DMN Implementation

---

Component structure

src/
├── components/tabs/
│   └── DMNTab.jsx                    # Main UI (900+ lines)
│       • File upload + card display
│       • Syntactic validation panel
│       • API configuration
│       • Deployment controls
│       • Single evaluate (Postman-style)
│       • Intermediate decision tests
│       • Test cases upload + runner
│       • Import preservation notice
│
├── utils/
│   ├── dmnHelpers.js                 # DMN TTL generation utilities (370 lines)
│   └── parseTTL.enhanced.js          # DMN block capture on import (523 lines)
│
└── config/
    └── vocabularies_config.js        # DMN entity type detection

---

DMN state shape

dmnData: {
  // File
  fileName: string,
  content: string,              // Raw DMN XML

  // Deployment
  decisionKey: string,          // Primary key extracted from DMN
  deployed: boolean,
  deploymentId: string | null,
  deployedAt: string | null,

  // API
  apiEndpoint: string,

  // Testing
  lastTestResult: object | null,
  lastTestTimestamp: string | null,
  testBody: string | null,

  // Import preservation (v1.5.1+)
  importedDmnBlocks: string | null,  // Raw Turtle lines preserved verbatim
  isImported: boolean,
}

---

Syntactic validation

Overview

When a DMN file is uploaded or an example is loaded, DMNTab.jsx calls the shared backend validation endpoint and stores the result in local component state.

// State added in v1.9.3
const [validationResult, setValidationResult] = useState(null);
const [isValidating, setIsValidating]         = useState(false);
const [validationExpanded, setValidationExpanded] = useState(false);

Backend call

const runBackendValidation = async (content) => {
  setIsValidating(true);
  try {
    const response = await fetch(
      `${process.env.REACT_APP_BACKEND_URL}/v1/dmns/validate`,
      {
        method: 'POST',
        headers: { 'Content-Type': 'application/json' },
        body: JSON.stringify({ content }),
      }
    );
    const data = await response.json();
    if (data.success) {
      setValidationResult(data.data);
      // Auto-expand the panel when errors are present
      setValidationExpanded(data.data.summary.errors > 0);
    }
  } catch (err) {
    // Validation failure is non-blocking — DMN workflow continues
  } finally {
    setIsValidating(false);
  }
};

The call is made:

• After handleFileUpload — reader.onload completes
• After loadExampleDMN — on successful fetch
• Cleared in handleClearFile — setValidationResult(null); setIsValidating(false);

Validation is non-blocking

A validation failure (network error or backend unavailable) does not prevent the DMN workflow from continuing. The panel simply does not appear. This ensures the editor remains functional in environments where the backend is unreachable.

Response shape

interface ValidationResult {
  valid: boolean;
  parseError: string | null;
  layers: {
    base:        { label: string; issues: Issue[] };
    business:    { label: string; issues: Issue[] };
    execution:   { label: string; issues: Issue[] };
    interaction: { label: string; issues: Issue[] };
    content:     { label: string; issues: Issue[] };
  };
  summary: { errors: number; warnings: number; infos: number };
}

interface Issue {
  severity: 'error' | 'warning' | 'info';
  code: string;      // e.g. 'EXEC-001', 'INT-005'
  message: string;
  location?: string; // element description e.g. '<decision id="d1">'
  line?: number;
  column?: number;
}

UI rendering

The validation panel is rendered inside the file card, between the file info row and the Deploy button. It is hidden when validationResult is null or isValidating is true (a spinner is shown instead).

The collapsible layer rows follow the same pattern as the Linked Data Explorer's DmnValidator component — each layer shows an icon and badge counts at a glance and expands on click to show individual issue rows.

---

Import preservation

Detection

vocabularies_config.js detects DMN entities before regular entities to avoid misclassification:

export const detectEntityType = (line) => {
  // DMN detection FIRST
  if (line.includes('a cprmv:DecisionModel')) return 'dmnModel';
  if (line.includes('a cpsv:Input'))          return 'dmnInput';
  if (line.includes('a cprmv:DecisionRule'))  return 'dmnRule';

  // Regular entity detection below...
};

Capture

parseTTL.enhanced.js captures DMN lines verbatim when detected:

let inDmnSection = false;
let dmnLines = [];

if (['dmnModel', 'dmnInput', 'dmnRule'].includes(detectedType)) {
  if (!inDmnSection) {
    inDmnSection = true;
    parsed.hasDmnData = true;
  }
  dmnLines.push(rawLine);  // exact line, no transformation
  continue;
}

if (parsed.hasDmnData && dmnLines.length > 0) {
  parsed.importedDmnBlocks = dmnLines.join('\n');
}

Export

ttlGenerator.js appends preserved blocks unchanged at the end of the generated output — after all form-based sections.

---

Primary decision key extraction

The extractPrimaryDecisionKey() helper skips constant parameters automatically:

// Filters decisions with p_* prefix (constants)
// Returns the last non-constant decision (typically the output decision)
// Falls back to first decision if all are constants

Console log on extraction:

[DMN] Extracted primary decision key: "zorgtoeslag_resultaat" (skipped 8 p_* constant(s))

---

Operaton REST API

Deploy endpoint:

POST /engine-rest/deployment/create
Content-Type: multipart/form-data
Body: deployment-name={serviceId}, upload={dmnFile}

Evaluate endpoint:

POST /engine-rest/decision-definition/key/{decisionKey}/evaluate
Content-Type: application/json
Body: { "variables": { ... } }

---

URI generation

DMN URIs are derived from the service identifier. Given service.identifier = "aow-leeftijd":

<https://regels.overheid.nl/services/aow-leeftijd/dmn>
    a cprmv:DecisionModel .

<https://regels.overheid.nl/services/aow-leeftijd/dmn/input/1>
    a cpsv:Input .

<https://regels.overheid.nl/services/aow-leeftijd/rules/DecisionRule_2020>
    a cpsv:Rule, cprmv:DecisionRule .

Spaces in the service identifier are replaced with hyphens. Full URIs in the organisation field are used as-is; short IDs are expanded.

---

Shell script parity

The intermediate tests and test cases features in the UI mirror the shell scripts in examples/organizations/*/:

Shell script	UI equivalent
test-dmn-zorgtoeslag.sh	DMN Tab → Intermediate Decision Tests
test-cases-zorgtoeslag.sh	DMN Tab → Test Cases

The shell scripts can still be used for CI/CD automation independently of the UI.