/*
* -----------------------------------------------------------------------
* Copyright © 2013-2015 Meno Hochschild, <http://www.menodata.de/>
* -----------------------------------------------------------------------
* This file (HttpClock.java) is part of project Time4J.
*
* Time4J is free software: You can redistribute it and/or modify it
* under the terms of the GNU Lesser General Public License as published
* by the Free Software Foundation, either version 2.1 of the License, or
* (at your option) any later version.
*
* Time4J is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU Lesser General Public License for more details.
*
* You should have received a copy of the GNU Lesser General Public License
* along with Time4J. If not, see <http://www.gnu.org/licenses/>.
* -----------------------------------------------------------------------
*/
package net.time4j.clock;
import net.time4j.Moment;
import net.time4j.base.MathUtils;
import java.io.IOException;
import java.net.HttpURLConnection;
import java.net.URL;
import java.text.ParseException;
import java.util.Date;
import static net.time4j.TemporalType.JAVA_UTIL_DATE;
/**
* <p>Represents a connection to a web server via the HTTP-protocol in
* order to evaluate the DATE-header of the HTTP-response. </p>
*
* @author Meno Hochschild
* @since 2.1
* @doctags.concurrency {threadsafe}
*/
/*[deutsch]
* <p>Repräsentiert eine Verbindung zu einem Web-Server über
* das HTTP-Protokoll, um den DATE-Header der HTTP-Antwort auszuwerten. </p>
*
* @author Meno Hochschild
* @since 2.1
* @doctags.concurrency {threadsafe}
*/
public class HttpClock
extends NetTimeConnector<NetTimeConfiguration> {
//~ Konstruktoren -----------------------------------------------------
/**
* <p>Creates a new clock which connects to given web server. </p>
*
* @param server web server address (example: www.google.com)
*/
/*[deutsch]
* <p>Erzeugt eine neue Uhr, die zum angegebenen Web-Server verbindet. </p>
*
* @param server web server address (example: www.google.com)
*/
public HttpClock(String server) {
super(new SimpleHttpConfiguration(server));
}
//~ Methoden ----------------------------------------------------------
@Override
protected Moment doConnect() throws IOException, ParseException {
final NetTimeConfiguration cfg = this.getNetTimeConfiguration();
URL url = new URL(cfg.getTimeServerAddress());
int timeoutMillis =
MathUtils.safeMultiply(cfg.getConnectionTimeout(), 1000);
HttpURLConnection conn = (HttpURLConnection) url.openConnection();
conn.setConnectTimeout(timeoutMillis);
conn.setReadTimeout(timeoutMillis);
conn.setUseCaches(false);
conn.setRequestMethod("HEAD");
int responseCode = conn.getResponseCode();
if (responseCode >= 200 && responseCode <= 399) {
return JAVA_UTIL_DATE.translate(new Date(conn.getDate()));
}
throw new IOException("HTTP server status: " + responseCode);
}
@Override
protected Class<NetTimeConfiguration> getConfigurationType() {
return NetTimeConfiguration.class;
}
//~ Innere Klassen ----------------------------------------------------
private static class SimpleHttpConfiguration
implements NetTimeConfiguration {
//~ Instanzvariablen ----------------------------------------------
private final String server;
//~ Konstruktoren -------------------------------------------------
SimpleHttpConfiguration(String server) {
super();
if (!server.startsWith("http")) {
this.server = "http://" + server;
} else {
this.server = server;
}
}
//~ Methoden ------------------------------------------------------
@Override
public String getTimeServerAddress() {
return this.server;
}
@Override
public int getTimeServerPort() {
return (this.server.startsWith("https:") ? 443 : 80);
}
@Override
public int getConnectionTimeout() {
return DEFAULT_CONNECTION_TIMEOUT;
}
@Override
public int getClockShiftWindow() {
return 0;
}
@Override
public String toString() {
StringBuilder sb = new StringBuilder();
sb.append("SimpleHttpConfiguration:[server=");
sb.append(this.server);
sb.append(",port=");
sb.append(this.getTimeServerPort());
sb.append(']');
return sb.toString();
}
}
}