Monday, 10 February 2014

Finding a use for an iPad 1

I'd noticed that most of the recent applications in the App Store won't install on my iPad 1 anymore. They either need a gyroscope or IOS 6 or 7. My iPad is stuck on IOS 5.

The first problem with this is that I haven't found a way to browse the App Store for applications that ARE compatible. This is incredibly frustrating, since its just left to trial and error finding some that will work.

I'd heard about the 'download the latest version that is compatible' feature, so decided that since my iPad is in awesome condition I'd gift it to my parents - who wouldn't be needing the latest and greatest features.

This hasn't been so simple, and I suspect others might have the same problem so I've tried to document what I've found:

  1. Doing a 'reset' to erase the iPad (before gifting it to someone) will leave you in the unfortunate situation of not being able to install many applications very easily.
  2. At this point, it doesn't seem possible to install applications requiring > IOS 5 via the device - its not compatible so not allowed.
  3. So to work around this, you can use iTunes to 'purchase' applications. Since using iTunes doesn't seem to be aware of your devices, it'll let you purchase anything.
  4. Now you have some purchases, you can return to your device and open the App Store. Go to the 'Purchased' tab and then individually install each application. Hopefully at this point you'll get the 'download the latest version that is compatible' message.
A couple of notes here:

  • I did all of this while connected over the cable to the computer running iTunes.
  • When I first did it, the applications seem to hang while installing, and never completed installing properly. The solution to this was to delete the applications from the device, then return to the 'Purchased' tab and reinstall. (I think the first installation of the apps may have been due to an iTunes sync which failed and never recovered - presumably because they are not compatible. By deleting them and reinstalling them from the iPad itself via the purchased tab, I got the 'install latest compatible' message which resulted in success).
  • Update 1: I am experiencing a lot of crashes on the device - mainly with the App Store and iTunes. I don't know if this happened before I reset/erased the iPad or if it has just started happening now.
Some obvious things could be improved here:

  1. The App Store could let you filter by 'compatible with device x' e.g. only show me those applications that will work on my 'iPad 1'
  2. When you install apps from the device, it could just install the latest compatible version right there (bypassing the need to do anything special).
If I've got any of this wrong, I'd love to hear. It would be extremely useful to be able to EASILY continue using the iPad 1.

Saturday, 17 August 2013

Using Selenium WebDriver to select JSF/PrimeFaces selectOneMenu options

I'm using JBehave with Selenium WebDriver to test my PrimeFaces (JSF2) application. Selecting an option from a SelectOne option list isn't standard though because of the HTML markup generated by the JSF component.


The facelets code to place the selectOneMenu uses the ID 'state':


This generates HTML div blocks with id's prefixed with this components id:


To select an option, I use a method which manipulates the appropriate divs - this can be used as illustrated below:


To reuse this type of utility method, I put it in a base Page Object class:



Monday, 12 August 2013

Some user feedback

I was exporting my banking transactions the other day. It's a much more tedious process than it has to be and after using this for years and not seeing any updates to the site I thought I'd send some feedback - written as stories:

As an Online Banking Customer, I want the system to remember my export preferences so that I can efficiently export my transactions ­ 
  • currently I have to set everything every time (even if you navigate from a selected account, you still have to pick an account) ­ 
  • file format (i.e CSV) ­ 
  • date format (dd/mm/yycc) 
As an Online Banking Customer, I want to export transactions for all my accounts in one go so that I can efficiently export my transactions ­ so I don't have to do them one at a time
  • ideally multiple accounts in one file 
As an Online Banking Customer, I want to be able to access more than 12 months worth of transactions so that I don't have to export so often. ­ 
  • not much history is available online ­and transactions can easily be lost if you don't remember to export frequently enough
And after getting confirmation of my feedback - where everything was on a single line of text without any of the formatting I used:
As an online user, I want formatting to be preserved when I provide feedback so that it can be clearly read and understood. ­
  • my last feedback suggestion removed all cr/lf so it was all printed on one line and not clearly readable ­ 
  • perhaps you could use the markdown format (customers wouldn't need to know, but it may provide an easily way to have some formatting without complicating things)

I was surprised to get a response - most companies don't bother. They reckon they'll be updating the site this year or next year - sounds like a BIG BANG approach, after not much in the way of incremental improvements for years. I guess I'll just have to continue with the tedium for a while yet.

Saturday, 25 May 2013

Exposing the version of your Maven built web application

Sometimes its useful to expose the version of your web application - I find it useful so vsConsole can display the version of the deployed application for each environment on the dashboard. If you build your app with Maven, you can use this code to get the version, and simply wire up a controller/rest endpoint to return it as text/plain. To expose the version of your maven built spring web application, you can use a REST controller like that shown below. Note, you won't see a valid version while running in the IDE - it'll only work when running the Maven built WAR. If you want to add the Jersey dependencies to your spring application try using the following dependency declaration.

