org.apache.calcite.adapter.druid.UnaryPrefixOperatorConversion.java Source code

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Here is the source code for org.apache.calcite.adapter.druid.UnaryPrefixOperatorConversion.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.calcite.adapter.druid;

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 com.google.common.collect.Iterables;

import java.util.List;

/**
 * Unary prefix Operator conversion class used to convert expression like Unary NOT and Minus
 */
public class UnaryPrefixOperatorConversion implements DruidSqlOperatorConverter {

    private final SqlOperator operator;
    private final String druidOperator;

    public UnaryPrefixOperatorConversion(final SqlOperator operator, final String druidOperator) {
        this.operator = operator;
        this.druidOperator = druidOperator;
    }

    @Override
    public SqlOperator calciteOperator() {
        return operator;
    }

    @Override
    public String toDruidExpression(RexNode rexNode, RelDataType rowType, DruidQuery druidQuery) {

        final RexCall call = (RexCall) rexNode;

        final List<String> druidExpressions = DruidExpressions.toDruidExpressions(druidQuery, rowType,
                call.getOperands());

        if (druidExpressions == null) {
            return null;
        }

        return DruidQuery.format("(%s %s)", druidOperator, Iterables.getOnlyElement(druidExpressions));
    }
}

// End UnaryPrefixOperatorConversion.java