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Memory game not revealing correct guesses

This program is a Domino memory game where you flip dominos until you make a correct guess where the correct dominos are supposed to stay revealed. However the problem is that while the game does work correctly the dominos do not stay revealed nor does the game end.
This is the code for my Domino Class
`
public class Domino {
private int top, bottom;
private boolean revealed;
public Domino(int x, int y) {
if (x > y) {
top = y;
bottom = x;
} else {
top = x;
bottom = y;
}
}
public int getTop() {
return top;
}
public int getBottom() {
return bottom;
}
public boolean isRevealed() {
if (revealed)
return true;
return false;
}
public void setRevealed(boolean revealed) {
this.revealed = revealed;
}
public boolean equals(Domino other) {
if (top == bottom)
return true;
return false;
}
}
`
Then here is the memory game class (called MemoryLane)
`
import java.util.Arrays;
import java.util.Random;
public class MemoryLane
{
private Domino[] board;
public MemoryLane(int max)
{
board = new Domino[(max * max) + max];
int i = 0;
for(int top = 1; top <= max; top++)
for(int bot = 1; bot <= max; bot++)
{
// make new Domino(2x) +
// save into array
if(top <= bot)
{
board[i] = new Domino(top, bot);
i++;
board[i] = new Domino(top, bot);
i++;
}
}
shuffle();
}
private void shuffle()
{
int index;
Random random = new Random();
for (int i = board.length - 1; i > 0; i--)
{
index = random.nextInt(i + 1);
if (index != i)
{
Domino temp = board[index];
board[index] = board[i];
board[i] = temp;
}
}
}
public boolean guess(int i, int k)
{
if(board[i] == board[k])
{
return true;
}
return false;
}
public String peek(int a, int b)
{
String text = new String();
text += ("[" + board[a].getTop()+ "] [" + board[b].getTop()+ "]\n");
text += ("[" + board[a].getBottom()+ "] [" + board[b].getBottom()+ "]\n");
return text;
}
public boolean gameOver() {
int count = 0;
for(int i=0; i< board.length; i++)
{
if(board[i].isRevealed())
count ++;
}
return (count == board.length);
}
public String toString() {
String text = new String();
for(int i=0; i< board.length; i++)
{
if(board[i].isRevealed())
text += ("[" + board[i].getTop()+ "] ");
else
text += ("[ ] ");
}
text += ('\n');
for(int i=0; i< board.length; i++)
{
if(board[i].isRevealed())
text += ("[" + board[i].getBottom()+ "] ");
else
text += ("[ ] ");
}
return text;
}
}
`
Then here is the driver (the driver was provided to me by a third party so it must work as it is presented and cannot be changed)
`
import java.util.Scanner;
public class MemoryLaneDriver
{
public static void main(String[] args)
{
String message = "Welcome to Memory Lane!" + "\n" +
"Choose two indexes to reveal the corresponding dominoes." + "\n" +
"If the dominoes match, they stay revealed." + "\n" +
"Reveal all the dominoes to win the game!" + "\n";
System.out.println(message);
Scanner input = new Scanner(System.in);
MemoryLane game = new MemoryLane(2);
long start = System.currentTimeMillis();
while(!game.gameOver())
{
System.out.println(game);
System.out.print("First: ");
int first = input.nextInt();
System.out.print("Second: ");
int second = input.nextInt();
game.guess(first, second);
System.out.println(game.peek(first, second) + "\n");
}
long stop = System.currentTimeMillis();
long elapsed = (stop - start) / 1000;
System.out.println(game);
System.out.println("\nYou win!");
System.out.println("Total time: " + elapsed + "s");
}
}
`
I have tried using the methods in Domino like setRevealed and isRevealed in the guess method (for example when i try board.setRevealed = true or board.isRevealed = true), but it wont work and turns up red in IntelliJ. I can also not use any Stringbuilder uses (such as append) because it is outside of what has been covered in class.
When I say the game is working correctly, I mean that it outputs my choices like:
`
Welcome to Memory Lane!
Choose two indexes to reveal the corresponding dominoes.
If the dominoes match, they stay revealed.
Reveal all the dominoes to win the game!
[ ] [ ] [ ] [ ] [ ] [ ]
[ ] [ ] [ ] [ ] [ ] [ ]
First: 1
Second: 3
[2] [2]
[2] [2]
[ ] [ ] [ ] [ ] [ ] [ ]
[ ] [ ] [ ] [ ] [ ] [ ]
First:
`
However as you can see it is not revealing the correct guess, and even if I guess all of the Dominos correctly the game does not end.

