private int calculateAveragePreviousPercentageComplete() {
    int result = 0;
    for (StudentActivityByAlbum activity : activities)
        result += activity.getPreviousPercentageCompleted();
    return result / activities.size();
}
 
private int calculateAverageCurrentPercentageComplete() {
    int result = 0;
    for (StudentActivityByAlbum activity : activities)
        result += activity.getPercentageCompleted();
    return result / activities.size();
}
 
private int calculateAverageProgressPercentage() {
    int result = 0;
    for (StudentActivityByAlbum activity : activities)
        result += activity.getProgressPercentage();
    return result / activities.size();
}

Here is my horrible solution:

private int calculateAveragePreviousPercentageComplete() {
    return new Average(activities) {
        public int value(StudentActivityByAlbum activity) {
            return activity.getPreviousPercentageCompleted();
        }
    }.result;
}
 
private int calculateAverageCurrentPercentageComplete() {
    return new Average(activities) {
        public int value(StudentActivityByAlbum activity) {
            return activity.getPercentageCompleted();
        }
    }.result;
}
 
private int calculateAverageProgressPercentage() {
    return new Average(activities) {
        public int value(StudentActivityByAlbum activity) {
            return activity.getProgressPercentage();
        }
    }.result;
}
 
private static abstract class Average {
    public int result;
 
    public Average(List<StudentActivityByAlbum> activities) {
        int total = 0;
        for (StudentActivityByAlbum activity : activities)
            total += value(activity);
        result = total / activities.size();
    }
 
    protected abstract int value(StudentActivityByAlbum activity);
}

if this were Ruby

@activities.inject(0.0){ |total, activity| total + activity.previous_percentage_completed? } / @activities.size
@activities.inject(0.0){ |total, activity| total + activity.percentage_completed? } / @activities.size
@activities.inject(0.0){ |total, activity| total + activity.progress_percentage? } / @activities.size

or even something more kewler

average_of :previous_percentage_completed?
average_of :percentage_completed?
average_of :progress_percentage?
 
def average_of(message)
	@activities.inject(0.0){ |total, activity| total + activity.send message } / @activities.size
end

• AS3 places classes inside package blocks. Which allows AS3 to have multiple package definitions per file
• In AS3 the variable have function scope not block scope
• AS3 is a mostly type safe language with Dynamic behavior. This means you can add new capabilities (functions and properties) to existing objects at run time.
• AS3 has metadata while Java has annotations
• In AS3 semicolons are options if you have one statement per line
• In AS3 casts look more like a function call through the type being cast or we can use the as operator
• AS3 does not support generics and typed collections, except it has typed arrays through the Vector class
• AS3 has E4X integrated into the language to query/manipulation XML
• In AS3, constructors are always public
• AS3 does not allow properties on interfaces. Only functions can be declared on interfaces
• There is no concept of “abstract” in AS3
• In AS3, because functions are Objects, they can be passed around (like Function Pointers)
• AS3 has the concept of anonymous functions useful for declaring callbacks or event handlers inline
• In AS3, the override keyword is required if the subclass declares a function with the same name
• AS3 does not support Function overloading. Default parameter values might help you achieve it to some extent
• AS3 has properties as a first-class citizen of the language. get and set keywords are defined as special getters/setters for properties
• AS3 allows Property access via strings
• AS3 supports Untyped property access – allows accessing property through the String accessor, even if the property is not present at compile time (you’ll get run-time error)
• All AS3 objects can act like String maps
• AS3 supports Untyped variables (mostly type safe language). This allows you to told references without declaring its type
• AS3 allows Initializing dynamic properties using JSON-like syntax. Create and Initializes the object in one statement

Thanks to Chet Haase for his insightful article on ActionScript for Java developers.

Step 1: Independently deploy your web application (WAR file) on each instance and make sure they can work independently.

Step 2: Stop tomcat

Step 3: Update the <Cluster> element under the <Engine> element in the Server.xml file (under the conf dir in tomcat installation dir) on both your servers with:

