Kevin's Technology Notes

How to disable dark-mode for java applications on OSX

2021-09-22T04:38:00.004-07:00

As a software engineer, I've been a big fan of the dark-mode that was added to BigSur OSX. The only problem is that one of my frequently used apps didn't like the new color schema. For instance, if you look at the following screen capture, you'll notice that the menu bar and table headers are black on black.

I did some research and found the following workaround. In OSX, you can disable dark-mode for a specific application.

To do this, you will need to run the following command:

defaults write <BundleID> NSRequiresAquaSystemAppearance -bool yes

But before you run that command, you need to find the <Bundle ID>. I found using the lsappinfo command the easiest way. When you run this command it displays a bunch of information about the current applications that are running. So for me, I just looked for the Luke and found the following?

70) "LukeMain" ASN:0x0-0x305305:

bundleID="net.java.openjdk.cmd"

bundle path="/Library/Java/JavaVirtualMachines/adoptopenjdk-8.jdk/Contents/Home/bin/java"

executable path="/Library/Java/JavaVirtualMachines/adoptopenjdk-8.jdk/Contents/Home/bin/java"

pid = 70611 type="Foreground" flavor=3 Version="1.0" fileType="APPL" creator="java" Arch=x86_64

checkin time = 2021/09/21 18:01:54 ( 9 minutes, 12.5975 seconds ago )

Since my application was Java bases this command did the trick for me.

defaults write net.java.openjdk.cmd NSRequiresAquaSystemAppearance -bool yes

And.... back to normal...

Setup Motion on raspberry pi

2017-05-04T04:53:00.002-07:00

Use the following procedure to setup motion on a raspberry pi zero w.

Setup raspbian on SD card via https://www.raspberrypi.org/documentation/installation/installing-images/README.md
Update config to enable it to boot as a network gadget https://gist.github.com/gbaman/975e2db164b3ca2b51ae11e45e8fd40a
ssh pi@rasberrypi.local
run raspi-config

reset password
rename host zero
enable camera module (under interfaces)
Reboot

ssh pi@zero.local
sudo apt-get update
sudo apt-get upgrade
sudo apt-get install motion
Edit /etc/default/motion

start_motion_daemon=yes

Add /etc/modules

# camera with v4l2 driver
bcm2835-v4l2

restart

How to expose a port to the internet

2017-03-24T06:37:00.001-07:00

I recently discovered localtunnel which is a slick little tool to expose a port to the internet.
https://localtunnel.github.io/www/

To Setup:

brew install npm
npm install -g localtunnel
lt --port 8080

How to workaround Kindle Fire's FreeTime App categories.

2016-01-03T08:11:00.001-08:00

We recently got our kinds the Kids version of Kindle Fire and was really disappointed to find that some Apps are flagged as Entertainment. In particular, our schools use RazKids and because of the categorization with FreeTime there isn't a way for us to allow our kinds to read using RazKids without giving them access to all games.

I was searching around for workarounds but didn't find anything so I'm posting the workaround that I came up with.

The solution that I found was:

Create a New Child Profile named RazKids
Under "FreeTime Unlimited", tap the "Manager Your Subscription" and uncheck the RazKids. This will disable all the standard content that is provided by FreeTime.
Now Tap, Add Content and select the "RazKids" app. This grants them permission to the RazKids app.
Now Tap, "Set Family Goals & Time Limits" and set whatever restrictions you would like to apply.

By doing this, you'll now see a second profile that has access just to RazKids. The kids can now switch between the regular profile with full FreeTime access and this special profile to use RazKids.

Jersey API Exception Handler

2015-12-15T08:11:00.000-08:00

In Jersey, you can register your own exception handler so can return an appropriate HTTP response for any exception In the handler, you can set the error response or convert it to any JSON object.

