org.apache.crunch.GroupingOptions.java Source code

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Here is the source code for org.apache.crunch.GroupingOptions.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;

import java.util.Collection;
import java.util.Collections;
import java.util.Map;
import java.util.Set;

import org.apache.hadoop.io.RawComparator;
import org.apache.hadoop.mapreduce.Job;
import org.apache.hadoop.mapreduce.Partitioner;

import com.google.common.collect.Maps;
import com.google.common.collect.Sets;

/**
 * Options that can be passed to a {@code groupByKey} operation in order to
 * exercise finer control over how the partitioning, grouping, and sorting of
 * keys is performed.
 * 
 */
public class GroupingOptions {

    private final Class<? extends Partitioner> partitionerClass;
    private final Class<? extends RawComparator> groupingComparatorClass;
    private final Class<? extends RawComparator> sortComparatorClass;
    private final int numReducers;
    private final Map<String, String> extraConf;
    private final Set<SourceTarget<?>> sourceTargets;

    private GroupingOptions(Class<? extends Partitioner> partitionerClass,
            Class<? extends RawComparator> groupingComparatorClass,
            Class<? extends RawComparator> sortComparatorClass, int numReducers, Map<String, String> extraConf,
            Set<SourceTarget<?>> sourceTargets) {
        this.partitionerClass = partitionerClass;
        this.groupingComparatorClass = groupingComparatorClass;
        this.sortComparatorClass = sortComparatorClass;
        this.numReducers = numReducers;
        this.extraConf = extraConf;
        this.sourceTargets = sourceTargets;
    }

    public int getNumReducers() {
        return numReducers;
    }

    public Class<? extends RawComparator> getSortComparatorClass() {
        return sortComparatorClass;
    }

    public Class<? extends RawComparator> getGroupingComparatorClass() {
        return groupingComparatorClass;
    }

    public Class<? extends Partitioner> getPartitionerClass() {
        return partitionerClass;
    }

    public Set<SourceTarget<?>> getSourceTargets() {
        return sourceTargets;
    }

    public void configure(Job job) {
        if (partitionerClass != null) {
            job.setPartitionerClass(partitionerClass);
        }
        if (groupingComparatorClass != null) {
            job.setGroupingComparatorClass(groupingComparatorClass);
        }
        if (sortComparatorClass != null) {
            job.setSortComparatorClass(sortComparatorClass);
        }
        if (numReducers > 0) {
            job.setNumReduceTasks(numReducers);
        }
        for (Map.Entry<String, String> e : extraConf.entrySet()) {
            job.getConfiguration().set(e.getKey(), e.getValue());
        }
    }

    public boolean isCompatibleWith(GroupingOptions other) {
        if (partitionerClass != other.partitionerClass) {
            return false;
        }
        if (groupingComparatorClass != other.groupingComparatorClass) {
            return false;
        }
        if (sortComparatorClass != other.sortComparatorClass) {
            return false;
        }
        if (!extraConf.equals(other.extraConf)) {
            return false;
        }
        return true;
    }

    public static Builder builder() {
        return new Builder();
    }

    /**
     * Builder class for creating {@code GroupingOptions} instances.
     * 
     */
    public static class Builder {
        private Class<? extends Partitioner> partitionerClass;
        private Class<? extends RawComparator> groupingComparatorClass;
        private Class<? extends RawComparator> sortComparatorClass;
        private int numReducers;
        private Map<String, String> extraConf = Maps.newHashMap();
        private Set<SourceTarget<?>> sourceTargets = Sets.newHashSet();

        public Builder() {
        }

        public Builder partitionerClass(Class<? extends Partitioner> partitionerClass) {
            this.partitionerClass = partitionerClass;
            return this;
        }

        public Builder groupingComparatorClass(Class<? extends RawComparator> groupingComparatorClass) {
            this.groupingComparatorClass = groupingComparatorClass;
            return this;
        }

        public Builder sortComparatorClass(Class<? extends RawComparator> sortComparatorClass) {
            this.sortComparatorClass = sortComparatorClass;
            return this;
        }

        public Builder numReducers(int numReducers) {
            if (numReducers <= 0) {
                throw new IllegalArgumentException("Invalid number of reducers: " + numReducers);
            }
            this.numReducers = numReducers;
            return this;
        }

        public Builder conf(String confKey, String confValue) {
            this.extraConf.put(confKey, confValue);
            return this;
        }

        @Deprecated
        public Builder sourceTarget(SourceTarget<?> st) {
            this.sourceTargets.add(st);
            return this;
        }

        public Builder sourceTargets(SourceTarget<?>... st) {
            Collections.addAll(this.sourceTargets, st);
            return this;
        }

        public Builder sourceTargets(Collection<SourceTarget<?>> st) {
            this.sourceTargets.addAll(st);
            return this;
        }

        public GroupingOptions build() {
            return new GroupingOptions(partitionerClass, groupingComparatorClass, sortComparatorClass, numReducers,
                    extraConf, sourceTargets);
        }
    }
}