<Engine name="<meaningful_unique_name>" defaultHost="localhost">      
     <Cluster className="org.apache.catalina.ha.tcp.SimpleTcpCluster"
              channelSendOptions="8">
          <Manager className="org.apache.catalina.ha.session.DeltaManager"
                   expireSessionsOnShutdown="false"
                   notifyListenersOnReplication="true"/>
          <Channel className="org.apache.catalina.tribes.group.GroupChannel">
               <Membership className="org.apache.catalina.tribes.membership.McastService"
                           address="228.0.0.4"
                           port="45564"
                           frequency="500"
                           dropTime="3000"/>
               <Receiver className="org.apache.catalina.tribes.transport.nio.NioReceiver"
                         address="auto"
                         port="4000"
                         autoBind="100"
                         selectorTimeout="5000"
                         maxThreads="6"/>
               <Sender className="org.apache.catalina.tribes.transport.ReplicationTransmitter">
                   <Transport className="org.apache.catalina.tribes.transport.nio.PooledParallelSender"/>
               </Sender>
               <Interceptor className="org.apache.catalina.tribes.group.interceptors.TcpFailureDetector"/>
               <Interceptor className="org.apache.catalina.tribes.group.interceptors.MessageDispatch15Interceptor"/>
          </Channel>
          <Valve className="org.apache.catalina.ha.tcp.ReplicationValve"
                 filter=".*\.gif;.*\.js;.*\.jpg;.*\.png;.*\.css;.*\.txt;"/>
          <ClusterListener className="org.apache.catalina.ha.session.ClusterSessionListener"/>
     </Cluster>
     ...
</Engine>

For more details on these parameters, check https://sec1.woopra.com/docs/cluster-howto.html

Step 4: Start tomcat and make sure it starts up correctly. You should be able to access http://locahost:8080. Most default tomcat installations come with an examples web app. Try access http://localhost:8080/examples/jsp/ You should see a list of JSP files.

Step 4.a: Also if you see catalina.out log file, you should see:

INFO: Initializing Coyote HTTP/1.1 on http-8080
Nov 9, 2009 9:29:43 AM org.apache.catalina.startup.Catalina load
INFO: Initialization processed in 762 ms
Nov 9, 2009 9:29:43 AM org.apache.catalina.core.StandardService start
INFO: Starting service <server_name>
Nov 9, 2009 9:29:43 AM org.apache.catalina.core.StandardEngine start
INFO: Starting Servlet Engine: Apache Tomcat/6.0.16
Nov 9, 2009 9:29:43 AM org.apache.catalina.ha.tcp.SimpleTcpCluster start
INFO: Cluster is about to start
Nov 9, 2009 9:29:43 AM org.apache.catalina.tribes.transport.ReceiverBase bind
INFO: Receiver Server Socket bound to:/<server_ip>:4000
Nov 9, 2009 9:29:43 AM org.apache.catalina.tribes.membership.McastServiceImpl setupSocket
INFO: Setting cluster mcast soTimeout to 500
Nov 9, 2009 9:29:43 AM org.apache.catalina.tribes.membership.McastServiceImpl waitForMembers
INFO: Sleeping for 1000 milliseconds to establish cluster membership, start level:4

Step 5: Stop tomcat.

Step 6: We’ll use the examples web app to test if our session replication is working as expected.

Step 6.a: Open the Web.xml file of the “examples” web app in your webapps. Mark this web app distributable, by adding a <distributable/> element at the end of the Web.xml file (just before the </web-app> element)

Step 6.b: Add the session JSP file. This JSP prints the contents of the session and also adds/increments a counter stored in the session.

Step 6.c: Start tomcat on both machines

Step 6.d: You should see the following log in catalina.out

Nov 9, 2009 9:29:44 AM org.apache.catalina.ha.tcp.SimpleTcpCluster memberAdded
INFO: Replication member added:org.apache.catalina.tribes.membership.MemberImpl[tcp://{-64, -88, 0, 101}:4000,{-64, -88, 0, 101},4000, alive=10035,id={68 106 92 39 -110 -8 73 124 -116 -122 -15 -3 11 117 56 105 }, payload={}, command={}, domain={}, ] 
 
Nov 9, 2009 9:29:49 AM org.apache.catalina.ha.session.DeltaManager start
INFO: Register manager /examples to cluster element Engine with name <server_name>
Nov 9, 2009 9:29:49 AM org.apache.catalina.ha.session.DeltaManager start
INFO: Starting clustering manager at /examples
Nov 9, 2009 9:29:49 AM org.apache.catalina.ha.session.DeltaManager getAllClusterSessions
WARNING: Manager [localhost#/examples], requesting session state from org.apache.catalina.tribes.membership.MemberImpl[tcp://{-64, -88, 0, 101}:4000,{-64, -88, 0, 101},4000, alive=15538,id={68 106 92 39 -110 -8 73 124 -116 -122 -15 -3 11 117 56 105 }, payload={}, command={}, domain={}, ]. This operation will timeout if no session state has been received within 60 seconds.
Nov 9, 2009 9:29:49 AM org.apache.catalina.ha.session.DeltaManager waitForSendAllSessions
INFO: Manager [localhost#/examples]; session state send at 11/9/09 9:29 AM received in 101 ms.
 
