com.zyxist.dirtyplayground.core.svc.ServiceRunnerImpl.java Source code

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Here is the source code for com.zyxist.dirtyplayground.core.svc.ServiceRunnerImpl.java

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/*
 * Copyright 2016 Tomasz Jdrzejewski <http://www.zyxist.com/>.
 *
 * Licensed 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 com.zyxist.dirtyplayground.core.svc;

import com.google.common.collect.Lists;
import com.google.inject.assistedinject.Assisted;
import java.util.HashSet;
import java.util.List;
import java.util.Objects;
import java.util.Set;
import javax.inject.Inject;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;

public class ServiceRunnerImpl implements ServiceRunner {
    private static final Logger log = LoggerFactory.getLogger(ServiceRunnerImpl.class);
    private final ServiceComposer serviceComposer;
    private final Set<StartableService> services;

    @Inject
    public ServiceRunnerImpl(ServiceComposer composer, @Assisted Set<StartableService> services) {
        this.serviceComposer = Objects.requireNonNull(composer);
        this.services = Objects.requireNonNull(services);
    }

    @Override
    public void execute(Runnable serviceAwareCode) {
        List<StartableService> orderedServices = serviceComposer.compose(services);
        List<StartableService> stopOrderedServices = Lists.reverse(orderedServices);
        Set<StartableService> correctlyStarted = new HashSet<>();

        try {
            if (startServices(orderedServices, correctlyStarted)) {
                serviceAwareCode.run();
            }
        } finally {
            stopServices(stopOrderedServices, correctlyStarted);
        }
    }

    private boolean startServices(List<StartableService> services, Set<StartableService> correctlyStarted) {
        for (StartableService svc : services) {
            String name = svc.getClass().getSimpleName();
            try {
                log.info("Starting service: " + name);
                svc.start();
                log.info("Started service: " + name);
                correctlyStarted.add(svc);
            } catch (Exception exception) {
                log.error("Service " + name + " failed during startup.", exception);
                return false;
            }
        }
        return true;
    }

    private void stopServices(List<StartableService> services, Set<StartableService> correctlyStarted) {
        for (StartableService svc : services) {
            if (correctlyStarted.contains(svc)) {
                String name = svc.getClass().getSimpleName();
                try {
                    log.info("Stopping service: " + name);
                    svc.stop();
                    log.info("Stopped service: " + name);
                } catch (Exception exception) {
                    log.error("Service " + name + " failed during shutdown.", exception);
                }
            }
        }
    }
}