The Ten Minute Rule

12 resolutions for programmers is a great thing to try

2012-01-11T13:15:00.000-08:00

Came across this post on hacker news by Matt Might a CS prof at Univ of Utah.

http://matt.might.net/articles/programmers-resolutions/

I'd like to add a couple of resources

For (1) and (2) - Go analog & Stay healthy.
jogging is a great way to keep your sanity. Try the from couch to 5k program
couch to 5k

go vegetarian or vegan
http://features.peta.org/VegetarianStarterKit/

For (4) - Learn a new programming language.
python python python
http://python.org/

For (5) - Automate the real world
Normally I would recommend Arduino but after talking to a good friend of mine I think Raspberry Pi will change the world in the realm of low cost automation. For $25 you can stick a full PC anywhere to control anything.
http://www.raspberrypi.org/

All in all a great list and even if you only do a few it seems like a fun time.

JavaScript as a first language?

2011-12-30T15:43:00.000-08:00

John Resig, noted JavaScript demigod, blogs about teaching JavaScript as a first language at the Kahn academy (http://www.khanacademy.org/).

I can see the advantages, I mean:

it is everywhere
no debug, compile cycle
fast path to visual results
job market is great

This still feels a little weird to me though. I mean JavaScript is such a franken-language. Or maybe it's me and too many years of Java as my bread and butter. I have been trained to think of OO and classical inheritance as the one true religion. But how in the world do you explain closures or the === versus the == operator or the bizarre behavior of with in JavaScript to a new person. Or do you just say "hey, this is a pretty cool language but some parts totally stink and all of this happened in the go go 90's when this whole internet thing was blowing up so just use this subset of the language and these libraries and you'll be fine"?

Open Source Physics Rocks!

2011-12-22T07:15:00.000-08:00

This is so cool, great site with tons of physics resources. The coolest part for me is the simulations. They use Java of course but this team has put together a nice tool set for building and bundling simulations. So you can describe a pendulum experiment and then bundle the simulation into a double clickable jar that will play on any platform.

http://www.compadre.org/osp/index.cfm

Simulations here
http://www.compadre.org/osp/search/categories.cfm?t=Simulation

For example, Doppler effect
http://www.compadre.org/OSP/document/ServeFile.cfm?ID=7902&DocID=678

JavaFX now shipping as part of SDK but it's not truly cross platform???

2011-12-20T05:35:00.000-08:00

This is good but what the heck, the system requirements are still windows? I mean something shouldn't go into the JDK until it is truly cross platform. I can't make up my mind about whether to be excited about JavaFX or not. There have been so many disappointments with Java GUI technology. And HTML5 is certainly sweeping the land. But if Java shops could crank out rich interfaces using nothing but their Java skills then it would be a big win even if it mainly is used in intra-company apps.

I saw this on Adam Bien's blog
http://www.adam-bien.com/roller/abien/entry/java_fx_2_8230_comes

The JDK release notes
http://www.oracle.com/technetwork/java/javase/7u2-relnotes-1394228.html

JavaFX system requirements
http://docs.oracle.com/javafx/2.0/system_requirements/jfxpub-system_requirements.htm

Spring context viewer

2011-12-12T19:30:00.000-08:00

Spring is a great tool but in a large code base with component scanning and autowiring it can be really easy to lose a handle on exactly what your application context looks like. I had just such a problem at work the other day where I needed a structured view of my Spring app context. This was a context at the war level that had another context as a parent at the ear level. There were some classloader issues involved. Anyway, I was able to query the context to figure out what I needed, but after work I thought about writing a quick ascii tree view of the context. It wasn't too hard and you get something like this.

 === Spring ApplicationContext Info ===

+<ApplicationContext 'shared.context'>

     -startupDate: 12/12/2011 09:19:14.667

     -id: shared.context

     -identityHashCode: 567e768e

     -classloader: EarLibClassLoader : urlSet = [URLEntry : file:/C:/code/sctx/dist/gfde....

