Hey there,

lately, I’ve been using the HTML 5 local and sessionStorage which is a great thing. However, one thing which annoyed me was that it’s not possible to store objects into a storage.

Also I wanted a better way to prevent errors (like the’s no value for a key, or even localStorage is not defined due to an outdated browser)

So I came up with a little “Framework” that does nothing more than provides a simple api for both session and localStorage.
The good thing is, that it takes care of any object, that you want to store into your storage. It simply transform it into a jSon String. If you read this string later, it will be parsed as an object.

Also there’s a meaningless Exception that will occure if you try to use sessionStorage while in localMode (file://). In this case, I’ll throw out a better Exception so that one understands what the problem is ;-)

You can download it here.

Have you ever tried to add a lot of data (and I really mean a lot, in my case 2600 rows of data) into the Android-internal database (SQLite)?

If so, you propably went the same road as I did.

I tried a normal InsertStatement which was way to slow (10 sec. in my emulator). Then I tried PreparedStatements. The time was better but still unacceptable. (6 sec.). After some frustrating hours of writing code and then throwing it away, I finally found a good solution.

The solution was Android’s InsertHelper (320 ms). (Imagine some angels singing right now ;) )

What is an InsertHelper?

The Android-OS provide the InsertHelper as a fast way to do bulk inserts.

To give you an overview of the performance (measured with an emulator on a crap computer, trying to insert 2600 rows of data):

• Insert-Statement
  10 seconds
• Prepared-Statements
  6 seconds
• InsertHelper
  320 ms

And here it is:

 public void fillDatabase(HashMap<String, int[]> localData){
		InsertHelper ih = new InsertHelper(this.db, TABLE_NAME);
		Iterator<Entry<String, int[]>> it = localData.entrySet().iterator();
		final int firstExampleColumn = ih.getColumnIndex("firstExampleColumn");
		final int secondExampleColumn = ih.getColumnIndex("secondExampleColumn");
		final int thirdExampleColumn = ih.getColumnIndex("thirdExampleColumn");
		try{
				while(it.hasNext()){
						Entry<String, int[]> entry = it.next();
						int[] values = entry.getValue();
						ih.prepareForInsert();
						ih.bind(firstExampleColumn, entry.getKey());
						ih.bind(secondExampleColumn, values[0]);
						ih.bind(thirdExampleColumn, values[1]);
						ih.execute();
				}
		}catch(Exception e){e.printStackTrace();}
				finally{
						if(ih!=null)
								ih.close();
				}
		}

The main differences to a “normal” insert are the binding to a specific column as well as the prepareForInsert() call.

Essentially an InsertHelper is nothing more than a wrapper around a compiled statement which can be found here.
However, most people find it easier to work with InsertHelper.

But… there is one more thing ;)

You can speed up the insertion even more with temporarily disable thread locks. This will gain about 30 % more performance. However it’s important to be sure that only one thread per time is using the database while inserting data due to it’s not threadsafe anymore.
@see here

 public void fillDatabase(HashMap<String, int[]> localData){
		//The InsertHelper needs to have the db instance + the name of the table where you want to add the data
		InsertHelper ih = new InsertHelper(this.db, TABLE_NAME);
		Iterator<Entry<String, int[]>> it = localData.entrySet().iterator();
		final int firstExampleColumn = ih.getColumnIndex("firstExampleColumn");
		final int secondExampleColumn = ih.getColumnIndex("secondExampleColumn");
		final int thirdExampleColumn = ih.getColumnIndex("thirdExampleColumn");
		try{
		this.db.setLockingEnabled(false);
				while(it.hasNext()){
						Entry<String, int[]> entry = it.next();
						int[] values = entry.getValue();
						ih.prepareForInsert();
						ih.bind(firstExampleColumn, entry.getKey());
						ih.bind(secondExampleColumn, values[0]);
						ih.bind(thirdExampleColumn, values[1]);
						ih.execute();
				}
		}catch(Exception e){e.printStackTrace();}
				finally{
						if(ih!=null)
								ih.close();
						this.db.setLockingEnabled(true);
				}
		}

http://qconlondon.com

The Qcon 2011 was based in London. From the 9th of March ’till the 11th, me and my work collegue Daniel Temme had the chance to meet awesome people from all over the world. The QCon is well known for it’s high standards and unique talks. It was a pleasure to meet people like Simon Brown, Michael Mahemoff, James Pearce or Peter Pilgrim.

The first day

The first day started with the keynote “Management and Organizational-design Consultant” by Craig Larman. He’s a very passionate speaker and gave me some great new ideas about what Scrum is essentially about. He talked about what an Architect is and what his role means for the team. Very interesting new perspective about what an Architect should and shouldn’t do..

Further Talks:
Dan North – From months to minutes
Adrian Kosmaczewski – Introducing in IOS Software Development
Lars Hesel Christensen – Do’s and dont’s in Android
Dan North – Chris Reed – Agile Operations – optimising the business one shell script at a time
Eoin Woods – Where did my architecture go?

Lars Hesel Christensen was a non experienced speaker, but non the less it was an interesting resume about good and bad style while using the Android framework.

See: Wednesday

The second day

The second day started with the keynote “Things I wish I would have known” by Spingsource founder Rod Johnson. He talked about how Springsource became a well known company and why today Spring is a framework, which every developer at least should know. He gave the audience tips how one can start his own business. Mainly it’s about having a dream, having passion and at least one should be willing to spend more time in business than in any other hobby. It’s still possible to be successful. But it will be pain…

Further Talks:
Tom Paquin – OnLive Launch Experience
Nick Callen – Data architecture at Twitter scale
Roy Osherove – Team Leadership in the Ager of Agile
Ian Robinson – Getting things done with Rest
Jason Sobel – Infrastructure at Facebook

I was deeply impressed from Roy Osherove’s talk. It was enlightening how he took situations, which occurs daily at work and described, how a leader can do better. Amazing, how many mistakes one can make while (trying) to communicate to others. After hearing him speak, I was aware why nearly no one could follow my orders correctly ;)

See: Thursday

Third day

The third and final day started with the Keynote “Innovation at Google” by Patrick Copeland. It was amazing to see, how he tries to turn problems around till he knows every detail of it. He explained, how he creates “prototypes” of “innovations” which means sometimes nothing more than taking a piece of wood and treat it like it’s a phone for example. The piece of wood must have the same dimension and the same weight. With this little piece, he tries to get a feeling whether this idea could work, or not. If not, it’s like “Google Wave” which was turned down after almost one year.. It’s all about trying things. The customer is not stupid and if he/she doesn’t want something, the vendor will know it. Sooner or later… So be the first, release what is possible to be released, or your competitor will do so.

Further Talks:

Michael Mahemoff – Single Page Apps
Kevlin Henney – Is it possible to do OO Programming in Java
David Recordon – HTML 5 @ Facebook
Glenn Vanderburg – Clojure and the Web
James Pearce – HTML 5 and the dawn of rich mobile internet applications

Michael Mahemoff, a very cool australian guy working for Google was talking about how single page Websites can create a whole new user-expercience.
It was also interesting to see, what HTML 5 means for Facebook.

See: Friday

In addition to the conference, we had the chance to network with some of “the big guys” of the industry, which maybe sooner or later could be a huge benefit. Who knows…

Anyway, thank you QCon, see you next year!