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Elasticsearch subproject :x-pack:plugin:esql:compute

There is a newer version: 8.16.1

/*
 * Copyright Elasticsearch B.V. and/or licensed to Elasticsearch B.V. under one
 * or more contributor license agreements. Licensed under the Elastic License
 * 2.0; you may not use this file except in compliance with the Elastic License
 * 2.0.
 */

package org.elasticsearch.compute.operator;

import org.elasticsearch.compute.data.Page;

import java.util.List;
import java.util.function.Consumer;
import java.util.function.Function;

/**
 * Sink operator that calls a given listener for each page received. The listener receives both the page as well as schema information,
 * i.e. the names of the rows that are outputted.
 */
public class OutputOperator extends SinkOperator {

    private final List columns;
    private final Consumer pageConsumer;
    private final Function mapper;

    public record OutputOperatorFactory(List columns, Function mapper, Consumer pageConsumer)
        implements
            SinkOperatorFactory {

        @Override
        public SinkOperator get(DriverContext driverContext) {
            return new OutputOperator(columns, mapper, pageConsumer);
        }

        @Override
        public String describe() {
            return OutputOperator.describe(columns);
        }
    }

    public OutputOperator(List columns, Function mapper, Consumer pageConsumer) {
        this.columns = columns;
        this.mapper = mapper;
        this.pageConsumer = pageConsumer;
    }

    boolean finished = false;

    @Override
    public boolean isFinished() {
        return finished;
    }

    @Override
    public void finish() {
        finished = true;
    }

    @Override
    public boolean needsInput() {
        return finished == false;
    }

    @Override
    protected void doAddInput(Page page) {
        pageConsumer.accept(mapper.apply(page));
    }

    @Override
    public void close() {

    }

    @Override
    public String toString() {
        return describe(columns);
    }

    private static String describe(List columns) {
        StringBuilder sb = new StringBuilder();
        sb.append("OutputOperator").append("[");
        sb.append("columns = ");
        if (columns.size() <= 10) {
            sb.append(columns);
        } else {
            sb.append('[').append(columns.size()).append(" columns").append(']');
        }
        sb.append("]");
        return sb.toString();
    }
}