Proxy OSGI Service zu HTTP Server für das Client Plugin

Activator.java

package com.example.miniscout.client;

import java.util.Dictionary;
import java.util.Hashtable;

import org.eclipse.ui.plugin.AbstractUIPlugin;
import org.osgi.framework.BundleContext;
import org.osgi.framework.Constants;

import com.example.miniscout.client.services.LocalDatabaseService;
import com.example.miniscout.client.services.ProxyDatabaseService;
import com.example.miniscout.shared.IDatabaseService;

public class Activator extends AbstractUIPlugin {

  private static Activator plugin;

  public void start(BundleContext context) throws Exception {
    super.start(context);
    plugin = this;
    context.registerService(IDatabaseService.class, new LocalDatabaseService(),
        null);

    // Register a proxy service with a higher priority:
    Dictionary<String, Object> props = new Hashtable<>();
    props.put(Constants.SERVICE_RANKING, 1000);
    context.registerService(IDatabaseService.class, new ProxyDatabaseService(),
        props);

  }

  public void stop(BundleContext context) throws Exception {
    plugin = null;
    super.stop(context);
  }

  public static Activator getDefault() {
    return plugin;
  }
}

ProxyDatabaseService.java

package com.example.miniscout.client.services;

import java.io.InputStream;
import java.io.InputStreamReader;
import java.net.URI;

import com.example.miniscout.shared.Form;
import com.example.miniscout.shared.IDatabaseService;
import com.google.common.base.Throwables;
import com.google.common.io.CharStreams;
import com.google.gson.Gson;

public class ProxyDatabaseService implements IDatabaseService {

  @Override
  public Form load(URI source) {
    try {
      if (!source.getScheme().startsWith("http")) {
        // we trick a bit. use hardcoded urls for demo purpose:
        // change for to the appropriate URL
        source = new URI("http://localhost:8080/form");
      }
      InputStream stream = source.toURL().openStream();
      String form = CharStreams.toString(new InputStreamReader(stream));
      return new Gson().fromJson(form, Form.class);
    } catch (Exception e) {
      throw Throwables.propagate(e);
    }
  }

  @Override
  public void save(Form form, URI target) {
    // we don't save implement save.
  }
}