com.comcast.viper.flume2storm.location.StaticLocationService.java Source code

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Here is the source code for com.comcast.viper.flume2storm.location.StaticLocationService.java

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/**
 * Copyright 2014 Comcast Cable Communications Management, LLC
 *
 * 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.comcast.viper.flume2storm.location;

import org.apache.commons.configuration.Configuration;
import org.apache.commons.lang.StringUtils;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;

import com.comcast.viper.flume2storm.F2SConfigurationException;
import com.google.common.collect.ImmutableList;
import com.google.common.collect.ImmutableList.Builder;

/**
 * An implementation of LocationService that gets the list of ServiceProviders
 * from a static configuration. No subsequent ServiceProvider
 * registration/unregistration is permitted.
 * 
 * @param <SP>
 *          The actual class for the ServiceProvider
 */
public class StaticLocationService<SP extends ServiceProvider<?>> extends AbstractLocationService<SP> {
    private static final Logger LOG = LoggerFactory.getLogger(StaticLocationService.class);
    private final ServiceProviderSerialization<SP> serialization;

    /**
     * @param configuration
     *          The configuration that contains the {@link ServiceProvider}
     * @param serialization
     *          The {@link ServiceProviderSerialization} to use
     * @throws F2SConfigurationException
     *           If the configuration is invalid
     */
    public StaticLocationService(Configuration configuration, final ServiceProviderSerialization<SP> serialization)
            throws F2SConfigurationException {
        this.serialization = serialization;
        StaticLocationServiceConfiguration staticLocationServiceConfig = StaticLocationServiceConfiguration
                .from(configuration);

        String configLoaderClassName = staticLocationServiceConfig.getConfigurationLoaderClassName();
        ServiceProviderConfigurationLoader<SP> spLoader = null;
        try {
            @SuppressWarnings("unchecked")
            Class<? extends ServiceProviderConfigurationLoader<SP>> loaderFactoryClass = (Class<? extends ServiceProviderConfigurationLoader<SP>>) Class
                    .forName(configLoaderClassName);
            spLoader = loaderFactoryClass.newInstance();
        } catch (Exception e) {
            throw new F2SConfigurationException("Failed to load ServiceProviderConfigurationLoader class", e);
        }
        assert spLoader != null;

        String spString = configuration.getString(StaticLocationServiceConfiguration.SERVICE_PROVIDER_LIST);
        LOG.trace("Service providers to load: {}", spString);
        if (spString == null)
            return;
        Configuration spConfig = configuration.subset(staticLocationServiceConfig.getServiceProviderBase());
        Builder<SP> spBuilders = ImmutableList.builder();
        for (String spName : StringUtils.split(spString,
                StaticLocationServiceConfiguration.SERVICE_PROVIDER_LIST_SEPARATOR)) {
            LOG.trace("Loading service provider: {}", spName);
            Configuration providerConfig = spConfig.subset(spName);
            SP serviceProvider = spLoader.load(providerConfig);
            if (serviceProvider != null) {
                LOG.debug("Loaded service provider {}: {}", spName, serviceProvider);
                spBuilders.add(serviceProvider);
            } else {
                LOG.error("Failed to load service provider identified with {}", spName);
            }
        }
        serviceProviderManager.set(spBuilders.build());
    }

    /**
     * @see com.comcast.viper.flume2storm.location.LocationService#start()
     */
    @Override
    public boolean start() {
        // Nothing to do
        return true;
    }

    /**
     * @see com.comcast.viper.flume2storm.location.LocationService#stop()
     */
    @Override
    public boolean stop() {
        // Nothing to do
        return true;
    }

    /**
     * @see com.comcast.viper.flume2storm.location.LocationService#register(com.comcast.viper.flume2storm.location.ServiceProvider)
     */
    public void register(SP serviceProvider) {
        // Nothing to do
    }

    /**
     * @see com.comcast.viper.flume2storm.location.LocationService#unregister(com.comcast.viper.flume2storm.location.ServiceProvider)
     */
    public void unregister(SP serviceProvider) {
        // Nothing to do
    }

    /**
     * @see com.comcast.viper.flume2storm.location.LocationService#getSerialization()
     */
    public ServiceProviderSerialization<SP> getSerialization() {
        return serialization;
    }
}