Problem:

Code works fine for a while and then freezes! At a guess i think it might be a memory link but i am quite new to java and cannot find out where the leak is. I have called system.gc() but the error still happens. This is the first time i have tried threading as well so that could be implemented wrong. Tried all sorts and everytime the program works for a while and then i get a memory error.

description:

The aim of the code is to fill 7 arrays with images from google using php/cUrl to scrape google search. Each array holds images of different colours. The thread continues to run and make sure that the arrays are full. The user can pop images from the array using the keys and the thread fills the array again.

Code(eclipse):

Code:

import processing.core.*;

public class mainprocessing extends PApplet {

imageStack[] imageStacks = new imageStack[7];
Thread[] wrappers = new Thread[7];
int x = 0; 

public void setup() {
	size(screen.width, screen.height);
	background(0);
	// start the imageStacks
	imageStacks[0] = new imageStack("red");
	imageStacks[1] = new imageStack("orange");
	imageStacks[2] = new imageStack("yellow");
	imageStacks[3] = new imageStack("green");
	imageStacks[4] = new imageStack("blue");
	imageStacks[5] = new imageStack("indigo");
	imageStacks[6] = new imageStack("violet");
	for (int i = 0; i < 7; i++)
	{
	  wrappers[i] = new Thread(imageStacks[i]);
	  wrappers[i].start();
	}
  }

  public void draw() {
	  try
	  {
	  fill(0,30);
	  rect(0,0,width,height);  
	  //user input
	  if ((keyPressed == true) && (key == 'r'))
		{
		  imageStacks[0].popStack();
		}
	  if ((keyPressed == true) && (key == 'o'))
		{
		  imageStacks[1].popStack();
		}
	  if ((keyPressed == true) && (key == 'y'))
		{
		  imageStacks[2].popStack();
		}
	  if ((keyPressed == true) && (key == 'g'))
		{
		  imageStacks[3].popStack();
		}
	  if ((keyPressed == true) && (key == 'b'))
		{
		  imageStacks[4].popStack();
		}
	  if ((keyPressed == true) && (key == 'i'))
		{
		  imageStacks[5].popStack();
		}
	  if ((keyPressed == true) && (key == 'v'))
		{
		  imageStacks[6].popStack();
		}
	  }
	finally
	{
	}
	  
  }
  //
  class imageStack implements Runnable
  {
    //the url to my php with the search param
    String url = "my php";
    //the main stack
    PImage[] imgStack = new PImage[5];
    //A vessel for what comes back from the web page
    String[] lines;
    //constructors mainly the color of the stack
    imageStack(String stackColor) 
    {
	url = url+stackColor;
    }
    // Main part of the thread where all the important loading of images happens
    public void run() 
    {
	while (true)
	{
	try
	{  
	  // if the top of the stack is empty bring all images up one place
	  for (int i = 4; i >= 0; i--)
	  {
	    //Keep loading new image till it is full
	    if ((imgStack[i] == null) || (imgStack[i].height < 0))  
	    {
		lines =  loadStrings(url);
		String href = lines[0];
		imgStack[i] = requestImage(href, "jpg");
	    }
	    
	  }   
	}
	finally
	{
	}
	//pause for a while
	delay(250);
	}
    }
     
    //pull an image from the top of the stack
    public void popStack()
    {
	boolean valid = false; 
	int count = 4;   
	while(valid == false)
	{
	  // check boolean to make sure image is valid
	  if ((imgStack[count] != null))
	  {
	    image(imgStack[count], 0, 0);
	    imgStack[count] = null;
	    valid=true;
	    //clear garbage
	    System.gc();
	  } 
	  count--;
	  if (count == 0)
	 {
	   valid = true;
	   
	 }
	}
    }
    
    //end
  }
}

 

This is becoming such a frustrating problem so any help would be much appreciated.

cheers

Thanks Quark you are a legend!!! i will have a good look at the tutorial and try and implement the technique. hopefully i can post a working version of this code tomorrow. Your help is most appreciated

cheers