     +beans

          +adder

               -prototype: true

               -singleton: false

               -type: class example.sctx.service.AdderImpl

               -identityHashCode: ec99b58

               -class: class example.sctx.service.AdderImpl

               -classloader: EarClassLoader : urlSet = [URLEntry : file:/C:/code/sctx/dist/gfdeplo...

          +ejb-context-holder

               -prototype: false

               -singleton: true

               -type: class example.sctx.ContextHolder

               -identityHashCode: 55f5b5fd

               -class: class example.sctx.ContextHolder

               -classloader: EarClassLoader : urlSet = [URLEntry : file:/C:/code/sctx/dist/gfdeplo...

     +<Root WebApplicationContext>

          -startupDate: 12/12/2011 09:19:14.999

          -id: org.springframework.web.context.WebApplicationContext:/sctx1-war

          -identityHashCode: 29d971d9

          -classloader: EarLibClassLoader : urlSet = [URLEntry : file:/C:/code/sctx/dist/gfde....

          +beans

               +webapp1-context-holder

                    -prototype: false

                    -singleton: true

                    -type: class example.sctx1.ContextHolder

                    -identityHashCode: 767f2121

                    -class: class example.sctx1.ContextHolder

                    -classloader: WebappClassLoader (delegate=true; repositories=WEB-INF/classes/)

               +subtractor

                    -prototype: false

                    -singleton: true

                    -type: class example.sctx1.service.SubtractorImpl

                    -identityHashCode: 2c5be151

                    -class: class example.sctx1.service.SubtractorImpl

                    -classloader: WebappClassLoader (delegate=true; repositories=WEB-INF/classes/)

The code to produce is below. It is a fairly short utility class with no external dependencies (other than Spring of course).

package example.springutil;

import java.text.SimpleDateFormat;
import java.util.ArrayList;
import java.util.Collections;
import java.util.Date;
import java.util.List;
import org.springframework.context.ApplicationContext;

/**
 * ContextViewer - create an ascii tree view of Spring context<br/>
 * usage:<blockquote><pre>  
 * ContextViewer viewer = new ContextViewer(ac);
 * String asciiTree = viewer.toString();
 * // then you can dump the tree to the logs or wherever
 * </pre></blockquote>
 * @author rick.lawson
 */
public class ContextViewer {
    private static final int MAX_LEN = 70;
    private static final String INDENT = "     ";
    private static final String CONTENT_NODE = "+";
    private static final String DATA_NODE = "-";
    private static final String DATE_FORMAT = "MM/dd/yyyy hh:mm:ss.S";
    private static final String NL = System.getProperty("line.separator");
    private static final String BASE_SPRING_PACKAGE = "org.springframework";
    private ApplicationContext ac = null;
    private StringBuilder sb = new StringBuilder();
    private String contextAsciiTree = null;
    private int currentLevel = 0;
    private boolean showSpringFrameworkBeans = false;
    private boolean getBeansFromContext = false;

    /**
     * Construct a spring context viewer 
     * @param ac ApplicationContext
     * @param showSpringFrameworkBeans set to true if you want to see internal spring framework beans
     * @param getBeansFromContext set to true if you want to get the beans from the context and display more detailed info<br/>
     * <b>only do this if you know it's ok for your application,</b> some beans may be lazy init'd which means they will<nr/>
     * get initialized here which may not be what you want
     */
    public ContextViewer(ApplicationContext ac, boolean showSpringFrameworkBeans, boolean getBeansFromContext) {
        this.ac = ac;
        this.getBeansFromContext = getBeansFromContext;
        this.contextAsciiTree = buildContextTree();
    }

    /**
     * Construct a spring context viewer<br/> 
     * Does not show internal spring beans<br/>
     * Does not get beans from context to get more detailed info
     * @param ac ApplicationContext
     */
    public ContextViewer(ApplicationContext ac) {
        this(ac, false, false);
    }

