Tuesday, August 18, 2009

JavaFX Script Sequences

Sequences are like arrays and hold a collection of object. The ordering is associated with the objects in the sequence.

Different way of defining sequences:

//Sequence of String with double quotes
def seq1 = ["JavaFX" , "Silverlight" , "Flash"];

//Sequence of String with single quote
def seq2 = [ 'JavaFX', 'Silverlight', 'Flash'];

//Sequence of String with embedded sequence
def seq3 = [["JavaFX" , [["Silverlight", "Flash"]];

//Sequence of Integers. The type is inferred automatically
def seq4 = [1,2,3,4];

//Sequence of series. The sequence will contain 1,2,3,4,5
def seq5 = [1..5];

//Sequence with type explicitly mentioned. seq6 contains Integer type.
def seq6 : Integer[] = [1..5];

//Sequence defined as a var
var seq7 : String[];

Sequences are immutable in nature. Values can be changed but any insertion or deletions results in a new sequence.

Accessing Sequence

Sequence can be accessed using index position starting at 0. Also embedded sequence are flattened.

//Sequence contains and embedded sequence
def seq = [["JavaFX" , [["Silverlight", "Flash"]];

//Sequence accessed in ordinal way, we do not access "Silverlight" as seq10  
Accessing sequence in a loop.

def seq = ["JavaFX" ,"Silverlight", "Flash"];

//Accessed in a loop  
for(value in seq){

sizeof operator tells the size of sequence

println(sizeof seq);

Operation on Sequence


//Start with a sequence. We are using var here as we will be modifying it.
var seq = ["JavaFX"];

//Insert into sequence
insert "Silverlight" into seq;

//Insert before a certain position in sequence
insert "Flash" before seq[1];

//Insert after a certain position in sequence.
insert "Swing" after seq[2];

//Print the sequence 
for(value in seq){


//Delete based on value
delete "Swing" from seq;

//Delete index
delete seq[2];

//Delete the sequence
delete seq;


//Reversing creates a new sequence and the older sequence is not modified.
//So assign it to the var or hold it in a new var
seq = reverse seq;


Sequences can be compared using == operator. The equality checks for both size and the values.

var seq10 = ["a", "b"];
var seq11 = ["a", "b"];
var seq12 = ["c","d"];

//Will print true
println(seq10 == seq11);

//Will print false
println(seq11 == seq12);

Extracting Subsequences from Sequence

Extracting based on logic expression

def seq = ["JavaFX", "Silverlight", "Flash"];

//Build a sequence removing "Silverlight"
def seq1 = seq[x|x != "Silverlight"];

//Will retain "Silverlight" and "Flash"
def seq2 = seq1..2;

//Will retain only JavaFX
def seq3 = seq[0..<1];

//Will retain "Silverlight" and "Flash"
def seq4 = seq[1..];

sequence can be build using steps over a range

//Sequence of 1,2,3,4,5,6,7,8,9,10
var nums = [1..10];

//Sequence of 1,5,9
var nums1 = [1..10 step 4];

//Sequence of 10,6,2. Note that the range is from 10 to 1   
var nums2 = [10..1 step -4];

More on JavaFX

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