org.apache.druid.query.expression.TimestampExtractExprMacro.java Source code

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Here is the source code for org.apache.druid.query.expression.TimestampExtractExprMacro.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.druid.query.expression;

import org.apache.druid.java.util.common.IAE;
import org.apache.druid.java.util.common.ISE;
import org.apache.druid.java.util.common.StringUtils;
import org.apache.druid.math.expr.Expr;
import org.apache.druid.math.expr.ExprEval;
import org.apache.druid.math.expr.ExprMacroTable;
import org.joda.time.DateTime;
import org.joda.time.DateTimeZone;
import org.joda.time.chrono.ISOChronology;

import javax.annotation.Nonnull;
import java.util.List;

public class TimestampExtractExprMacro implements ExprMacroTable.ExprMacro {
    public enum Unit {
        EPOCH, MICROSECOND, MILLISECOND, SECOND, MINUTE, HOUR, DAY, DOW, ISODOW, DOY, WEEK, MONTH, QUARTER, YEAR, ISOYEAR, DECADE, CENTURY, MILLENNIUM
    }

    @Override
    public String name() {
        return "timestamp_extract";
    }

    @Override
    public Expr apply(final List<Expr> args) {
        if (args.size() < 2 || args.size() > 3) {
            throw new IAE("Function[%s] must have 2 to 3 arguments", name());
        }

        if (!args.get(1).isLiteral() || args.get(1).getLiteralValue() == null) {
            throw new IAE("Function[%s] unit arg must be literal", name());
        }

        if (args.size() > 2 && !args.get(2).isLiteral()) {
            throw new IAE("Function[%s] timezone arg must be literal", name());
        }

        final Expr arg = args.get(0);
        final Unit unit = Unit.valueOf(StringUtils.toUpperCase((String) args.get(1).getLiteralValue()));
        final DateTimeZone timeZone;

        if (args.size() > 2) {
            timeZone = ExprUtils.toTimeZone(args.get(2));
        } else {
            timeZone = DateTimeZone.UTC;
        }

        final ISOChronology chronology = ISOChronology.getInstance(timeZone);

        class TimestampExtractExpr extends ExprMacroTable.BaseScalarUnivariateMacroFunctionExpr {
            private TimestampExtractExpr(Expr arg) {
                super(arg);
            }

            @Nonnull
            @Override
            public ExprEval eval(final ObjectBinding bindings) {
                Object val = arg.eval(bindings).value();
                if (val == null) {
                    // Return null if the argument if null.
                    return ExprEval.of(null);
                }
                final DateTime dateTime = new DateTime(val, chronology);
                long epoch = dateTime.getMillis() / 1000;

                switch (unit) {
                case EPOCH:
                    return ExprEval.of(epoch);
                case MICROSECOND:
                    return ExprEval.of(epoch / 1000);
                case MILLISECOND:
                    return ExprEval.of(dateTime.millisOfSecond().get());
                case SECOND:
                    return ExprEval.of(dateTime.secondOfMinute().get());
                case MINUTE:
                    return ExprEval.of(dateTime.minuteOfHour().get());
                case HOUR:
                    return ExprEval.of(dateTime.hourOfDay().get());
                case DAY:
                    return ExprEval.of(dateTime.dayOfMonth().get());
                case DOW:
                    return ExprEval.of(dateTime.dayOfWeek().get());
                case ISODOW:
                    return ExprEval.of(dateTime.dayOfWeek().get());
                case DOY:
                    return ExprEval.of(dateTime.dayOfYear().get());
                case WEEK:
                    return ExprEval.of(dateTime.weekOfWeekyear().get());
                case MONTH:
                    return ExprEval.of(dateTime.monthOfYear().get());
                case QUARTER:
                    return ExprEval.of((dateTime.monthOfYear().get() - 1) / 3 + 1);
                case YEAR:
                    return ExprEval.of(dateTime.year().get());
                case ISOYEAR:
                    return ExprEval.of(dateTime.year().get());
                case DECADE:
                    // The year field divided by 10, See https://www.postgresql.org/docs/10/functions-datetime.html
                    return ExprEval.of(Math.floor(dateTime.year().get() / 10));
                case CENTURY:
                    return ExprEval.of(dateTime.centuryOfEra().get() + 1);
                case MILLENNIUM:
                    // Years in the 1900s are in the second millennium. The third millennium started January 1, 2001.
                    // See https://www.postgresql.org/docs/10/functions-datetime.html
                    return ExprEval.of(Math.round(Math.ceil(dateTime.year().get() / 1000)));
                default:
                    throw new ISE("Unhandled unit[%s]", unit);
                }
            }

            @Override
            public Expr visit(Shuttle shuttle) {
                Expr newArg = arg.visit(shuttle);
                return shuttle.visit(new TimestampExtractExpr(newArg));
            }
        }

        return new TimestampExtractExpr(arg);
    }
}