    @Override
    public String toString() {
        return contextAsciiTree;
    }

    private String buildContextTree() {
        // create a new StringBuilder
        sb = new StringBuilder(NL);
        sb.append("=== Spring ApplicationContext Info ===").append(NL);
        // check for null
        if (ac == null) {
            sb.append("null context!").append("\n");
            return sb.toString();
        }
        // build our list of application contexts
        List<ApplicationContext> appContexts = new ArrayList<ApplicationContext>();
        appContexts.add(ac);
        ApplicationContext parent = ac.getParent();
        while (parent != null) {
            appContexts.add(parent);
            parent = parent.getParent();
        }
        // reverse the list to get top node first
        Collections.reverse(appContexts);
        // build the ascii context tree
        int level = 0;
        for (ApplicationContext ctx : appContexts) {
            currentLevel = level;
            buildContext(ctx);
            level++;
        }
        sb.append("======================================").append(NL);
        return sb.toString();
    }

    private void buildContext(ApplicationContext ac) {
        if (ac == null) {
            buildContentNode("null context!");
            return;
        }
        String displayName = ac.getDisplayName();
        String id = ac.getId();
        String classloader = shorten(ac.getClass().getClassLoader());
        String identityHashCode = Integer.toHexString(System.identityHashCode(ac));
        Date startupDate = new Date(ac.getStartupDate());
        SimpleDateFormat sdf = new SimpleDateFormat(DATE_FORMAT);
        buildContentNode("<" + displayName + ">");
        buildDataNode("startupDate", sdf.format(startupDate));
        buildDataNode("id", id);
        buildDataNode("identityHashCode", identityHashCode);
        buildDataNode("classloader", classloader);
        buildContentNode("beans");
        String[] beanDefs = ac.getBeanDefinitionNames();
        for (String b : beanDefs) {
            String type = ac.getType(b) + "";
            if (showSpringFrameworkBeans == false) {
                if (b.contains(BASE_SPRING_PACKAGE) || type.contains(BASE_SPRING_PACKAGE)) {
                    continue;
                }
            }
            buildContentNode(b);

            buildDataNode("prototype", ac.isPrototype(b));
            buildDataNode("singleton", ac.isSingleton(b));
            buildDataNode("type", type);
            if (getBeansFromContext) {
                try {
                    Object bean = ac.getBean(b);
                    String beanIdentityHashCode = Integer.toHexString(System.identityHashCode(bean));
                    buildDataNode("identityHashCode", beanIdentityHashCode);
                    buildDataNode("class", bean.getClass());
                    buildDataNode("classloader", bean.getClass().getClassLoader());
                } catch (Throwable e) {
                    buildDataNode("error getting bean", e);
                }
            }
            currentLevel--;
        }
        sb.append(NL);
        return;
    }

    private void buildContentNode(String s) {
        buildIndent();
        sb.append(CONTENT_NODE);
        sb.append(s);
        sb.append(NL);
        currentLevel++;
    }

    private void buildDataNode(String name, Object value) {
        buildIndent();
        sb.append(DATA_NODE);
        sb.append(name);
        sb.append(": ");
        value = value + "";
        value = shorten(value);
        sb.append(value);
        sb.append(NL);
    }

    private void buildIndent() {
        if (currentLevel < 0) {
            return;
        }
        for (int i = 0; i < currentLevel; i++) {
            sb.append(INDENT);
        }
    }

    private String shorten(Object in) {
        String out = in + "";
        if (out.length() > MAX_LEN) {
            out = out.substring(0, MAX_LEN) + "...";
        }
        out = out.replace("\n", "");
        out = out.replace("\r", "");
        return out;
    }
}

So Android was kind of an accident?

