org.apache.crunch.io.FormatBundle.java Source code

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Here is the source code for org.apache.crunch.io.FormatBundle.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.crunch.io;

import java.io.ByteArrayInputStream;
import java.io.ByteArrayOutputStream;
import java.io.DataInput;
import java.io.DataInputStream;
import java.io.DataOutput;
import java.io.DataOutputStream;
import java.io.IOException;
import java.io.ObjectInputStream;
import java.io.ObjectOutputStream;
import java.io.Serializable;
import java.util.Map;

import org.apache.commons.codec.binary.Base64;
import org.apache.commons.lang.builder.HashCodeBuilder;
import org.apache.hadoop.conf.Configurable;
import org.apache.hadoop.conf.Configuration;
import org.apache.hadoop.io.Text;
import org.apache.hadoop.io.Writable;
import org.apache.hadoop.mapreduce.InputFormat;
import org.apache.hadoop.mapreduce.OutputFormat;

import com.google.common.collect.Maps;

/**
 * A combination of an {@link InputFormat} or {@link OutputFormat} and any extra 
 * configuration information that format class needs to run.
 * 
 * <p>The {@code FormatBundle} allow us to let different formats act as
 * if they are the only format that exists in a particular MapReduce job, even
 * when we have multiple types of inputs and outputs within a single job.
 */
public class FormatBundle<K> implements Serializable, Writable, Configurable {

    private Class<K> formatClass;
    private Map<String, String> extraConf;
    private Configuration conf;

    public static <T> FormatBundle<T> fromSerialized(String serialized, Configuration conf) {
        ByteArrayInputStream bais = new ByteArrayInputStream(Base64.decodeBase64(serialized));
        try {
            FormatBundle<T> bundle = new FormatBundle<T>();
            bundle.setConf(conf);
            bundle.readFields(new DataInputStream(bais));
            return bundle;
        } catch (IOException e) {
            throw new RuntimeException(e);
        }
    }

    public static <T extends InputFormat<?, ?>> FormatBundle<T> forInput(Class<T> inputFormatClass) {
        return new FormatBundle<T>(inputFormatClass);
    }

    public static <T extends OutputFormat<?, ?>> FormatBundle<T> forOutput(Class<T> outputFormatClass) {
        return new FormatBundle<T>(outputFormatClass);
    }

    public FormatBundle() {
        // For Writable support
    }

    private FormatBundle(Class<K> formatClass) {
        this.formatClass = formatClass;
        this.extraConf = Maps.newHashMap();
    }

    public FormatBundle<K> set(String key, String value) {
        this.extraConf.put(key, value);
        return this;
    }

    public Class<K> getFormatClass() {
        return formatClass;
    }

    public Configuration configure(Configuration conf) {
        for (Map.Entry<String, String> e : extraConf.entrySet()) {
            conf.set(e.getKey(), e.getValue());
        }
        return conf;
    }

    public String serialize() {
        ByteArrayOutputStream baos = new ByteArrayOutputStream();
        try {
            DataOutputStream dos = new DataOutputStream(baos);
            write(dos);
            return Base64.encodeBase64String(baos.toByteArray());
        } catch (IOException e) {
            throw new RuntimeException(e);
        }
    }

    public String getName() {
        return formatClass.getSimpleName();
    }

    @Override
    public int hashCode() {
        return new HashCodeBuilder().append(formatClass).append(extraConf).toHashCode();
    }

    @Override
    public boolean equals(Object other) {
        if (other == null || !(other instanceof FormatBundle)) {
            return false;
        }
        FormatBundle<K> oib = (FormatBundle<K>) other;
        return formatClass.equals(oib.formatClass) && extraConf.equals(oib.extraConf);
    }

    @Override
    public void readFields(DataInput in) throws IOException {
        this.formatClass = readClass(in);
        int ecSize = in.readInt();
        this.extraConf = Maps.newHashMap();
        for (int i = 0; i < ecSize; i++) {
            String key = Text.readString(in);
            String value = Text.readString(in);
            extraConf.put(key, value);
        }
    }

    @Override
    public void write(DataOutput out) throws IOException {
        Text.writeString(out, formatClass.getName());
        out.writeInt(extraConf.size());
        for (Map.Entry<String, String> e : extraConf.entrySet()) {
            Text.writeString(out, e.getKey());
            Text.writeString(out, e.getValue());
        }
    }

    private Class readClass(DataInput in) throws IOException {
        String className = Text.readString(in);
        try {
            return conf.getClassByName(className);
        } catch (ClassNotFoundException e) {
            throw new RuntimeException("readObject can't find class", e);
        }
    }

    @Override
    public Configuration getConf() {
        return conf;
    }

    @Override
    public void setConf(Configuration conf) {
        this.conf = conf;
    }
}