Nov 9, 2009 9:29:49 AM org.apache.catalina.core.ApplicationContext log
INFO: ContextListener: contextInitialized()
Nov 9, 2009 9:29:49 AM org.apache.catalina.core.ApplicationContext log
INFO: SessionListener: contextInitialized()
Nov 9, 2009 9:29:50 AM org.apache.coyote.http11.Http11Protocol start
INFO: Starting Coyote HTTP/1.1 on http-8080
Nov 9, 2009 9:29:50 AM org.apache.jk.common.ChannelSocket init
INFO: JK: ajp13 listening on /0.0.0.0:8009
Nov 9, 2009 9:29:50 AM org.apache.jk.server.JkMain start
INFO: Jk running ID=0 time=0/49  config=null
Nov 9, 2009 9:29:50 AM org.apache.catalina.startup.Catalina start
INFO: Server startup in 6331 ms

Step 6.e: Try to access http://localhost:8080/examples/jsp/session.jsp Try refreshing the page a few times, you should see the counter getting updated.

Step 6.f: You should see the same behavior when you try to access the other tomcat server. Open another tab in your browser and hit http://<other_server_ip>:8080/examples/jsp/session.jsp

Step 6.g: At this point we know the app works fine and the session is working correctly. Now we want to check if the tomcat cluster is replicating the session info. To check this, we want to pass the session from server 1 to session 2 and see if it increments the counter from where we left.

Step 6.h: Before accessing the page, make sure you copy the j_session_id from server 1 (displayed on the http://localhost:8080/examples/jsp/session.jsp). Also make sure to clear all cookies from server 2. (All browsers give you a facility to clear cookies from a specific host/ip).

Step 6.i: Now hit http://<server_2_ip>:8080/examples/jsp/session.jsp;jsessionid=<jsession_id_from_server1>

Step 6.j: If you see the counter incrementing from where ever you had left, congrats! You have session replication working.

Step 6.k: Also catalina.out log file should have:

Nov 9, 2009 9:42:03 AM org.apache.catalina.core.ApplicationContext log
INFO: SessionListener: sessionCreated('CDC57B8C5CFDFDDC2C8572E7D14C0D28')
Nov 9, 2009 9:42:03 AM org.apache.catalina.core.ApplicationContext log
INFO: SessionListener: attributeAdded('CDC57B8C5CFDFDDC2C8572E7D14C0D28', 'counter', '1')
Nov 9, 2009 9:42:05 AM org.apache.catalina.core.ApplicationContext log
INFO: SessionListener: attributeReplaced('CDC57B8C5CFDFDDC2C8572E7D14C0D28', 'counter', '2')

While this might like smooth, I ran into lot of issues when getting to this point. Following are some trap routes I ran into:

1) java.sql.SQLException: No suitable driver tomcat cluster
Make sure your DB Driver jar (in our case mysql-connector-java-x.x.xx-bin.jar) is in tomcat/lib folder

2) In catalina.org if you see the following exception:

Nov 7, 2009 3:48:53 PM org.apache.catalina.ha.session.DeltaManager requestCompleted
SEVERE: Unable to serialize delta request for sessionid [1F43C3926FF3CC231574EF248896DCA6]
java.io.NotSerializableException: com.company.product.Class
	at java.io.ObjectOutputStream.writeObject0(ObjectOutputStream.java:1156)
	at java.io.ObjectOutputStream.writeObject(ObjectOutputStream.java:326)
	at java.util.ArrayList.writeObject(ArrayList.java:570)
	at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
	at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:39)
	at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:25)
	at java.lang.reflect.Method.invoke(Method.java:597)

This means that you are storing com.company.product.Class object (or some other object that holds a reference to this Object) in your session. And you’ll need to make com.company.product.Class implement Serializable interface.

3) In your catalina.out log if you see

INFO: Register manager /<your_app_name> to cluster element Engine with name <tomcat_engine_name>
Nov 7, 2009 11:56:20 AM org.apache.catalina.ha.session.DeltaManager start
INFO: Starting clustering manager at /<your_app_name>
Nov 7, 2009 11:56:20 AM org.apache.catalina.ha.session.DeltaManager getAllClusterSessions
INFO: Manager [localhost#/<your_app_name>]: <strong>skipping state transfer. No members active in cluster group</strong>.

