Java Code Repository

[Tiwaking!]

If you have a JPanel or some kind of GUI Container and would like to completely CHANGE (i.e JPanel displayPanel=new JPanel()) the container then you must do the following:
a) Remove the component from the container i.e remove(displayPanel)
b) change the component to what you want i.e displayPanel=new JPanel()
c) add the changed component back to the container i.e add(displayPanel)
d) validate or pack the container

This is a quick and dirty way to do it. The actual way to do it is to ensure the event dispatch is set to update the parent container on change followed by blah blah blah blah blah changnesia.

[oefox]

For those that never see it nor use it or have heard of bitwise operations, this is great boolean operator:

a |= b;
is the same as
a = a || b;

It's a bitwise inclusive or assignment, use it all the time myself to make lines more readable, but have found fellow developers have never seen it. Now you have.

IE:
canHasCheeseBurger |= hasEnoughMoney;
canHasCheeseBurger = canHasCheeseBurder || hasEnoughMoney;

[Apostrophe Spacemonkey]

ok, that's cool.

Does &= work as well?

[Xenolightning]

For those that never see it nor use it or have heard of bitwise operations, this is great boolean operator:

a |= b;
is the same as
a = a || b;

It's a bitwise inclusive or assignment, use it all the time myself to make lines more readable, but have found fellow developers have never seen it. Now you have.

IE:
canHasCheeseBurger |= hasEnoughMoney;
canHasCheeseBurger = canHasCheeseBurder || hasEnoughMoney;

You should probably change that to what it actually is, as to avoid confusion for the people that attempt to use it for other types, not sure who would attempt to use it in this way for any other types except booleans though.

a |= b;
is the same as
a = a | b;

But because booleans are 0x0 and 0x1, a bitwise OR is equivalent to a logical OR.

I do agree it is a nice code shortcut, but sometimes I think the format a = a || b can be more readable. There is no advantage of using one over the other at a performance level, it comes down to personal taste

@SpaceMonkey: Yes, yes it does.

[Tiwaking!]

For those that never see it nor use it or have heard of bitwise operations, this is great boolean operator

Java indeed contains bitwise operators:
http://docs.oracle.com/javase/tutorial/java/nutsandbolts/op3.html
and yes: Most people are never taught them. They are meant to flow on from the simple mathematical logic learned from Karnaugh maps. Unfortunately: That is no longer a requirement.

The Java programming language also provides operators that perform bitwise and bit shift operations on integral types. The operators discussed in this section are less commonly used. Therefore, their coverage is brief; the intent is to simply make you aware that these operators exist.

The unary bitwise complement operator "~" inverts a bit pattern; it can be applied to any of the integral types, making every "0" a "1" and every "1" a "0". For example, a byte contains 8 bits; applying this operator to a value whose bit pattern is "00000000" would change its pattern to "11111111".

The signed left shift operator "<<" shifts a bit pattern to the left, and the signed right shift operator ">>" shifts a bit pattern to the right. The bit pattern is given by the left-hand operand, and the number of positions to shift by the right-hand operand. The unsigned right shift operator ">>>" shifts a zero into the leftmost position, while the leftmost position after ">>" depends on sign extension.

The bitwise & operator performs a bitwise AND operation.

The bitwise ^ operator performs a bitwise exclusive OR operation.

The bitwise | operator performs a bitwise inclusive OR operation.

The following program, BitDemo, uses the bitwise AND operator to print the number "2" to standard output.

class BitDemo {
    public static void main(String[] args) {
        int bitmask = 0x000F;
        int val = 0x2222;
        // prints "2"
        System.out.println(val & bitmask);
    }
}

[oefox]

It's a given that code should be readable. Just as important though is understanding operators.

E: I'm going to go test something

[Xenolightning]

What test? Hows it going?

[oefox]

Just searched my entire subversion repository for uses of bitwise operators to see who and what usage there is, wasn't very interesting, only my projects have them and only I use them.

[Xenolightning]

Yeah, bit logic isn't very common place in OOP. It kind of defeats the purpose of OOP, most situations you you bitwise operators you can replace it with inheritance or the likes.

