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Batch Flow Path Service - Domain-Driven Design

Overview

The Batch Flow Path Service manages batch picking and put-wall consolidation workflows for multi-item orders. It handles approximately 15-20% of all warehouse orders through batch picking with subsequent put-wall sorting.

Service Information

Attribute Value
Port 8085
Package com.paklog.wms.processpath.batch
Database MongoDB
Messaging Apache Kafka

Domain Model

Aggregates

PickBatch (Root Aggregate)

Represents a batch of orders grouped for efficient picking with put-wall consolidation.

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public class PickBatch {
    private String batchId;
    private String warehouseId;
    private String waveId;
    private List<String> orderIds;
    private int totalItems;
    private int totalUnits;
    private BatchStatus status;
    private String assignedPicker;
    private LocalDateTime createdAt;
    private LocalDateTime pickingStartedAt;
    private LocalDateTime pickingCompletedAt;
}

State Machine:

stateDiagram-v2
    [*] --> CREATED
    CREATED --> ASSIGNED: assignPicker()
    ASSIGNED --> PICKING: startPicking()
    PICKING --> SORTING: completePicking()
    SORTING --> COMPLETED: completeConsolidation()

    CREATED --> CANCELLED: cancel()
    ASSIGNED --> CANCELLED: cancel()

Business Rules:

PutWall

Represents a physical put-wall with slots for order consolidation.

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public class PutWall {
    private String wallId;
    private String warehouseId;
    private int totalSlots;
    private int availableSlots;
    private List<PutSlot> slots;
    private WallStatus status;
}

Value Objects

PutSlot

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public record PutSlot(
    int slotNumber,
    String orderId,
    SlotStatus status,
    int expectedItems,
    int receivedItems,
    LocalDateTime assignedAt,
    LocalDateTime completedAt
) {
    public boolean isComplete() {
        return receivedItems >= expectedItems;
    }
}

Domain Events

Events Published

Event Type Description
BatchCreatedEvent com.paklog.processpath.batch.batch-created.v1 Batch created for picking
BatchPickingCompletedEvent com.paklog.processpath.batch.picking-completed.v1 All items picked for batch
PutWallSortCompletedEvent com.paklog.processpath.batch.sort-completed.v1 Item sorted to put-wall slot
OrderConsolidatedEvent com.paklog.processpath.batch.order-consolidated.v1 Order consolidated in put-wall

Events Consumed

Source Topic Event Handler
Process Path Routing process-path.routing.v1.events ShipmentRoutedToPathEvent PathAssignedEventConsumer
Pack & Ship wes.pack.v1.events PackingCompletedEvent PackingCompletedHandler

Domain Services

PickBatchService

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public interface PickBatchService {
    PickBatch createBatch(String warehouseId, String waveId, List<String> orderIds, int totalItems);
    PickBatch assignPicker(String batchId, String pickerId);
    PickBatch startPicking(String batchId);
    PickBatch completePicking(String batchId);
    PickBatch completeConsolidation(String batchId);
    PickBatch getBatch(String batchId);
    List<PickBatch> getBatchesByWave(String waveId);
}

PutWallService

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public interface PutWallService {
    PutSlot assignOrderToSlot(String wallId, int slotNumber, String orderId, int expectedItems);
    PutSlot putItemToSlot(String wallId, int slotNumber, String itemId);
    PutSlot completeSlot(String wallId, int slotNumber);
    void clearSlot(String wallId, int slotNumber);
    PutWall getWallStatus(String wallId);
}

BatchWorkAssignmentService

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public interface BatchWorkAssignmentService {
    void handlePathAssignment(ShipmentRoutedToPathEvent event);
    void handlePackingCompleted(PackingCompletedEvent event);
}

API Endpoints

Pick Batches

Method Endpoint Description
POST /api/v1/pick-batches Create batch
PUT /api/v1/pick-batches/{batchId}/assign-picker Assign picker
PUT /api/v1/pick-batches/{batchId}/start-picking Start picking
PUT /api/v1/pick-batches/{batchId}/complete-picking Complete picking
PUT /api/v1/pick-batches/{batchId}/complete-consolidation Complete consolidation
GET /api/v1/pick-batches/{batchId} Get batch details
GET /api/v1/pick-batches/wave/{waveId} Get batches by wave

Put Walls

Method Endpoint Description
PUT /api/v1/put-walls/{wallId}/slots/{slotNumber}/assign Assign order to slot
PUT /api/v1/put-walls/{wallId}/slots/{slotNumber}/put-item Put item to slot
PUT /api/v1/put-walls/{wallId}/slots/{slotNumber}/complete Complete slot
PUT /api/v1/put-walls/{wallId}/slots/{slotNumber}/clear Clear slot
GET /api/v1/put-walls/{wallId} Get put wall status

Workflow

sequenceDiagram
    participant ROUTING as Routing Service
    participant BATCH as Batch Flow Service
    participant PICKER as Picker
    participant WALL as Put Wall
    participant SLAM as SLAM Service

    ROUTING->>BATCH: ShipmentRoutedToPathEvent
    BATCH->>BATCH: Create/Add to batch
    BATCH->>PICKER: Assign batch

    PICKER->>PICKER: Pick items
    BATCH-->>BATCH: BatchPickingCompletedEvent

    PICKER->>WALL: Sort items to slots
    BATCH-->>BATCH: PutWallSortCompletedEvent

    WALL->>WALL: Complete order consolidation
    BATCH-->>SLAM: OrderConsolidatedEvent

Repository Interfaces

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public interface PickBatchRepository {
    PickBatch save(PickBatch batch);
    Optional<PickBatch> findById(String batchId);
    List<PickBatch> findByWaveId(String waveId);
    List<PickBatch> findByStatus(BatchStatus status);
}

public interface PutWallRepository {
    PutWall save(PutWall wall);
    Optional<PutWall> findById(String wallId);
    List<PutWall> findByWarehouseId(String warehouseId);
}

Integration Patterns

Customer-Supplier

Conformist

Technology Stack

Component Technology
Language Java 21
Framework Spring Boot 3.3.3
Database MongoDB 7.0
Messaging Apache Kafka 7.5.0
Event Format CloudEvents 2.5.0

References