@Entity
@Table(name = "draft_order")
public class DraftOrder implements Serializable {

    @Id
    @GeneratedValue(strategy = GenerationType.AUTO)
    private Integer id;

    @Column(name = "c_number")
    private String cNumber;

    @Column(name = "source_time_in_ms")
    private Long sourceTimeInMs;

    @Column(name = "source_item_id")
    private String sourceItemId;

    @Column(name = "shipment", columnDefinition = "json")
    private String shipment;

    @Column(name = "shipment_id")
    private String shipmentId;

    @Column(name = "quantity")
    private Integer quantity;

    @Column(name = "source_system")
    private String sourceSystem;

    @Column(name = "status")
    private String status;
}

@Entity
@Table(name = "draft_order_combined")
public class DraftOrderCombined implements Serializable {

    @Id
    @GeneratedValue(strategy = GenerationType.AUTO)
    private Integer id;

    @Column(name = "combined_id")
    private String combinedId;

    @OneToOne(cascade = CascadeType.ALL)
    @JoinColumn(name = "draft_order_id")
    private DraftOrder draftOrder;
}

public class CombinedIdSourceTimeInMs {

    private Long counter;
    private String combinedId;
    private Long sourceTimeInMs;

    public CombinedIdSourceTimeInMs(Long counter, String combinedId, Long sourceTimeInMs) {
        this.counter = counter;
        this.combinedId = combinedId;
        this.sourceTimeInMs = sourceTimeInMs;
    }
}

public interface DraftOrderRepository extends CrudRepository<DraftOrder, Integer> {

    List<DraftOrder> findByCNumberAndStatusOrderBySourceTimeInMsDesc(String cNumber, String status, Pageable pageable);

    List<DraftOrder> findByCNumberAndSourceItemIdIn(String cNumber, List<String> sourceItemIds);

    DraftOrder findByCNumberAndSourceItemId(String cNumber, String sourceItemId);
    
    List<DraftOrder> findByShipmentIdInAndStatusAndSourceSystem(List<String> shipmentIds, String status, String sourceSystem);

    List<DraftOrder> findByCNumberAndId(String cNumber, Integer id);

    Long countByCNumberAndStatus(String cNumber, String status);
}

public interface DraftOrderCombinedRepository extends CrudRepository<DraftOrderCombined, Integer> {

    String FIND_QUERY =
            "SELECT new org.paradise.data.dao.CombinedIdSourceTimeInMs"
                    + "(count(doc) as counter, doc.combinedId as combinedId, min(doc.draftOrder.sourceTimeInMs) as sourceTimeInMs) "
                    + " FROM DraftOrderCombined doc WHERE doc.draftOrder.cNumber = :cNumber AND doc.draftOrder.status = :status "
                    + " GROUP BY combinedId "
                    + " ORDER BY sourceTimeInMs DESC";

    String COUNT_QUERY = "SELECT count(1) FROM "
            + "(SELECT count(1) FROM DraftOrderCombined doc WHERE doc.draftOrder.cNumber = :cNumber AND doc.draftOrder.status = :status"
            + "  GROUP BY doc.combinedId)";

    @Query(value = FIND_QUERY, countQuery = COUNT_QUERY)
    List<CombinedIdSourceTimeInMs> countPerCombinedIdAndSourceTimeInMs(@Param("cNumber") String cNumber,
                                                                       @Param("status") String status, Pageable pageable);

    List<DraftOrderCombined> findByCombinedIdOrderByDraftOrderDaoSourceTimeInMsDesc(String combinedId);
}

package org.paradise.function;

import java.util.HashMap;
import java.util.Map;
import java.util.function.Function;

/**
 * Created by terrence on 12/12/2016.
 */
public final class FactorialFunction {

    public static final Map<Integer, Long> FACTORIAL_MAP = new HashMap<>();

    public static final Function<Integer, Long> FACTORIAL = (x) ->
            FACTORIAL_MAP.computeIfAbsent(x,
                    n -> n * FactorialFunction.FACTORIAL.apply(n - 1));

    static {
        FACTORIAL_MAP.put(1, 1L); // FACTORIAL(1)
    }

    private FactorialFunction() {

    }

}

package org.paradise.function;

import org.junit.Test;

import static org.junit.Assert.assertEquals;

/**
 * Created by terrence on 12/12/2016.
 */
public class FactorialFunctionTest {

    @Test
    public void testFactorialFunction() throws Exception {

        assertEquals("Incorrect result", Long.valueOf(1), FactorialFunction.FACTORIAL.apply(1));
        assertEquals("Incorrect result", Long.valueOf(2), FactorialFunction.FACTORIAL.apply(2));

        assertEquals("Incorrect result", Long.valueOf(3628800), FactorialFunction.FACTORIAL.apply(10));
    }

}

package org.paradise.function;

import java.util.HashMap;
import java.util.Map;
import java.util.function.Function;

/**
 * Created by terrence on 12/12/2016.
 */
public final class FibonacciFunction {

    public static final Map<Integer, Long> FIBONACCI_MAP = new HashMap<>();

    public static final Function<Integer, Long> FIBONACCI = (x) ->
            FIBONACCI_MAP.computeIfAbsent(x,
                    n -> FibonacciFunction.FIBONACCI.apply(n - 2) + FibonacciFunction.FIBONACCI.apply(n - 1));

    static {
        FIBONACCI_MAP.put(0, 0L); // FIBONACCI(0)
        FIBONACCI_MAP.put(1, 1L); // FIBONACCI(1)
    }

    private FibonacciFunction() {

    }

}

package org.paradise.function;

import org.junit.Test;

import static org.junit.Assert.assertEquals;

/**
 * Created by terrence on 12/12/2016.
 */
public class FibonacciFunctionTest {

    @Test
    public void testFibonacciFunction() throws Exception {

        assertEquals("Incorrect result", Long.valueOf(0), FibonacciFunction.FIBONACCI.apply(0));
        assertEquals("Incorrect result", Long.valueOf(1), FibonacciFunction.FIBONACCI.apply(1));
        assertEquals("Incorrect result", Long.valueOf(1), FibonacciFunction.FIBONACCI.apply(2));
        assertEquals("Incorrect result", Long.valueOf(2), FibonacciFunction.FIBONACCI.apply(3));
        assertEquals("Incorrect result", Long.valueOf(3), FibonacciFunction.FIBONACCI.apply(4));
        assertEquals("Incorrect result", Long.valueOf(5), FibonacciFunction.FIBONACCI.apply(5));
        assertEquals("Incorrect result", Long.valueOf(8), FibonacciFunction.FIBONACCI.apply(6));

        assertEquals("Incorrect result", Long.valueOf(13), FibonacciFunction.FIBONACCI.apply(7));
        assertEquals("Incorrect result", Long.valueOf(21), FibonacciFunction.FIBONACCI.apply(8));
        assertEquals("Incorrect result", Long.valueOf(34), FibonacciFunction.FIBONACCI.apply(9));
        assertEquals("Incorrect result", Long.valueOf(55), FibonacciFunction.FIBONACCI.apply(10));

        assertEquals("Incorrect result", Long.valueOf(12586269025L), FibonacciFunction.FIBONACCI.apply(50));
    }

}