@Provider

public class ApiExceptionHandler implements ExceptionMapper<Exception> {

@Override

public Response toResponse(Exception exception) {
// TODO : insert logger statement

return Response.status(Status.BAD_REQUEST).entity(exception.getMessage()).build();

}

Using awk to filter by value

2015-09-22T05:18:00.000-07:00

Here's a simple example of an awk script that will find rows where there value is greater than 1000. I often forget the syntax of this command but in the following example, I'm trying to find rows where the 11th column is greater than 1000.

awk '{if ( int($11) >= 1000 ) print $7, $11;}'

Creating a custom generic GWT event

2015-06-15T09:03:00.000-07:00

I keep having trouble setting up a GWT event handler which is parameterized. All of the magic needs to happen in the GwtEvent class itself.

public class CustomClickEvent<T> extends GwtEvent<HasClickHandler<T>> {
	private static Type<HasClickHandler<?>> TYPE = new Type<HasClickHandler<?>>();

	
	
	private LazyCellClickEvent() {}
	
	@Override
	protected void dispatch(CustomClickEventHandler<T> clickEvent) {
		clickEvent.onClick(this);
	}

	@SuppressWarnings({ "unchecked", "rawtypes" })
	@Override
	public Type<HasClickHandler<T>> getAssociatedType() {

		return (Type)TYPE;
	}
	
	public static final Type<HasClickHandler<?> getType() {

		return TYPE;
	}
	
	public static  void fire(HasCustomEventHandler<T> handler) {
		CustomClickEvent<T> event = new CustomClickEvent<T>();
		handler.fireEvent(event);
	}	
}

GWT Custom Serializer

2015-04-02T10:19:00.000-07:00

GWT allows you to build your own customer serializers. In the past, I've found issues/bugs with certain serialization of classes and this allows you to provide your own implementation. The key to this is that you have to put your class in the com.google.gwt.user.client.rpc.core + your class package.

The following example you be to create a custom serializer for the my.package.ApiException class.

package com.google.gwt.user.client.rpc.core.my.package;

public class ApiException_CustomFieldSerializer extends CustomFieldSerializer {

     @Override
     public void deserializeInstance(SerializationStreamReader streamReader, ApiException instance) throws SerializationException {
           deserialize(streamReader,instance);
      }

    @Override
    public void serializeInstance(SerializationStreamWriter streamWriter, ApiException instance) throws SerializationException {
           serialize(streamWriter,instance);
    }
 
    public static void serialize(SerializationStreamWriter streamWriter,ApiException instance) throws SerializationException {
           streamWriter.writeString( instance.getMessage() );
    }
 
    public static void deserialize(SerializationStreamReader streamReader,ApiException instance) throws SerializationException {
           instance.setMessage( streamReader.readString() );
    }
 
    public static ApiException instantiate(SerializationStreamReader reader) throws SerializationException {
          return new ApiException();
    }
}

Prevent HTTP 304 for GWT's nocache.js files.

2015-03-19T06:18:00.002-07:00

I recently deployed a release of our product which caused a majority of our users to clear their browsers cache in order to access our sites. Of course, this is quite embarrassing and I was asked to identify the problem. Since day one we've always had the standard solution of deploying a ServletFilter which sets the standard Cache-Control headers so it was confusing why all of a sudden a large percent of users were reporting this issue.

The good news is that I believe I've solved my problem and since I've never seen any reference to it I figured it would write it down.

Disclaimer: You'll have to forgive me but we're running Tomcat 7.0.22 (yeah, I know) so this might have changed in more recent versions.

So the first thing that I noticed is that in the tomcat access logs there are HTTP 304 (File Not Modified) being returned for my nocache.js files. After many hours of Googling and debugging, I found that the DefaultServlet. checkIfModifiedSince() compares the files timestamp with the "If-Not-Modified" header to determine if that file has changed. We're deploying our app as a WAR file which means that files timestamp gets set to the time that is stored in the WAR. Now to further complicate this issue GWT seems to be caching this file someone (not the GWT working directory) so in our build it was getting set to the time when we created the branch and jenkins plan.

So to summarize, my problem was the timestamp of this file was being set to the time of the branch creation (which was days before deployment). So anyone who used the application between the time we branched and them time we deployed would cache a copy of the nocache.js file with the current timestamp. When the WAR was finally deployed, the timestamp was updated to branch time and new request would start getting 304s because they were passing in "If-Modified-Since" headers that were greater than the time of the branch.