2011-12-11T12:49:00.001-08:00

So in the latest hacker news there is a really interesting article about how Google acquired the base of Android from a Palo Alto startup. I had assumed that Google had carefully engineered Android as a natural evolution of their need to grow the mobile space into a platform for their advertising. But it seems, like always, the real world has a lot to do with chance and unforeseen consequences.

http://nikcub.appspot.com/posts/google-android-the-accidental-empire

Blazemeter is JMeter in the cloud

2011-12-07T18:26:00.001-08:00

From the "why didn't I think of this" department. These guys took JMeter, the ubiquitous Java test tool, and put it in the cloud. When I have used JMeter before that was definitely a pain point, setting up all the distributed JMeter instances (which, I think used RMI to communicate which is always fun).

I just wonder how useful this is for QA testing though, since most folks have their QA instance internal instead of publicly accessible.

http://www.datamation.com/open-source/blazemeter-brings-apache-jmeter-to-cloud.html

I wonder what other open source tools are being "cloud-ified"?

Tired of paying WebEx, then try OpenMeetings

2011-12-07T05:36:00.001-08:00

OpenMeetings is a nice project, available to download and run yourself (free and open source) or they have a hosted service. Not all of the WebEx features but an impressive feature set nonetheless. They are incubating at Apache too so that's nice.

http://code.google.com/p/openmeetings/

Forget agile, try Defect Driven Design (D3)

2011-12-06T04:32:00.001-08:00

This is hilarious! D3 is sweeping the development world!

http://weblogs.java.net/blog/kcpeppe/archive/2011/11/29/defect-driven-design-makes-comeback

BitNami Tomcat stack

2011-12-05T16:50:00.001-08:00

Ok, so it's been a while since I used a BitNami stack - I think I last used them to setup a Wordpress stack or some other PHP thingy. But since I'm mainly a Java guy I was happy to see that they have a nice Tomcat stack (either 6 or 7) + MySQL. You can pick from the usual native installers or VMWare images or EC2 AMIs.

http://bitnami.org/stack/tomcatstack

The Twelve-Factor App is a must read if you are writing software as a service

2011-12-04T12:12:00.001-08:00

This is a really powerful article. Boils down to 12 principle the best practices for building scalable, testable and reliable web apps. The goals are in the introduction but are worth repeating:

Use declarative formats for setup automation, to minimize time and cost for new developers joining the project;
Have a clean contract with the underlying operating system, offering maximum portability between execution environments;
Are suitable for deployment on modern cloud platforms, obviating the need for servers and systems administration;
Minimize divergence between development and production, enabling continuous deployment for maximum agility;
And can scale up without significant changes to tooling, architecture, or development practices.

Read the full article here: http://www.12factor.net/

Java and Kerberos (krb5.conf)

2011-12-03T12:24:00.001-08:00

I had an interesting situation the other day where I needed to restrict the encryption types used in a Java webapp that authenticated via Kerberos. This is pretty common in that Kerberos is the default authentication protocol for Windows 2000 and onwards.

Now Kerberos and Active Directory are huge topics so I'm only going to focus on one thing that tripped me up, namely, where is the krb5.conf file for a Java application and what in the world can you use it for. Well it turns out the krb5.conf is a very useful file if you need to tweak things. Here is how you tell Java where your krb5.conf file is:

-Djava.security.krb5.conf=/path/to/your/krb5.conf

Now you need to make sure that you aren't setting either of these parameters or your krb5.conf file will be ignored:

-Djava.security.krb5.realm
-Djava.security.krb5.kdc

So inside your krb5.conf file, you can set your realm & kdc (key distribution center), your default realm and the default encryption types. Different versions of Windows Domain Controllers differ in the encryption types they support so you may need to tweak the following lines (they may have different types in your file, depending on Java version):

default_tkt_enctypes = aes128-cts des3-cbc-sha1 rc4-hmacdes-cbc-md5 des-cbc-crc
default_tgs_enctypes = aes128-cts des3-cbc-sha1 rc4-hmacdes-cbc-md5 des-cbc-crc
permitted_enctypes = aes128-cts des3-cbc-sha1 rc4-hmac des-cbc-md5des-cbc-crc

The following links are quite helpful:

Java6 security tech note - new features
Java security tech note - troubleshooting
Wikipedia - Kerberos
Forum posting for encryption type difference between Windows Server 2003 and 2008

Great introduction to setting up a working python development environment

2011-12-03T11:44:00.001-08:00

Best overall introduction to setting up your python work environment I have seen. Really good practical info on packaging and dependecy management (virtualenv, pip), the different python versions and important frameworks (django, fabric, flask, scipy).