If both your tomcat instance are up and running, then check if your tomcat servers can communicate with each other using Multicast with the following commands:

$ ping -t 1 -c 2 228.0.0.4
PING 228.0.0.4 (228.0.0.4): 56 data bytes
64 bytes from <server_1_ip>: icmp_seq=0 ttl=64 time=0.076 ms
64 bytes from <server_2_ip>: icmp_seq=0 ttl=64 time=0.645 ms

— 228.0.0.4 ping statistics —
1 packets transmitted, 1 packets received, +1 duplicates, 0.0% packet loss

or

$ sudo tcpdump -ni en0 host 228.0.0.4
tcpdump: verbose output suppressed, use -v or -vv for full protocol decode
listening on en0, link-type EN10MB (Ethernet), capture size 65535 bytes
22:11:50.016147 IP <server_1_ip>.45564 > 228.0.0.4.45564: UDP, length 69
22:11:50.033336 IP <server_2_ip>.45564 > 228.0.0.4.45564: UDP, length 69
22:11:50.516746 IP <server_1_ip>.45564 > 228.0.0.4.45564: UDP, length 69
22:11:50.533613 IP <server_2_ip>.45564 > 228.0.0.4.45564: UDP, length 69
…

If you don’t see the results as described above, you might want to read my blog on Enabling Multicast.

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WARN:  Nested in org.apache.jasper.JasperException: org.apache.jasper.JasperException: Unable to initialize TldLocationsCache: null:
org.apache.jasper.JasperException: Unable to initialize TldLocationsCache: null
at org.apache.jasper.compiler.TldLocationsCache.init (TldLocationsCache.java:253)
at org.apache.jasper.compiler.TldLocationsCache.getLocation (TldLocationsCache.java:224)
at org.apache.jasper.JspCompilationContext.getTldLocation (JspCompilationContext.java:526)
at org.apache.jasper.compiler.Parser.parseTaglibDirective (Parser.java:422)
...

No clue why this is happening. Surprising this is, this issue cannot be reproduced on a Windows box. Only on my Mac with JDK 1.6 and Maven 2.0, I’m getting this issue.

On goolging for this issue, I make across this bug report which kind of indicated that this might be an issue with the Cargo Maven Plugin. On upgrading the plugin to version 1.0, the issue was solved.

Need to find out what caused the problem in the first place.

Following is my refactored solution (take 1) to the poorly written code.

Wrote some Acceptance Test to understand how the RpnCalculator works:

Then I updated the perform method to

@Deprecated
public void perform(final String operatorName) {
  perform(operators.get(operatorName));
}
 
public void perform(final Operator operator) {
  operator.eval(stack);
  currentMode = Mode.inserting;
}

Notice I’ve deprecated the old method which takes String. I want to kill primitive obsession at its root.

Had to temporarily add the following map (this should go away once our deprecated method is knocked off).

private static Map operators = new HashMap() {
  {
    put("+", Operator.ADD);
    put("-", Operator.SUBTRACT);
    put("!", Operator.FACTORIAL);
  }
 
  @Override
  public Operator get(final Object key) {
    if (!super.containsKey(key)) {
      throw new MathOperatorNotFoundException();
    }
    return super.get(key);
  }
};

Defined various Operators

private static abstract class Operator {
  private static final Operator ADD = new BinaryOperator() {
    @Override
    protected int eval(final int op1, final int op2) {
      return op1 + op2;
    }
  };
 
  private static final Operator SUBTRACT = new BinaryOperator() {
    @Override
    protected int eval(final int op1, final int op2) {
      return op2 - op1;
    }
  };
 
  private static final Operator FACTORIAL = new UnaryOperator() {
    @Override
    protected int eval(final int op1) {
      int result = 1;
      int currentOperandValue = op1;
      while (currentOperandValue > 1) {
        result *= currentOperandValue;
        --currentOperandValue;
      }
      return result;
    }
  };
 
  public abstract void eval(final OperandStack stack);
}

Declared two types of Operators (BinaryOperator and UnaryOperator) to avoid duplication and to make it easy for adding new operators.

public static abstract class BinaryOperator extends Operator {
  @Override
  public void eval(final OperandStack s) {
    s.push(eval(s.pop(), s.pop()));
  }
 
  protected abstract int eval(int op1, int op2);
}

and

public static abstract class UnaryOperator extends Operator {
  @Override
  public void eval(final OperandStack s) {
    s.push(eval(s.pop()));
  }
 
  protected abstract int eval(int op1);
}

To start off, the team did not have an automated build. So I quickly put an Ant script together. Last 2 days I had helped them write some acceptance tests using FitNesse. I set up the build file to run the FitNesse tests as part of the build. Once I had the testing in place, I wanted to see what kind of code coverage we had. So we started adding Cobertura Ant tasks to the build. This was a fairly trivial task. But surprisingly cobertura-report kept displaying N/A for Line and Branch coverage. Clearly there was something wrong.