So how do you fix this problem? A simple unix command:

find -name '*.nocache.js" -exec touch {} \;

Now, I also went a step further and wanted to try to fix the programmatically. The only workaround that I could find was to build an HttpServletRequest interceptor that prevents that header from being returned.

public class GWTCacheControlFilter implements Filter {
 
 private static final long SECONDS = 1000;
 private static final long MINUTES = 60 * SECONDS;
 private static final long HOURS = 60 * MINUTES;
 private static final long DAYS = 24 * HOURS;
 
 public void destroy() {
 }

 public void init(FilterConfig config) throws ServletException {
 }

 public void doFilter(ServletRequest request, ServletResponse response, FilterChain filterChain) throws IOException, ServletException {

  HttpServletRequest httpRequest = (HttpServletRequest) request;
  String requestURI = httpRequest.getRequestURI();
  
  if (requestURI.contains(".nocache.")) {
   try {
    request = createProxy(httpRequest);
   } catch (Throwable t) {
    logger.error("Failed to creative interceptor",t);
   }
   
   Date now = new Date();
   HttpServletResponse httpResponse = (HttpServletResponse) response;
   httpResponse.setDateHeader("Date", now.getTime());

   
   httpResponse.setDateHeader("Last-Modified", now.getTime() );
   httpResponse.setDateHeader("Expires", now.getTime() - 30 * DAYS );
   httpResponse.setHeader("Pragma", "no-cache");
   httpResponse.setHeader("Cache-control", "no-cache, no-store, must-revalidate,  max-age=0");
  }

  filterChain.doFilter(request, response);
 }
 
 
 private static final HttpServletRequest createProxy(final HttpServletRequest source) {
  return (HttpServletRequest) Proxy.newProxyInstance( GWTCacheControlFilter.class.getClassLoader() , new Class[] { HttpServletRequest.class } , new InvocationHandler() {
   @Override
   public Object invoke(Object proxy, Method method, Object[] args) throws Throwable {
    
    String name = method.getName();
    if ( name.equals("getDateHeader") && args.length == 1 && args[0].equals("If-Modified-Since") ) {
     return 0l;
    }
    
    if ( name.equals("getHeader") && args.length == 1 && args[0].equals("If-Modified-Since") ) {
     return null;
    }
    
    if ( name.equals("getIntHeader") && args.length == 1 && args[0].equals("If-Modified-Since") ) {
     return 0;
    }
    
    return method.invoke(source, args);
   }
  });
 }
 
}

HOW-TO Use GWT SuperDevMode

2014-09-29T14:14:00.000-07:00

GWT 2.5 introduced a concept of SuperDevMode which is a pretty awesome concept but I found it almost impossible to get it to work. The documentation just didn't explain enough of the missing pieces.
So before I get started, let me explain what it is/does. Recently a bunch of the browsers started to support the concept of source code maps. This feature has nothing to do with GWT and it just a way for someone to debug javascript that has been optimized/generated. These maps contains a mapping of the compiled source to the original source which then allows the debugged to display the original source.

So what GWT has done is provided a mechanism to integrate with this browser debugging feature to provide a way to debug through the compiled javascript BUT see the original java code. Awesome right!

The key thing I found extremely confusing is that you need to build and deploy the production version of your application. I use maven/tomcat to do this but you could use anything.

Compile your application as normal (mvn clean install -DskipTests)
Install the war into your local tomcat and start tomcat
Execute java program at the bottom which will start the Code Server
Go to http://localhost:9876/ and copy the bookmarks to you bookmark directory
Go to the location version of the app (http://localhost:8080/yourwar/
Click the "Dev Mode On" bookmark

You should now see the a SDM dialog come up and ask you to compile the app. Once it is done compiling the app, you now are running a newly compiled version of the app within the browsers debugger. So you're not going to use the IDEs debugger anymore. Now you'll can open Chromes debugger and you should see the JAVA source instead of the javascript sources. You should be able to set a breakpoint.

While this is an awesome feature, I've found that using the standard mode still more useful for day-to-day debugging. I do run into cases where its been essential. Recently, I had a race condition which never showed up in the standard debugger because it always executed so slowly.

https://www.youtube.com/watch?v=WqiZLM32kXY

public class SuperDevMode {

 public static final void main(String[] args) throws Exception {
  new File("target/gwt.tmp").mkdirs();
  CodeServer.main( new String[] {
    "-workDir" , "target/gwt.tmp",
    "-src","../gwt-utils/src/main/java",
    "-src","src/main/java",
    "com.gwt.module"
  });
 }
}

HOW-TO execute a maven plugin within eclipse?

