iotdb-core/datanode/src/main/java/org/apache/iotdb/db/queryengine/transformation/dag/column/binary/BinaryColumnTransformer.java

/*
 * 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
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package org.apache.iotdb.db.queryengine.transformation.dag.column.binary;

import org.apache.iotdb.db.queryengine.transformation.dag.column.ColumnTransformer;

import org.apache.tsfile.block.column.Column;
import org.apache.tsfile.block.column.ColumnBuilder;
import org.apache.tsfile.read.common.type.Type;

public abstract class BinaryColumnTransformer extends ColumnTransformer {

  protected final ColumnTransformer leftTransformer;

  protected final ColumnTransformer rightTransformer;

  protected BinaryColumnTransformer(
      Type returnType, ColumnTransformer leftTransformer, ColumnTransformer rightTransformer) {
    super(returnType);
    this.leftTransformer = leftTransformer;
    this.rightTransformer = rightTransformer;
    checkType();
  }

  @Override
  public void evaluate() {
    leftTransformer.tryEvaluate();
    rightTransformer.tryEvaluate();
    // attention: get positionCount before calling getColumn
    int positionCount = leftTransformer.getColumnCachePositionCount();
    Column leftColumn = leftTransformer.getColumn();
    Column rightColumn = rightTransformer.getColumn();

    ColumnBuilder builder = returnType.createColumnBuilder(positionCount);
    doTransform(leftColumn, rightColumn, builder, positionCount);
    initializeColumnCache(builder.build());
  }

  protected abstract void doTransform(
      Column leftColumn, Column rightColumn, ColumnBuilder builder, int positionCount);

  public ColumnTransformer getLeftTransformer() {
    return leftTransformer;
  }

  public ColumnTransformer getRightTransformer() {
    return rightTransformer;
  }
}