おれおれ Slim3 BaseController

BaseController.java

import com.google.appengine.repackaged.org.apache.commons.codec.binary.Base64;
import com.google.appengine.repackaged.org.apache.commons.codec.binary.StringUtils;
import com.google.gson.Gson;
import org.slim3.controller.Controller;
import org.slim3.controller.Navigation;
import java.io.IOException;

abstract public class BaseController extends Controller {
    // Working with JSON

    static final String APPLICATION_JSON = "application/json";

    protected Navigation json(Object object) throws IOException {
        writeAsJson(object);

        return null;
    }

    protected void writeAsJson(Object object) throws IOException {
        response.setContentType(APPLICATION_JSON);
        response.getWriter().write(getGson().toJson(object));
    }

    // Should override if you want to override GSON
    protected Gson getGson() {
        return new Gson();
    }

    // Header Manipulation

    protected void setCacheMaxAgeHeader(long maxAge) {
        response.setHeader("Cache-Control", "max-age=" + maxAge + ", must-revalidate");
    }

    protected void setVaryUserAgentHeader(boolean varyUserAgent) {
        if (varyUserAgent) {
            response.setHeader("Vary", "User-Agent");
        }
    }

    protected void setContentTypeHeader(String contentType) {
        response.setContentType(contentType);
    }

    // User Agent Detection

    protected boolean isMobile() {
        // @see http://stackoverflow.com/questions/11381673/detecting-a-mobile-browser
        final String userAgent = request.getHeader("User-Agent");
        if (userAgent.contains("Android")) { return true; }
        if (userAgent.contains("webOS")) { return true; }
        if (userAgent.contains("iPhone")) { return true; }
        if (userAgent.contains("iPad")) { return true; }
        if (userAgent.contains("iPod")) { return true; }
        if (userAgent.contains("BlackBerry")) { return true; }
        if (userAgent.contains("Windows Phone")) { return true; }

        return false;
    }

    // Content Negotiation

    protected String[] getPreferredLanguages() {
        final String acceptLanguage = request.getHeader("Accept-Language");
        final String[] languages = acceptLanguage.split(",");
        final String[] preferredLanguages = new String[languages.length];
        for (int i = 0; i < languages.length; i++) {
            preferredLanguages[i] = languages[i].split(";")[0];
        }
        return preferredLanguages;
    }

    // Basic Authentication

    static final String HEADER_AUTHORIZATION = "Authorization";

    protected String getBasicAuthUsername() {
        final String auth = request.getHeader(HEADER_AUTHORIZATION).substring(6); // - "Basic "
        return decode(auth).split(":")[0];
    }

    protected String getBasicAuthPassword() {
        final String auth = request.getHeader(HEADER_AUTHORIZATION).substring(6); // - "Basic "
        return decode(auth).split(":")[0];
    }

    private static String decode(String s) {
        return StringUtils.newStringUtf8(Base64.decodeBase64(s));
    }

    // Template Attributes

    protected void setAttribute(String key, Object object) {
        request.setAttribute(key, object);
    }

}

SampleController.java

public class SampleController extends BaseController {
    @Override
    protected Navigation run() throws Exception {
        final Book book = new Book("Alice's Adventures in Wonderland");
        
        return json(book);
    }
}