2014-09-29T13:45:00.000-07:00

If you're running maven with eclipse you've probably been frustrated by "Plugin execution not covered by lifecycle configuration" error. Well after while I finally managed to get it to do what I wanted. The key is that there is a org.eclipse.m2e:ifecycle-mapping maven plugin that does nothing but let eclipse know how you want to handle a specific goal. For instance in the following example
I've instructed to execute the hibernate3-maven-plugin:run goal. If you take a look at the eclipse doc you'll see there is also an ignore option. For the longest time, I was just setting them to ignore but recently I learned about the execution option. This seems to work for me although for certain incremental builds its not re-executing the command.

It does however seem to alway run when I do an eclipse clean.

http://wiki.eclipse.org/M2E_plugin_execution_not_covered

    <buld>

  <pluginManagement>

   <plugins>

    <plugin>
     <groupid>org.eclipse.m2e</groupid>
     <artifactid>lifecycle-mapping</artifactid>
     <version>1.0.0</version>
     <configuration>
      <lifecyclemappingmetadata>
       <pluginexecutions>
        <pluginexecution>
         <pluginexecutionfilter>
          <groupid>org.codehaus.mojo</groupid>
          <artifactid>hibernate3-maven-plugin</artifactid>
          <versionrange>[3.0,)</versionrange>
          <goals>
           <goal>run</goal>
          </goals>
         </pluginexecutionfilter>
         <action>
          <execute>
         </execute></action>
        </pluginexecution>
       </pluginexecutions>
      </lifecyclemappingmetadata>
     </configuration>
    </plugin>
   </plugins>

watch SQL script.

2014-01-15T09:16:00.000-08:00

The following script is a way to execute a mysql command every second. I wrote the script because OSX doesn't have a watch command and mysql takes the SQL statement from stndin.

#!/bin/bash

SQL=`cat -`

while true;

clear

echo $SQL

echo "$SQL" | mysql $*

date

sleep 1

done

JIRA Agile Script

2013-09-17T05:06:00.003-07:00

We recently converted to JIRA and apart of our process allows engineerings to accept Ad-Hoc requests from the business owners. So I wanted to the ability for a developer to quickly be able to grab a new ticket and add it to the current sprint. The only solution I could find was to write a script using the JIRA Script Runner plugin.

The following is the script that I wrote. It does the following:


automatically assigns members of the "jira-product" group as watchers of the issue
adds the issues to the current sprint. The algorithm is to find the lowest number sprint ID that is not closed.
sets our custom field "Ad Hoc Requests" (id=10305) to 1. This way we can run reports on these requests.

importPackage(java.lang);

run();

function run() {
 var componentManager = com.atlassian.jira.ComponentManager.getInstance();
 var user = componentManager.getJiraAuthenticationContext().getUser();

 var watcherManager = componentManager.getWatcherManager();
 var userManager = componentManager.getComponentInstanceOfType( com.atlassian.jira.user.util.UserManager );
 var groupManager = componentManager.getComponentInstanceOfType( com.atlassian.jira.security.groups.GroupManager );

 if ( ! userManager ) {
     log("User Manager not found");
     return 0;
 }

 if ( ! groupManager ) {
     log("Group Manager not found");
     return 0;
 }


 var admin = userManager.getUserByName("admin");
 log("JIRA="+admin);

 var productGroup = groupManager.getGroup("jira-product");
 if ( productGroup ) {
     var users = com.atlassian.jira.user.ApplicationUsers.from(groupManager.getUsersInGroup(productGroup)).iterator();
     while ( users.hasNext() ) {
  var usr = users.next();
  
  log("Adding Watcher : " + usr.getClass() );
  watcherManager.startWatching( usr , issue );
     }
 }

