3 import java.awt.*;
4
5 public class Main {
6
7 public static void main(String[] args) {
8 Point point1 = new Point(x:1, y:1);
9 Point point2 = point1;
10 point1.x = 2;
11 System.out.println(point2);
12 }
13 }
I'm getting an error that ')', ';' is expected in line 8 and line 8 is not a statement. (Currently using Java15)
Below fixed the issue for me
import java.awt.*;
public class Main {
public static void main(String[] args) {
System.out.println("Hello World");
Point point1 = new Point(1, 1);
Point point2 = point1;
point1.x = 2;
System.out.println(point2);
}
}
Related
As an exercise I am trying to calculate a recursive EMA with a burn period in Esper, EPL. It has moderately complex startup logic, and I thought this would be a good test for evaluating the sorts of things Esper could achieve.
Assuming a stream of values x1, x2, x3 at regular intervals, we want to calculate:
let p = 0.1
a = average(x1, x2, x3, x4, x5) // Assume 5, in reality use a parameter
y1 = p * x1 + (p - 1) * a // Recursive calculation initialized with look-ahead average
y2 = p * x2 + (p - 1) * y1
y3 = p * x3 + (p - 1) * y2
....
The final stream should only publish y5, y6, y7, ...
I was toying with a context that produces an event containing the average a, and that event triggers a second context that begins the recursive calculations. But by the time I try to get the first context to trigger once and once only, and the second context to handle the initial case using a and subsequent events recursively I end up with a messy tangle of logic.
Is there a straight-forward way to approach this problem?
(I'm ignoring using a custom aggregator, since this is a learning exercise)
This doesn't answer the question, but might be useful - implementation as a custom aggregation function, tested with esper 7.1.0
public class EmaFactory implements AggregationFunctionFactory {
int burn = 0;
#Override
public void setFunctionName(String s) {
// Don't know why/when this is called
}
#Override
public void validate(AggregationValidationContext ctx) {
#SuppressWarnings("rawtypes")
Class[] p = ctx.getParameterTypes();
if ((p.length != 3)) {
throw new IllegalArgumentException(String.format(
"Ema aggregation required three parameters, received %d",
p.length));
}
if (
!(
(p[0] == Double.class || p[0] == double.class) ||
(p[1] == Double.class || p[1] == double.class) ||
(p[2] == Integer.class || p[2] == int.class))) {
throw new IllegalArgumentException(
String.format(
"Arguments to Ema aggregation must of types (Double, Double, Integer), got (%s, %s, %s)\n",
p[0].getName(), p[1].getName(), p[2].getName()) +
"This should be made nicer, see AggregationMethodFactorySum.java in the Esper source code for " +
"examples of correctly dealing with multiple types"
);
}
if (!ctx.getIsConstantValue()[2]) {
throw new IllegalArgumentException(
"Third argument 'burn' to Ema aggregation must be constant"
);
}
;
burn = (int) ctx.getConstantValues()[2];
}
#Override
public AggregationMethod newAggregator() {
return new EmaAggregationFunction(burn);
}
#SuppressWarnings("rawtypes")
#Override
public Class getValueType() {
return Double.class;
}
}
public class EmaAggregationFunction implements AggregationMethod {
final private int burnLength;
private double[] burnValues;
private int count = 0;
private double value = 0.;
EmaAggregationFunction(int burn) {
this.burnLength = burn;
this.burnValues = new double[burn];
}
private void update(double x, double alpha) {
if (count < burnLength) {
value += x;
burnValues[count++] = x;
if (count == burnLength) {
value /= count;
for (double v : burnValues) {
value = alpha * v + (1 - alpha) * value;
}
// in case burn is long, free memory
burnValues = null;
}
} else {
value = alpha * x + (1 - alpha) * value;
