public static <T extends Comparable<T>> T getMaximum(Iterable<T> values) {
T max = null;
for (T value : values) {
if (max == null || max.compareTo(value) < 0) {
max = value;
}
}
return max;
}
Sometimes we want to iterate in reverse order over a list in Java – without (re)sorting the list. Code example:
for (T item : backwards(list)) {
// do something
}
Here is a backwards() method that does this for you (maybe put this code into a util class and use a static import):
public static <T> Iterable<T> backwards(final List<T> list) {
return new Iterable<T>() {
@Override
public Iterator<T> iterator() {
return backwardsIterator(list);
}
};
}
private static <T> Iterator<T> backwardsIterator(List<T> list) {
final ListIterator<T> iter = list.listIterator(list.size());
return new Iterator<T>() {
@Override
public boolean hasNext() {
return iter.hasPrevious();
}
@Override
public T next() {
return iter.previous();
}
@Override
public void remove() {
iter.remove();
}
};
}
According to the current TIOBE index, Objective-C market share is growing the fastest. This is the native programming language of Apple devices like iPhone, iPad and iMac.
Absolute volume: Java is still leading the pack (as of 2011/2012).
Relative growth: Look at Scala and Ruby …
Sonatype’s Maven integration for Eclipse (m2e) has been migrated to eclipse.org and is now available from the default update site for Indigo.
This means that you no longer have to add any Sonatype update sites as mentioned on the old (now outdated) m2eclipse site.
In particular, this also means that the old “m2e-extras” update site is obsolete for Eclipse 3.7.x and later. Things like WTP integration or Subclipse integration are now available as “m2e connectors” through Window – Preferences – Maven – Discovery.
All of this is very poorly (or not at all) documented on the new m2e home page and some people had problems with these changes.
Topics I want to cover in the future about Java methods:
Some Java related RSS feeds:
Forums:
A Jenkins build server (LTS release) can now be easily installed on the minimalistic Debian VM:
You can go to “Manage Jenkins” – “Configure System” and see that JDK, Ant and Maven entries are already configured for you.
Important: Make sure to change root and user passwords to something secure, as mentioned in debian-stable-amd64-minimal.txt.
I uploaded a lightweight Eclipse package (based on Helios 3.6.1) for web development (includes Maven, SVN and basic Spring integration, JEE / web tools plugins, but no Mylyn or other non-essential stuff) … This is currently only for Windows. It requires a JDK and is completely free / open source software.
See the txt file for quick installation steps.
This is for a 64bit system:
Download Oracle’s JDK7 RPM package for 64bit Linux. The filename should be “jdk-7-linux-x64.rpm”.
Then as root:
zypper install jdk-7-linux-x64.rpm cd /usr/java/jdk1.7.0/bin for bin in *; do update-alternatives --install /usr/bin/$bin $bin $(pwd)/$bin 20000; done
On all the pages of my webapp I want to see when the WAR was built (i.e. a build timestamp). Here is how I did it:
Add this to the pom.xml of your webapp module:
<build>
<resources>
<resource>
<directory>src/main/resources</directory>
<filtering>true</filtering>
</resource>
</resources>
</build>
<properties>
<mavenBuildTimestamp>${maven.build.timestamp}</mavenBuildTimestamp>
</properties>
Create a file src/main/resources/build.properties in in your webapp module with the following content:
# Build Time Information
build.timestamp=${mavenBuildTimestamp}
The Maven build will replace the Maven property and the resulting file WEB-INF/classes/build.properties will look like this:
# Build Time Information build.timestamp=20101016-0303
Now we just need a Spring PropertiesFactoryBean definition to make properties available at runtime:
<bean id="appProperties" class="org.springframework.beans.factory.config.PropertiesFactoryBean">
<property name="locations">
<list>
<value>classpath:build.properties</value>
</list>
</property>
</bean>
I used a simple Spring bean to make the timestamp easily available in Spring Web Flow / Spring Faces EL expressions:
@Component
public class ViewUtil {
private Properties appProperties;
/**
* @param appProperties Global Application properties
*/
@Resource
public void setAppProperties(Properties appProperties) {
this.appProperties = appProperties;
}
/**
* @return The Build Timestamp as generated by Maven
*/
public String getBuildTimestamp() {
return appProperties.getProperty("build.timestamp", "UNKNOWN");
}
}
The EL expression code in the JSF page is then something like this:
Build timestamp: #{viewUtil.buildTimestamp}
And this is what the result looks like on the page:
If you want to be able to refer to properties directly by name in your Spring configuration you can define a Spring PropertyPlaceholderConfigurer:
<bean id="propertyConfigurer"
class="org.springframework.web.context.support.ServletContextPropertyPlaceholderConfigurer">
<property name="properties" ref="appProperties" />
</bean>