     // finish adding watchers

 log("JS : " + user + " " + issue + " " + issue.getClass() );

 var commentManager = componentManager.getComponentInstanceOfType( com.atlassian.jira.issue.comments.CommentManager ); 
 var customFieldManager = componentManager.getComponentInstanceOfType( com.atlassian.jira.issue.CustomFieldManager );

 if ( ! customFieldManager ) {
  log("Null Custom Field Manager");
         return 0;
 }

 var sprintFld = customFieldManager.getCustomFieldObject( 10000 );
 var adhocFld = customFieldManager.getCustomFieldObject( 10305 );  
 if ( ! sprintFld ) {
  log("Sprint field not found");
  return 0;
 }

 if ( ! adhocFld ) {
     log("Ad Hock Field Not Found");
 }

        var sprintManager = getSprintManager();

 if ( ! sprintManager ) {
     log("SprintManager not found");
     return 0;
 } else {
     log("Found SprintManager");
 }

 if ( commentManager && issue ) {
     if ( sprintManager ) {
  var sprintId = null;
  var sprint = null;
  var value = issue.getCustomFieldValue(sprintFld);
  
  log("Sprint = " + value );
  var soutcome = sprintManager.getAllSprints();
  if ( soutcome.isValid() ) {
      var allSprints = soutcome.getValue();
      
      if ( allSprints ) {
   var itt = allSprints.iterator();
   while( itt.hasNext() ) {
       var next = itt.next();
       if ( next.isClosed() ) continue;
       
       if ( ! sprintId || sprintId.longValue() > next.getId().longValue() ) {
    sprintId = next.getId();
    sprint = next;
       }
   }
      }
  }
  
  if ( sprint ) {
      var newValue = new java.util.ArrayList();
      newValue.add( sprint );
      sprintFld.updateValue(null, issue, new com.atlassian.jira.issue.ModifiedValue(value,newValue), new com.atlassian.jira.issue.util.DefaultIssueChangeHolder());

      adhocFld.updateValue(null,issue,new com.atlassian.jira.issue.ModifiedValue(issue.getCustomFieldValue(adhocFld),1), new com.atlassian.jira.issue.util.DefaultIssueChangeHolder());
  }
     }

     var msg = user + " accepted story as ad-hoc request";
     if ( sprint ) {
  msg = msg + " and assigned to sprint: " + sprint.getName();
     }
     commentManager.create(issue, admin , msg , true);
     issue.store();
 }
}


function getSprintManager() {
    var appCtx = getGreenHopperAppCtx();
    if ( appCtx ) {
 log("Found AppCtx");
 return appCtx.getBean( "sprintManagerImpl" );
    }
    return null;
}

function getGreenHopperAppCtx() {
    var componentManager = com.atlassian.jira.ComponentManager.getInstance();
    var osgi = componentManager.getComponentInstanceOfType (com.atlassian.plugin.osgi.container.OsgiContainerManager);
    if ( ! osgi ) {
 java.lang.System.out.println("OSGI Not Found");
 return null;
    }

    var bundles = osgi.getBundles();

    var sprintManager;
    for(var i=0;i<bundles.length;i++) {
 var bundle = bundles[i];

        if ( "com.pyxis.greenhopper.jira".equals( bundle.getSymbolicName() ) ) {
     log("Found JIRA Agile Plugin");

     var bctx = bundle.getBundleContext();
            var refs = bctx.getAllServiceReferences(null,null);
     if ( refs ) {
  for(var j=0; j<refs.length;j++) {
      var prop = refs[j].getProperty("org.springframework.context.service.name");
      if ( "com.pyxis.greenhopper.jira".equals(prop) ) {
   log ( "Found Greenhopper ServiceReference : " +  prop );
   return bctx.getService( refs[j] );
      }
  }
     }
 }

 //log ( bundle );

    }

    return null;
}

function log(msg) {
    java.lang.System.out.println( "" + msg);
}

HOWTO add Emma Support to Maven GWT

2013-01-22T12:43:00.001-08:00

I've had to do this a couple times so I'm finally writing it down for future me. But for anyone else that might be interested, this posting will (hopefully) walk you through how to add Emma code coverage support to GWT via maven.

For those of you that might not be that familiar with code coverage tools, there are two common ways to generate code coverage. In both cases, your code is modified to include counters for each time a thread enters / exists a code block. This process is call instrumentation hence, in java there are two ways: re-write the code and compile the classes or re-write the classes directly.

So lets talk a little about why emma works. First of all, Google has a patched jar but the reason that emma works well is that emma instruments the classes not the source. This is key to GWT because if you instrument the code, then GWT compile will not be able to find any of the instrumentation classes and it won't compile. So by instrumenting the classes the GWT compiler can compile your source but the classes files still get instrumented.