So, in your original code, you were using board[i] == board[k] which is comparing memory address locations and not the object properties, instead, you should be using board[i].equals(board[k]).
In this case you need to override equals method of the Domino class in order to change how the comparison works, for example...
#Override
public int hashCode() {
int hash = 7;
hash = 59 * hash + this.getTop();
hash = 59 * hash + this.getBottom();
return hash;
}
#Override
public boolean equals(Object obj) {
if (this == obj) {
return true;
}
if (!(obj instanceof Domino)) {
return false;
}
final Domino other = (Domino) obj;
if (this.getTop() != other.getTop()) {
return false;
}
if (this.getBottom() != other.getBottom()) {
return false;
}
return true;
}
It's important to remember, if you override equals you should also override hashCode as they have an important relationship to each other.
You also never call setRevealed, which I guess should be done in guess
public boolean guess(int i, int k) {
if (board[i].equals(board[k])) {
board[i].setRevealed(true);
board[k].setRevealed(true);
return true;
}
return false;
}
Runnable example...
import java.util.Random;
import java.util.Scanner;
public class Main {
public static void main(String[] args) {
new Main();
}
Main() {
String message = "Welcome to Memory Lane!" + "\n"
+ "Choose two indexes to reveal the corresponding dominoes." + "\n"
+ "If the dominoes match, they stay revealed." + "\n"
+ "Reveal all the dominoes to win the game!" + "\n";
System.out.println(message);
Scanner input = new Scanner(System.in);
MemoryLane game = new MemoryLane(2);
long start = System.currentTimeMillis();
while (!game.gameOver()) {
// This is just making it easier to cheat.
System.out.println(game.debug());
System.out.println(game);
System.out.print("First: ");
int first = input.nextInt();
System.out.print("Second: ");
int second = input.nextInt();
game.guess(first, second);
System.out.println(game.peek(first, second) + "\n");
}
long stop = System.currentTimeMillis();
long elapsed = (stop - start) / 1000;
System.out.println(game);
System.out.println("\nYou win!");
System.out.println("Total time: " + elapsed + "s");
}
public class Domino {
private int top, bottom;
private boolean revealed;
public Domino(int x, int y) {
if (x > y) {
top = y;
bottom = x;
} else {
top = x;
bottom = y;
}
}
public int getTop() {
return top;
}
public int getBottom() {
return bottom;
}
public boolean isRevealed() {
return revealed;
}
public void setRevealed(boolean revealed) {
this.revealed = revealed;
}
#Override
public int hashCode() {
int hash = 7;
hash = 59 * hash + this.getTop();
hash = 59 * hash + this.getBottom();
return hash;
}
#Override
public boolean equals(Object obj) {
if (this == obj) {
return true;
}
if (!(obj instanceof Domino)) {
return false;
}
final Domino other = (Domino) obj;
if (this.getTop() != other.getTop()) {
return false;
}
if (this.getBottom() != other.getBottom()) {
return false;
}
return true;
}
}
public class MemoryLane {
private Domino[] board;
public MemoryLane(int max) {
board = new Domino[(max * max) + max];
int i = 0;
for (int top = 1; top <= max; top++) {
for (int bot = 1; bot <= max; bot++) {
// make new Domino(2x) +
// save into array
if (top <= bot) {
board[i] = new Domino(top, bot);
i++;
board[i] = new Domino(top, bot);
i++;
}
}
}
shuffle();
}
private void shuffle() {
int index;
Random random = new Random();
for (int i = board.length - 1; i > 0; i--) {
index = random.nextInt(i + 1);
if (index != i) {
Domino temp = board[index];
board[index] = board[i];
board[i] = temp;
}
}
}
public boolean guess(int i, int k) {
if (board[i].equals(board[k])) {
board[i].setRevealed(true);
board[k].setRevealed(true);
return true;
}
return false;
}
public String peek(int a, int b) {
String text = new String();
text += ("[" + board[a].getTop() + "] [" + board[b].getTop() + "]\n");
text += ("[" + board[a].getBottom() + "] [" + board[b].getBottom() + "]\n");
return text;
}
public boolean gameOver() {
int count = 0;
for (int i = 0; i < board.length; i++) {
if (board[i].isRevealed()) {
count++;
}
}
return (count == board.length);
}
public String debug() {
String text = new String();
for (int i = 0; i < board.length; i++) {
text += ("[" + board[i].getTop() + "] ");
}
text += ('\n');
for (int i = 0; i < board.length; i++) {
text += ("[" + board[i].getBottom() + "] ");
}
return text;
}
public String toString() {
String text = new String();
for (int i = 0; i < board.length; i++) {
if (board[i].isRevealed()) {
text += ("[" + board[i].getTop() + "] ");
} else {
text += ("[ ] ");
}
}
text += ('\n');
for (int i = 0; i < board.length; i++) {
if (board[i].isRevealed()) {
text += ("[" + board[i].getBottom() + "] ");
} else {
text += ("[ ] ");
}
}
return text;
}
}
}

I figured it out
The problem was my equals method was comparing top to bottom which is why i was getting such weird results. I changed it to
public boolean equals(Domino other){
return this.top == other.top && this.bottom == other.bottom
}
and now it works perfectly fine thanks for all of the help guys!