After spending a good amount of time, I realized that we need to compile the source code with debug=true option, else Cobertura does not generate any coverage numbers. What’s amazing is, it does not complain (in the normal mode) about this nor does cobertura’s documentation talks about this. When I ran the ant build in verbose mode, it showed the following warning

[cobertura-instrument] WARN visitEnd, No line number information found for class

That’s when it occurred to me that I need to compile my source code with debug=true option.

Once I solved this problem I hit the next roadblock. Even thought I fixed the debug=true option issue, cobertura-report was still displaying N/A for Line and Branch coverage. I quickly wrote a dummy unit tests and that seemed to work. Cobertura report started showing some numbers. But I was not able to generate any coverage numbers from the main Java application (server) that I was trying to test.

I knew there was some problem with the Shutdown hook not been executed correctly to flush the coverage numbers to the ser file. It turned out that if you have a server which is started as a daemon process in a forked JVM in the build, it needs to have a way to shutdown the server gracefully. So I ended up writing a shutdown command for the server which would basically do a System.exit(0). One need to explicitly call the shutdown script before calling the cobertura report target.

Finally after 3 hrs, there was some ray of hope in my life when I saw a good 86% code coverage. This meant I could now go and refactor the code till I dropped dead.

Returns a string representation of the object. In general, the 

1

toString

 method returns a string that “textually represents” this object. The result should be a concise but informative representation that is easy for a person to read. It is recommended that all subclasses override this method.

public @interface Override

Indicates that a method declaration is intended to override a method declaration in a superclass. If a method is annotated with this annotation type but does not override a superclass method, compilers are required to generate an error message.

One would read this and think the following code should work perfectly fine:

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interface I {
  void m1();
}

1

class C implements I {

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  @Override
  public void m1() {
  }
}

But guess what? In Java 5, the compiler gives the following error: “The method m1() of type C must override a superclass method”

Once I’ve added a file, if I try to commit the file using

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protected void commit(File file) throws SVNException {
final SVNClientManager manager = SVNClientManager.newInstance();
final SVNCommitClient commitClient = manager.getCommitClient();
final File[] filesToCommit = new File[] { file };
commitClient.doCommit(filesToCommit, false, "Auto Commit", false, false);
}

I get the following exception:

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svn: Unable to open an ra_local session to URL
at org.tmatesoft.svn.core.internal.wc.SVNErrorManager.error(SVNErrorManager.java:55)
at org.tmatesoft.svn.core.internal.wc.SVNErrorManager.error(SVNErrorManager.java:40)
at org.tmatesoft.svn.core.wc.SVNCommitClient.doCommit(SVNCommitClient.java:582)
at org.tmatesoft.svn.core.wc.SVNCommitClient.doCommit(SVNCommitClient.java:549)

Trying to Google for this, did not take me anywhere. Finally after debugging thru svnkit’s code, I stumbled upon the following line which throws the exception:

1

SVNRepository repository = SVNRepositoryFactory.create(SVNURL.parseURIDecoded(url));

Basically, they have SVNRepositoryFactory class which expects the client to register an appropriate driver to handle the given protocol. Their javadocs says:

Depending on what protocol a user exactly would like to use to access the repository he should first of all set up an appropriate extension of this factory. So, if the user is going to work with the repository via the custom svn-protocol (or svn+xxx) he initially calls

1	SVNRepositoryFactoryImpl.setup();

More details: http://svnkit.com/kb/javadoc/org/tmatesoft/svn/core/io/SVNRepositoryFactory.html

Solution: Since I’m using File System (file://) protocol, I had to add the following line in a static block of my adapter class:

1

FSRepositoryFactory.setup();

