• Better documentation.

I’ll have more plans once I get to know the code a little better.

* Add a new action to delete connections. * Add support for viewing serialized Java objects. * Move the preferences to a separate dialog. * Add support for editing messages before republishing. Along with some more code cleanup. After that I’m planning to push for a 2.0 release which should contain a much more robust export mechanism, persistent record ledgers, and graphical charts. Finally, once the code settles down a bit I’m going to look into supporting EMS messages (as a separate project, emsSnoop).