I have been looking for a while but people seem to be waaaaay ahead of me on on the chess front. All i want to do is have a method in a class to resolve the colour of a tile but my colour keeps coming up as "null".
import java.util.Scanner;
public class ChessTileTest {
public static void main(String[] args) {
Scanner in = new Scanner(System.in);
String tileColour;
chessTile test = new chessTile();
System.out.print(" Enter chess move : ");
String move = in.next();
tileColour = test.setColour(move);
System.out.println(tileColour);
}
}
public class chessTile {
private String colour;
private String address;
public chessTile(){
}
public String setColour(String move){
char letter;
int number;
letter = move.charAt(0);
number = move.charAt(1);
if((letter=='a'||letter=='c'||letter=='e'||letter=='g')&&(number/2==1)){
colour = "Black";
}
else if((letter=='a'||letter=='c'||letter=='e'||letter=='g')&&(number/2==0)){
colour = "white";
}
else if((letter=='b'||letter=='d'||letter=='f'||letter=='h')&&(number/2==1)){
colour = "white";
}
else if((letter=='b'||letter=='d'||letter=='f'||letter=='h')&&(number/2==0)){
colour = "Black";
}
return colour;
}
}
First lines of setColour(...) are
char letter = move.charAt(0); // gets ASCII character at index 0
int number = move.charAt(1); // gets **int value of** ASCII character at index 1
So, for exmaple, if your string is "a1", then letter = a but number = 49 because the integer ASCII value of the character "1" is 49. See this ASCII chart for more . . . http://www.asciitable.com/index/asciifull.gif
You will need to convert the character into a proper int. You can do that with the following . . .
int number = Character.getNumericValue( move.charAt(1) );
Since you are probably getting a bad value, none of the if-statements are satisfied and a null value is returned
Related
I have two strings (text) and (a). I want to remove (a) from (text) after an if statement
this is what I have
public string text;
public string a = 'a';
void Update(){
if(text.Contains('a')){
text - a;
}
}
but I get error with this that I cannot use - how do I remove it
A simple way of doing this is using the string.Replace
string text = "This is my text";
string a = "i";
text = text.Replace(a, "");
'text' will be: Ths s my text
I am trying to change the value of a TextField for display only. Ie - when users attempt to enter phone number, they only enter the digits and when they leave the field, it displays formatted without changing the data in the field.
Let's say I have a TextField for a phone number and it should allow digits only, maximum of 10 characters:
2085551212
I can handle that with a TextFormatter using a UnaryOperator.
UnaryOperator<TextFormatter.Change> filter = new UnaryOperator<TextFormatter.Change>() {
#Override
public TextFormatter.Change apply(TextFormatter.Change change) {
int maxlength = 14;
if(change.getControlText().indexOf('(') == -1) {
maxlength = 10;
}
System.out.println(change);
if (change.getControlText().length() + change.getText().length() >= maxlength) {
int maxPos = maxlength - change.getControlText().length();
change.setText(change.getText().substring(0, maxPos));
}
String text = change.getText();
for (int i = 0; i < text.length(); i++)
if (!Character.isDigit(text.charAt(i)))
return null;
return change;
}
};
However I would like to format the value to be when it's 10 characters long (likely unformatted when != 10):
(208) 555-1212
When I use a TextFormatter to format it, it changes the value of the string to (208) 555-1212. We store only the digits in the database 2085551212.
I attempted this with a StringConverter. But I couldn't make it work. In the toString() method I strip out the formatting, however when I do that my TextField doesn't display.
