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Kusto client library for executing queries and retrieving data
There is a newer version: 5.2.0
package com.microsoft.azure.kusto.data;

import java.util.ArrayList;
import java.util.List;
import java.util.function.BiConsumer;
import java.util.function.Supplier;

/**
 * A class for mapping Kusto results to a list of pojos
 *
 * @param 
 *            pojo type returned by the mapping
 */
public class KustoResultMapper {

    public static class Builder {
        final List> queryResultColumns = new ArrayList<>();
        final Supplier objConstructor;

        public Builder(Supplier objConstructor) {
            this.objConstructor = objConstructor;
        }

        /**
         * Add a column by name. Using this function will cause the KustoResultMapper to lookup the column by name once per column per call to
         * {@link KustoResultMapper#extractList(KustoResultSetTable)} or {@link KustoResultMapper#extractSingle(KustoResultSetTable)}
         *
         * @param 
         *            Java type returned by the column (based on the KustoType parameter)
         * @param type
         *            {@link KustoType} returned by the column
         * @param name
         *            column name
         * @param isNullable
         *            whether the column may contains null values
         * @param setter
         *            function for setting a cell value into a pojo instance
         * @return {@link Builder} of the provided type of the object being populated (determined by the object the setter belongs to)
         */
        public  Builder addColumn(KustoType type, String name, boolean isNullable, BiConsumer setter) {
            this.queryResultColumns.add(KustoResultColumnPopulator.of(name, type, isNullable, setter));
            return this;
        }

        /**
         * Add a column by name and ordinal (column index). The ordinal value will be preferred for extracting values from the
         * {@link KustoResultSetTable}.
         *
         * @param 
         *            Java type returned by the column (based on the KustoType parameter)
         * @param type
         *            {@link KustoType} returned by the column
         * @param name
         *            column name
         * @param ordinal
         *            index of the column in the
         * @param isNullable
         *            whether the column may contains null values
         * @param setter
         *            function for setting a cell value into a pojo instance
         * @return {@link Builder} of the provided type of the object being populated (determined by the object the setter belongs to)
         */
        public  Builder addColumn(KustoType type, String name, int ordinal, boolean isNullable, BiConsumer setter) {
            this.queryResultColumns.add(KustoResultColumnPopulator.of(name, ordinal, type, isNullable, setter));
            return this;
        }

        /**
         * Add a column by ordinal (column index).
         *
         * @param 
         *            Java type returned by the column (based on the KustoType parameter)
         * @param type
         *            {@link KustoType} returned by the column
         * @param ordinal
         *            index of the column in the
         * @param isNullable
         *            whether the column may contains null values
         * @param setter
         *            function for setting a cell value into a pojo instance
         * @return {@link Builder} of the provided type of the object being populated (determined by the object the setter belongs to)
         */
        public  Builder addColumn(KustoType type, int ordinal, boolean isNullable, BiConsumer setter) {
            this.queryResultColumns.add(KustoResultColumnPopulator.of(ordinal, type, isNullable, setter));
            return this;
        }

        public KustoResultMapper build() {
            return new KustoResultMapper<>(this.queryResultColumns, this.objConstructor);
        }
    }

    public static  Builder newBuilder(Supplier objConstructor) {
        return new Builder<>(objConstructor);
    }

    final List> columns;
    final Supplier objConstructor;

    private KustoResultMapper(List> columns, Supplier objConstructor) {
        this.columns = columns;
        this.objConstructor = objConstructor;
    }

    public R extractSingle(KustoResultSetTable resultSet) {
        R ret = null;
        if (resultSet.next()) {
            ret = this.objConstructor.get();
            for (KustoResultColumnPopulator col : this.columns) {
                col.populateFrom(ret, resultSet);
            }
        }
        return ret;
    }

    public List extractList(KustoResultSetTable resultSet) {
        List ret = new ArrayList<>(resultSet.count());
        int[] columnOrdinals = new int[this.columns.size()];
        for (int i = 0; i < this.columns.size(); i++) {
            columnOrdinals[i] = this.columns.get(i).columnIndexInResultSet(resultSet);
        }
        while (resultSet.next()) {
            R resultObject = this.objConstructor.get();
            for (int i = 0; i < this.columns.size(); i++) {
                KustoResultColumnPopulator col = this.columns.get(i);
                col.populateFrom(resultObject, resultSet, columnOrdinals[i]);
            }
            ret.add(resultObject);
        }
        return ret;
    }
}