Is there something wrong with the setZone method?

I'm making a program that extends the clock to feature the names of the time zones. The derived class needs to have a static String array data member with values: EST, CST, MST, PST, EDT, CDT, MDT, PDT, a zone data member, a default constructor, a constructor with parameters, the setZone() method, the getZone() method, the printTime() method, the toString(), the equals() method, a makeCopy() method, and a getCopy() method.
public class Clock {
private int hr;
private int min;
private int sec;
public Clock() {
hr = 0;
min = 0;
sec = 0;
}
public Clock(int hours, int minutes, int seconds) {
if (0 <= hours && hours < 24) {
hr = hours;
}
else {
hr = 0;
}
if (0 <= minutes && minutes < 60) {
min = minutes;
}
else {
min = 0;
}
if (0 <= seconds && seconds < 60) {
sec = seconds;
}
else {
sec = 0;
}
}
public Clock(Clock otherClock) {
hr = otherClock.hr;
min = otherClock.min;
sec = otherClock.sec;
}
public void setTime(int hours, int minutes, int seconds) {
if (0 <= hours && hours < 24) {
hr = hours;
}
else {
hr = 0;
}
if (0 <= minutes && minutes < 60) {
min = minutes;
}
else {
min = 0;
}
if (0 <= seconds && seconds < 60) {
sec = seconds;
}
else {
sec = 0;
}
}
public int getHours() {
return hr;
}
public int getMinutes() {
return min;
}
public int getSeconds() {
return sec;
}
public void printTime() {
if (hr < 10) {
System.out.print("0");
}
System.out.print(hr + ":");
if (min < 10) {
System.out.print("0");
}
System.out.print(min + ":");
if (sec < 10) {
System.out.print("0");
}
System.out.print(sec);
}
public void incrementHours() {
hr++;
if (hr > 23) {
hr = 0;
}
}
public void incrementMinutes() {
min++;
if (min > 59) {
min = 0;
incrementHours();
}
}
public void incrementSeconds() {
sec++;
if (sec > 59) {
sec = 0;
incrementMinutes();
}
}
public boolean equals(Clock otherClock) {
return (hr == otherClock.hr && min == otherClock.min && sec == otherClock.sec);
}
public void makeCopy(Clock otherClock) {
hr = otherClock.hr;
min = otherClock.min;
sec = otherClock.sec;
}
public Clock getCopy() {
Clock temp = new Clock();
temp.hr = hr;
temp.min = min;
temp.sec = sec;
return temp;
}
public String toString() {
String str = "";
if (hr < 10) {
str = "0";
}
str += hr + ":";
if (min < 10) {
str += "0";
}
str += min + ":";
if (sec < 10) {
str += "0";
}
str += sec;
return str;
}
}
class ExtClock extends Clock {
static String[] timeZone = {"EST", "CST", "MST", "PST", "EDT", "CDT", "MDT", "PDT"};
private String zone;
public ExtClock() {
super();
zone = "";
}
public ExtClock(int hours, int minutes, int seconds, String tz) {
super(hours, minutes, seconds);
zone = tz;
}
public void setZone(int hours, int minutes, int seconds, String tz) {
setTime(hours, minutes, seconds);
zone = tz;
}
public String getZone() {
return zone;
}
public void printTime() {
super.printTime();
System.out.println(" " + zone);
}
public String toString() {
return super.toString() + " " + zone;
}
public boolean equals(ExtClock otherClock) {
return super.equals(otherClock) && zone.equalsIgnoreCase(otherClock.zone);
}
}
public class ExtClockTest {
public static void main(String[] args) {
ExtClock myExtClock = new ExtClock(5,4,30,"EST");
ExtClock yourExtClock = new ExtClock(0,0,0,"");
setZone.yourExtClock(5,45,16,"CDT");
}
}
The derived class compiles fine, but the ExtClockTest program wouldn't compile because it says that it cannot find the symbol. Am I doing something wrong?

You have put the method before the object.
setZone.yourExtClock(5,45,16,"CDT");
It should be:
Obj.method()
yourExtClock.setZone(5,45,16,"CDT");

