GravatarUtil.java

package org.bubblecloud.ilves.util;

import com.vaadin.server.ExternalResource;
import com.vaadin.server.Sizeable;
import com.vaadin.ui.Link;
import org.apache.commons.codec.digest.DigestUtils;
import org.bubblecloud.ilves.exception.SiteException;
import org.bubblecloud.ilves.site.Site;

import java.net.MalformedURLException;
import java.net.URL;

/**
 * Utility class for accessing gravatar images.
 */
public class GravatarUtil {
    /** The gravatar URL. */
    private final static String GRAVATAR_URL = "http://www.gravatar.com/avatar/";

    public static Link getGravatarImageLink(final String email) {
        final URL gravatarUrl = GravatarUtil.getGravatarUrl(email, 32);
        final Link link = new Link(null, new ExternalResource("http://www.gravatar.com/"));
        link.setStyleName("gravatar");
        link.setIcon(new ExternalResource(gravatarUrl));
        link.setWidth(32, Sizeable.Unit.PIXELS);
        link.setHeight(32, Sizeable.Unit.PIXELS);
        return link;
    }

    /**
     * Get the gravatar URL based on email address.
     * @param email the email address
     * @param size the size in pixels
     * @return the gravatar URL
     */
    public static URL getGravatarUrl(final String email, int size) {
        if (Site.getCurrent().getSiteContext().getObject("gravatar-url-" + email) == null) {
            Site.getCurrent().getSiteContext().putObject("gravatar-url-" + email, constructGravatarUrl(email, size));
        }
        try {
            return new URL((String) Site.getCurrent().getSiteContext().getObject("gravatar-url-" + email));
        } catch (MalformedURLException e) {
            throw new SiteException("Error in gravatar URL format: "
                    + Site.getCurrent().getSiteContext().getObject("gravatar-url"));
        }
    }

    /**
     * Constructs gravatar URL from email address.
     * @param email the email address
     * @param size the size in pixels
     * @return the gravatar URL.
     */
    private static String constructGravatarUrl(final String email, final int size) {
        return GRAVATAR_URL + DigestUtils.md5Hex(email.toLowerCase().trim()) + ".jpg?s=" + size + "&d=mm&r=g";
    }

}