org.apache.hoya.providers.HoyaProviderFactory.java Source code

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Here is the source code for org.apache.hoya.providers.HoyaProviderFactory.java

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/*
 * Licensed to the Apache Software Foundation (ASF) under one
 * or more contributor license agreements.  See the NOTICE file
 * distributed with this work for additional information
 * regarding copyright ownership.  The ASF licenses this file
 * to you 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 org.apache.hoya.providers;

import org.apache.hadoop.conf.Configuration;
import org.apache.hadoop.conf.Configured;
import org.apache.hoya.HoyaKeys;
import org.apache.hoya.HoyaXmlConfKeys;
import org.apache.hoya.exceptions.BadClusterStateException;
import org.apache.hoya.exceptions.HoyaException;
import org.apache.hoya.providers.agent.AgentKeys;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;

/**
 * Base class for factories
 */
public abstract class HoyaProviderFactory extends Configured {

    public static final String DEFAULT_CLUSTER_TYPE = AgentKeys.PROVIDER_AGENT;

    protected static final Logger log = LoggerFactory.getLogger(HoyaProviderFactory.class);
    public static final String PROVIDER_NOT_FOUND = "Unable to find provider of application type %s";

    public HoyaProviderFactory(Configuration conf) {
        super(conf);
    }

    protected HoyaProviderFactory() {
    }

    public abstract AbstractClientProvider createClientProvider();

    public abstract ProviderService createServerProvider();

    /**
     * Create a provider for a specific application
     * @param application app
     * @return app instance
     * @throws HoyaException on any instantiation problem
     */
    public static HoyaProviderFactory createHoyaProviderFactory(String application) throws HoyaException {
        Configuration conf = loadHoyaConfiguration();
        if (application == null) {
            application = DEFAULT_CLUSTER_TYPE;
        }
        String providerKey = String.format(HoyaXmlConfKeys.KEY_PROVIDER, application);
        if (application.contains(".")) {
            log.debug("Treating {} as a classname", application);
            String name = "classname.key";
            conf.set(name, application);
            providerKey = name;
        }

        Class<? extends HoyaProviderFactory> providerClass;
        try {
            providerClass = conf.getClass(providerKey, null, HoyaProviderFactory.class);
        } catch (RuntimeException e) {
            throw new BadClusterStateException(e, "Failed to load provider %s: %s", application, e);
        }
        if (providerClass == null) {
            throw new BadClusterStateException(PROVIDER_NOT_FOUND, application);
        }

        Exception ex;
        try {
            HoyaProviderFactory providerFactory = providerClass.newInstance();
            providerFactory.setConf(conf);
            return providerFactory;
        } catch (InstantiationException e) {
            ex = e;
        } catch (IllegalAccessException e) {
            ex = e;
        } catch (Exception e) {
            ex = e;
        }
        //by here the operation failed and ex is set to the value 
        throw new BadClusterStateException(ex, "Failed to create an instance of %s : %s", providerClass, ex);
    }

    public static Configuration loadHoyaConfiguration() {
        Configuration conf = new Configuration();
        conf.addResource(HoyaKeys.HOYA_XML);
        return conf;
    }
}