MLFQ only functions when other class runs

I have a multi-level feedback class which I am not sure what its doing - it only ever seems to print the output I want when I run a pre-emptive multi-level class before it, when I don't it prints a different output. I am not sure how these are connected and making this happen.
import java.util.ArrayList;
import java.util.Collections;
import java.util.List;
public class MultiLevelFeedback {
List<Process> processList;
private int timeQuantum1;
private int timeQuantum2;
private int count;
int j=0;
private int ganntP[];
private int ganntT[];
private int totalWaitingTime = 0;
private int totalTurnAroundTime = 0;
private float avgWatingTime = 0;
private float avgTurnaroundTime = 0;
MultiLevelFeedback(List<Process> processList, int timeQuantum1,int timeQuantum2) {
count = processList.size();
ganntT=new int[200];
ganntP=new int[200];
this.timeQuantum1 = timeQuantum1;
this.timeQuantum2 = timeQuantum2;
this.processList=new ArrayList<Process>();
for(Process p : processList)
{
this.processList.add(new Process(p.getProcessId(), p.getArrivalTime(), p.getBurstTime(),p.getPriority()));
}
Collections.sort(this.processList, Process.BY_PRIORITY);
}
public void simulate() {
int currentTime =0;
int remainingProcess = count;
while (remainingProcess > processList.size()/2)
{
int clockTime=currentTime;
for (int i = 0; i < count; i++)
{
Process current = processList.get(i);
if(currentTime<current.getArrivalTime())
break;
if (current.getStartTime() == -1)
current.setStartTime(currentTime);
ganntP[j]=current.getProcessId();
ganntT[j]=currentTime;
j++;
if (current.getRemainingTime() <= timeQuantum1 && current.getEndTime()==-1)
{
current.setEndTime(currentTime + current.getRemainingTime());
currentTime += current.getRemainingTime();
current.setRemainingTime(0);
remainingProcess--;
}
else if (current.getRemainingTime()>timeQuantum1)
{
currentTime += timeQuantum1;
current.setRemainingTime(current.getRemainingTime()-timeQuantum1);
}
}
if(clockTime==currentTime)
{
currentTime++;
}
}
while (remainingProcess > processList.size()/2)
{
int clockTime=currentTime;
for (int i = 0; i < count; i++)
{
Process current = processList.get(i);
if(currentTime<current.getArrivalTime())
break;
if (current.getStartTime() == -1)
current.setStartTime(currentTime);
ganntP[j]=current.getProcessId();
ganntT[j]=currentTime;
j++;
if (current.getRemainingTime() <= timeQuantum2 && current.getEndTime()==-1)
{
current.setEndTime(currentTime + current.getRemainingTime());
currentTime += current.getRemainingTime();
current.setRemainingTime(0);
remainingProcess--;
}
else if (current.getRemainingTime()>timeQuantum2)
{
currentTime += timeQuantum2;
current.setRemainingTime(current.getRemainingTime()-timeQuantum2);
}
}
if(clockTime==currentTime)
{
currentTime++;
}
}
for(int i=0;i<count;i++)
{
Process current=processList.get(i);
if(current.getRemainingTime()>0 )
{
if(currentTime<current.getArrivalTime())
{
currentTime=current.getArrivalTime();
current.setStartTime(currentTime);
}
current.setEndTime(currentTime+current.getRemainingTime());
currentTime+=current.getRemainingTime();
}
}
for (int i = 0; i < count; i++)
{
Process current = processList.get(i);
current.setWaitingTime(current.getEndTime()-current.getBurstTime()-current.getArrivalTime());
current.setTurnaroundTime(current.getEndTime() - current.getArrivalTime());
totalWaitingTime += current.getWaitingTime();
totalTurnAroundTime += current.getTurnaroundTime();
}
avgWatingTime = (float) totalWaitingTime / count;
avgTurnaroundTime = (float) totalTurnAroundTime / count;
}
public void printResult()
{
System.out.println("Simulation result of MultiLevelFeedback ");
System.out.println("PId ArrivalT BurstT Priority StartT EndT WaitingT TurnAroundT");
for (Process p : processList)
{
System.out.println(p);
}
System.out.println("Average Waiting Time of MultiLevelFeedback "
+ avgWatingTime);
System.out.println("Average TurnAround Time of MultiLevelFeedback "
+ avgTurnaroundTime);
for(int i=0;i<j;i++)
{
System.out.println("time "+ganntT[i]+" process "+ganntP[i]);
}
System.out.println();
}
}
I am confused as there's nothing in the mlfq class which has anything to do with the pre-emptive multi-level class - they are both separate algorithms - except it is differing the output when I run both.

Failed to make my ArrayList Thread-Safe. Exception in thread "main" java.lang.ClassCastException: What is wrong?