}
}
#Override
public void enter(Object tmp) {
Object[] o = (Object[]) tmp;
assert o[0] != null;
assert o[1] != null;
assert o[2] != null;
assert (int) o[2] == burnLength;
update((double) o[0], (double) o[1]);
}
#Override
public void leave(Object o) {
}
#Override
public Object getValue() {
if (count < burnLength) {
return null;
} else {
return value;
}
}
#Override
public void clear() {
// I don't know when / why this is called - this part untested
count = 0;
value = 0.;
burnValues = new double[burnLength];
}
}
public class TestEmaAggregation {
private EPRuntime epRuntime;
private SupportUpdateListener listener = new SupportUpdateListener();
void send(int id, double value) {
epRuntime.sendEvent(
new HashMap<String, Object>() {{
put("id", id);
put("value", value);
}},
"CalculationEvent");
}
#BeforeEach
public void beforeEach() {
EPServiceProvider provider = EPServiceProviderManager.getDefaultProvider();
EPAdministrator epAdministrator = provider.getEPAdministrator();
epRuntime = provider.getEPRuntime();
ConfigurationOperations config = epAdministrator.getConfiguration();
config.addPlugInAggregationFunctionFactory("ema", EmaFactory.class.getName());
config.addEventType(
"CalculationEvent",
new HashMap<String, Object>() {{ put("id", Integer.class); put("value", Double.class); }}
);
EPStatement stmt = epAdministrator.createEPL("select ema(value, 0.1, 5) as ema from CalculationEvent where value is not null");
stmt.addListener(listener);
}
Double getEma() {
return (Double)listener.assertOneGetNewAndReset().get("ema");
}
#Test
public void someTest() {
send(1, 1);
assertEquals(null, getEma());
send(1, 2);
assertEquals(null, getEma());
send(1, 3);
assertEquals(null, getEma());
send(1, 4);
assertEquals(null, getEma());
// Last of the burn period
// We expect:
// a = (1+2+3+4+5) / 5 = 3
// y1 = 0.1 * 1 + 0.9 * 3 = 2.8
// y2 = 0.1 * 2 + 0.9 * 2.8
// ... leading to
// y5 = 3.08588
send(1, 5);
assertEquals(3.08588, getEma(), 1e-10);
// Outside burn period
send(1, 6);
assertEquals(3.377292, getEma(), 1e-10);
send(1, 7);
assertEquals(3.7395628, getEma(), 1e-10);
send(1, 8);
assertEquals(4.16560652, getEma(), 1e-10);
}
}
Output
I think the following code isn't giving the correct result.
What's wrong withe following code?
public class ImagePadder
{
public static Bitmap Pad(Bitmap image, int newWidth, int newHeight)
{
int width = image.Width;
int height = image.Height;
if (width >= newWidth) throw new Exception("New width must be larger than the old width");
if (height >= newHeight) throw new Exception("New height must be larger than the old height");
Bitmap paddedImage = Grayscale.CreateGrayscaleImage(newWidth, newHeight);
BitmapLocker inputImageLocker = new BitmapLocker(image);
BitmapLocker paddedImageLocker = new BitmapLocker(paddedImage);
inputImageLocker.Lock();
paddedImageLocker.Lock();
//Reading row by row
for (int y = 0; y < image.Height; y++)
{
for (int x = 0; x < image.Width; x++)
{
Color col = inputImageLocker.GetPixel(x, y);
paddedImageLocker.SetPixel(x, y, col);
}
}
string str = string.Empty;
paddedImageLocker.Unlock();
inputImageLocker.Unlock();
return paddedImage;
}
}
Relevant Source Code:
public class BitmapLocker : IDisposable
{
//private properties
Bitmap _bitmap = null;
BitmapData _bitmapData = null;
private byte[] _imageData = null;
//public properties
public bool IsLocked { get; set; }
public IntPtr IntegerPointer { get; private set; }
public int Width { get { return _bitmap.Width; } }
public int Height { get { return _bitmap.Height; } }
public int Stride { get { return _bitmapData.Stride; } }
public int ColorDepth { get { return Bitmap.GetPixelFormatSize(_bitmap.PixelFormat); } }
public int Channels { get { return ColorDepth / 8; } }
