org.asoem.greyfish.cli.ExperimentMonitorService.java Source code

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Here is the source code for org.asoem.greyfish.cli.ExperimentMonitorService.java

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/*
 * Copyright (C) 2015 The greyfish authors
 *
 * This program is free software: you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation, either version 3 of the License, or
 * (at your option) any later version.
 *
 * This program 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 this program.  If not, see <http://www.gnu.org/licenses/>.
 */

package org.asoem.greyfish.cli;

import com.google.common.base.Strings;
import com.google.common.collect.Lists;
import com.google.common.eventbus.EventBus;
import com.google.common.eventbus.Subscribe;
import com.google.common.util.concurrent.AbstractScheduledService;
import org.asoem.greyfish.core.environment.Environment;
import org.asoem.greyfish.core.model.SimulationCreatedEvent;

import java.io.OutputStream;
import java.io.OutputStreamWriter;
import java.io.PrintWriter;
import java.io.UnsupportedEncodingException;
import java.util.List;
import java.util.concurrent.TimeUnit;

import static com.google.common.base.Preconditions.checkNotNull;

/**
 * This service monitors a given {@link org.asoem.greyfish.core.environment.DiscreteTimeEnvironment} and prints messages
 * to a given {@link OutputStream} every second.
 */
final class ExperimentMonitorService extends AbstractScheduledService {

    private List<ObservedSimulation> activeSimulations = Lists.newCopyOnWriteArrayList();

    private final PrintWriter writer;
    private String lastMessage = "";

    public ExperimentMonitorService(final OutputStream outputStream, final EventBus eventBus) {
        checkNotNull(eventBus);
        eventBus.register(this);

        checkNotNull(outputStream);

        final OutputStreamWriter outputStreamWriter;
        try {
            outputStreamWriter = new OutputStreamWriter(outputStream, "UTF-8");
        } catch (UnsupportedEncodingException e) {
            throw new AssertionError(e);
        }
        writer = new PrintWriter(outputStreamWriter, true);
    }

    @Subscribe
    public void simulationCreatedEventHandler(final SimulationCreatedEvent event) {
        checkNotNull(event);
        activeSimulations.add(new ObservedSimulation(event));
    }

    @Override
    protected void runOneIteration() throws Exception {
        StringBuilder stringBuilder = new StringBuilder();
        for (ObservedSimulation event : activeSimulations) {
            final String status = event.simulation().getStatusInfo();
            stringBuilder.append(event.simulation().getName()).append("\t")
                    .append(duration(System.currentTimeMillis() - event.timestamp())).append("\t").append(status)
                    .append(System.getProperty("line.separator"));
        }
        replaceStatusLine(stringBuilder.toString(), false);
    }

    private static String duration(final long millis) {
        return String.format("%02d:%02d.%03ds", millis / 60000, (millis % 60000) / 1000, (millis % 1000));
    }

    @Override
    protected void shutDown() throws Exception {
        replaceStatusLine("", true);
    }

    private void replaceStatusLine(final String message, final boolean newLine) {
        writer.print("\r" + Strings.repeat(" ", lastMessage.length()));
        writer.print("\r" + message);
        if (newLine) {
            writer.println();
        }
        writer.flush();
        lastMessage = message;
    }

    @Override
    protected Scheduler scheduler() {
        return Scheduler.newFixedRateSchedule(0, 1, TimeUnit.SECONDS);
    }

    private static class ObservedSimulation {
        private final SimulationCreatedEvent event;
        private final long timestamp;

        public ObservedSimulation(final SimulationCreatedEvent event) {
            this.event = event;
            timestamp = System.currentTimeMillis();
        }

        public Environment<?> simulation() {
            return event.simulation();
        }

        public long timestamp() {
            return timestamp;
        }
    }
}