I decided to optimize the piece of code below but encounter with problem. I tried to change the ArrayList to thread-safe collection by using this discussion but unfortunately something went wrong. The code is compiling but throw the exception.
Exception in thread "main" java.lang.ClassCastException:
java.util.Collections$SynchronizedRandomAccessList cannot be cast to
java.util.ArrayList at
bfpasswrd_multi.PasswordCracker.doItMulti(PasswordCracker.java:73) at
bfpasswrd_multi.PasswordCracker.runMulti(PasswordCracker.java:60) at
bfpasswrd_multi.Test.main(Test.java:16)
Please, tell me what is wrong ?
package bfpasswrd_multi;
import java.util.Scanner;
public class Test
{
public static void main(String[] args)
{
System.out.print("Type password to be cracked: ");
#SuppressWarnings("resource")
String input = new Scanner(System.in).nextLine();
PasswordCracker cracker = new PasswordCracker();
System.out.println("Multithreaded");
cracker.runMulti(input);
cracker = new PasswordCracker();
System.out.println("Finished...");
}
}
package bfpasswrd_multi;
import java.util.ArrayList;
import java.util.Collections;
import java.util.concurrent.ExecutorService;
import java.util.concurrent.Executors;
import java.util.concurrent.Future;
public class PasswordCracker
{
String passwordToCrack;
public boolean passwordFound;
int min;
int max;
StringBuffer crackedPassword;
public void prepare(String text)
{
passwordToCrack = text;
passwordFound = false;
min = 48;
max = 57; // http://ascii.cl/
crackedPassword = new StringBuffer();
crackedPassword.append((char) (min - 1));
}
public void result()
{
System.out.println("Cracked Password is: " + crackedPassword.toString());
}
public void incrementString(StringBuffer toCrack, int min, int max)
{
toCrack.setCharAt(0, (char) ((int) toCrack.charAt(0) + 1));
for (int i = 0; i < toCrack.length(); i++)
{
if (toCrack.charAt(i) > (char) max)
{
toCrack.setCharAt(i, (char) min);
if (toCrack.length() == i + 1)
{
toCrack.append((char) min);
}
else
{
toCrack.setCharAt(i + 1, (char) ((int) toCrack.charAt(i + 1) + 1));
}
}
}
}
public void runMulti(String text)
{
prepare(text);
double time = System.nanoTime();
doItMulti();
time = System.nanoTime() - time;
System.out.println(time / (1000000000));
result();
}
public void doItMulti()
{
int cores = Runtime.getRuntime().availableProcessors();
ArrayList<Future<?>> tasks ; // How do I make my ArrayList Thread-Safe? Another approach to problem in Java?
// https://stackoverflow.com/questions/2444005/how-do-i-make-my-arraylist-thread-safe-another-approach-to-problem-in-java
tasks = (ArrayList<Future<?>>) Collections.synchronizedList(new ArrayList<Future<?>>(cores));
// ArrayList<Future<?>> tasks = new ArrayList<>(cores);
ExecutorService executor = Executors.newFixedThreadPool(cores);
final long step = 2000;
for (long i = 0; i < Long.MAX_VALUE; i += step)
{
while(tasks.size() > cores)
{
for(int w = 0; w < tasks.size();w++)
{
if(tasks.get(w).isDone())
{
tasks.remove(w);
break;
}
}
try
{
Thread.sleep(0);
}
catch (InterruptedException e)
{
// TODO Auto-generated catch block
e.printStackTrace();
}
}
{
final long j = i;
if (passwordFound == false)
{
tasks.add(executor.submit(new Runnable()
{
public void run()
{
long border = j + step;
StringBuffer toCrack = new StringBuffer(10);
toCrack.append(constructString3(j, min, max));
for (long k = j; k < border; k++)
{
incrementString(toCrack, min, max);
boolean found = toCrack.toString().equals(passwordToCrack);
if (found)
{
crackedPassword = toCrack;
passwordFound = found;
break;
}
}
}
}));
}
else
{
break;
}
}
}
executor.shutdownNow();
}
public String constructString3(long number, long min, long max)
{
StringBuffer text = new StringBuffer();
if (number > Long.MAX_VALUE - min)
{
number = Long.MAX_VALUE - min;
}
ArrayList<Long> vector = new ArrayList<Long>(10);
vector.add(min - 1 + number);
long range = max - min + 1;
boolean nextLetter = false;
for (int i = 0; i < vector.size(); i++)
{
long nextLetterCounter = 0;
while (vector.get(i) > max)
{
nextLetter = true;
long multiplicator = Math.abs(vector.get(i) / range);
if ((vector.get(i) - (multiplicator * range)) < min)
{
multiplicator -= 1;
}
vector.set(i, vector.get(i) - (multiplicator * range));
nextLetterCounter += multiplicator;
}
if (nextLetter)
{
vector.add((long) (min + nextLetterCounter - 1));
nextLetter = false;
}
text.append((char) vector.get(i).intValue());
}
return text.toString();
}
}
Many thanks in advance !

