Thursday, January 20, 2011

Banshee "seek" function problem solved

Apparently my fav player has been refusing to let me use the 'seek' bar for some time now and I dodged looking for a solution too long now. After 2 minutes of research I found out that all I needed to do was to install the package gstreamer0.10-plugins-ugly and restart Banshee. Funny thing is I don't even remember uninstalling it in the first place (presuming that it was pre-installed).
Anyway.... another bug fix in my F1 Notebook

Saturday, January 15, 2011

Sunday, January 9, 2011

New features Java EE 6.0

I found a nice article on this topic here: http://www.javabeat.net/articles/99-new-features-in-java-ee-60-1.html

Thursday, January 6, 2011

Linux Subdirectories of Root directory [cheatsheet]

  • /bin - Common programs, shared by the system, the system administrator and the users.
  • /boot - The startup files and the kernel, vmlinuz. In some recent distributions also grub data. Grub is the GRand Unified Boot loader and is an attempt to get rid of the many different boot-loaders we know today.
  • /dev - Contains references to all the CPU peripheral hardware, which are represented as files with special properties.
  • /etc - Most important system configuration files are in /etc, this directory contains data similar to those in the Control Panel in Windows
  • /home - Home directories of the common users.
  • /initrd - (on some distributions) Information for booting. Do not remove!
  • /lib - Library files, includes files for all kinds of programs needed by the system and the users.
  • /lost+found - Every partition has a lost+found in its upper directory. Files that were saved during failures
    are here.

  • /misc - For miscellaneous purposes.
  • /mnt - Standard mount point for external file systems, e.g. a CD-ROM or a digital camera.
  • /net - Standard mount point for entire remote file systems
  • /opt - Typically contains extra and third party software
  • /proc - A virtual file system containing information about system resources. More information about the
    meaning of the files in proc is obtained by entering the command man proc in a terminal
    window. The file proc.txt discusses the virtual file system in detail.

  • /root - The administrative user's home directory. Mind the difference between /, the root directory and
    /root, the home directory of the root user.

  • /sbin - Programs for use by the system and the system administrator.
  • /tmp - Temporary space for use by the system, cleaned upon reboot, so don't use this for saving any work!
  • /usr - Programs, libraries, documentation etc. for all user-related programs.
  • /var - Storage for all variable files and temporary files created by users, such as log files, the mail
    queue, the print spooler area, space for temporary storage of files downloaded from the Internet,
    or to keep an image of a CD before burning it.

Wednesday, December 1, 2010

The Filter Pattern - Selective Iterators

The following code is from: http://www.erik-rasmussen.com/blog/2008/01/18/the-filter-pattern-java-conditional-abstraction-with-iterables/ 


import
java.util.Iterator;

import java.util.NoSuchElementException;


public abstract class Filter<T> {

  public abstract boolean passes(T object);


  public Iterator<T> filter(Iterator<T> iterator) {

    return new FilterIterator(iterator);

  }


  public Iterable<T> filter(Iterable<T> iterable) {

    return new Iterable<T>() {

      public Iterator<T> iterator() {

        return filter(iterable.iterator());

      }

    };

  }


  private class FilterIterator implements Iterator<T> {

    private Iterator<T> iterator;

    private T next;


    private FilterIterator(Iterator<T> iterator) {

      this.iterator = iterator;

      toNext();

    }


    public boolean hasNext() {

      return next != null;

    }


    public T next() {

      if (next == null)

        throw new NoSuchElementException();

      T returnValue = next;

      toNext();

      return returnValue;

    }


    public void remove() {

      throw new UnsupportedOperationException();

    }


    private void toNext() {

      next = null;

      while (iterator.hasNext()) {

        T item = iterator.next();

        if (item != null && passes(item)) {

          next = item;

          break;

        }

      }

    }

  }

}

Tuesday, November 30, 2010

A little insight on Java's 'type erasure' terminology

As everyone knows, generics have been introduced since Java 1.5 to enforce compile-time type-correctness. However, at run-time, all the type safety is removed via a process called 'type erasure'. So all typed Collections will have their type removed from the bytecode at runtime and explicit casts will be introduced when extracting elements from the Collections.  For example List<Double> list = new ArrayList<Double>();  will be translated at runtime to List list = new ArrayList(); . As a result of type erasure, type parameters cannot be determined at runtime. This change has been introduced in ordered to ensure pre-Java 5 code (you may call it 'legacy code') inter-operates peacefully with the newly introduced generics.