com.moz.fiji.mapreduce.bulkimport.impl.FijiBulkImporters.java Source code

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Here is the source code for com.moz.fiji.mapreduce.bulkimport.impl.FijiBulkImporters.java

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/**
 * (c) Copyright 2012 WibiData, Inc.
 *
 * See the NOTICE file distributed with this work for additional
 * information regarding copyright ownership.
 *
 * 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.moz.fiji.mapreduce.bulkimport.impl;

import java.io.IOException;

import org.apache.hadoop.conf.Configuration;
import org.apache.hadoop.util.ReflectionUtils;

import com.moz.fiji.annotations.ApiAudience;
import com.moz.fiji.mapreduce.bulkimport.FijiBulkImporter;
import com.moz.fiji.mapreduce.framework.FijiConfKeys;

/** Utility methods for working with <code>FijiBulkImporter</code>. */
@ApiAudience.Private
public final class FijiBulkImporters {
    /** Utility class. */
    private FijiBulkImporters() {
    }

    /**
     * <p>Create an instance of the bulk importer specified by the
     * {@link org.apache.hadoop.conf.Configuration}.</p>
     *
     * The configuration would have stored the bulk importer
     * name only if it was configured by a FijiBulkImportJob, so don't try
     * calling this method with any old Configuration object.
     *
     * @param <K> The map input key for the bulk importer.
     * @param <V> The map input value for the bulk importer.
     * @param conf The job configuration.
     * @return a brand-spankin'-new FijiBulkImporter instance.
     * @throws IOException If the bulk importer cannot be loaded.
     */
    @SuppressWarnings("unchecked")
    public static <K, V> FijiBulkImporter<K, V> create(Configuration conf) throws IOException {
        final Class<? extends FijiBulkImporter> bulkImporterClass = conf
                .getClass(FijiConfKeys.FIJI_BULK_IMPORTER_CLASS, null, FijiBulkImporter.class);
        if (null == bulkImporterClass) {
            throw new IOException("Unable to load bulk importer class");
        }

        return ReflectionUtils.newInstance(bulkImporterClass, conf);
    }

    /**
     * Loads a FijiBulkImporter class by name.
     *
     * @param className Fully qualified name of the class to load.
     * @return the loaded class.
     * @throws ClassNotFoundException if the class is not found.
     * @throws ClassCastException if the class is not a FijiBulkImporter.
     */
    @SuppressWarnings("rawtypes")
    public static Class<? extends FijiBulkImporter> forName(String className) throws ClassNotFoundException {
        return Class.forName(className).asSubclass(FijiBulkImporter.class);
    }
}