Categories
Java

A List with a fixed size

There isn’t a class that extends List for which you can set a limit on its size and that it behaves like a Queue object if you add an item beyond its fixed size.

Categories
Java

Stopping the threads

Starting a thread is very easy in java, after you create it you need to call the method start(), for example:

where MyRunnable is a class implementing the Runnable interface overidden the method run().

Categories
Java

Copying an array in java

In this post I show some ways to copy arrays of primitive data and objects to another array.

Categories
Java

Running a fortran program from java

In this post I write an example about how to launch a fortran executable form a java program passing some arguments and getting back a result.
The chosen example uses code written in fortran to get primes, it is from Sieve of Eratosthenes.

Categories
Java

Getting the variables of the outer class from an inner class

The inner classes, and then not static, can access even if with some limitation to the variables of the outer class.

Categories
Java

How to set a default method to running code on the creation or destruction of a bean

In the post Executing code on the creation or destruction of a bean in Spring I explain three ways to execute code on the creation or destruction of a Bean in Spring.
With two of these ways you can set the execution of a specific custom method:

  • with the annotations @PostConstruct and @PreDestroy
  • configuring the properties init-method and destroy-method

There is a very convenient way in the case that more beans have methods with the same name to be executed on their creation and destruction, i.e. you can specify a default method for all the beans.

Categories
Java

Varargs: passing a variable number of arguments to a method

From version 5 of Java you can call a method passing a variable number of arguments.
A variable of this type is called varargs, you can only use in a method signature and its syntax is the primitive type or object type followed by 3 dots (ellipsis).

Categories
Java

Creating a singleton in java

In this post I explain how to create only one object of a java class, then a single instance is available in the application.
An object of this type is called singleton and a starting class can be the following:

Categories
Java

MessageSource in Spring 3

The MessageSource interface supports the parameterization and internationalization of messages and provides 2 implementations:

  1. ResourceBundleMessageSource, built on top of the standard ResourceBundle
  2. ReloadableResourceBundleMessageSource, being able to reload message definitions without restarting the VM

The following is an example of ResourceBundleMessageSource to get messages in the specified language in Spring 3.

Categories
Lotus

Exporting a lotus view to excel

In this post I explain how to export all the documents in a view of a lotus database to an excel spreadsheet using the library Apache POI.
It is a very simple example that exports the string for each column in the view for every document, but you can add other features such as the formatting of the cell contents, or other features of excel.