MemoryTest.java

package ij.plugin;

import java.awt.*;
import java.awt.image.*;
import java.util.Vector;
import ij.*;
import ij.gui.*;

public class MemoryTest implements PlugIn {


    public void run(String arg) {
    
        boolean okay = IJ.showMessageWithCancel("Memory Test", 
            "The MemoryTest plugin opens as many\n"
            + "1024x1024x8-bit images as possible and then\n"
            + "calculates how much memory was used for each\n"
            + "image. This is a demanding test that may require\n"
            + "ImageJ to be restarted, may crash your browser, \n"
            + "or may even crash your machine."
            );
        if (!okay)
            return;

        int width = 1024;
        int arraySize = 1024*1024;
        Vector objects;
        int nArrays = 0;
        int nImages = 0;
        byte[] pixels;
        ColorModel cm;
        Image img, saveImg=null;

        IJ.write("");
        IJ.write("Opening " + width + "x" + width + " 8-bit image windows...");
        collectGarbage();
        int[] times = new int[2000];
        long time, time2;
        time = System.currentTimeMillis();
        try {
            while(true) {
                NewImage.open(""+(nImages+1), width, width, 1, NewImage.GRAY8, NewImage.FILL_WHITE);
                time2 = System.currentTimeMillis();
                times[nImages] = (int)(time2-time);
                time = time2;
                nImages++;
            }
        }
        catch(OutOfMemoryError ex) {
            collectGarbage();
        }

        IJ.wait(100);
        objects = new Vector();
        IJ.write("Probing memory...");
        try {
            while(true) {
                System.gc();
                byte[] a = new byte[arraySize];
                objects.addElement(a);
                nArrays++;
                IJ.showStatus((nArrays*arraySize)/(1024*1024) + "MB");
                IJ.wait(50);
            }
        }
        catch(OutOfMemoryError e) {
            objects = null;
            collectGarbage();
            IJ.write(arraySize*nArrays/(1024*1024) + "MB is available");
            IJ.write(nImages + " images were opened");
            if (nImages>0)
                IJ.write("~" + arraySize*nArrays/(nImages*1024) + "K was required for each image");
            IJ.write("");
            //for (int i=0; i<nImages; i++)
            //  IJ.write((i+1)+": "+times[i]);
            IJ.showStatus("");
        }

    }

    void collectGarbage() {
        for (int i=0; i<10; i++)
            System.gc();
    }

}