StringConverter<String> formatter = new StringConverter<String>() {
#Override
public String fromString(String string) {
System.out.println("fromString(): before = " + string);
if (string.length() == 14) {
System.out.println("fromString(): after = " + string);
return string;
} else if (string.length() == 10 && string.indexOf('-') == -1) {
String result = String.format("(%s) %s-%s", string.substring(0, 3), string.substring(3, 6),
string.substring(6, 10));
System.out.println("fromString(): after = " + result);
return result;
} else {
return null;
}
}
#Override
public String toString(String object) {
System.out.println("toString(): before = " + object);
if(object == null) {
return "";
}
Pattern p = Pattern.compile("[\\p{Punct}\\p{Blank}]", Pattern.UNICODE_CHARACTER_CLASS);
Matcher m = p.matcher(object);
object = m.replaceAll("");
System.out.println("toString(): after = " + object);
return object;
}
};
I bound to a TextField like this which I assumed would work:
txtPhone.setTextFormatter(new TextFormatter<String>(formatter, null, filter));
t2.textProperty().bindBidirectional(foo.fooPropertyProperty(), formatter); //I was just testing to see the results in another textfield to see if it would work.
So I am at a loss. I essentially want to allow only digits and then when the user leaves the field present the value in a formatted way - without actually changing the string value that goes to the database.
You are confusing the purpose of toString() and fromString() methods with each other in your converter. toString() converts the value property of your text editor to the displayed text, not the other way around. Try switching the code in these methods and it should work.
The reason why your text field does not display anything after loosing focus is because fromString() method is called and returns null (from the else clause). This commits null to the value property of your editor. The change in value property updates the displayed text (textProperty) by calling toString(null) which changes the text property of your editor to an empty string.
EDIT
Below is my test code that is a follow-up to the discussion in the comments. I reused a large amount of your original code. I created an FXML JavaFX project and defined TextField and Label in FXML file. The TextField accepts user's input and formats it. The Label displays value of the text formatter (only digits) that should go to the database. The value is accessible by calling formatter.valueProperty().get(). I hope it helps.
import java.net.URL;
import java.util.ResourceBundle;
import java.util.function.UnaryOperator;
import java.util.regex.Matcher;
import java.util.regex.Pattern;
import javafx.fxml.FXML;
import javafx.fxml.Initializable;
import javafx.scene.control.Label;
import javafx.scene.control.TextField;
import javafx.scene.control.TextFormatter;
import javafx.util.StringConverter;
public class FXMLDocumentController implements Initializable {
// label displays phone number containing only digits (for database)
#FXML private Label label;
/* field displays formatted text (XXX)-XXX-XXXX after user types
10 digits and presses Enter or if the field looses focus */
#FXML private TextField field;
#Override
public void initialize(URL url, ResourceBundle rb) {
UnaryOperator<TextFormatter.Change> filter = new UnaryOperator<TextFormatter.Change>() {
#Override
public TextFormatter.Change apply(TextFormatter.Change change) {
if (!change.isContentChange()) {
/* nothing is added or deleted but change must be returned
* as it contains selection info and caret position
*/
return change;
}
int maxlength = 14;
if (change.getControlText().indexOf('(') == -1) {
maxlength = 10;
}
if (change.getControlNewText().length() > maxlength
|| change.getText().matches("\\D+")) {
// invalid input. Cancel the change
return null;
}
return change;
}
};
StringConverter<String> converter = new StringConverter<String>() {
// updates displayed text from commited value
#Override
public String toString(String commitedText) {
if (commitedText == null) {
// don't change displayed text
return field.getText();
}
if (commitedText.length() == 10 && !commitedText.matches("\\D+")) {
return String.format("(%s) %s-%s", commitedText.substring(0, 3), commitedText.substring(3, 6),
commitedText.substring(6, 10));
} else {
/* Commited text can be either null or 10 digits.