The issue that you're seeing is with this line:
tasks = (ArrayList<Future<?>>) Collections.synchronizedList(new ArrayList<Future<?>>(cores));
Collections.synchronizedList doesn't return an ArrayList; it returns some subclass of List - java.util.Collections$SynchronizedRandomAccessList to be exact - and I don't know anything about that class other than it's a List, but it's not an ArrayList.
The easy solution to this is to declare tasks to be a List<Future<?>>:
List<Future<?>> tasks =
Collections.synchronizedList(new ArrayList<Future<?>>(cores));

Dear community members thanks you for your comments. It seems that now my safe-thread list is working. For the people who interesting in solution I will submit the resolved code below. Also, probably I should mention that I rename task
to futures, please pay attention. Once again everybody thanks !
package bfpasswrd_multi;
import java.util.ArrayList;
import java.util.Collections;
import java.util.List;
import java.util.concurrent.ExecutorService;
import java.util.concurrent.Executors;
import java.util.concurrent.Future;
public class PasswordCracker
{
String passwordToCrack;
public boolean passwordFound;
int min;
int max;
StringBuffer crackedPassword;
public void prepare(String text)
{
passwordToCrack = text;
passwordFound = false;
min = 48;
max = 57; // http://ascii.cl/
crackedPassword = new StringBuffer();
crackedPassword.append((char) (min - 1));
}
public void result()
{
System.out.println("Cracked Password is: " + crackedPassword.toString());
}
public void incrementString(StringBuffer toCrack, int min, int max)
{
toCrack.setCharAt(0, (char) ((int) toCrack.charAt(0) + 1));
for (int i = 0; i < toCrack.length(); i++)
{
if (toCrack.charAt(i) > (char) max)
{
toCrack.setCharAt(i, (char) min);
if (toCrack.length() == i + 1)
{
toCrack.append((char) min);
}
else
{
toCrack.setCharAt(i + 1, (char) ((int) toCrack.charAt(i + 1) + 1));
}
}
}
}
public void runMulti(String text)
{
prepare(text);
double time = System.nanoTime();
doItMulti();
time = System.nanoTime() - time;
System.out.println(time / (1000000000));
result();
}
public void doItMulti()
{
int cores = Runtime.getRuntime().availableProcessors();
// ArrayList<Future<?>> task; // HOW IT WAS
//
// tasks = (ArrayList<Future<?>>) Collections.synchronizedList(new ArrayList<Future<?>>(cores)); // HOW IT WAS
List<Future<?>> futures ; // THE SOLUTION
futures = Collections.synchronizedList(new ArrayList<Future<?>>(cores)); // THE SOLUTION
// ArrayList<Future<?>> tasks = new ArrayList<>(cores);
ExecutorService executor = Executors.newFixedThreadPool(cores);
final long step = 2000;
for (long i = 0; i < Long.MAX_VALUE; i += step)
{
while(futures.size() > cores)
{
for(int w = 0; w < futures.size();w++)
{
if(futures.get(w).isDone())
{
futures.remove(w);
break;
}
}
try
{
Thread.sleep(0);
}
catch (InterruptedException e)
{
// TODO Auto-generated catch block
e.printStackTrace();
}
}
{
final long j = i;
if (passwordFound == false)
{
futures.add(executor.submit(new Runnable()
{
public void run()
{
long border = j + step;
StringBuffer toCrack = new StringBuffer(10);
toCrack.append(constructString3(j, min, max));
for (long k = j; k < border; k++)
{
incrementString(toCrack, min, max);
boolean found = toCrack.toString().equals(passwordToCrack);
if (found)
{
crackedPassword = toCrack;
passwordFound = found;
break;
}
}
}
}));
}
else
{
break;
}
}
}
executor.shutdownNow();
}
public String constructString3(long number, long min, long max)
{
StringBuffer text = new StringBuffer();
if (number > Long.MAX_VALUE - min)
{
number = Long.MAX_VALUE - min;
}
ArrayList<Long> vector = new ArrayList<Long>(10);
vector.add(min - 1 + number);
long range = max - min + 1;
boolean nextLetter = false;
for (int i = 0; i < vector.size(); i++)
{
long nextLetterCounter = 0;
while (vector.get(i) > max)
{
nextLetter = true;
long multiplicator = Math.abs(vector.get(i) / range);
if ((vector.get(i) - (multiplicator * range)) < min)
{
multiplicator -= 1;
}
vector.set(i, vector.get(i) - (multiplicator * range));
nextLetterCounter += multiplicator;
}
if (nextLetter)
{
vector.add((long) (min + nextLetterCounter - 1));
nextLetter = false;
}
text.append((char) vector.get(i).intValue());
}
return text.toString();
}
}

Why do object arrays in my ArrayList fail to retain their values?