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javax.xml.parsers.FactoryConfigurationError:
Provider com.sun.org.apache.xerces.internal.jaxp.
DocumentBuilderFactoryImpl could not be instantiated: java.lang.NullPointerException
[java] at javax.xml.parsers.DocumentBuilderFactory.newInstance
(DocumentBuilderFactory.java:104)
[java] at fitnesse.util.XmlUtil.<clinit>
[java] at fitnesse.wiki.WikiPageProperties.loadFromXmlStream
[java] at fitnesse.wiki.FileSystemPage.attemptToReadPropertiesFile
[java] at fitnesse.wiki.FileSystemPage.loadAttributes
[java] at fitnesse.wiki.FileSystemPage.makePageData
[java] at fitnesse.wiki.CachingPage.getData
[java] at fitnesse.responders.run.FitClientResponder.readyToSend
[java] at fitnesse.responders.run.PuppetResponse.readyToSend
[java] at fitnesse.FitNesseExpediter.sendResponse
[java] at fitnesse.FitNesseExpediter.start
[java] at fitnesse.FitNesseServer.serve
[java] at fitnesse.FitNesseServer.serve
[java] at fitnesse.socketservice.SocketService$ServerRunner.run
[java] at java.lang.Thread.run(Thread.java:595)

If I use JDK 1.4, everything works fine. But there seems to be some backward compatibility issues with JDK 1.5.

After trying different things for a while, I came across a site that stated that “The J2SE 1.4 platform included the ‘Crimson‘ reference implementation for JAXP 1.1. The J2SE 5 platform includes a reference implementation for JAXP 1.3 based on the Apache ‘Xerces‘ library.”

In JDK 1.4, xerces and xalan are embedded in the JDK. In JDK 1.5 too, but the packages are under com/sun (so com.sun.org.apache….).

So you would think all this should be transparent to developers. But no.

To verify the above statement, I opened up the DocumentBuilderFactory in JDK 1.5 and I found

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public static DocumentBuilderFactory newInstance() {
try {
return (DocumentBuilderFactory) FactoryFinder.find(
/* The default property name according to the JAXP spec */
"javax.xml.parsers.DocumentBuilderFactory",
/* The fallback implementation class name */
"com.sun.org.apache.xerces.internal.jaxp.
DocumentBuilderFactoryImpl");
} catch (FactoryFinder.ConfigurationError e) {
throw new FactoryConfigurationError(e.getException(),
e.getMessage());
}

}
while the JDK 1.4‘s DocumentBuilderFactory class had:

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public static DocumentBuilderFactory newInstance()
throws FactoryConfigurationError
{
try {
return (DocumentBuilderFactory) FactoryFinder.find(
/* The default property name according to the JAXP spec */
"javax.xml.parsers.DocumentBuilderFactory",
/* The fallback implementation class name */
"org.apache.crimson.jaxp.
DocumentBuilderFactoryImpl");
} catch (FactoryFinder.ConfigurationError e) {
throw new FactoryConfigurationError (e.getException(),
e.getMessage());
}
}

After all this research I still don‘t know what is the exact problem. But I have a solution.

Solution: Luckily adding the xerces.jar to the classpath solved the problem.

Would appreciate if someone would let me know the answer.

Lattu is a framework for testing Eclipse RCP Applications. It can run both Unit and Functional tests. Essentially, it is an Eclipse Plugin which provides Fitnesse extension to run unit and acceptance tests. It uses JUnit for unit testing and Abbot for GUI tests.

More details: http://lattu.sourceforge.net

Here is a simple way to fix date parsing problem using FitLibrary.

Fit Page

|set date format as|MM/dd/yyyy|

|date|
|11/23/2006|

|set date format as|dd-MMM-yyyy|

|date|
|23-Nov-2006|

Fixture Class

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<br />
public void setDateFormatAs(String format) {<br />
ValueAdapter.registerParseDelegate(java.sql.Date.class, new SimpleDateFormat(format));<br />
ValueAdapter.registerParseDelegate(java.util.Date.class, new SimpleDateFormat(format));<br />
}</p>
	<p>

How this works?
The ValueAdapter class holds a static HashMap called PARSE_DELEGATES which contains all the ParseDelegators. The ParseDelegator‘s job is to implement a parse method which take a String and returns the Object of your Data Type. You can register the Data Type and its respective ParseDelegator using the registerParseDelegate() method.

In this case, my ParseDelegator is SimpleDateFormat which has the following method

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<br />
public Date parse(String source) throws ParseException{<br />
ParsePosition pos = new ParsePosition(0);<br />
Date result = parse(source, pos);<br />
if (pos.index == 0)<br />
throw new ParseException("Unparseable date: " + source ,<br />
pos.errorIndex);<br />
return result;<br />
}</p>
	<p>

All that matters is the following method signature:
public Date parse(String source){

You can use the same mechanism to parse any object of choice.

com.ibm.etools.j2ee.commonarchivecore.exception.
DeploymentDescriptorLoadException: IWAE0022E Exception occurred loading deployment descriptor

Context:
Check your web.xml.
If you are using the following XSD as the DOCTYPE of your web.xml http://java.sun.com/xml/ns/j2ee/web-app_2_4.xsd
Then you might want to check your servlet tag to make sure they match the Servlet 2.4 specification.