public int PaddingOffset { get { return _bitmapData.Stride - (_bitmap.Width * Channels); } }
public PixelFormat ImagePixelFormat { get { return _bitmap.PixelFormat; } }
public bool IsGrayscale { get { return Grayscale.IsGrayscale(_bitmap); } }
//Constructor
public BitmapLocker(Bitmap source)
{
IsLocked = false;
IntegerPointer = IntPtr.Zero;
this._bitmap = source;
}
/// Lock bitmap
public void Lock()
{
if (IsLocked == false)
{
try
{
// Lock bitmap (so that no movement of data by .NET framework) and return bitmap data
_bitmapData = _bitmap.LockBits(
new Rectangle(0, 0, _bitmap.Width, _bitmap.Height),
ImageLockMode.ReadWrite,
_bitmap.PixelFormat);
// Create byte array to copy pixel values
int noOfBitsNeededForStorage = _bitmapData.Stride * _bitmapData.Height;
int noOfBytesNeededForStorage = noOfBitsNeededForStorage / 8;
_imageData = new byte[noOfBytesNeededForStorage * ColorDepth];//# of bytes needed for storage
IntegerPointer = _bitmapData.Scan0;
// Copy data from IntegerPointer to _imageData
Marshal.Copy(IntegerPointer, _imageData, 0, _imageData.Length);
IsLocked = true;
}
catch (Exception)
{
throw;
}
}
else
{
throw new Exception("Bitmap is already locked.");
}
}
/// Unlock bitmap
public void Unlock()
{
if (IsLocked == true)
{
try
{
// Copy data from _imageData to IntegerPointer
Marshal.Copy(_imageData, 0, IntegerPointer, _imageData.Length);
// Unlock bitmap data
_bitmap.UnlockBits(_bitmapData);
IsLocked = false;
}
catch (Exception)
{
throw;
}
}
else
{
throw new Exception("Bitmap is not locked.");
}
}
public Color GetPixel(int x, int y)
{
Color clr = Color.Empty;
// Get color components count
int cCount = ColorDepth / 8;
// Get start index of the specified pixel
int i = (Height - y - 1) * Stride + x * cCount;
int dataLength = _imageData.Length - cCount;
if (i > dataLength)
{
throw new IndexOutOfRangeException();
}
if (ColorDepth == 32) // For 32 bpp get Red, Green, Blue and Alpha
{
byte b = _imageData[i];
byte g = _imageData[i + 1];
byte r = _imageData[i + 2];
byte a = _imageData[i + 3]; // a
clr = Color.FromArgb(a, r, g, b);
}
if (ColorDepth == 24) // For 24 bpp get Red, Green and Blue
{
byte b = _imageData[i];
byte g = _imageData[i + 1];
byte r = _imageData[i + 2];
clr = Color.FromArgb(r, g, b);
}
if (ColorDepth == 8)
// For 8 bpp get color value (Red, Green and Blue values are the same)
{
byte c = _imageData[i];
clr = Color.FromArgb(c, c, c);
}
return clr;
}
public void SetPixel(int x, int y, Color color)
{
// Get color components count
int cCount = ColorDepth / 8;
// Get start index of the specified pixel
int i = (Height - y - 1) * Stride + x * cCount;
try
{
if (ColorDepth == 32) // For 32 bpp set Red, Green, Blue and Alpha
{
_imageData[i] = color.B;
_imageData[i + 1] = color.G;
_imageData[i + 2] = color.R;
_imageData[i + 3] = color.A;
}
if (ColorDepth == 24) // For 24 bpp set Red, Green and Blue
{
_imageData[i] = color.B;
_imageData[i + 1] = color.G;
_imageData[i + 2] = color.R;
}
if (ColorDepth == 8)
// For 8 bpp set color value (Red, Green and Blue values are the same)
{
_imageData[i] = color.B;
}
}
catch (Exception ex)
{
throw new Exception("(" + x + ", " + y + "), " + _imageData.Length + ", " + ex.Message + ", i=" + i);
}
}
public void Dispose()
{
Dispose(true);
GC.SuppressFinalize(this);
}
protected virtual void Dispose(bool disposing)
{
if (disposing)
{
// free managed resources
_bitmap = null;
_bitmapData = null;
_imageData = null;
IntegerPointer = IntPtr.Zero;
}
}
}
The layout of a Windows bitmap is different than you might expect. The bottom line of the image is the first line in memory, and continues backwards from there. It can also be laid out the other way when the height is negative, but those aren't often encountered.
