Developers Howto

Contents 1 How to get tracks for a given artist, album, year or genre ? 2 How to get playable files for any item (logical or physical)? 3 How to filter a list of items ? 4 How to get the number of items (track, files...) ? 5 How to add a new option ? 6 How are managed window startup sizes and positions ? 7 How to manage mouse events and right clicks ? 8 How to use the font manager ? 9 How to format dates ? 10 How to get good random value ?

How to get tracks for a given artist, album, year or genre ?

Use:

TrackManager.getAssociatedTracks()

How to get playable files for any item (logical or physical)?

• Use methods

Util.getPlayableFiles()

How to filter a list of items ?

• Use method

Filter.filterItems(<list>,<property name>,<value>)

How to get the number of items (track, files...) ?

• Use this method from ItemManager? public int getElementCount()
• Exemple : to get number of tracks in the collection, use:

TrackManager.getInstance().getElementCount()

How to add a new option ?

• Add the option name in org.jajuk.util.Const:

public static final String CONF_AUDIOSCROBBLER_ENABLE = "jajuk.network.audioscrobbler"; 

• don't forget to set a default value in org.jajuk.util.Conf :

properties.put(CONF_AUDIOSCROBBLER_ENABLE, FALSE);

• Use setProperty() method to set it in the program and getBoolean, getProperty(), getInt()... methods to retrieve it. Options are automatically saved to the conf.properties file at shutdown and loaded at startup.

How are managed window startup sizes and positions ?

• Default size is set using this algorithm:

begin
 width = screen width
 if width > 1400  
   width = 1200  //deal with dual heads
 else
   width = screen width - 120
 height = screen height
 if height > 1200  
  height = 1000  //deal with dual heads
 else
  height = screen height - 120
end

• Then size is set at each startup using:

begin
 if we find a forced position in conf.properties (jajuk.frame.forced_position entry)
  use this position/size (used to allow XGL users to force a position)
 else
  if window manager buggy
    Apply (60,60,screen width - 120, screen height - 120)
  else 
    if stored position (jajuk.window_position) contains "max" (maximalize)
      if window manager supports expand
      	expand (the window manager then deal with task bars)
      else
   	Apply (60,60,screen width - 120, screen height - 120)
    else
     int x = configurated x
     int y = configurated y
     int width = configurated width
     int height = configurated height
     if x < 0 or x > screen width
      x = 60
     if y < 0 or y > screen height
      y = 60
     if width <= 0 or width > screen width
      width = window width - 120
     if height <= 0 or height > screen height 
      height = screen height - 120
     Apply (x,y,width,height)
end

How to manage mouse events and right clicks ?

• Do not override directly MouseAdapter to manage mouse clicks but use JajukMouseAdapter class instead (see its detailed javadoc for reasons, handling right click on every OS is a bit complicated)
• Note that what makes all this so complexe is the fact that most items can throw at the same time popup on right click and realize an action when the left click is recognized.

How to use the font manager ?

• Please always use the FontManager class to deal with fonts for code mutualization and performance
• If you don't find a required font in JajukFont enum, please create a new one (set its properties in the registerFonts() method)
• Fonts are accessed using  :

FontManager.getInstance().getFont(<a JajukFont>)

How to format dates ?

• Use UtilString.getLocaleDateFormatter() and UtilString.getAdditionDateFormatter() date formatters. The first method return the default date formatter for the current user and is intended for human display purpose. The second is used to store dates to be stored, it is the format used to store the date when tracks have been discovered (YYYYMMDD format)

How to get good random value ?

• Use only this method to get random value :

UtilSystem.getRandom()