History for DMN Decisions

After a decision definition was evaluated either from a BPMN process, CMMN case or through the Decision Service, the inputs and outputs are saved in the History of the platform. The history entity is of type HistoricDecisionInstance and has the event type evaluate.

For details about the history mechanism as such, refer to the History and Audit Event Log.

History Level

History level of FULL is required. Otherwise, no history for decisions is created.

Query for evaluated Decisions

The History Service can be used to query for HistoricDecisionInstances. For example, use the following query to get all history entries for a decision definition with key checkOrder ordered by the time when the decision was evaluated.

List<HistoricDecisionInstance> historicDecisions = processEngine
  .getHistoryService()
  .createHistoricDecisionInstanceQuery()
  .decisionDefinitionKey("checkOrder")
  .orderByEvaluationTime()
  .asc()
  .list();

Decisions which where evaluated from a BPMN business rule task can be filtered by the process definition id or key and process instance id.

HistoryService historyService = processEngine.getHistoryService();

List<HistoricDecisionInstance> historicDecisionInstances = historyService
  .createHistoricDecisionInstanceQuery()
  .processDefinitionId("processDefinitionId")
  .list();

historicDecisionInstances = historyService
  .createHistoricDecisionInstanceQuery()
  .processDefinitionKey("processDefinitionKey")
  .list();

historicDecisionInstances = historyService
  .createHistoricDecisionInstanceQuery()
  .processInstanceId("processInstanceId")
  .list();

Decisions which where evaluated from a CMMN decision task can be filtered by the case definition id or key and case instance id.

HistoryService historyService = processEngine.getHistoryService();

List<HistoricDecisionInstance> historicDecisionInstances = historyService
  .createHistoricDecisionInstanceQuery()
  .caseDefinitionId("caseDefinitionId")
  .list();

historicDecisionInstances = historyService
  .createHistoricDecisionInstanceQuery()
  .caseDefinitionKey("caseDefinitionKey")
  .list();

historicDecisionInstances = historyService
  .createHistoricDecisionInstanceQuery()
  .caseInstanceId("caseInstanceId")
  .list();

Note that the inputs and outputs of a decision are not included in the query result by default. Call the methods includeInputs() and includeOutputs() on the query to retrieve the inputs and outputs from the result.

List<HistoricDecisionInstance> historicDecisions = processEngine
  .getHistoryService()
  .createHistoricDecisionInstanceQuery()
  .decisionDefinitionKey("checkOrder")
  .includeInputs()
  .includeOutputs()
  .list();

The Historic Decision Instance

The HistoricDecisionInstance contains information about a single evaluation of a decision.

HistoricDecisionInstance historicDecision = ...;

// id of the decision definition
String decisionDefinitionId = historicDecision.getDecisionDefinitionId();

// key of the decision definition
String decisionDefinitionKey = historicDecision.getDecisionDefinitionKey();

// name of the decision
String decisionDefinitionName = historicDecision.getDecisionDefinitionName();

// time when the decision was evaluated
Date evaluationTime = historicDecision.getEvaluationTime();

// inputs of the decision (if includeInputs was specified in the query)
List<HistoricDecisionInputInstance> inputs = historicDecision.getInputs();

// outputs of the decision (if includeOutputs was specified in the query)
List<HistoricDecisionOutputInstance> outputs = historicDecision.getOutputs();

In case the decision was evaluated from a process, information of the process definition, the process instance and the activity is set in the HistoricDecisionInstance. The same applies for decisions evaluated from a case, where the history instance will reference the corresponding case instances.

Additionally, if the decision is a decision table with hit policy collect and an aggregator function, then the result of the aggregation can be retrieved by the getCollectResultValue() method.

For more information on supported hit policies please see the DMN 1.1 reference.

Historic Decision Input Instance

The HistoricDecisionInputInstance represents one input clause of an evaluated decision.

HistoricDecisionInputInstance input = ...;

// id of the input clause
String clauseId = input.getClauseId();

// label of the input clause
String clauseName = input.getClauseName();

// evaluated value of the input expression
Object value = input.getValue();

// evaluated value of the input expression as typed value
// which contains type information
TypedValue typedValue = input.getTypedValue();

Note that the value may be the result of a type transformation in case the input expression specifies a type.

Historic Decision Output Instance

The HistoricDecisionOutputInstance represents one output entry of an evaluated decision. The Historic Decision Instance contains one Historic Decision Output Instance for each output clause and matched rule.

HistoricDecisionOutputInstance output = ...;

// id of the output clause
String clauseId = output.getClauseId();

// label of the output clause
String clauseName = output.getClauseName();

// evaluated value of the output entry
Object value = output.getValue();

// evaluated value of the output entry as typed value
// which contains type information
TypedValue typedValue = output.getTypedValue();

// id of matched rule the output belongs to
String ruleId = output.getRuleId();

// the position of the rule in the list of matched rules
Integer ruleOrder = output.getRuleOrder();

// name of the output clause used as output variable identifier
String variableName = output.getVariableName();

Note that the value may be the result of a type transformation in case the output specifies a type.

Cockpit

You can audit the evaluated decision definitions in the Cockpit webapp.

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