Your calculation of an offset into the bitmap appears to take that into account, so your problem must be more subtle.
int i = (Height - y - 1) * Stride + x * cCount;
The problem is that the BitmapData class already takes this into account and tries to fix it for you. The bitmap I described above is a bottom-up bitmap. From the documentation for BitmapData.Stride:
The stride is the width of a single row of pixels (a scan line), rounded up to a four-byte boundary. If the stride is positive, the bitmap is top-down. If the stride is negative, the bitmap is bottom-up.
It is intended to be used with the Scan0 property to access the bitmap in a consistent fashion whether it's top-down or bottom-up.
this is my complete code for a small gui to take variables from user and return them to the rest of program(r.o.p) for calculations, however doesn't seem to be passing to r.o.p. and no output file is observerd.
Any help would be much appreciated, I think the problem is with the listener for the Draw New Graph command. Thanks
Code:
import java.text.*;
import java.io.*;
import java.util.*;
import javax.swing.*;
import java.awt.*;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import java.awt.event.MouseEvent;
import java.awt.event.MouseListener;
public class RungeKutta {
// class to create slider and window
private static File file1;
public static double A(double v, double x, double wc, double beta) {
return (-2 * beta * v - (Math.pow(wc, 2)) * Math.sin(x));
}
public static File getFile1() {
return file1;
}
public static void setFile1(File file1) {
RungeKutta.file1 = file1;
}
public static void main(String[] argv) throws IOException, ParseException {
createAndShowGUI();
}
private static void createAndShowGUI() {
//create and set up the window.
JFrame frame = new JFrame("RungeKutta");
GridLayout first = new GridLayout(14,1);
frame.setLayout(first);
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
//Create, name and Populate TextField
JTextField PL = new JTextField("Pendulum Length", 20);
//Set TextField to Uneditable. Each will have Empty Field Below For Variables
PL.setEditable(false);
//Set Textfield for user entered dat
JTextField PLv = new JTextField();
//Allow input from text field to be taken
JTextField AD = new JTextField("Angular Displacement", 20);
AD.setEditable(false);
JTextField ADv = new JTextField();
JTextField AV = new JTextField("Angular Velocity", 20);
AV.setEditable(false);
JTextField Avv = new JTextField();
JTextField TS= new JTextField("Time Steps", 20);
TS.setEditable(false);
JTextField TSv = new JTextField();
JTextField MT = new JTextField("Max Time", 20);
MT.setEditable(false);
JTextField MTv = new JTextField();
JTextField V = new JTextField("Viscosity (0-1)", 20);
V.setEditable(false);
JTextField Vv = new JTextField();
//Create Button to Restart and Button to take in Values for usage
JLabel emptyLabel = new JLabel("");
