org.apache.hadoop.hive.ql.udf.generic.GenericUDFFromUtcTimestamp.java Source code

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Here is the source code for org.apache.hadoop.hive.ql.udf.generic.GenericUDFFromUtcTimestamp.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.hadoop.hive.ql.udf.generic;

import java.sql.Timestamp;
import java.util.TimeZone;

import org.apache.commons.logging.Log;
import org.apache.commons.logging.LogFactory;
import org.apache.hadoop.hive.ql.exec.Description;
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.serde2.io.TimestampWritable;
import org.apache.hadoop.hive.serde2.objectinspector.ObjectInspector;
import org.apache.hadoop.hive.serde2.objectinspector.PrimitiveObjectInspector;
import org.apache.hadoop.hive.serde2.objectinspector.primitive.PrimitiveObjectInspectorConverter.TextConverter;
import org.apache.hadoop.hive.serde2.objectinspector.primitive.PrimitiveObjectInspectorConverter.TimestampConverter;
import org.apache.hadoop.hive.serde2.objectinspector.primitive.PrimitiveObjectInspectorFactory;

@Description(name = "from_utc_timestamp", value = "from_utc_timestamp(timestamp, string timezone) - "
        + "Assumes given timestamp is UTC and converts to given timezone (as of Hive 0.8.0)")
public class GenericUDFFromUtcTimestamp extends GenericUDF {

    static final Log LOG = LogFactory.getLog(GenericUDFFromUtcTimestamp.class);

    private transient PrimitiveObjectInspector[] argumentOIs;
    private transient TimestampConverter timestampConverter;
    private transient TextConverter textConverter;

    @Override
    public ObjectInspector initialize(ObjectInspector[] arguments) throws UDFArgumentException {
        if (arguments.length != 2) {
            throw new UDFArgumentLengthException(
                    "The function " + getName() + " requires two " + "argument, got " + arguments.length);
        }
        try {
            argumentOIs = new PrimitiveObjectInspector[2];
            argumentOIs[0] = (PrimitiveObjectInspector) arguments[0];
            argumentOIs[1] = (PrimitiveObjectInspector) arguments[1];
        } catch (ClassCastException e) {
            throw new UDFArgumentException("The function " + getName() + " takes only primitive types");
        }

        timestampConverter = new TimestampConverter(argumentOIs[0],
                PrimitiveObjectInspectorFactory.writableTimestampObjectInspector);
        textConverter = new TextConverter(argumentOIs[1]);
        return PrimitiveObjectInspectorFactory.javaTimestampObjectInspector;
    }

    @Override
    public Object evaluate(DeferredObject[] arguments) throws HiveException {
        Object o0 = arguments[0].get();
        if (o0 == null) {
            return null;
        }
        Object o1 = arguments[1].get();
        if (o1 == null) {
            return null;
        }

        String tzStr = textConverter.convert(o1).toString();
        TimeZone timezone = TimeZone.getTimeZone(tzStr);

        Timestamp timestamp = ((TimestampWritable) timestampConverter.convert(o0)).getTimestamp();

        int offset = timezone.getOffset(timestamp.getTime());
        if (invert()) {
            offset = -offset;
        }
        return applyOffset(offset, timestamp);
    }

    protected Timestamp applyOffset(long offset, Timestamp t) {
        long newTime = t.getTime() + offset;
        Timestamp t2 = new Timestamp(newTime);
        t2.setNanos(t.getNanos());

        return t2;
    }

    @Override
    public String getDisplayString(String[] children) {
        StringBuilder sb = new StringBuilder();
        sb.append("Converting field ");
        sb.append(children[0]);
        sb.append(" from UTC to timezone: ");
        if (children.length > 1) {
            sb.append(children[1]);
        }
        return sb.toString();
    }

    public String getName() {
        return "from_utc_timestamp";
    }

    protected boolean invert() {
        return false;
    }
}