I am creating a program in Java to simulate evolution. The way I have it set up, each generation is composed of an array of Organism objects. Each of these arrays is an element in the ArrayList orgGenerations. Each generation, of which there could be any amount before all animals die, can have any amount of Organism objects.
For some reason, in my main loop when the generations are going by, I can have this code without errors, where allOrgs is the Organism array of the current generation and generationNumber is the number generations since the first.
orgGenerations.add(allOrgs);
printOrgs(orgGenerations.get(generationNumber));
printOrgs is a method to display an Organism array, where speed and strength are Organism Field variables:
public void printOrgs(Organism[] list)
{
for (int x=0; x<list.length; x++)
{
System.out.println ("For organism number: " + x + ", speed is: " + list[x].speed + ", and strength is " + list[x].strength + ".");
}
}
Later on, after this loop, when I am trying to retrieve the data to display, I call this very similar code:
printOrgs(orgGenerations.get(0));
This, and every other array in orgGenerations, return a null pointer exception on the print line of the for loop. Why are the Organism objects loosing their values?
Alright, here is all of the code from my main Simulation class. I admit, it might be sort of a mess. The parts that matter are the start and simulator methods. The battle ones are not really applicable to this problem. I think.
import java.awt.FlowLayout;
import java.util.*;
import javax.swing.JFrame;
public class Simulator {
//variables for general keeping track
static Organism[] allOrgs;
static ArrayList<Organism[]> orgGenerations = new ArrayList <Organism[]>();
ArrayList<Integer> battleList = new ArrayList<Integer>();
int deathCount;
boolean done;
boolean runOnce;
//setup
Simulator()
{
done = false;
Scanner asker = new Scanner(System.in);
System.out.println("Input number of organisms for the simulation: ");
int numOfOrgs = asker.nextInt();
asker.close();
Organism[] orgArray = new Organism[numOfOrgs];
for (int i=0; i<numOfOrgs; i++)
{
orgArray[i] = new Organism();
}
allOrgs = orgArray;
}
//graphsOrgs
public void graphOrgs() throws InterruptedException
{
JFrame f = new JFrame("Evolution");
f.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
f.setSize(1000,500);
f.setVisible(true);
Drawer bars = new Drawer();
//System.out.println(orgGenerations.size());
for (int iterator=0;iterator<(orgGenerations.size()-1); iterator++)
{
printOrgs(orgGenerations.get(0));
//The 0 can be any number, no matter what I do it wont work
//System.out.println("first");
f.repaint();
bars.data = orgGenerations.get(iterator);
f.add(bars);
//System.out.println("before");
Thread.sleep(1000);
//System.out.println("end");
}
}
//prints all Orgs and their statistics
public void printOrgs(Organism[] list)
{
System.out.println("Number Of Organisms: " + list.length);
for (int x=0; x<list.length; x++)
{
System.out.println ("For organism number: " + x + ", speed is: " + list[x].speed + ", and strength is " + list[x].strength + ".");
}
System.out.println();
}
//general loop for the organisms lives
public void start(int reproductionTime) throws InterruptedException
{
int generationNumber = 0;
orgGenerations.add(allOrgs);
printOrgs(orgGenerations.get(0));
generationNumber++;
while(true)
{
deathCount = 0;
for(int j=0; j<reproductionTime; j++)
{
battleList.clear();
for(int m=0; m<allOrgs.length; m++)
{
if (allOrgs[m].alive == true)
oneYearBattleCheck(m);
}
battle();
}
reproduction();
if (done == true)
break;
orgGenerations.add(allOrgs);
printOrgs(orgGenerations.get(generationNumber));
generationNumber++;
}
printOrgs(orgGenerations.get(2));
}
//Checks if they have to fight this year
private void oneYearBattleCheck(int m)
{
Random chaos = new Random();
int speedMod = chaos.nextInt(((int)Math.ceil(allOrgs[m].speed/5.0))+1);
int speedSign = chaos.nextInt(2);
if (speedSign == 0)
speedSign--;
speedMod *= speedSign;
int speed = speedMod + allOrgs[m].speed;
if (speed <= 0)
speed=1;
Random encounter = new Random();
boolean battle = false;
int try1 =(encounter.nextInt(speed));
int try2 =(encounter.nextInt(speed));
int try3 =(encounter.nextInt(speed));
int try4 =(encounter.nextInt(speed));
if (try1 == 0 || try2 == 0 || try3 == 0 || try4 == 0 )
{
battle = true;
}
if(battle == true)
{
battleList.add(m);
}
}
//Creates the matches and runs the battle
private void battle()
{
Random rand = new Random();
if (battleList.size()%2 == 1)
{
int luckyDuck = rand.nextInt(battleList.size());
battleList.remove(luckyDuck);
}
for(int k=0; k<(battleList.size()-1);)
{
int competitor1 = rand.nextInt(battleList.size());