emptyLabel.setPreferredSize(new Dimension(600,500));
frame.getContentPane().add(PL, first);
frame.getContentPane().add(PLv, first);
frame.getContentPane().add(AD, first);
frame.getContentPane().add(ADv, first);
frame.getContentPane().add(AV, first);
frame.getContentPane().add(Avv, first);
frame.getContentPane().add(TS, first);
frame.getContentPane().add(TSv, first);
frame.getContentPane().add(MT, first);
frame.getContentPane().add(MTv, first);
frame.getContentPane().add(V, first);
frame.getContentPane().add(Vv, first);
JButton BNewGraph = new JButton("Draw New Graph"); //Button to restart entire drawing process
frame.getContentPane().add(BNewGraph, first);
//display the window
frame.pack();
frame.setVisible(true);
class intakegui implements ActionListener
{
public intakegui()
{
BNewGraph.addActionListener((ActionListener) this);
BNewGraph.setActionCommand("Click to Draw");
}
#Override
public void actionPerformed(ActionEvent e) {
double l = Double.parseDouble(PLv.getText());
double xi = Double.parseDouble(ADv.getText());
double vi = Double.parseDouble(Avv.getText());
double dt = Double.parseDouble(TSv.getText());
double n = Double.parseDouble(MTv.getText());
double beta = Double.parseDouble(Vv.getText());
SimpleDateFormat dform = new SimpleDateFormat("ddMMyyyysmH");
Date d = Calendar.getInstance().getTime();
String dstr = dform.format(d);
String filename = ("result " + dstr + ".txt");
file1 = new File(filename);
PrintWriter savedValues = null;
try {
savedValues = new PrintWriter(filename);
} catch (FileNotFoundException e1) {
// TODO Auto-generated catch block
e1.printStackTrace();
}
//declare variable for gravity and omega*c
double g = 9.8;
double wc = Math.sqrt(g / l);
savedValues.println("#Initial Values Entered");
savedValues.println("#" + l + "," + vi + "," + xi + "," + dt + "," + n
+ "," + beta);
double[] dispTime = new double[(int) n];
double[] velTime = new double[(int) n];
// let a = angular acceleration
for (double j = 0; j < (int) n; j++) {
// int time = 1;
double k1v = dt * j * A(vi, xi, wc, beta);
double k1x = dt * j * vi;
double k2v = dt * j * A(vi, xi + (0.5 * k1x), wc, beta);
double k2x = dt * j * (vi + (0.5 * k1v));
double k3v = dt * j * A(vi, xi + (0.5 * k2x), wc, beta);
double k3x = dt * j * (vi + (0.5 * k2v));
double k4v = dt * j * A(vi, xi + k3x, wc, beta);
double k4x = dt * j * (vi + k3v);
xi += k1x / 6 + k2x / 3 + k3x / 3 + k4x / 6;
vi += k1v / 6 + k2v / 3 + k3v / 3 + k4v / 6;
dispTime[(int) j] = xi;
velTime[(int) j] = vi;
System.out.println(xi + "," + vi);
}
for (int i = 0; i < (int) n; i++) {
savedValues.println(dispTime[i] + " " + velTime[i]);
}
savedValues.close();
System.out.println("File saved. File name: " + filename);
}
}
}
}
You forgot to add listener to your button. You need to add listener as below:
BNewGraph.addActionListener(new intakegui());
Now when user clicks on button, you would see the file.