The biggest use I see for bitwise is flags.

eg

Code: [Select]

enum Direction
{
   North = 0x1,
   South= 0x10,
   East = 0x100,
   West = 0x1000
}

Where you can easily figure what direction someone is travelling. Assigning here is weird though..

Code: [Select]

Direction SpaceMonkey = Direction.North;
SpaceMonkey |= Direction.South;
System.out.println(SpaceMonkey); //SpaceMonkey does the moonwalk.


[Apostrophe Spacemonkey]

I read the Wiki article on Bitwise operation.

I don't see the point of it. In what real world situations would this be useful?

[oefox]

IIRC it's a legacy thing from when performance was very important and using floats/doubles were the norm. F**k I hate floats.

If I am not mistaken, bitwise operations actually occur under the hood for normal operations, hence 3GL and 4GL languages don't need bitwise operators.

[Pyromanik]

I read the Wiki article on Bitwise operation.

I don't see the point of it. In what real world situations would this be useful?

WTF, not sure if srs.

[oefox]

Fuck yes, my whole team can related to almost every single one:

http://martinvalasek.com/blog/pictures-from-a-developers-life

[Xenolightning]

^ Love it.

[Tiwaking!]

If, for some reason, you would like to make an image using text which contains a specialised font, you can do so in the following manner.
If you do this, then you can add the ImageIcon to a JButton and set the ActionCommand or Text to be a String.
This is one way to avoid the use of a customised JButton if you are using it to store a String as opposed to a full blown object.

Code: [Select]

protected ImageIcon createIcon(int w,int h,AttributedString line){
public void createButtons(){
String[]HAND_SIGNS={"Fingers","Palm","Snap","Wave","Digit","Clap"};
AttributedString[]letters = new AttributedString[HAND_SIGNS.length];
Font font2 = new Font("Monotype Corsiva", Font.BOLD, 50);
for(int i=0;i<HAND_SIGNS.length;i++){
AttributedString a=new AttributedString(HAND_SIGNS[i].substring(0,1));
a.addAttribute(TextAttribute.FONT, font2);
letters[i]=a;
}//4 hand_signs.length
JButton[]btns=new JButton[letters.length];
int w=100;
for(int i=0;i<btns.length;i++){
JButton btn=new JButton(createIcon(w,w,letters[i]));
btn.setPreferredSize(new Dimension(w,w));
btns[i]=btn;
btn.setActionCommand(String.format(&quot;btn%s&quot;,HAND_SIGNS[i]));
//btn.addActionListener(this);
btns[i]=btn;
}//4 btns.length
}//method create buttons
protected ImageIcon createIcon(int w,int h,AttributedString line){
BufferedImage image=new BufferedImage(w,h,BufferedImage.TYPE_INT_RGB);
Graphics g = image.createGraphics();
g.setColor(Color.BLACK);
g.fillRect(0,0,w,h);
g.setColor(Color.WHITE);
g.drawString(line.getIterator(),25,70);//given a w=100,h=100: font size=50
return new ImageIcon(image);
}//me createIcon


If I am not mistaken, bitwise operations actually occur under the hood for normal operations, hence 3GL and 4GL languages don't need bitwise operators.

Yep. You should use them in PHP though, but since this is not a PHP thread, that observation is irrelevant.

Fuck yes, my whole team can related to almost every single one:

http://martinvalasek.com/blog/pictures-from-a-developers-life

Genki Sudo and Singham. That is amazing.

[Apostrophe Spacemonkey]

Why is it called a JButton? Why not just a Button? Why does Java have to put a J in front of Jeverything?

[Tiwaking!]