For Java folks, this is the equivalent of telling a new Java programmer about Maven, Ant, Spring, etc.

http://mirnazim.org/writings/python-ecosystem-introduction/

SOLR

2007-01-12T15:55:00.000-08:00

Wow !

If you have worked with Lucene, then you owe it to yourself to check out SOLR. It's just about to graduate to a full fledged apache project and it's a doozy. Basically take Lucene, add a REST'ful interface on top, basic web administration and goodies like replication & caching. What makes this cool is it is usable by both Java and non-Java tools. So you can run SOLR for your search engine but have a Django based front end. Did I mention it powers the search for some major sites - like shopper.com and was donated by CNET.

Just post xml docs following a dead simple format to SOLR and it takes care of indexing them. Post another xml doc to query it and it shoots you back the search results.

I'm working on scaling up www.getlocalbiz.com and SOLR will definitely be a part of it (we are already using Lucene for search)

Mochislide

2007-01-07T04:54:00.000-08:00

Ok, here's how to do a simple slideshow with fading images in mochkit. Simple and powerful, Lord how I love mochikit ! Example is here


var images = new Array();
// Set up your images here 
images[0]="images/deedee.gif";
images[1]="images/dexter.jpg";

var imageObjs = new Array(); 

var currentIdx = 0;

// preload images
for(idx in images){
    var tmp = new Image();
    var imageName = images[idx];
    tmp.src = imageName;
    imageObjs[idx] = tmp;
}

// start interval times
var slideInterval = setInterval('onInterval()', 5000); 

function onInterval(){
    // increment image index and reset if necessary
    currentIdx = currentIdx + 1;
    if(currentIdx >= images.length){
        currentIdx = 0;
    }
    // fade out existing image
    // and pull in next image
    fade("slideshow", {"to" : "0.1", "duration" : "0.4", afterFinish: function () {
    $("slideshow").src = imageObjs[currentIdx].src;
    appear("slideshow", {"duration" : "0.4"});
    }});
    
}

Image fade with MochiKit

2006-12-17T14:47:00.000-08:00

MochiKit rocks. I needed to add an image fade for a site I am revamping and it was suprisingly easy using Mochikit. Go here for an example. Here's the relevant code

var deedee = new Image();
deedee.src = 'images/deedee.gif';
var dexter = new Image();
dexter.src = 'images/dexter.jpg';


function onImageMouseover(){
fade("bigPic", {"to" : "0.1", "duration" : "0.4", 
"queue" : "break", afterFinish: function () {
$("bigPic").src = dexter.src;
appear('bigPic', {"duration" : "0.4", "queue" : "break"});
}});
}

function onImageMouseout(){
fade("bigPic", {"to" : "0.1", "duration" : "0.4", 
"queue" : "break", afterFinish: function () {
$("bigPic").src = deedee.src;
appear('bigPic', {"duration" : "0.4", "queue" : "break"});
}});
}

Insanely Great

2006-12-02T13:37:00.000-08:00

I've been reading Stephen Levy's book about the rise of the Macintosh - Insanely Great. It's a really good read if a little dated. I still remember that tingly feeling when I first saw a Mac Plus and it really was insanely great for it's time. We owe a lot to the Mac and the emphasis on instant usability and intuitive interfaces is something we would do well to emulate in our fancy Web 2.0 interfaces.