battleList.remove(competitor1);
int competitor2 = rand.nextInt(battleList.size());
battleList.remove(competitor2);
//Competitor 1 strength
int strengthMod = rand.nextInt(((int)Math.ceil(allOrgs[competitor1].strength/5.0))+1);
int strengthSign = rand.nextInt(2);
if (strengthSign == 0)
strengthSign--;
strengthMod *= strengthSign;
int comp1Strength = strengthMod + allOrgs[competitor1].strength;
//Competitor 2 strength
strengthMod = rand.nextInt(((int)Math.ceil(allOrgs[competitor2].strength/5.0))+1);
strengthSign = rand.nextInt(2);
if (strengthSign == 0)
strengthSign--;
strengthMod *= strengthSign;
int comp2Strength = strengthMod + allOrgs[competitor2].strength;
//Fight!
if (comp1Strength>comp2Strength)
{
allOrgs[competitor1].life ++;
allOrgs[competitor2].life --;
}
else if (comp2Strength>comp1Strength)
{
allOrgs[competitor2].life ++;
allOrgs[competitor1].life --;
}
if (allOrgs[competitor1].life == 0)
{
allOrgs[competitor1].alive = false;
deathCount++;
}
if (allOrgs[competitor2].life == 0)
{
allOrgs[competitor2].alive = false;
deathCount ++ ;
}
}
}
//New organisms
private void reproduction()
{
//System.out.println("Number of deaths: " + deathCount + "\n");
if (deathCount>=(allOrgs.length-2))
{
done = true;
return;
}
ArrayList<Organism> tempOrgs = new ArrayList<Organism>();
Random chooser = new Random();
int count = 0;
while(true)
{
int partner1 = 0;
int partner2 = 0;
boolean partnerIsAlive = false;
boolean unluckyDuck = false;
//choose partner1
while (partnerIsAlive == false)
{
partner1 = chooser.nextInt(allOrgs.length);
if (allOrgs[partner1] != null)
{
if (allOrgs[partner1].alive == true)
{
partnerIsAlive = true;
}
}
}
count++;
//System.out.println("Count 2: " + count);
partnerIsAlive = false;
//choose partner2
while (partnerIsAlive == false)
{
if (count+deathCount == (allOrgs.length))
{
unluckyDuck=true;
break;
}
partner2 = chooser.nextInt(allOrgs.length);
if (allOrgs[partner2] != null)
{
if (allOrgs[partner2].alive == true)
{
partnerIsAlive = true;
}
}
}
if (unluckyDuck == false)
count++;
//System.out.println("count 2: " + count);
if (unluckyDuck == false)
{
int numOfChildren = (chooser.nextInt(4)+1);
for (int d=0; d<numOfChildren; d++)
{
tempOrgs.add(new Organism(allOrgs[partner1].speed, allOrgs[partner2].speed, allOrgs[partner1].strength, allOrgs[partner2].strength ));
}
allOrgs[partner1] = null;
allOrgs[partner2] = null;
}
if (count+deathCount == (allOrgs.length))
{
Arrays.fill(allOrgs, null);
allOrgs = tempOrgs.toArray(new Organism[tempOrgs.size()-1]);
break;
}
//System.out.println(count);
}
}
}
Main method:
public class Runner {
public static void main(String[] args) throws InterruptedException {
Simulator sim = new Simulator();
int lifeSpan = 20;
sim.start(lifeSpan);
sim.graphOrgs();
}
}
Organism class:
import java.util.Random;
public class Organism {
static Random traitGenerator = new Random();
int life;
int speed;
int strength;
boolean alive;
Organism()
{
speed = (traitGenerator.nextInt(49)+1);
strength = (50-speed);
life = 5;
alive = true;
}
Organism(int strength1, int strength2, int speed1, int speed2)
{
Random gen = new Random();
int speedMod = gen.nextInt(((int)Math.ceil((speed1+speed2)/10.0))+1);
int speedSign = gen.nextInt(2);
if (speedSign == 0)
speedSign--;
speedMod *= speedSign;
//System.out.println(speedMod);
int strengthMod = gen.nextInt(((int)Math.ceil((strength1+strength2)/10.0))+1);
int strengthSign = gen.nextInt(2);
if (strengthSign == 0)
strengthSign--;
strengthMod *= strengthSign;
//System.out.println(strengthMod);
strength = (((int)((strength1+strength2)/2.0))+ strengthMod);
speed = (((int)((speed1+speed2)/2.0))+ speedMod);
alive = true;
life = 5;
}
}
The problem lies in the graphOrgs class when I try to print to check if it is working in preparation for graphing the results. This is when it returns the error. When I try placing the print code in other places in the Simulator class the same thing occurs, a null pointer error. This happens even if it is just after the for loop where the element has been established.

You have code that sets to null elements in your allOrgs array.
allOrgs[partner1] = null;
allOrgs[partner2] = null;
Your orgGenerations list contains the same allOrgs instance multiple times.
Therefore, when you write allOrgs[partner1] = null, the partner1'th element becomes null in all the list elements of orgGenerations, which is why the print method fails.
You should create a copy of the array (you can use Arrays.copy) each time you add a new generation to the list (and consider also creating copies of the Organism instances, if you want each generation to record the past state of the Organisms and not their final state).