I have 2 matrices and I need to multiply them and then print the results of each cell. As soon as one cell is ready I need to print it, but for example I need to print the [0][0] cell before cell [2][0] even if the result of [2][0] is ready first. So I need to print it by order.
So my idea is to make the printer thread wait until the multiplyThread
notifies it that the correct cell is ready to be printed and then the printerThread
will print the cell and go back to waiting and so on..
So I have this thread that does the multiplication:
public void run()
{
int countNumOfActions = 0; // How many multiplications have we done
int maxActions = randomize(); // Maximum number of actions allowed
for (int i = 0; i < size; i++)
{
result[rowNum][colNum] = result[rowNum][colNum] + row[i] * col[i];
countNumOfActions++;
// Reached the number of allowed actions
if (countNumOfActions >= maxActions)
{
countNumOfActions = 0;
maxActions = randomize();
yield();
}
}
isFinished[rowNum][colNum] = true;
notify();
}
Thread that prints the result of each cell:
public void run()
{
int j = 0; // Columns counter
int i = 0; // Rows counter
System.out.println("The result matrix of the multiplication is:");
while (i < creator.getmThreads().length)
{
synchronized (this)
{
try
{
this.wait();
}
catch (InterruptedException e1)
{
}
}
if (creator.getmThreads()[i][j].getIsFinished()[i][j] == true)
{
if (j < creator.getmThreads()[i].length)
{
System.out.print(creator.getResult()[i][j] + " ");
j++;
}
else
{
System.out.println();
j = 0;
i++;
System.out.print(creator.getResult()[i][j] + " ");
}
}
}
Now it throws me these exceptions:
Exception in thread "Thread-9" java.lang.IllegalMonitorStateException
at java.lang.Object.notify(Native Method)
at multiplyThread.run(multiplyThread.java:49)
Exception in thread "Thread-6" Exception in thread "Thread-4" java.lang.IllegalMonitorStateException
at java.lang.Object.notify(Native Method)
at multiplyThread.run(multiplyThread.java:49)
java.lang.IllegalMonitorStateException
at java.lang.Object.notify(Native Method)
at multiplyThread.run(multiplyThread.java:49)
Exception in thread "Thread-5" java.lang.IllegalMonitorStateException
at java.lang.Object.notify(Native Method)
at multiplyThread.run(multiplyThread.java:49)
Exception in thread "Thread-8" java.lang.IllegalMonitorStateException
at java.lang.Object.notify(Native Method)
at multiplyThread.run(multiplyThread.java:49)
Exception in thread "Thread-7" java.lang.IllegalMonitorStateException
at java.lang.Object.notify(Native Method)
at multiplyThread.run(multiplyThread.java:49)
Exception in thread "Thread-11" java.lang.IllegalMonitorStateException
at java.lang.Object.notify(Native Method)
at multiplyThread.run(multiplyThread.java:49)
Exception in thread "Thread-10" java.lang.IllegalMonitorStateException
at java.lang.Object.notify(Native Method)
at multiplyThread.run(multiplyThread.java:49)
Exception in thread "Thread-12" java.lang.IllegalMonitorStateException
at java.lang.Object.notify(Native Method)
at multiplyThread.run(multiplyThread.java:49)
line 49 in multiplyThread
is the "notify()"..I think I need to use the synchronized differently but I am not sure how.
If anyone can help this code to work I will really appreciate it.