So you may be thinking, if GWT compiler compiles your code pre-instrumentation how can it generate the coverage information for you client code? The answer is simple, the unit test MUST run in development mode. By doing this, the GWT compiler will run your application in java not javascript.

So here are the changes (ordered by maven lifecycle).

Add Emma dependency

The first thing you'll need to do is add the emma dependency. I was unable to find Googles patched jar in any publish maven repo so I just uploaded it to a local nexus server. If you're not using nexus you'll need to install it manually into the your local repo:

mvn install:install-file -Dfile=<path-to-file> -DgroupId=emmca -DartifactId=emma -Dversion=2.0.5312-patched -Dpackaging=jar

Then add the following dependency to your pom.xml

<version>2.0.5312-patched</version>

</dependency>

Instrument your classes.

I found that running emma via ant-run was the easier way to get it to do what I wanted. Check out the emma document for other options but I followed there offline instructions

<artifactId>maven-antrun-plugin</artifactId>

<id>Emma instrumentation</id>

<phase>process-classes</phase>

<skip>${skipEmma}</skip>

<java

fork="true"

classpathref="maven.test.classpath"

classname="emma">

</java>

</target>

</configuration>

<goals>

</goals>

</execution>

.....

Update Surefire plugin

Next we need to update your surefire plugin to force the output file to get put into target. This isn't required but it cleaner with maven.

<emma.coverage.out.file>${project.basedir}/target/emma/emma.ec</emma.coverage.out.file>

</systemPropertyVariables>

Here's my full surefire plugin in case there are any issues.

<groupId>org.apache.maven.plugins</groupId>

<artifactId>maven-surefire-plugin</artifactId>

<useManifestOnlyJar>false</useManifestOnlyJar>

<forkMode>always</forkMode>

</additionalClasspathElements>

<emma.coverage.out.file>${project.basedir}/target/emma/emma.ec</emma.coverage.out.file>

</systemPropertyVariables>

</configuration>

</plugin>

Generate the Report

Finally, you need to add this second execution to the ant-run plugin we defined above. This will then generate the report via the emma.em file and emma.ec file that were generated from the two previous steps.

It should also be noted that I call <fail> at the end of the ant run. This is just a safe guard so I don't generate a jar that contains the instrumented cases.

<id>Emma Report</id>

<phase>prepare-package</phase>

<skip>${skipEmma}</skip>

<java

dir="${project.basedir}/target/emma-report"

fork="true"

classpathref="maven.test.classpath"

classname="emma">

</java>

</target>

</configuration>

<goals>

</goals>

</execution>

GWT CssResource not working...

2012-10-29T09:48:00.001-07:00

I recently was trying to use a CssResource and I couldn't figure out why it wasn't working. It was inserting the class attribute into the Element but it wasn't actually adding the CSS file into the document. I finally noticed that there is an method called ensureInjected() on the generate CssResource and that seemed to fix my problem. My assumption is that somewhere in GWT when it loads the ClientBundle its calling this method somewhere but in my case the class that was calling it was just a regular class and not some sort of widget. Anyway, call ensureInjected() and it should fix your problem.

Custom Containers with GWT UiBinder

2012-07-31T05:13:00.001-07:00

I just wasted a whole day at work trying to figure out how to create my own container widget that will work with in GWT's UiBinder. In the end, I was forced to dig through the source to find the solution. If you take a look at the UIBinderClass.registerParsers(), you'll see that it has a list of hard coded ElementParsers. If you take a close look, you'll notice that google has registered 4 generic parsers: HasText,HasHTML,HasTreeItems,HasWidgets. So if you're Composite class implements any one of these interfaces then it will you're widget will support having some child element's within it's XML. In my case, I just wanted to create a custom decorated panel. So I simple created a class that extended the HasWidget interface.

public class Decorated extends Composite implements HasWidgets {
 private static DecoratedUiBinder uiBinder = GWT.create(DecoratedUiBinder.class);

 interface DecoratedUiBinder extends UiBinder {
 }

 public Decorated() {
  initWidget(uiBinder.createAndBindUi(this));
 }

 @UiField SimplePanel placeholder;
 
 @Override
 protected Widget getWidget() {
  return placeholder.getWidget();
 }

 @Override
 protected void setWidget(Widget widget) {
  placeholder.setWidget(widget);
 }

