Slow peformance with MariaDB Java Client Connector?

Noticing a small delay in executing queries using the MariaDB Java Client Connector? Especially when the amount of data returned is small (say, a count() or something)?

Try setting this property for your JDBC connection:

tcpNoDelay=true

It's because of Nagle's Algorithm
 

Making reusable Java 8 Lambda Functions/Filters

You can create a function with parameters using Lambda in Java 8 to reduce duplicate code.
Then you can create a predicate using that function allowing you to use it as a filter for stream() allowing you to re-use your new function any number of times.This way you don't need to make a different predicate for age == 12 or age == 21.


Function< Integer, Predicate< Person >> agefunction = (age) -> person -> person.age == age;
 
private List< Person > getPeopleOfAge(final List< Person > people, final int testAge)
    {
       
        Predicate< Person > ageFilter = agefunction.apply(testAge);
        return people.stream().filter(ageFilter).collect(Collectors.toList());
    }

Acronis Backup and Recovery

We got Acronis Backup and Recovery 10 for a small business of about 10 machines. When it worked, it was really great, simple to use. When it didn't work, pounding your head against a break wall was more fun.


Pros

• De-duplication
• Central management
• Any kind of backup type and schedule you can think of
• Built in Wake on Lan
• Restore to dissimilar hardware
• Backup conversion to VM image
• Can automatically handle if a non-managed backup location is swapped out
• Built in PXE server to boot to recovery mode.

Cons

• User interface is laggy, slow, buggy and often wrong. (This is a really big issue)
• Its database(SQLITE) needs constant cleaning out to keep performance up
• Incomprehensible error messages.
• Management Server constantly crashes, freezes and wont restart.
• Wake on Lan doesn't work

Want to monitor your progress while rendering a BIRT report at a finer level then just page level and actually know how many elements you've done and how many are left?

First, record all the line numbers of every element in your report

            final TreeSet lineNos = new TreeSet();
            for (DesignElement de : rpd.getAllElements())
                lineNos.add(rpd.getLineNo(de));


Then you add a progress monitor to your task in the usual way, and at the start of each query you get the line number of the element being processed.

EventBus Annotation Processor

I was playing with EventBus to allow communication between classes. One thing that bothered me was that to use the Annotations system (eg,  @EventSubscriber(eventClass=StatusEvent.class) ), you have to have the annotation processed by calling:

org.bushe.swing.event.annotation.AnnotationProcessor.process(this)

Where this is the object that wants to register all it's annotations. However, you have to add a call to that in every class that will have that annotation.
Well, screw that. I got eclipse and I want it to be automatic.

Long story short, you gotta write your own annotation processor. Its not particularly complicated,but I'll just go and give you teh source and codez: Event Bus Annotation Processor
You plug it into Eclipse using the following instructions: Getting started with APT
Now, once that's working you'll get a file called eventbus.classes appearing in the .apt_generated directory.
That file contains a list of all classes that use the EventSubscriber annotation, but we still need a way to automatically get those classes to register with EventBus. You could play with classloading, but i chose Javassist.

Simply put, some code reads the eventbus.classes file, and uses Javassist to embed a call to register the instance at the end of every constructor in the class:

CtClass ctclass = ClassPool.getDefault().get(classname);
CtConstructor[] ctconstructor = ctclass.getConstructors();
for (CtConstructor c : ctconstructor)
{
 c.insertAfter("org.bushe.swing.event.annotation.AnnotationProcessor.process(this);");
}
ctclass.toClass(null, null);


And that is that. Everytime a class of that kind is instantiated, you'll get it auto registering to EventBus without you having to do it yourself.

All you need is a call to begin the reading of eventbus.classes.

Note: If you use some kind of serializing library that doesn't call constructors (eg, XStream), you'll need to register it yourself. You can either do that when it's loading, or if you are feeling adventurous you could extend the Javassist code above to include a call to the annotation processor in the readResolve() method XStream uses.

Upgrading the BIRT Web Viewer Example prototype.js version.

The latest version of BIRT (4.2) comes with an OLD version of prototype.js. 1.4.. It so old it doesn't even show on the prototype.js page anymore. If you want to use jquery you also need to upgrade the prototype.js version.

But if you upgrade the prototype.js version to 1.7 the viewer will suddenly stop working properly including things like the progress bar not showing, and being unable to click on stuff.

To fix it, you need to follow the advice in this article which mentions some things that have changed between 1.4 and 1.5. Specifically this part which talks about the backwards compatibility:


====================
Backward compatibility change: toggle(), show(), and hide(), as well as Field.clear() and Field.present(), no longer take an arbitrary number of arguments. Before upgrading to Prototype 1.5, check the various JS files in Birt/webcontent/birt/ajax for instances like this:

Element.toggle('page', 'sidebar', 'content') // Old way; won't work in 1.5
['page', 'sidebar', 'content'].each(Element.toggle) // New way; 1.5-compatible

Element.show('page', 'sidebar', 'content') // Old way; won't work in 1.5
['page', 'sidebar', 'content'].each(Element.show) // New way; 1.5-compatible

Element.hide('page', 'sidebar', 'content') // Old way; won't work in 1.5
['page', 'sidebar', 'content

====================

Eve-Central Trade Finder results fix

When I was playing a bit of Eve Online, I loved using the Trade Finder from Eve-Central. It helped me make my first 100 million when some dude put a zero in the wrong place when buying some guns. A bit of trading here to there with heart beating hoping no-one would beat me and wooo! money enough to keep me going for a while.

However, the search results returned aren't exactly the best and are poorly formatted and hard to read.
Luckily for me, a bit of Greasemonkey lets me make the results into an actual table, and Stylish lets me make it easier to read. Problem is solved!

Source: Stylish Script
Source: GreaseMonkey script