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java.lang.Object
   |
   +----XColour

Summary

public class  XColour
     extends java.lang.Object
{
          // Fields 2
     private static final String colourFile;
     private static Hashtable hashColours;

          // Constructors 1
     public XColour();

          // Methods 6
     public static Color Color(float, float, float);
     public static Color Color(int);
     public static Color Color(int, int, int);
     public static Color Color(String);
     private static void buildColourHashTable();
     private static int readInt(BufferedReader) throws IOException;

}

A demonstration of the use of a class which gives extended Color capabilities but is not a subclass of Color.

Creates a new Class that extends the Java Object. This means that we will inherit various data and methods from this class. This class just encapsulates the methods for returning different colours based upon different colour specifications.

This is an addition to the fifth Java example about Event capabilities.

Author:

© Andrew Marriott. , Curtin University of Technology 1998

See Also: Color

Fields

· hashColours

Summary  |  Top

   private static Hashtable hashColours

Use this to hold the X11 colours read from the X11 Colour database.

See Also: Hashtable

   private static final String colourFile

The constant String which holds the X11 Colour database filename. Note that this is a Unix thing!!

Constructors

· XColour

Summary  |  Top

   public XColour() 

Default constructor

   private static int readInt(BufferedReader in)  throws IOException

A private method used to read a single integer string from input.

Parameter	Description
in	The I/O stream which holds the character making up the integer.

See Also: BufferedReader, read, IOException

   private static void buildColourHashTable() 

Build the colour database hashtable from the X11 database file.

Try to open the file. Remember we may not be on a Unix system.

Create a BufferedReader and continue to read lines, getting the (r,g,b) component and the colour name. These are put into the hashtable along with the name as the key.

The file is closed upon end of File.

See Also: Color, FileReader, BufferedReader, Hashtable

   public static Color Color(int r, 
                             int g, 
                             int b) 

Pretend we are the Color class with these parameters.

Parameter	Description
r	The red integer component to the colour
g	The green integer component to the colour
b	The blue integer component to the colour

See Also: Color

   public static Color Color(float r, 
                             float g, 
                             float b) 

Pretend we are the Color class with these parameters.

Parameter	Description
r	The red float component to the colour
g	The green float component to the colour
b	The blue float component to the colour

See Also: Color

   public static Color Color(int rgb) 

Pretend we are the Color class with these parameters.

Parameter	Description
rgb	The red/green/blue integer component of the colour

See Also: Color

   public static Color Color(String colourname) 

Pretend we are the Color class with a colourname which we try to find in the X11 Colour database. Return that Color or null if we cannot retrieve it.

Parameter	Description
colourname	the standard X11 Colour name.

See Also: HashTable, HashTable

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