org.kiji.mapreduce.pivot.impl.KijiPivoters.java Source code

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Here is the source code for org.kiji.mapreduce.pivot.impl.KijiPivoters.java

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/**
 * (c) Copyright 2013 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 org.kiji.mapreduce.pivot.impl;

import java.io.IOException;

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

import org.kiji.annotations.ApiAudience;
import org.kiji.mapreduce.framework.KijiConfKeys;
import org.kiji.mapreduce.pivot.KijiPivoter;

/** Utility methods for working with {@link KijiPivoter}. */
@ApiAudience.Private
public final class KijiPivoters {
    /** Utility class. */
    private KijiPivoters() {
    }

    /**
     * Create an instance of {@link KijiPivoter} as specified from a given
     * {@link org.apache.hadoop.conf.Configuration}.
     *
     * @param conf The job configuration.
     * @return a new {@link KijiPivoter} instance.
     * @throws IOException if the class cannot be loaded.
     */
    public static KijiPivoter create(Configuration conf) throws IOException {
        final Class<? extends KijiPivoter> tableMapperClass = conf.getClass(KijiConfKeys.KIJI_PIVOTER_CLASS, null,
                KijiPivoter.class);
        if (null == tableMapperClass) {
            throw new IOException("Unable to load pivoter class");
        }
        return ReflectionUtils.newInstance(tableMapperClass, conf);
    }

    /**
     * Loads a {@link KijiPivoter} 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 {@link KijiPivoter}.
     */
    public static Class<? extends KijiPivoter> forName(String className) throws ClassNotFoundException {
        return Class.forName(className).asSubclass(KijiPivoter.class);
    }
}