Enterprise Integration

<!-- Canonical Order Model (XML Schema) -->
<xs:complexType name="CanonicalOrder">
  <xs:sequence>
    <xs:element name="orderId" type="xs:string"/>
    <xs:element name="customerId" type="xs:string"/>
    <xs:element name="orderDate" type="xs:dateTime"/>
    <xs:element name="totalAmount" type="xs:decimal"/>
    <xs:element name="currency" type="xs:string"/>
    <xs:element name="items" type="OrderItems"/>
  </xs:sequence>
</xs:complexType>

<!-- Transform from SAP format to Canonical -->
<!-- Transform from Salesforce format to Canonical -->
<!-- All consumers work with Canonical format -->

<!-- WSDL 1.1 Service Definition -->
<definitions xmlns="http://schemas.xmlsoap.org/wsdl/"
             targetNamespace="http://example.com/orders">
  
  <!-- Types: XML Schema definitions -->
  <types>
    <xs:schema targetNamespace="http://example.com/orders">
      <xs:element name="GetOrderRequest">
        <xs:complexType>
          <xs:sequence>
            <xs:element name="orderId" type="xs:string"/>
          </xs:sequence>
        </xs:complexType>
      </xs:element>
      <xs:element name="GetOrderResponse">
        <xs:complexType>
          <xs:sequence>
            <xs:element name="order" type="tns:Order"/>
          </xs:sequence>
        </xs:complexType>
      </xs:element>
    </xs:schema>
  </types>
  
  <!-- Messages -->
  <message name="GetOrderRequestMsg">
    <part name="parameters" element="tns:GetOrderRequest"/>
  </message>
  <message name="GetOrderResponseMsg">
    <part name="parameters" element="tns:GetOrderResponse"/>
  </message>
  
  <!-- Port Type: Operations -->
  <portType name="OrderServicePortType">
    <operation name="GetOrder">
      <input message="tns:GetOrderRequestMsg"/>
      <output message="tns:GetOrderResponseMsg"/>
    </operation>
  </portType>
  
  <!-- Binding: Protocol details -->
  <binding name="OrderServiceBinding" type="tns:OrderServicePortType">
    <soap:binding transport="http://schemas.xmlsoap.org/soap/http"/>
    <operation name="GetOrder">
      <soap:operation soapAction="http://example.com/GetOrder"/>
      <input><soap:body use="literal"/></input>
      <output><soap:body use="literal"/></output>
    </operation>
  </binding>
  
  <!-- Service: Endpoint -->
  <service name="OrderService">
    <port name="OrderServicePort" binding="tns:OrderServiceBinding">
      <soap:address location="http://example.com/services/orders"/>
    </port>
  </service>
</definitions>

<!-- SOAP Message with WS-Security -->
<soap:Envelope xmlns:soap="http://schemas.xmlsoap.org/soap/envelope/">
  <soap:Header>
    <wsse:Security xmlns:wsse="http://docs.oasis-open.org/wss/...">
      <wsse:UsernameToken>
        <wsse:Username>client123</wsse:Username>
        <wsse:Password Type="PasswordDigest">...</wsse:Password>
        <wsse:Nonce>...</wsse:Nonce>
        <wsse:Created>2024-01-15T10:30:00Z</wsse:Created>
      </wsse:UsernameToken>
    </wsse:Security>
  </soap:Header>
  <soap:Body>
    <GetOrderRequest>
      <orderId>12345</orderId>
    </GetOrderRequest>
  </soap:Body>
</soap:Envelope>

# BPMN Process Example: Order Fulfillment

StartEvent → PlaceOrder (ServiceTask)
    ↓
  Gateway [stock available?]
    ↓ Yes                    ↓ No
  ReserveInventory      NotifyBackorder
    ↓                         ↓
  ChargePayment            End
    ↓
  [payment success?]
    ↓ Yes          ↓ No
  ShipOrder    RefundReserve
    ↓                ↓
  SendNotification  End
    ↓
  EndEvent

<!-- Camunda BPMN Process Definition -->
<bpmn:process id="order-fulfillment" name="Order Fulfillment" isExecutable="true">
  
  <bpmn:startEvent id="start" name="Order Received"/>
  
  <bpmn:serviceTask id="checkInventory" name="Check Inventory"
                    camunda:delegateExpression="${inventoryService}">
    <bpmn:incoming>start</bpmn:incoming>
    <bpmn:outgoing>gateway1</bpmn:outgoing>
  </bpmn:serviceTask>
  
  <bpmn:exclusiveGateway id="gateway1" name="Stock available?">
    <bpmn:incoming>checkInventory</bpmn:incoming>
    <bpmn:outgoing>yesFlow</bpmn:outgoing>
    <bpmn:outgoing>noFlow</bpmn:outgoing>
  </bpmn:exclusiveGateway>
  
  <bpmn:sequenceFlow id="yesFlow" sourceRef="gateway1" targetRef="chargePayment">
    <bpmn:conditionExpression>
      ${inventory.available == true}
    </bpmn:conditionExpression>
  </bpmn:sequenceFlow>
  
  <bpmn:serviceTask id="chargePayment" name="Charge Payment"
                    camunda:delegateExpression="${paymentService}">
    <bpmn:incoming>yesFlow</bpmn:incoming>
    <bpmn:outgoing>end</bpmn:outgoing>
  </bpmn:serviceTask>
  
  <bpmn:endEvent id="end" name="Order Complete"/>
  
</bpmn:process>

# ETL Job: Daily Order Extract

1. Extract:
   - Query: SELECT * FROM orders WHERE created_at >= YESTERDAY
   - Format: CSV with header
   - Location: /exports/orders_YYYYMMDD.csv

2. Transform:
   - Map fields to canonical model
   - Validate data quality (required fields, formats)
   - Enrich with reference data
   - Handle errors → error file

3. Load:
   - SFTP to partner server: sftp.partner.com/inbox/
   - Send success notification
   - Archive file: /archive/orders_YYYYMMDD.csv
   - Update integration audit log

# Phase 1: Proxy
Client → API Gateway → Legacy System

# Phase 2: Intercept & Route
Client → API Gateway → [Router]
                         ├─> New Service (10% traffic)
                         └─> Legacy System (90% traffic)

# Phase 3: Migrate Function by Function
Client → API Gateway → [Router]
                         ├─> New Service A (Orders: 100%)
                         ├─> New Service B (Inventory: 50%)
                         └─> Legacy System (Inventory: 50%, others)

# Phase 4: Complete
Client → API Gateway → New Services (100%)
                       Legacy System decommissioned

// Anti-Corruption Layer: Translate legacy to domain model

class LegacyOrderAdapter {
  // Legacy system has terrible field names
  toDomainModel(legacyOrder: any): Order {
    return {
      id: legacyOrder.ORD_ID,
      customerId: legacyOrder.CUST_NO,
      total: this.parseAmount(legacyOrder.TOT_AMT_STR), // String to number
      status: this.mapStatus(legacyOrder.STATUS_CD),    // Map codes
      items: legacyOrder.ITEMS?.map(this.mapItem) ?? [],
      createdAt: this.parseDate(legacyOrder.CRT_DT)    // YYYYMMDD to ISO
    };
  }
  
  private mapStatus(code: string): OrderStatus {
    const mapping = {
      'P': OrderStatus.Pending,
      'C': OrderStatus.Confirmed,
      'S': OrderStatus.Shipped,
      'X': OrderStatus.Cancelled
    };
    return mapping[code] ?? OrderStatus.Unknown;
  }
}