Monday, 6 May 2013

Avoid embedding database connection information in your code

I've seen projects where the application code base contains database connection information - passwords and all, or, WAR files are rebuilt for each environment with properties substituted appropriately for the target environment.

Rather than putting database information in the application code, it makes more sense to use a JDNI data source provided by the container. This way the exact same application code is deployed to all environments, and we don't encounter any exposed passwords - since the owner of the container (in production environments the infrastructure/support team) define the data source themselves.

Database access via JNDI data source in Tomcat

In your application server you want to define a data source which points to the database server and schema of your choice. Here, I'm using the H2 database, and assuming this is the DEV Tomcat server, I point it to the DEV schema - define this resource in the Tomcat context.xml:

 <Resource name="jdbc/app1db" auth="Container" type="javax.sql.DataSource"
               maxActive="100" maxIdle="30" maxWait="10000"
               username="sa" password="" driverClassName="org.h2.Driver"
               url="jdbc:h2:tcp://devDbServer/~/dev"/>
In your TST, UAT, PRD servers you define similar data sources, pointing to the appropriate schemas, all with the same name.

Your application server MUST have the database driver on its classpath, so you will want to add the appropriate driver jar to TOMCAT_HOME/lib.

Other containers such as GlassFish, WebLogic, WebSphere and JBoss will have equivalent ways of achieving this same configuration.

Now, in your application all you need to do is define the JNDI data source, which never changes:

    <bean id="dataSource" class="org.springframework.jndi.JndiObjectFactoryBean">
        <property name="jndiName" value="java:comp/env/jdbc/app1db"/>
    </bean>
With the database connection information encapsulated within the container, you don't need these details in the source code, you don't expose passwords to anyone and you don't need to repackage your application for each environment - deployment is simple. 

Another similar use-case is for the mail server. You may also want to expose a String which could point to a properties file or server address - this can then be referenced in your spring application context.


Below are xml snippets of a Tomcat configuration which exposes some resources and a Spring application context file that uses those resources.




Thursday, 2 May 2013

Deploying to Tomcat 7 with Maven

It's sometimes nice to be able to update a development Tomcat 7 server from Maven - this makes it simple to hook automatic deployment into a CI server or just update the dev server as a developer.

First, the Tomcat manager application needs to be installed (check Tomcat's webapps directory for the manager application) and configured with the appropriate user credentials:

Now, I needed to define the server admin credentials in my maven settings (~/.m2/settings.xml):

Then, I updated the POM to configure the maven tomcat plugin:


Now, using 'mvn tomcat7:redeploy' lets me update the dev server.

Note however, on Windows you may have some problems with undeploying the application - after an undeploy command, some jars may be left over in the webapps/appname directory. When you try to redeploy your app you'll see an error containing "cannot invoke tomcat manager fail - unable to delete...".

To work around this, you can change the TOMCAT_HOME/conf/context.xml to include the 'antiJARLocking' attribute like so:
<Context antiJARLocking="true">
The documentation points out though that this will impact start up times of applications.

In my case, I noticed problems when doing a redeploy to Tomcat - most likely unrelated to Maven and/or the maven tomcat plugin and more to do with PermGen (I saw perm gen OutOfMemory: PermGen space errors in the tomcat7-stderr logs, and the Tomcat process was consuming 100% cpu). Adding the following switches to the Tomcat JVM settings seems to have fixed it for now:
-XX:+CMSClassUnloadingEnabled -XX:+CMSPermGenSweepingEnabled -XX:PermSize=64m -XX:MaxPermSize=128m -Xmx992M
 (In this instance, I'm running Tomcat 7 as a Windows service on JDK7 with a 50MB WAR file).

Tuesday, 23 April 2013

Exception: AbstractMethodError requires c3p0 upgrade

photo credit: markchadwickart
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I just encountered this exception:
Exception in thread "main" java.lang.AbstractMethodError: com.mchange.v2.c3p0.impl.NewProxyPreparedStatement.setCharacterStream(ILjava/io/Reader;J)V at org.hibernate.type.descriptor.sql.ClobTypeDescriptor$4$1.doBind(ClobTypeDescriptor.java:114) at org.hibernate.type.descriptor.sql.BasicBinder.bind(BasicBinder.java:92)
It turns out that upgrading c3p0 does the trick (from 0.9.1.2 to 0.9.2.1):

        <dependency>
            <groupId>com.mchange</groupId>
            <artifactId>c3p0</artifactId>
            <version>0.9.2.1</version>
        </dependency>