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

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Here is the source code for org.apache.druid.query.expression.TimestampParseExprMacro.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.DateTimes;
import org.apache.druid.java.util.common.IAE;
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.DateTimeZone;
import org.joda.time.format.DateTimeFormat;
import org.joda.time.format.DateTimeFormatter;
import org.joda.time.format.DateTimeFormatterBuilder;
import org.joda.time.format.DateTimeParser;
import org.joda.time.format.ISODateTimeFormat;

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

public class TimestampParseExprMacro implements ExprMacroTable.ExprMacro {
    @Override
    public String name() {
        return "timestamp_parse";
    }

    @Override
    public Expr apply(final List<Expr> args) {
        if (args.size() < 1 || args.size() > 3) {
            throw new IAE("Function[%s] must have 1 to 3 arguments", name());
        }

        final Expr arg = args.get(0);
        final String formatString = args.size() > 1 ? (String) args.get(1).getLiteralValue() : null;
        final DateTimeZone timeZone;

        if (args.size() > 2 && args.get(2).getLiteralValue() != null) {
            timeZone = DateTimes.inferTzFromString((String) args.get(2).getLiteralValue());
        } else {
            timeZone = DateTimeZone.UTC;
        }

        final DateTimes.UtcFormatter formatter = formatString == null ? createDefaultParser(timeZone)
                : DateTimes.wrapFormatter(DateTimeFormat.forPattern(formatString).withZone(timeZone));

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

            @Nonnull
            @Override
            public ExprEval eval(final ObjectBinding bindings) {
                final String value = arg.eval(bindings).asString();
                if (value == null) {
                    return ExprEval.of(null);
                }

                try {
                    return ExprEval.of(formatter.parse(value).getMillis());
                } catch (IllegalArgumentException e) {
                    // Catch exceptions potentially thrown by formatter.parseDateTime. Our docs say that unparseable timestamps
                    // are returned as nulls.
                    return ExprEval.of(null);
                }
            }

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

        return new TimestampParseExpr(arg);
    }

    /**
     * Default formatter that parses according to the docs for this method: "If the pattern is not provided, this parses
     * time strings in either ISO8601 or SQL format."
     */
    private static DateTimes.UtcFormatter createDefaultParser(final DateTimeZone timeZone) {
        final DateTimeFormatter offsetElement = new DateTimeFormatterBuilder().appendTimeZoneOffset("Z", true, 2, 4)
                .toFormatter();

        DateTimeParser timeOrOffset = new DateTimeFormatterBuilder()
                .append(null,
                        new DateTimeParser[] { new DateTimeFormatterBuilder().appendLiteral('T').toParser(),
                                new DateTimeFormatterBuilder().appendLiteral(' ').toParser() })
                .appendOptional(ISODateTimeFormat.timeElementParser().getParser())
                .appendOptional(offsetElement.getParser()).toParser();

        return DateTimes.wrapFormatter(new DateTimeFormatterBuilder().append(ISODateTimeFormat.dateElementParser())
                .appendOptional(timeOrOffset).toFormatter().withZone(timeZone));
    }
}