I didn't know that parkour was so popular until I saw the video above. This is a short definition from Wikipedia:
Parkour (sometimes abbreviated to PK) or l'art du déplacement (English: the art of displacement) is recreational activity of French origin, the aim of which is to move from point A to point B as efficiently and quickly as possible, using principally the abilities of the human body.
If you are not already using it, I suggest you start using cURL. cURL, or Client for URLs, or see URL comes in two flavours, a command line tool for getting and sending files using URL syntax and a library, libcurl, for use by other programs. It supports more than a dozen protocols (FTP, FTPS, HTTP, HTTPS, SCP, SFTP, TFTP, TELNET, DICT, FILE, LDAP), cookies, proxy tunneling, transfer resume, authentication (Basic, Digest, NTLM, Negotiate, kerberos...), SSL certificates, HTTP uploads, progress meter, speed limit, you name it. Here's some examples:
Upload a file as multipart/form-data plus extra params to a URL:
curl -F upload=@localfilename -F press=OK [URL]
Use an agent of your choice:
curl -A "Mozilla/4.0 (compatible; MSIE 5.01; Windows NT 5.0)" [URL]
Get the last 500 bytes of a document:
curl -r -500 http://www.get.this/
ftp upload through a proxy:
curl --proxytunnel -x proxy:port -T localfile ftp.upload.com
Read and write cookies from a netscape cookie file:
curl -b cookies.txt -c cookies.txt www.example.com
Download resume:
curl -C - -o file http://www.server.com/
Once I wanted to create clones of tree nodes, naming the clones of node say A as A-Copy-1, A-Copy-2, etc.
My first thought was using the parent's child-count property and start counting copies from that value onwards. However, if the nodes are
A, A-Copy-1 and A-Copy-2, when A-Copy-1 gets deleted the child-count becomes 2 and if that is used you get the same name as one of the
existing children. Then I thought I would simply iterate through all children named A-Copy-i, for i = 1 to child-count, and create clones
whenever that name was for take. That would reuse slots created by previous deletions but would make distinguishing the new nodes impossible.
This was easily fixed by finding the maximum copy count of A and start creating clones after that so, if A-Copy-4 and A-Copy-6 sibling nodes are left
in the tree, any new copies would be named as A-Copy-7, A-Copy-8 etc. That way you would always get a nice continuous set of cloned nodes in
the tree. Even if you wanted to clone A-Copy-i node, that would quite naturally become A-Copy-i-Copy-j. I decided to use regular expressions
to look for <node name>-Copy-<copy count> sibling nodes. That gave the extra benefit of having the copy count part available by means of a
capturing group. To force any metacharacters in the node name to be treated like ordinary characters, I preceded
every single character in the name with backslashes:
StringBuffer escapedNodeName =
new StringBuffer(nodeName.length()*2);
for (int i = 0; i < nodeName.length(); i++) {
escapedNodeName.append('\\').append(nodeName.charAt(i));
}
RE exp = new RE(escapedNodeName.toString() + "-Copy-([1-9]\\d*$)");
\Q and \E). No sooner had I done this than I realised that
even that had its own fallacy: what if the node name had a \E in it? Proper quoting required some more effort:
StringBuilder escapedNodeName =
new StringBuilder(nodeName.length() * 2);
escapedNodeName.append("\\Q");
slashEIndex = 0;
int current = 0;
while ((slashEIndex = nodeName.indexOf("\\E", current)) != -1) {
escapedNodeName.append(nodeName.substring(current,
slashEIndex));
current = slashEIndex + 2;
escapedNodeName.append("\\E\\\\E\\Q");
}
escapedNodeName.append(nodeName.substring(current,
nodeName.length()));
escapedNodeName.append("\\E");
java.util.regex.Pattern.quote(String) method since Java 1.5.