 @Override
 public void add(Widget w) {
  setWidget(w);
 }

 @Override
 public void clear() {
  setWidget(null);
 }

 @Override
 public Iterator iterator() {
  return Arrays.asList( getWidget() ).iterator();
 }

 @Override
 public boolean remove(Widget w) {
  if ( getWidget() == w ) {
   clear();
   return true;
  }
  return false;
 } 
}

<ui:UiBinder xmlns:ui="urn:ui:com.google.gwt.uibinder" xmlns:g="urn:import:com.google.gwt.user.client.ui">
  <g:HTMLPanel>
    <div>
      <div>
         <g:SimplePanel ui:field="placeholder" />
      </div>
    </div>
  </g:HTMLPanel>
</ui:UiBinder>

Regular Expressions Syntax

2012-06-12T12:24:00.002-07:00

Perl

Repeats
* Match 0 or more times
+ Match 1 or more times
? Match 1 or 0 times
{n} Match exactly n times
{n,} Match at least n times
{n,m} Match at least n but not more than m times

RegEx
. Match any character
\w Match "word" character (alphanumeric plus "_")
\W Match non-word character
\s Match whitespace character
\S Match non-whitespace character
\d Match digit character
\D Match non-digit character
\t Match tab
\n Match newline
\r Match return
\f Match formfeed
\a Match alarm (bell, beep, etc)
\e Match escape
\021 Match octal char ( in this case 21 octal)
\xf0 Match hex char ( in this case f0 hexidecimal)

SQL Syntax

2012-06-12T12:12:00.000-07:00

Not sure what it is about the SQL case statement but I never can seem to remember it..

case when 1 then when 2 then else end
case when then when then else end

Here's a link to the SQL spec for those hardcore people out there..

Eclipse Keystrokes..

2012-06-12T11:58:00.002-07:00

Here's a list of my favorite Eclipse keystrokes.

CTRL+SHIFT+R - Open Resource
CTRL+SHIFT+T - Open Type

CTRL+SHIFT+Y - To Lower Case
CTRL+SHIFT+X - To Upper Case

CTRL+1 - Quick Fix
CTRL+O - Opens Overview(ish) window
CTRL+SPACE - Text Completion Window
CTRL+L - Go to Line
CTRL+Q - Go to last edit
CTRL+T - Open Inheritance window
CTRL+E - Open Editor

Emac Notes

2012-06-12T11:56:00.001-07:00

I'm not even close to an emacs user but I do like it better than notepad or whatever lame editors come with the OS. Here's a like of commands I always need but forget.

alt-x hexl-mode - opens hex mode viewer

GWT Unit Tests

2012-06-12T11:51:00.002-07:00

About a year ago, I spent about two months trying to figure out how to integrate GWT's unit tests within a custom web container. The problem what that we had an embedded jetty server which which had access to the full ClassLoader (i.e. disabled J2EE compliance).

In development mode, this wasn't an issue because there is two easy workarounds. I started out by using the -server option and build a customer ServletContainerLauncher which allowed my to start the whole application (jetty server and all) within the dev-mode. This solution worked fine and even supported the "restart/reload" option with eclipse but after working with GWT for a while, I realized this was an overkill. Instead, I realize that you can use the -no-server option to achieve the same thing. So instead of trying to force our application to run the GWT container, I started up our application and the GWT engine in dev mode. GWT engine then generated the javascript and dumped it in our applications webapp directory. When the browser hit our web server it would then serve up the html and js files that GWT generated but because the ?gwt.codesrv= argument existed on the URI, the GWT browser plugin would then communicate to the GWT engine. Of course, in this mode the reload/restart button didn't work in eclipse but one advantage of this solution is you can easily swap between production and dev mode.

Unfortunately, getting JUnit tests running was not as easy. So in order to get junit tests running within our own servlet container, I was forced to patch the JUnitShell class. The patch does the following:

Add a -server option to the enable a custom ServletContainerLauncher
Created a CustomerLauncher that subclasses the ServletContainerLauncher. This allowed for the JunitTest to resolve the Jetty container and map the servlets from the my GWT module into the junit modules that was generated. See line 148

The patch is attached to the following google ticket.

HTML Color Palette Generator.

