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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.runtime.arrow.writers.ArrowFieldWriter;
import org.apache.flink.util.Preconditions;

import org.apache.arrow.vector.VectorSchemaRoot;

/**
 * Writer which serializes the Flink rows to Arrow format.
 *
 * @param  Type of the row to write.
 */
@Internal
public final class ArrowWriter {

    /** Container that holds a set of vectors for the rows to be sent to the Python worker. */
    private final VectorSchemaRoot root;

    /**
     * An array of writers which are responsible for the serialization of each column of the rows.
     */
    private final ArrowFieldWriter[] fieldWriters;

    public ArrowWriter(VectorSchemaRoot root, ArrowFieldWriter[] fieldWriters) {
        this.root = Preconditions.checkNotNull(root);
        this.fieldWriters = Preconditions.checkNotNull(fieldWriters);
    }

    /** Gets the field writers. */
    public ArrowFieldWriter[] getFieldWriters() {
        return fieldWriters;
    }

    /** Writes the specified row which is serialized into Arrow format. */
    public void write(IN row) {
        for (int i = 0; i < fieldWriters.length; i++) {
            fieldWriters[i].write(row, i);
        }
    }

    /** Finishes the writing of the current row batch. */
    public void finish() {
        root.setRowCount(fieldWriters[0].getCount());
        for (ArrowFieldWriter fieldWriter : fieldWriters) {
            fieldWriter.finish();
        }
    }

    /** Resets the state of the writer to write the next batch of rows. */
    public void reset() {
        root.setRowCount(0);
        for (ArrowFieldWriter fieldWriter : fieldWriters) {
            fieldWriter.reset();
        }
    }
}