* Nothing else is allowed by fromString() method unless changed directly
*/
throw new IllegalStateException(
"Unexpected or incomplete phone number value: " + commitedText);
}
}
// commits displayed text to value
#Override
public String fromString(String displayedText) {
// remove formatting characters
Pattern p = Pattern.compile("[\\p{Punct}\\p{Blank}]", Pattern.UNICODE_CHARACTER_CLASS);
Matcher m = p.matcher(displayedText);
displayedText = m.replaceAll("");
if (displayedText.length() != 10) {
// user is not done typing the number. Don't commit
return null;
}
return displayedText;
}
};
TextFormatter<String> formatter = new TextFormatter<String>(converter, "1234567890", filter);
field.setTextFormatter(formatter);
label.textProperty().bind(formatter.valueProperty());
}
}
When ever i execute the program the output says not a palindrome when it is a palindrome(only does this when input has spaces or punctuation) can some one tell me where i went wrong in my code?
public class Palindromes
{
public static void main(String[]args)
{
ConsoleIO keyboard=new ConsoleIO();
String word, word2="",terminate;
int length;
do
{
System.out.print("Enter a string:");
word=keyboard.readLine();
word=word.toLowerCase();
word=word.trim();
word=word.replaceAll("\\W", "");
word=word.replaceAll(" ","");
length=word.length();
//finding the reverse of the string
for(int i=length-1;i>=0;i--)
{
word2+=word.charAt(i);
}
//checking to see if the string is a palindrome
if(word.length()==1)
{
System.out.println("The string you entered is not a palindrome");
}
else if(word.equals(word2))
{
System.out.println("The string you entered is a palindrome.");
}
else
{
System.out.println("The string you entered is not a palindrome.");
}
System.out.print("Do you want to continue (yes or no):");
terminate=keyboard.readLine();
System.out.println();
}
while(terminate.equalsIgnoreCase("yes"));
}
}
I think you'd need to account for the punctuation because that will affect the plaindrome test you have. ra.cecar is not otherwise a palindrome. Have you tried adding more lines like the following?
word=word.replaceAll(".", "");
word=word.replaceAll("?", "");
word=word.replaceAll("!", "");
word=word.replaceAll("-", "");
To end all problem to Palindrome, I've made this Java program that will end all suffering to it. It's in Java so you're in luck. It basically strip every non-word character, put it to lower case just with 13 lines. Hope this help haha! Let's hope other guys would get lucky to find this too.
import java.util.Scanner;
public class Palindrome {
public static void main(String[]args){
if(isReverse()){System.out.println("This is a palindrome.");}
else{System.out.print("This is not a palindrome");}
}
public static boolean isReverse(){
Scanner keyboard = new Scanner(System.in);
System.out.print("Please type something: ");
String line = ((keyboard.nextLine()).toLowerCase()).replaceAll("\\W","");
return (line.equals(new StringBuffer(line).reverse().toString()));
}
}
i am trying to write a program, and the rest of the code so far works but i am getting a incompatible types found : double required :Grocery Item in line 38. Can anyone help me in explaining why I am receiving this error and how to correct it? Thank you. here is my code:
import java.util.Scanner;
public class GroceryList {
private GroceryItem[]groceryArr; //ARRAY HOLDS GROCERY ITEM OBJECTS
private int numItems;
private String date;
private String storeName;
public GroceryList(String inputDate, String inputName) {
//FILL IN CODE HERE
// CREATE ARRAY, INITIALIZE FIELDS
groceryArr = new GroceryItem[10];
numItems = 0;
}
public void load() {
Scanner keyboard = new Scanner(System.in);
double sum = 0;
System.out.println ("Enter the trip date and then hit return:");
date = keyboard.next();
keyboard.nextLine();
System.out.println("Enter the store name and then hit return:");
storeName = keyboard.next();
keyboard.nextLine();
double number = keyboard.nextDouble();
//NEED TO PROMPT USER FOR, AND READ IN THE DATE AND STORE NAME.
