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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.flink.table.runtime.arrow;

import org.apache.flink.annotation.Internal;
import org.apache.flink.table.data.RowData;
import org.apache.flink.table.data.columnar.ColumnarRowData;
import org.apache.flink.table.data.columnar.vector.ColumnVector;
import org.apache.flink.table.data.columnar.vector.VectorizedColumnBatch;
import org.apache.flink.util.Preconditions;

/** {@link ArrowReader} which read the underlying Arrow format data as {@link RowData}. */
@Internal
public final class ArrowReader {

    /**
     * An array of vectors which are responsible for the deserialization of each column of the rows.
     */
    private final ColumnVector[] columnVectors;

    /** Reusable row used to hold the deserialized result. */
    private final ColumnarRowData reuseRow;

    public ArrowReader(ColumnVector[] columnVectors) {
        this.columnVectors = Preconditions.checkNotNull(columnVectors);
        this.reuseRow = new ColumnarRowData();
        this.reuseRow.setVectorizedColumnBatch(new VectorizedColumnBatch(columnVectors));
    }

    /** Gets the column vectors. */
    public ColumnVector[] getColumnVectors() {
        return columnVectors;
    }

    /** Read the specified row from underlying Arrow format data. */
    public RowData read(int rowId) {
        reuseRow.setRowId(rowId);
        return reuseRow;
    }
}