JavaFX Code Recipes - JavaFX: Developing Rich Internet Applications - page 330

Figure 12.10 Slider

Matrix

In JavaFX, sequences are one dimensional and you cannot create a sequence of a
sequence. There is no notion of a two-dimensional array, like Object[][] . Even
if you attempt to create a matrix by assigning another sequence to one item, the
original sequence actually inserts the assigned sequence into itself. To get around
this, we have created a matrix class that uses a JavaFX sequence as a backing
store, but allows manipulation of the individual items using a row, column
approach.

The Matrix class contains a variable, sequence , that holds the backing
sequence. In addition, the columns variable holds the number of columns,
whereas rows holds the number or rows in the matrix. Notice that rows is read
only and is calculated based on the number of columns and the size of the
sequence . Matrix is defined as illustrated in Listing 12.25.

Listing 12.25 Matrix

public class Matrix {
/** number of columns in Matrix */
public var columns : Integer = 1;

/** backing sequence for Matrix */
public var sequence : Object[];

/** number of rows in Matrix */
public-read var rows : Integer = bind
if(sizeof sequence mod columns > 0)
sizeof sequence / columns + 1

else
sizeof sequence / columns;

There are also get and set functions that use the row, column addressing
scheme to manipulate cell contents. These use the function getIndex() to calcu-
late the offset into the backing sequence by multiplying the row by the number of
columns and adding the column parameter to this.