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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.calcite.adapter.druid;
import org.apache.calcite.avatica.util.DateTimeUtils;
import org.apache.calcite.rel.type.RelDataType;
import org.apache.calcite.rex.RexCall;
import org.apache.calcite.rex.RexNode;
import org.apache.calcite.sql.SqlOperator;
import org.apache.calcite.sql.fun.SqlStdOperatorTable;
import org.apache.calcite.sql.type.SqlTypeName;
import com.google.common.collect.ImmutableList;
import org.joda.time.Period;
import java.util.TimeZone;
/**
* Druid cast converter operator used to translates calcite casts to Druid expression cast
*/
public class DruidSqlCastConverter implements DruidSqlOperatorConverter {
@Override public SqlOperator calciteOperator() {
return SqlStdOperatorTable.CAST;
}
@Override public String toDruidExpression(RexNode rexNode, RelDataType topRel,
DruidQuery druidQuery) {
final RexNode operand = ((RexCall) rexNode).getOperands().get(0);
final String operandExpression = DruidExpressions.toDruidExpression(operand,
topRel, druidQuery);
if (operandExpression == null) {
return null;
}
final SqlTypeName fromType = operand.getType().getSqlTypeName();
String fromTypeString = dateTimeFormatString(fromType);
final SqlTypeName toType = rexNode.getType().getSqlTypeName();
final String timeZoneConf = druidQuery.getConnectionConfig().timeZone();
final TimeZone timeZone = TimeZone.getTimeZone(timeZoneConf == null ? "UTC" : timeZoneConf);
final boolean nullEqualToEmpty = druidQuery.getConnectionConfig().nullEqualToEmpty();
if (fromTypeString == null) {
fromTypeString = nullEqualToEmpty ? "" : null;
}
if (SqlTypeName.CHAR_TYPES.contains(fromType)
&& SqlTypeName.DATETIME_TYPES.contains(toType)) {
//case chars to dates
return castCharToDateTime(toType == SqlTypeName.TIMESTAMP_WITH_LOCAL_TIME_ZONE
? timeZone : DateTimeUtils.UTC_ZONE,
operandExpression, toType, fromTypeString);
} else if (SqlTypeName.DATETIME_TYPES.contains(fromType)
&& SqlTypeName.CHAR_TYPES.contains(toType)) {
//case dates to chars
return castDateTimeToChar(fromType == SqlTypeName.TIMESTAMP_WITH_LOCAL_TIME_ZONE
? timeZone : DateTimeUtils.UTC_ZONE, operandExpression, fromType);
} else if (SqlTypeName.DATETIME_TYPES.contains(fromType)
&& toType == SqlTypeName.TIMESTAMP_WITH_LOCAL_TIME_ZONE) {
if (timeZone.equals(DateTimeUtils.UTC_ZONE)) {
// bail out, internal representation is the same,
// we do not need to do anything
return operandExpression;
}
// to timestamp with local time zone
return castCharToDateTime(
timeZone,
castDateTimeToChar(DateTimeUtils.UTC_ZONE, operandExpression, fromType),
toType,
fromTypeString);
} else if (fromType == SqlTypeName.TIMESTAMP_WITH_LOCAL_TIME_ZONE
&& SqlTypeName.DATETIME_TYPES.contains(toType)) {
if (toType != SqlTypeName.DATE && timeZone.equals(DateTimeUtils.UTC_ZONE)) {
// bail out, internal representation is the same,
// we do not need to do anything
return operandExpression;
}
// timestamp with local time zone to other types
return castCharToDateTime(
DateTimeUtils.UTC_ZONE,
castDateTimeToChar(timeZone, operandExpression, fromType),
toType,
fromTypeString);
} else {
// Handle other casts.
final DruidType fromExprType = DruidExpressions.EXPRESSION_TYPES.get(fromType);
final DruidType toExprType = DruidExpressions.EXPRESSION_TYPES.get(toType);
if (fromExprType == null || toExprType == null) {
// Unknown types bail out.
return null;
}
final String typeCastExpression;
if (fromExprType != toExprType) {
typeCastExpression = DruidQuery.format("CAST(%s, '%s')", operandExpression,
toExprType
.toString());
} else {
// case it is the same type it is ok to skip CAST
typeCastExpression = operandExpression;
}
if (toType == SqlTypeName.DATE) {
// Floor to day when casting to DATE.
return DruidExpressions.applyTimestampFloor(
typeCastExpression,
Period.days(1).toString(),
"",
TimeZone.getTimeZone(druidQuery.getConnectionConfig().timeZone()));
} else {
return typeCastExpression;
}
}
}
private static String castCharToDateTime(
TimeZone timeZone,
String operand,
final SqlTypeName toType, String format) {
// Cast strings to date times by parsing them from SQL format.
final String timestampExpression = DruidExpressions.functionCall(
"timestamp_parse",
ImmutableList.of(
operand,
DruidExpressions.stringLiteral(format),
DruidExpressions.stringLiteral(timeZone.getID())));
if (toType == SqlTypeName.DATE) {
// case to date we need to floor to day first
return DruidExpressions.applyTimestampFloor(
timestampExpression,
Period.days(1).toString(),
"",
timeZone);
} else if (toType == SqlTypeName.TIMESTAMP
|| toType == SqlTypeName.TIMESTAMP_WITH_LOCAL_TIME_ZONE) {
return timestampExpression;
} else {
throw new IllegalStateException(
DruidQuery.format("Unsupported DateTime type[%s]", toType));
}
}
private static String castDateTimeToChar(
final TimeZone timeZone,
final String operand,
final SqlTypeName fromType) {
return DruidExpressions.functionCall(
"timestamp_format",
ImmutableList.of(
operand,
DruidExpressions.stringLiteral(dateTimeFormatString(fromType)),
DruidExpressions.stringLiteral(timeZone.getID())));
}
public static String dateTimeFormatString(final SqlTypeName sqlTypeName) {
if (sqlTypeName == SqlTypeName.DATE) {
return "yyyy-MM-dd";
} else if (sqlTypeName == SqlTypeName.TIMESTAMP) {
return "yyyy-MM-dd HH:mm:ss";
} else if (sqlTypeName == SqlTypeName.TIMESTAMP_WITH_LOCAL_TIME_ZONE) {
return "yyyy-MM-dd'T'HH:mm:ss.SSS'Z'";
} else {
return null;
}
}
}
// End DruidSqlCastConverter.java
