com.cloudera.exhibit.hive.WithinUDF.java Source code

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Here is the source code for com.cloudera.exhibit.hive.WithinUDF.java

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/*
 * Copyright (c) 2015, Cloudera, Inc. All Rights Reserved.
 *
 * Cloudera, Inc. 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
 *
 * This software 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.cloudera.exhibit.hive;

import com.cloudera.exhibit.core.Calculator;
import com.cloudera.exhibit.core.Exhibit;
import com.cloudera.exhibit.core.Frame;
import com.cloudera.exhibit.core.Obs;
import com.cloudera.exhibit.core.ObsDescriptor;
import com.cloudera.exhibit.core.simple.SimpleExhibit;
import com.cloudera.exhibit.sql.SQLCalculator;
import com.google.common.base.Joiner;
import com.google.common.collect.Iterables;
import com.google.common.collect.Lists;
import com.google.common.collect.Maps;
import org.apache.hadoop.hive.ql.exec.UDFArgumentException;
import org.apache.hadoop.hive.ql.exec.UDFArgumentLengthException;
import org.apache.hadoop.hive.ql.metadata.HiveException;
import org.apache.hadoop.hive.ql.udf.generic.GenericUDF;
import org.apache.hadoop.hive.serde2.objectinspector.ObjectInspector;

import java.util.List;
import java.util.Map;

public class WithinUDF extends GenericUDF {

    private Calculator calculator;
    private transient Exhibit exhibit;

    public WithinUDF() {
    }

    @Override
    public ObjectInspector initialize(ObjectInspector[] args) throws UDFArgumentException {
        if (args.length <= 1) {
            throw new UDFArgumentLengthException("The 'within' function takes at least two arguments");
        }

        ObjectInspector first = args[0];
        String[] queries = HiveUtils.getQueries(first);

        Map<String, Frame> frames = Maps.newHashMap();
        for (int i = 1; i < args.length; i++) {
            HiveFrame frame = HiveUtils.getHiveFrame(args[i]);
            frames.put("T" + i, frame);
        }
        this.exhibit = new SimpleExhibit(Obs.EMPTY, frames);
        this.calculator = new SQLCalculator(queries);
        ObsDescriptor od = calculator.initialize(exhibit.descriptor());
        return HiveUtils.fromDescriptor(od, false);
    }

    @Override
    public Object evaluate(DeferredObject[] args) throws HiveException {
        for (int i = 1; i < args.length; i++) {
            ((HiveFrame) exhibit.frames().get("T" + i)).updateValues(args[i].get());
        }
        return getResult(Iterables.getOnlyElement(calculator.apply(exhibit)));
    }

    private Object getResult(Obs obs) {
        if (obs.descriptor().size() == 1) {
            return HiveUtils.asHiveType(obs.get(0));
        } else {
            List<Object> values = Lists.newArrayListWithExpectedSize(obs.descriptor().size());
            for (int i = 0; i < obs.descriptor().size(); i++) {
                values.add(HiveUtils.asHiveType(obs.get(i)));
            }
            return values;
        }
    }

    @Override
    public String getDisplayString(String[] args) {
        assert (args.length > 1);
        return "within(" + Joiner.on(',').join(args) + ")";
    }
}