/**
* Licensed to the Apache Software Foundation (ASF) under one
* or more contributor license agreements. See the NOTICE file
* distributed with this work for additional information
* regarding copyright ownership. The ASF licenses this file
* to you under the Apache License, Version 2.0 (the
* "License"); you may not use this file except in compliance
* with the License. You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing,
* software distributed under the License is distributed on an
* "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
* KIND, either express or implied. See the License for the
* specific language governing permissions and limitations
* under the License.
*/
package org.waveprotocol.box.server.rpc;
import com.google.common.cache.CacheBuilder;
import com.google.common.cache.CacheLoader;
import com.google.common.cache.LoadingCache;
import org.waveprotocol.box.server.persistence.file.FileAccountStore;
import org.waveprotocol.box.server.persistence.file.FileUtils;
import java.io.IOException;
import java.io.PrintWriter;
import java.util.concurrent.ExecutionException;
import java.util.concurrent.TimeUnit;
import java.util.logging.Level;
import java.util.logging.Logger;
import javax.inject.Singleton;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
/**
* The servlet for fetching available gadgets from a json file on the server.
*/
@SuppressWarnings("serial")
@Singleton
public class GadgetProviderServlet extends HttpServlet {
private static final Logger LOG = Logger.getLogger(FileAccountStore.class.getName());
private final LoadingCache<String, String> jsonCache = CacheBuilder.newBuilder().expireAfterWrite(5,
TimeUnit.MINUTES).build(new CacheLoader<String, String>() {
public String load(String key) {
String jsonString = "";
try {
jsonString = FileUtils.getStringFromFile("jsongadgets.json");
} catch (IOException e) {
LOG.log(Level.WARNING, "Error while loading gadgets json", e);
}
return jsonString;
}
});
@Override
protected void doGet(HttpServletRequest request, HttpServletResponse response) throws IOException {
try {
String jsonString = jsonCache.get("");
if (jsonString.equals("")) {
response.sendError(HttpServletResponse.SC_INTERNAL_SERVER_ERROR,
"Error loading json data from file");
} else {
PrintWriter out = response.getWriter();
out.print(jsonCache.get(""));
out.flush();
}
} catch (ExecutionException ex) {
throw new IOException(ex);
}
}
}