import java.awt.image.BufferedImage;
import java.io.File;
import java.util.concurrent.ForkJoinPool;
import java.util.concurrent.RecursiveAction;
import javax.imageio.ImageIO;
import java.awt.*;
class Multicore1 extends RecursiveAction
{
private int[] msource;
private int mstart;
private int mlength;
private int[] mDestination;
private int window=15;
private BufferedImage mimage;
public Multicore1(int[] src,int start,int length,int[] dest,BufferedImage image)
{
msource=src;
mstart=start;
mlength=length;
mDestination=dest;
mimage=image;
}
protected void computeDirectly(BufferedImage Img)
{
int rgb;
int lum;
int grayval;
int rgbVal;
int x,y;
int sliding=(window-1)/2;
System.out.println(" mlenght valu is " + mlength);
System.out.println(" mstart valu is " + mstart);
float r=0; float g=0;float b=0;
int red=0,green=0,blue=0;
// the image after conversion doesnot seem to be properly converted to grayscal. please look upon my code if there is any mistake
for(x=mstart;x <(double) mstart+mlength; x++)
{
for( y=sliding; y <= sliding; y++)
{
int mindex = Math.min(Math.max(x+y , 0), msource.length - 1);
rgb=msource[mindex];
//rgbVal = msource.getRGB(x,y);
r = (float)((rgb & 0xff0000) >>16 ) ;
g = (float)((rgb & 0x00ff00)>> 8);
b = (float)((rgb & 0x0000ff) >>0 ) ;
}
lum=(int) Math.round(0.2126*r+0.7152*g+0.0722*b);
grayval=(lum<<16)|(lum<<8)|lum;
mDestination[x] =(grayval);
}
}
protected static int sThreshold = 10000;
#Override
protected void compute() {
if (mlength < sThreshold) {
computeDirectly(mimage);
return;
}
int split = mlength / 2;
invokeAll(new Multicore1(msource, mstart, split, mDestination,mimage),
new Multicore1(msource, mstart + split, mlength - split,
mDestination,mimage));
}
public static void main(String args[]) throws Exception
{
BufferedImage image=ImageIO.read(new File("xyz.jpg"));
int w=image.getWidth();
int h=image.getHeight();
BufferedImage convertedimg=grayscale(w,h,image);
String dstName = "Gray.jpg";
File dstFile = new File(dstName);
ImageIO.write(convertedimg,"jpg",dstFile);
}
public static BufferedImage grayscale(int w,int h,BufferedImage image)
{
int[] src=image.getRGB(0, 0, w, h, null, 0, w);
int[] dst=new int[src.length];
System.out.println("hello");
System.out.println("Array size is " + src.length);
System.out.println("Threshold is " + sThreshold);
Multicore1 m1=new Multicore1(src,0,src.length,dst,image);
ForkJoinPool pool=new ForkJoinPool();
long starttime=System.currentTimeMillis();
pool.invoke(m1);
long endtime=System.currentTimeMillis();
System.out.println("Time took:" +(endtime-starttime));
BufferedImage dstimage=new BufferedImage(w,h,BufferedImage.TYPE_INT_ARGB);
//Color c=new Color(0,0,0);
dstimage.setRGB(0, 0, w, h, dst, 0, w);
//dstimage.setRGB(0,0,c.getRGB());
return dstimage;
}
}
grayval**=*(0xff000000)*|**(lum<<16)|(lum<<8)|lum;
You need to apply a mask before you move the bits.
class FirstClass{
public static void main(String[] args) {
class XORShift64 {
long x;
public XORShift64(long seed) {
x = seed==0 ? 0xdeadbeef : seed;
}
public long randomLong() {
x ^= (x << 21);
x ^= (x >>> 35);
x ^= (x << 4);
system.out.print();
return x;
}
}
}
}
So I have this code, to generate a random number using Xorshift, and it compiles fine, but when I add line "system.out.print();" it immediately shows an error, though I can't read what the error is.
Thanks for any help, I am just started java programming.
You need to capitalize the class name System, use the method println(), and pass the method an argument which you want printed out.
System.out.println("something to print");
Here is fix for your program. Try to run this and let us know htis what exactly you want.
import java.util.Random;
class FirstClass {
static long x;
static Random randomGenerator = new Random();
public static void main(String[] args) {
for (int i = 0; i <= 100; i++) {
long randomInt = randomGenerator.nextLong();
System.out.println("returned value :" + randomLong(randomInt));
}
}
public static long randomLong(long xx) {
xx ^= (xx << 21);
xx ^= (xx >>> 35);
xx ^= (xx << 4);
System.out.println("Inside Method: " + xx);
return xx;
}
}