| /* |
| * 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.common.config.NullHandling; |
| import org.apache.druid.java.util.common.DateTimes; |
| import org.apache.druid.java.util.common.IAE; |
| import org.apache.druid.java.util.common.granularity.PeriodGranularity; |
| import org.apache.druid.math.expr.Expr; |
| import org.joda.time.Chronology; |
| import org.joda.time.DateTime; |
| import org.joda.time.DateTimeZone; |
| import org.joda.time.Period; |
| import org.joda.time.chrono.ISOChronology; |
| |
| import javax.annotation.Nullable; |
| |
| public class ExprUtils |
| { |
| private static final Expr.ObjectBinding NIL_BINDINGS = name -> null; |
| |
| public static Expr.ObjectBinding nilBindings() |
| { |
| return NIL_BINDINGS; |
| } |
| |
| static DateTimeZone toTimeZone(final Expr timeZoneArg) |
| { |
| if (!timeZoneArg.isLiteral()) { |
| throw new IAE("Time zone must be a literal"); |
| } |
| |
| final Object literalValue = timeZoneArg.getLiteralValue(); |
| return literalValue == null ? DateTimeZone.UTC : DateTimes.inferTzFromString((String) literalValue); |
| } |
| |
| static PeriodGranularity toPeriodGranularity( |
| final Expr periodArg, |
| @Nullable final Expr originArg, |
| @Nullable final Expr timeZoneArg, |
| final Expr.ObjectBinding bindings |
| ) |
| { |
| final Period period = new Period(periodArg.eval(bindings).asString()); |
| final DateTime origin; |
| final DateTimeZone timeZone; |
| |
| if (timeZoneArg == null) { |
| timeZone = null; |
| } else { |
| final String value = timeZoneArg.eval(bindings).asString(); |
| timeZone = value != null ? DateTimes.inferTzFromString(value) : null; |
| } |
| |
| if (originArg == null) { |
| origin = null; |
| } else { |
| Chronology chronology = timeZone == null ? ISOChronology.getInstanceUTC() : ISOChronology.getInstance(timeZone); |
| final Object value = originArg.eval(bindings).value(); |
| if (value instanceof String && NullHandling.isNullOrEquivalent((String) value)) { |
| // We get a blank string here, when sql compatible null handling is enabled |
| // and expression contains empty string for for origin |
| // e.g timestamp_floor(\"__time\",'PT1M','','UTC') |
| origin = null; |
| } else { |
| origin = value != null ? new DateTime(value, chronology) : null; |
| } |
| } |
| |
| return new PeriodGranularity(period, origin, timeZone); |
| } |
| |
| static String createErrMsg(String functionName, String msg) |
| { |
| String prefix = "Function[" + functionName + "] "; |
| return prefix + msg; |
| } |
| |
| static void checkLiteralArgument(String functionName, Expr arg, String argName) |
| { |
| Preconditions.checkArgument(arg.isLiteral(), createErrMsg(functionName, argName + " arg must be a literal")); |
| } |
| |
| /** |
| * True if Expr is a string literal. |
| * |
| * In non-SQL-compliant null handling mode, this method will return true for null literals as well (because they are |
| * treated equivalently to empty strings, and we cannot tell the difference.) |
| * |
| * In SQL-compliant null handling mode, this method will return true for actual strings only, not nulls. |
| */ |
| static boolean isStringLiteral(final Expr expr) |
| { |
| return (expr.isLiteral() && expr.getLiteralValue() instanceof String) |
| || (NullHandling.replaceWithDefault() && isNullLiteral(expr)); |
| } |
| |
| /** |
| * True if Expr is a null literal. |
| * |
| * In non-SQL-compliant null handling mode, this method will return true for either a null literal or an empty string |
| * literal (they are treated equivalently and we cannot tell the difference). |
| * |
| * In SQL-compliant null handling mode, this method will only return true for an actual null literal. |
| */ |
| static boolean isNullLiteral(final Expr expr) |
| { |
| return expr.isLiteral() && expr.getLiteralValue() == null; |
| } |
| } |