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package com.vaadin.tests.minitutorials.v7a1;
import java.awt.image.BufferedImage;
import java.io.IOException;
import java.net.MalformedURLException;
import java.net.URL;
import javax.imageio.ImageIO;
import com.vaadin.server.ExternalResource;
import com.vaadin.server.RequestHandler;
import com.vaadin.server.VaadinSession;
import com.vaadin.server.WrappedRequest;
import com.vaadin.server.WrappedResponse;
import com.vaadin.tests.components.AbstractTestUI;
import com.vaadin.ui.Embedded;
public class DynamicImageUI extends AbstractTestUI {
@Override
public void setup(WrappedRequest request) {
// Add the request handler that handles our dynamic image
getSession().addRequestHandler(new DynamicImageRequestHandler());
// Create a URL that we can handle in DynamicImageRequestHandler
URL imageUrl;
try {
imageUrl = new URL(getSession().getURL(),
DynamicImageRequestHandler.IMAGE_URL + "?text=Hello!");
} catch (MalformedURLException e) {
// This should never happen
throw new RuntimeException(e);
}
// Add an embedded using the created URL
Embedded embedded = new Embedded("A dynamically generated image",
new ExternalResource(imageUrl));
embedded.setType(Embedded.TYPE_IMAGE);
getContent().addComponent(embedded);
}
@Override
protected String getTestDescription() {
return "Mini tutorial for https://vaadin.com/wiki/-/wiki/Main/Generating%20dynamic%20resources%20based%20on%20URI%20or%20parameters";
}
@Override
protected Integer getTicketNumber() {
return null;
}
}
class DynamicImageRequestHandler implements RequestHandler {
public static final String IMAGE_URL = "myimage.png";
@Override
public boolean handleRequest(VaadinSession application,
WrappedRequest request, WrappedResponse response)
throws IOException {
String pathInfo = request.getRequestPathInfo();
if (("/" + IMAGE_URL).equals(pathInfo)) {
// Create an image, draw the "text" parameter to it and output it to
// the browser.
String text = request.getParameter("text");
BufferedImage bi = new BufferedImage(100, 30,
BufferedImage.TYPE_3BYTE_BGR);
bi.getGraphics().drawChars(text.toCharArray(), 0, text.length(),
10, 20);
response.setContentType("image/png");
ImageIO.write(bi, "png", response.getOutputStream());
return true;
}
// If the URL did not match our image URL, let the other request
// handlers handle it
return false;
}
}
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