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

Introduction

Here is the source code for org.apache.druid.query.expression.TimestampFormatExprMacro.java

Source

/*
 * 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 com.google.common.base.Preconditions;
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.ISODateTimeFormat;

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

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

    @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;
        final DateTimeZone timeZone;

        if (args.size() > 1) {
            Preconditions.checkArgument(args.get(1).isLiteral(), "Function[%s] format arg must be a literal",
                    name());
            formatString = (String) args.get(1).getLiteralValue();
        } else {
            formatString = null;
        }

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

        final DateTimeFormatter formatter = formatString == null ? ISODateTimeFormat.dateTime()
                : DateTimeFormat.forPattern(formatString).withZone(timeZone);

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

            @Nonnull
            @Override
            public ExprEval eval(final ObjectBinding bindings) {
                ExprEval eval = arg.eval(bindings);
                if (eval.isNumericNull()) {
                    // Return null if the argument if null.
                    return ExprEval.of(null);
                }
                return ExprEval.of(formatter.print(arg.eval(bindings).asLong()));
            }

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

        return new TimestampFormatExpr(arg);
    }
}