com.metamx.druid.query.Queries.java Source code

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Here is the source code for com.metamx.druid.query.Queries.java

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/*
 * Druid - a distributed column store.
 * Copyright (C) 2012  Metamarkets Group Inc.
 *
 * This program is free software; you can redistribute it and/or
 * modify it under the terms of the GNU General Public License
 * as published by the Free Software Foundation; either version 2
 * of the License, or (at your option) any later version.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program; if not, write to the Free Software
 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301, USA.
 */

package com.metamx.druid.query;

import com.google.common.base.Function;
import com.google.common.base.Preconditions;
import com.google.common.collect.Lists;
import com.google.common.collect.Sets;
import com.metamx.druid.aggregation.AggregatorFactory;
import com.metamx.druid.aggregation.post.PostAggregator;

import javax.annotation.Nullable;
import java.util.List;
import java.util.Set;

/**
 */
public class Queries {
    public static void verifyAggregations(List<AggregatorFactory> aggFactories, List<PostAggregator> postAggs) {
        Preconditions.checkNotNull(aggFactories, "aggregations cannot be null");
        Preconditions.checkArgument(aggFactories.size() > 0, "Must have at least one AggregatorFactory");

        if (postAggs != null && !postAggs.isEmpty()) {
            Set<String> combinedAggNames = Sets
                    .newHashSet(Lists.transform(aggFactories, new Function<AggregatorFactory, String>() {
                        @Override
                        public String apply(@Nullable AggregatorFactory input) {
                            return input.getName();
                        }
                    }));

            for (PostAggregator postAgg : postAggs) {
                Set<String> dependencies = postAgg.getDependentFields();
                Set<String> missing = Sets.difference(dependencies, combinedAggNames);

                Preconditions.checkArgument(missing.isEmpty(), "Missing fields [%s] for postAggregator [%s]",
                        missing, postAgg.getName());
                combinedAggNames.add(postAgg.getName());
            }
        }
    }
}