There is a feature comparison sheet on Freemarker site, listing why Freemarker is a superior templating engine to Velocity. Not very objective you may say, but there are certain features, like the use of JSP tags and XML transformation capabilities that Velocity lacks. Freemarker more closely follows the MVC pattern, in that Velocity allows you to change the model from the view (e.g. request.session.removeAttribute(attrName) will remove the attribute) while Freemarker does not let you do so. I do not think that any of the two engines is a serious contender for a full blown web engine to be honest, but I would be interested to see some speed statistics, especially for uses in high volume messaging applications where every single message would need to go through the engine. Furthermore, the quest for separation of the model from the view reminds me of that other quest for over-validation. I don't want templates that change my model, sure, but I don't want to have to recompile my classes just because an email wants person.surname in addition to person.name in it, either.
There's been an interesting development in the area of Enterprise Content Management (ECM) space during the last couple of years, that goes by the name Alfresco. I've been meaning to write about it for quite some time when I got tickled again by one recent email of theirs, announcing the release of Alfresco Community 2.1. For those of you not familiar with it who still think that ECM is all about boring apps organizing boring docs made by boring cos, think again. Alfresco is open source based on best-of-breed technologies, including Spring, Hibernate, Lucene, jBPM, MyFaces, Rhino etc and providing a rich set of interfaces like CIFS/SMB, FTP, WebDAV, Web Services, REST. It was started in 2005 by John Newton co-founder of Documentum and John Powell, former COO of Business Objects and has since been downloaded some 600,000 times and installed at more than 12,000 sites and going strong. I wonder what the implications will be on the likes of IBM (FileNet), Interwoven and Oracle.
Here's an idea: after the usual spam checks, pass every incoming email automatically through Snopes, as a last resort to spam prevention. These emails are hard to detect as the senders have usually added their very own personal comment, and most of the time they are among your trusted friends. Therefore, you not only stumble upon the email in your inbox instead of it being automatically thrown to your trash can, you are fooled by the sender into actually opening and reading the email before you realise it is yet another hoax. Worse still, you have to go manually through Snopes, just in case it is real. Life is beautiful is one of these hoaxes that was first circulated on the Internet back in 2002 and got sent to me again... today.
Vista has surely spiced up things a bit, as far as user interfaces go, and Mac's new Leopard is really beautiful. But how about rethinking the whole desktop and the ways one can interact with it? Anand Agarawala has done exactly that, with BumpTop, a physically-based, casual user interface that pushes the desktop metaphor with physics, piles and the pen. For the more inclined, Anand's Masters Thesis (Enriching the Desktop Metaphor with Physics, Piles and the Pen) and a paper co-authored with Ravin Balakrishnan say it all.
We all know the various software development cycles. Alpha used to be mostly for internal testing. Beta represented versions released to the wider public for the purpose of real world testing. Nobody dared call their version Gamma out of fear that people would confuse that with their Gamma Phi Beta sorority. So most stuck to Beta, using enumerations to denote post-Beta releases like Beta I (or 1), Beta II (or 2) etc. Then Microsoft figured that an operating system was entitled to a brand new concept of post-Beta test cycles and, that system being Windows, they probably were right. So they started issuing what they euphemistically called Release Candidate versions to the public. Of course, you could always find some very peculiar versioning conventions if you looked hard enough, like Knuth's TeX ever approaching Pi numbers. By the time open source software became de facto, and releases were mostly Web Server software updates, Release Candidate sounded too formal and rigorous, so Gamma became the new Beta II. Now Flickr calls one of its recent releases "LOVES YOU", instead of Delta, Gamma II, Super/Post Candidate Release I, signalling a new era of version naming standard. Who knows what the next release will be? WILL MARRY YOU perhaps.
Google recently acquired the Sweden-based Gapminder, the "non-profit venture for development and provision of free software that visualise human development", makers of the amazing Trendalyzer®. Not many people have heard of them up until now, but the visualization and real-time interaction possibilities are just mind blowing. Have a look at this demo. Now I know what you must be thinking: how can I have something like that in my webapp? I'm afraid you'll have to resort to good old jfree chart.
I recently came across Humanized, a company that tries to bring the command line to the common man, by exposing operating system or application operations as simple commands, that can be typed at any time. For example, by holding down [Ctrl] and typing "open with" or a part of it, it will automatically open whatever has been selected with the application of your choice. This is part their Enso Launcher application, the other one being Enso Words. Enso Words lets you do all kind of things you would normally do from within a word processor through the humanized command line, from spell checking to word counting. A pleasant change.