System.out.println("Enter each item bought and the price (then return).");
System.out.println("Terminate with an item with a negative price.");
number = keyboard.nextDouble();
while (number >= 0 && numItems < groceryArr.length) {
groceryArr[numItems] = number;
numItems++;
sum += number;
System.out.println("Enter each item bought and the price (then return).");
System.out.println("Terminate with an item with a negative price.");
number = keyboard.nextDouble();
}
/*
//READ IN AND STORE EACH ITEM. STORE NUMBER OF ITEMS
}
private GroceryItem computeTotalCost() {
//add code here
}
public void print() {
\\call computeTOtalCost
}
*/
}
}
"groceryArr[numItems] = number;"
groceryArr[numItems] is an instance of GroceryItem() - 'number' is a double
You need a double variable in your GroceryItem() object to store the 'number' value.
I need to create an Eclipse plugin that displays a tooltip when I hover the mouse over a String literal.
But only if that String literal is the first parameter of a special method.
Here is the Test.java file I use to test my plugin:
package test;
public class Test {
public static void main(String[] args) {
String hello = "Hello";
String world = Translator.get("Test.worldLabel");
System.out.println(hello + " " + world);
}
}
I created a class implementing IJavaEditorTextHover and I need to compile the currently edited Java file to compute if the cursor is hovering a String that needs to be translated or not.
Hovering "Hello" will do nothing.
Hovering "Test.worldLabel" will display my tooltip because that literal is included inside a Translator.get() method call.
At first I used this (170 is inside "Test.worldLabel"):
ITypeRoot typeRoot = (ITypeRoot)
JavaUI.getEditorInputJavaElement(editorPart.getEditorInput());
JavaElement foundElement = (JavaElement) typeRoot.getElementAt(170);
But the foundElement contains the whole main() method: it is not fine-grained enough.
Then, the correct way is, I think:
private static ASTNode parse(ICompilationUnit unit, int position) {
ASTParser parser = ASTParser.newParser(AST.JLS3);
parser.setKind(ASTParser.K_COMPILATION_UNIT);
parser.setSource(unit);
parser.setResolveBindings(true);
parser.setIgnoreMethodBodies(false);
// TODO Future optimisation: parser.setFocalPosition(position);
return parser.createAST((IProgressMonitor) null); // parse
}
And in my IJavaEditorTextHover.getHoverInfo(...) implementation:
ICompilationUnit compilationUnit = (ICompilationUnit)
JavaUI.getEditorInputJavaElement(editor.getEditorInput())
int position = 170/*hoverRegion.getOffset()*/;
ASTNode ast = parse(compilationUnit, position);
And now, here is my question:
How, from this ast node, do I get the ASTNode reprensenting the StringLiteral at position 170 in the source code (the "Test.worldLabel" String)?
Bonus question: did I choose the right solution? On a performance basis.
Edit:
Well, here is a solution I found:
private StringLiteral findStringLiteralAtPosition(final ASTNode parent, final int position) {
final List<StringLiteral> stringLiterals = new ArrayList<StringLiteral>();
parent.accept(new ASTVisitor() {
#Override
public boolean visit(StringLiteral stringLiteral) {
int start = stringLiteral.getStartPosition();
int end = start + stringLiteral.getLength();
if (start <= position && position <= end) {
stringLiterals.add(stringLiteral);
}
return super.visit(stringLiteral);
}
});
return (stringLiterals.size() > 0 ? stringLiterals.get(0) : null);
}
Does it seam OK?
Or is it an easier way or a more performant one?
One solution will be not using the offset logic at all.
You can generalise the solution by using a node parent check.
Here is a sample code:
public boolean visit(StringLiteral stringLiteral) {
// Check if parent is a method inovacation.
if (stringLiteral.getParent().getNodeType() == ASTNode.METHOD_INVOCATION) {
// get the parent method inovacation.
MethodInvocation miNode = (MethodInvocation) stringLiteral.getParent();
//To do: null and empty check on argument list.
// Check if is the special method and this is the 1st argument
if (miNode.getName().toString().equals("SpecialMethod")
&& miNode.arguments().get(0).toString().equals(stringLiteral.toString())) {
System.out.println("Found it : " + stringLiteral.toString());
}
}
return true;
}