org.openbase.bco.ontology.lib.commun.monitor.ServerConnection.java Source code

Introduction

Here is the source code for org.openbase.bco.ontology.lib.commun.monitor.ServerConnection.java

Source

/**
 * ==================================================================
 *
 * This file is part of org.openbase.bco.ontology.lib.
 *
 * org.openbase.bco.ontology.lib is free software: you can redistribute it and modify
 * it under the terms of the GNU General Public License (Version 3)
 * as published by the Free Software Foundation.
 *
 * org.openbase.bco.ontology.lib 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 General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with org.openbase.bco.ontology.lib. If not, see <http://www.gnu.org/licenses/>.
 * ==================================================================
 */
package org.openbase.bco.ontology.lib.commun.monitor;

import org.apache.http.HttpResponse;
import org.apache.http.client.HttpClient;
import org.apache.http.client.methods.HttpGet;
import org.apache.http.impl.client.HttpClients;
import org.openbase.bco.ontology.lib.commun.web.SparqlHttp;
import org.openbase.bco.ontology.lib.system.config.OntConfig;
import org.openbase.jul.exception.CouldNotPerformException;
import org.openbase.jul.exception.NotAvailableException;
import org.openbase.jul.exception.printer.ExceptionPrinter;
import org.openbase.jul.exception.printer.LogLevel;
import org.openbase.jul.pattern.ObservableImpl;
import org.openbase.jul.pattern.Remote.ConnectionState;
import org.openbase.jul.schedule.GlobalScheduledExecutorService;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;

import java.io.IOException;
import java.util.concurrent.TimeUnit;

/**
 * @author agatting on 27.02.17.
 */
public final class ServerConnection {

    /**
     * Informs about the server connection state.
     */
    public static final ObservableImpl<ConnectionState> SERVER_STATE_OBSERVABLE = new ObservableImpl<>(false);

    private static final Logger LOGGER = LoggerFactory.getLogger(ServerConnection.class);

    private ServerConnection() throws NotAvailableException {
    }

    /**
     * Method creates a monitoring thread to observe the connection state between ontology manager and ontology server. In case the server can't be
     * reached, an observable informs.
     *
     * @throws NotAvailableException is thrown in case there is no thread available.
     */
    public static void newServerConnectionObservable() throws NotAvailableException {
        GlobalScheduledExecutorService.scheduleWithFixedDelay(() -> {
            try {
                try {
                    final HttpClient httpclient = HttpClients.createDefault();
                    final HttpGet httpGet = new HttpGet(OntConfig.getOntologyPingUrl());
                    final HttpResponse httpResponse = httpclient.execute(httpGet);

                    SparqlHttp.checkHttpRequest(httpResponse, null);
                    SERVER_STATE_OBSERVABLE.notifyObservers(ConnectionState.CONNECTED);
                } catch (IOException | CouldNotPerformException ex) {
                    SERVER_STATE_OBSERVABLE.notifyObservers(ConnectionState.DISCONNECTED);
                }
            } catch (CouldNotPerformException ex) {
                ExceptionPrinter.printHistory(ex, LOGGER, LogLevel.ERROR);
            }
        }, 0, 1, TimeUnit.SECONDS);
    }
}