For example, the following servlet causes the above exception when it tries to deploy the app.

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<br />
&lt;servlet&gt;<br />
&lt;servlet-name&gt;sampleservlet&lt;/servlet-name&gt;<br />
&lt;servlet-class&gt;ABCClass&lt;/servlet-class&gt;<br />
&lt;init-param&gt;<br />
&lt;param-name&gt;ABCParamName&lt;/param-name&gt;<br />
&lt;param-value&gt;ABCParamValue&lt;/param-value&gt;<br />
&lt;description&gt;some desc&lt;/description&gt;<br />
&lt;/init-param&gt;<br />
&lt;/servlet&gt;<br />

Surprising this works perfectly fine if your web.xml is using http://java.sun.com/dtd/web-app_2_3.dtd as the DOCTYPE

Solution:
Removing the

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<br />
&lt;description&gt;some desc&lt;/description&gt;<br />

tag from

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<br />
&lt;init-param&gt;<br />

tag fixes the problem.

Another problem with DTDs:
If you are using DTD, the order of the tag elements within the web.xml must follow the order reflected in the DTD. Else you will get similar exception message. The order of the tags in web.xml is very important when using DTD. But it should not matter if you are using XSD.

If you open the DTD, it would list the order of the tags in there.
For example, web-app_2_3.dtd specifies the following order that the tags must have in order for the document to be considered a valid XML document:

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<br />
&lt;!ELEMENT web-app (icon?, display-name?, description?, distributable?, context-param*, filter*, filter-mapping*, listener*, servlet*, servlet-mapping*, session-config?, mime-mapping*, welcome-file-list?, error-page*, taglib*, resource-env-ref*, resource-ref*, security-constraint*, login-config?, security-role*, env-entry*, ejb-ref*, ejb-local-ref*)&gt;<br />

Hence

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<br />
&lt;ejb-ref&gt;<br />

tag element must be before

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<br />
&lt;ejb-local-ref&gt;<br />

tag.

The objective of my talk was to show:

1. How to write acceptance tests for Web UIs? The focus was on driving UI development from a functional stand-point using acceptance tests.
2. How to quickly build regression/functional tests for an application with existing UI [legacy code] using Selenium?
3. Last but not the least, to introduce Selenium

For the demo, I used VQWiki as my test application. The wiki is a simple yet powerful application to demonstrate some of the core selenium and acceptance testing fundas. Coz of this, the Wiki turned out to be an interesting application for the demo. I had tests in Selenium core and Selenium remote control. This was sufficient to show the power of Selenium. Finally when I recorded a test scenario using Selenium IDE, the audience went gaga over Selenium.

I‘m hoping to upload the tutorial soon. Till then you can have a look at the presentation here.

An initial list of complains from people about Fitnesse:

1. Lack of version control compatibility. This issue can be quite limiting if you are using a version control system which has pessimistic locking [makes all checked in files to read-only].
2. Crazy wiki syntax
3. Search sucks big time
4. Lack of support for integration with Ant and similar tools
5. Continuous Integration servers do not have a built in mechanism to display Fitnesse results. For Ex: CruiseControl does not have a style sheet to display Fitnesse results.
6. Fitnesse cannot execute tests inside an application/web server. By default Fitnesse spins of a new process called FitServer, which runs all the tests. In this setup it is not possible to debug your fixtures and application code.
7. Lack of standard out-of-box Fixtures which let you deal with databases. I know about JdbcFixtures. But it is crazy to expect people who write fit tests to know SQL. It is also crazy to mention all the DB connection properties on every single fit document [test].
8. Lack of patterns /anti-patterns around Fitnesse. Ex: Should we use statics to share data between fixtures? How to design Fixtures [to inherit or not to inherit]? Etc.

Following is the list of work around we found:

1. Version control compatibility: Fitnesse is pretty extensible. It lets you add plugins by adding new responders. So we added a plugin which lets one checkout files from ClearCase. Now users can click on the ckeckout menu item and easy checkout files from the fitnesse page. This can be easily extended to other version control systems. Please note that we have not added checkin facility. The rationale behind it is, we have FitnesseRoot under the project directory. So once the developer has done all the changes and are ready to checkin, they find checkouts at the project level and checkins all the files, including the content.txt and properties.xml file. This is great coz it lets developers do atomic checkins.
   Hopefully I can add support for different Version controls and contribute it back to Fitnesse or spawn another open source project.
2. There is not much we can do about the wiki syntax except reading the MarkupLanguageReference. There are lot of good tricks and tips.
3. Right now we are using Google Desktop to search our wiki pages. In future, I plan to write a plugin for FitNesse to make use of the Lucene Search Engine.
4. We are able to run all our fit tests thru add by using the following target.