Java uses Time in a surprisingly obscure manner. The Time class is actually the java.sql.Time package which wraps a java.util.Date class. This means the default 'Time' is set to January 1, 1970 and the 'Time' is actually the number of milliseconds since January 1, 1970
One of your best bets at using the Time class is to create your own Object which surpresses the Deprecated Time Constructor

Time(int hour, int minute, int second) - Deprecated. Use the constructor that takes a milliseconds value in place of this constructor

Code: [Select]


class TimeIndex extends java.sql.Time{
// int hours;
// int minutes;
// int seconds;
// @SuppressWarning("deprecated")
protected int milliseconds;
@SuppressWarnings("deprecation")
public TimeIndex(){
super(0,0,0);
}//c
public int getMilliseconds(){
return milliseconds;
}
public void setMilliseconds(int n){
if(n>999)n=0;
milliseconds=n;
}
// public int getSeconds(){
// return seconds;
// }
public String toString(){
return String.format("%s,%d",super.toString(),milliseconds);
}//toString
}//class


Why is it called a JButton? Why not just a Button? Why does Java have to put a J in front of Jeverything?

Why does C# use 'using' instead of import?
Why does everyone say "Smorgasbord" instead of the correct "Smörgåsbord"?
Why does everyone outside of Deustchland called it Germany, and everyone outside of Sverige and Danmark call it "Sweden" and "Denmark"?

[Pyromanik]

Fuck yes, my whole team can related to almost every single one:

http://martinvalasek.com/blog/pictures-from-a-developers-life

Most of them copied from:
http://devopsreactions.tumblr.com/

[Bell]

In random developer news, I installed an incorrect crontab last night which resulted in a call from the georgian government this morning inquiring about a possible cyber-attack.

I hope to not go to jail

[Tiwaking!]

When testing an application it is usually important to read files from a Hard Drive or Local Resource.
An easy way to do this is by creating an Object that reads the and stores the names of files held in a directory

Code: [Select]

import java.io.File;
public class DirectoryReader{
private String path;
private String[]files;
public DirectoryReader(){
}//constructor
public DirectoryReader(String path){
try{
this.path=path;
File folder = new File(path);
File[] listOfFiles = folder.listFiles();
files=new String[listOfFiles.length];
for (int i = 0; i < listOfFiles.length; i++) {
if (listOfFiles[i].isFile()) {
files[i]=listOfFiles[i].toString();
}//if
}//for
}catch(NullPointerException npe){
javax.swing.JOptionPane.showMessageDialog(null,npe  .toString(),&quot;Directory empty or does not exist!&quot;,javax.swing.JOptionPane.INFORMATION_MESSAGE);
}//method
}//constructor
public String[] getImages(){
return getFiles();
}//method
public String[] getFiles(){
return files;
}//method
public int getSize(){
return getLength();
}//method
public int getLength(){
return files.length;
}//method
public String toString(){
return &quot;I am an object which can read directories!&quot;;
}//method
}//class

You must be aware that this Object cannot be used in a Web Based environment, but is easily replaced by code which reads the contents of Local Web Resources (any resource located on the same Web Domain) OR the contents of an applications Jar file

Programming zzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzz  zzzzzzzz

I didn't think such thing as a java enthusiast existed.

They're as rare as Chaotic Neutral Paladins

Spoiler :

Vessel: The vessel is chosen (whether by a deity or institution) for their paladin abilities. They are typically already martially proficient, or if they are not then they are typically trained to be so. Vessels have their own alignment however they must follow the whim of whoever granted them their abilities (which usually goes by a code of conduct similar to that of the zealot) or lose them altogether (fallen). Unlike the zealot, a vessel's abilities do not correspond to their alignment.

CN - Chaotic Neutral paladins are identical to the chaotic good paladin listed above, with the addition that their smite is identical to the true neutral paladin's in how it functions.

[Bell]

whoops

[Apostrophe Spacemonkey]

You have a heavy flow there Bell.

[Bell]

The part between about 11pm and 6am is when I crashed a government server. At around 9 they blocked the machines IP address.
I believe i'll be called into a meeting with the government tomorrow....

[Apostrophe Spacemonkey]

I'm talking half a days leave today.

This will be me after lunch.

[Pyromanik]

In random developer news, I installed an incorrect crontab last night which resulted in a call from the georgian government this morning inquiring about a possible cyber-attack.

I hope to not go to jail

Oh deployments before leaving.
I always dread pushing the boat out on friday afternoons then coming back on monday to some kind of angry shitstorm.