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/*
* 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 sample;
import java.io.IOException;
import java.io.Writer;
import java.util.Timer;
import java.util.TimerTask;
import javax.servlet.AsyncContext;
import javax.servlet.ServletException;
import javax.servlet.annotation.WebServlet;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import org.apache.log4j.Logger;
import org.oasisopen.sca.annotation.Reference;
@WebServlet(asyncSupported = true, urlPatterns = "/stock")
public class StockServlet extends HttpServlet {
private static final long serialVersionUID = 1L;
private static final long MILLIS_PER_SECOND = 1000L;
// @Reference
private StockService service = new StockServiceImpl();
private AsyncContext asyncContext;
private Timer timer;
private long updatePeriod = 1L; // default 1 sec
private Logger logger = Logger.getLogger(StockServlet.class);
protected void doGet(HttpServletRequest req, HttpServletResponse resp)
throws ServletException {
logger.debug("Received request.");
logger.debug("Starting async context...");
asyncContext = req.startAsync();
logger.debug("Service reference: " + service);
logger.debug("Setting timer...");
timer = new Timer();
logger.debug("Setting update period...");
this.updatePeriod = Long.parseLong(req.getParameter("period"));
timer.scheduleAtFixedRate(new StockTask(), 0, updatePeriod * MILLIS_PER_SECOND);
logger.debug("Exiting doGet method...");
}
public void updateClient() {
try {
logger.debug("Updating response...");
asyncContext.getResponse().setContentType("text/plain");
Writer writer = asyncContext.getResponse().getWriter();
writer.write("Symbol: " + service.getSymbol() + ", Price "
+ service.getValue() + "\n");
writer.flush();
asyncContext.getResponse().flushBuffer();
logger.debug("Flushed response.");
} catch (IOException e) {
logger.debug(e.getMessage(), e);
asyncContext.complete();
}
}
//-----------------------------------------------------------
public class StockTask extends TimerTask {
@Override
public void run() {
updateClient();
}
}
}
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