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   <br /> &lt;target name="fitNesseTest" description="Run FitNesse acceptance tests." if="project.fitnesse.tests"&gt;<br /> &lt;echo&gt;About to run fitnesse server&lt;/echo&gt;<br /> &lt;property name="fitnesse.port" value="8090" /&gt;<br /> &lt;parallel&gt;<br /> &lt;daemons&gt;<br /> &lt;java classname="fitnesse.FitNesse" classpath="${fitnesse.root}/fitnesse.jar"&gt;<br /> &lt;arg value="-p" /&gt;<br /> &lt;arg value="${fitnesse.port}" /&gt;<br /> &lt;arg value="-e" /&gt;<br /> &lt;arg value="0" /&gt;<br /> &lt;arg value="-d" /&gt;<br /> &lt;arg value="${fitnesse.root.location}" /&gt;<br /> &lt;/java&gt;<br /> &lt;/daemons&gt;<br /> &lt;sequential&gt;<br /> &lt;echo&gt;sleeping for 3 seconds to let FitNesse server start&lt;/echo&gt;<br /> &lt;sleep seconds="3" /&gt;<br /> &lt;echo&gt;running fit tests from ${fitnesse.location}&lt;/echo&gt;<br /> &lt;echo&gt;Running fit tests at "${project.smoke.tests.suite.page}"&lt;/echo&gt;<br /> &lt;java classname="fitnesse.runner.TestRunner" classpath="${fitnesse.root}/fitnesse.jar " fork="true" jvm="${java.home}/bin/java.exe" dir="${fitnesse.location}" resultproperty="fit.test.failures"&gt;<br /> &lt;classpath&gt;<br /> &lt;!-- you can add classpath here. Not required if you are using standard fitnesse--&gt;<br /> &lt;/classpath&gt;<br /> &lt;arg value="-debug"/&gt;<br /> &lt;arg value="-nopath"/&gt;<br /> &lt;arg value="-html" /&gt;<br /> &lt;arg value="${fitnesse.output.html.file.location}" /&gt;<br /> &lt;!-- optional --&gt;<br /> &lt;arg value="-xml" /&gt;<br /> &lt;arg value="${fitnesse.output.xml.file.location}" /&gt;<br /> &lt;!-- end of optional --&gt;<br /> &lt;arg value="${fitnesse.host.address}" /&gt;&lt;!-- usually localhost --&gt;<br /> &lt;arg value="${fitnesse.port}" /&gt;<br /> &lt;arg value="${project.smoke.tests.suite.page}" /&gt;&lt;!-- Ex: FronPage.projectName --&gt;<br /> &lt;/java&gt;<br /> &lt;echo&gt;Finished FIT tests: ${fit.test.failures} failures/exceptions&lt;/echo&gt;<br /> &lt;fail message="FIT test failures/exceptions: ${fit.test.failures}"&gt;<br /> &lt;condition&gt;<br /> &lt;not&gt;<br /> &lt;equals arg1="${fit.test.failures}" arg2="0" /&gt;<br /> &lt;/not&gt;<br /> &lt;/condition&gt;<br /> &lt;/fail&gt;<br /> &lt;/sequential&gt;<br /> &lt;/parallel&gt;<br /> &lt;/target&gt;<br />

   It would be great to have build-in ant task which an do this.

5. There are some simple things you can do to integrate Fitnesse with Continuous integration server like CruiseControl. For more details: Integrating Fitnesse with CruiseControl
6. I have an open source project called Patang, which lets you run Fit and Fitnesse tests inside the application/web server. For more details: Patang on SourceForge and Running Fitnesse inside the container
7. We have developed a list of standard fixtures which help you insert data into the database tables, clean it up based on ids, etc. It uses properties file to read all the database connection parameters. It also hides any SQL from the user. I‘ll shortly blog about these fixtures. May be it deserves another small open source project.
8. Am planning to expand the Patterns on the Fitnesse website.

After reading this blog, you might get a feeling that I‘m crazy about spawning new open source projects. That‘s not true. There is a reason behind me making that decision.