2012-04-26T10:00:00.002-07:00

From time to time,I need to find a set of colors that look good together and it turns out this is much easier than you think. Color theory states that if you look at the color wheel and that is exactly opposite (180 degrees) your color, it will match. Now that will give you 2 colors. Say you want 3. Then you create a triangle between your color and the two other colors that are exactly 120 degrees. It turns out you can keep doing this. For instance, if you want 6 colors than 360 / 6 = 60 and therefor you want the colors that are at 60,120,180,240,300 degrees away from your point. So here's a little bit of javascript that will generate a color palette off of a single HEX color. Just enter the color,the count, hit generate, and it will dump the colors that look good with your original color. I've found this stuff pretty useful and couldn't find anything on that web that would do all the conversion for me.... Enjoy.
Color:
Count:

How to enable port forwarding in openssh

2012-01-05T07:19:00.000-08:00

How to enable port forwarding in openssh? Add the following lines to the /etc/sshd_conf file to enable port forwarding and GatewayPort. This will allow you to map ports to other boxes within your private network.

AllowTcpForwarding yes
GatewayPorts yes

Where's did my 300m of internal storage go?

2011-07-12T07:19:00.000-07:00

For a while now, I've been using App 2 SD to manage the internal storage on HTC EVO. But recently, I started to notice that the numbers weren't adding up. For instance, it said that I had used 400m of internal storage but the apps installed to internal storage only totaled 100m. So where was there other 300m? After Googling around, I finally found DiskUsage app. This app allows you to determine what applications are using internal storage. And the answer to this missing 300m? To my surprise, the ONLY thing installed on the SD drive is the application itself. The Application Data can still use internal storage and Android is using the internal storage to cache the binaries. I felt this is extremely misleading and Google really needs to fix this.

DiskUsage isn't the best UI but it does allow you to select/filter the 3 types of memory (app,data,cache).

Maven Color Coding

2011-05-06T08:27:00.000-07:00

Here is my bash script that will color code that output of maven. The goal is to highlight any important lines to make it easier to identify if something failed. I highlight all passed unit tests it green and red for the failing tests.

Enjoy,

#!/bin/sh

# other colors
#export COLOR_RED=`echo -e '\033[1;41m\033[37m'`
#export COLOR_GREEN=`echo -e '\033[1;42m\033[37m'`
#export COLOR_NORMAL=`echo -e '\033[0m'`
#export BACKGROUND_BLACK=`tput setab 0`
#export BACKGROUND_RED=`tput setab 1`
#export BACKGROUND_GREEN=`tput setab 2`
#export BACKGROUND_YELLOW=`tput setab 3`
#export BACKGROUND_BLUE=`tput setab 4`
#export BACKGROUND_MAGENTA=`tput setab 5`
#export BACKGROUND_CYAN=`tput setab 6`
#export BACKGROUND_WHITE=`tput setab 7`

export BOLD=`tput bold`
export UNDERLINE_ON=`tput smul`
export UNDERLINE_OFF=`tput rmul`
export TEXT_BLACK=`tput setaf 0`
export TEXT_RED=`tput setaf 1`
export TEXT_GREEN=`tput setaf 2`
export TEXT_YELLOW=`tput setaf 3`
export TEXT_BLUE=`tput setaf 4`
export TEXT_MAGENTA=`tput setaf 5`
export TEXT_CYAN=`tput setaf 6`
export TEXT_WHITE=`tput setaf 7`
export RESET_FORMATTING=`tput sgr0`

mvn $* | sed \
-e "s/$\[WARNING\].*$/${TEXT_YELLOW}\1${RESET_FORMATTING}/g" \
-e "s/$\[ERROR\].*$/${TEXT_RED}\1${RESET_FORMATTING}/g" \
-e "s/$.*Failures:\s*[123456789].*$/$TEXT_RED\1$RESET_FORMATTING/i" \
-e "s/$.*Errors:\s*[123456789].*$/$TEXT_RED\1$RESET_FORMATTING/i" \
-e "s/$.*Failures:\s*0,\s*Errors:\s*0.*$/$TEXT_GREEN\1$RESET_FORMATTING/i" \
-e "s/$.*Errors:\s*0,\s*Failures:\s*0.*$/$TEXT_GREEN\1$RESET_FORMATTING/i"