content: /*
   * Copyright 2010-2025 Hyland Software, Inc. and its affiliates.
   *
   * Licensed under the Apache License, Version 2.0 (the "License");
   * you may not use this file except in compliance with the License.
   * You may obtain a copy of the License at
   *
   *     http://www.apache.org/licenses/LICENSE-2.0
   *
   * Unless required by applicable law or agreed to in writing, software
   * distributed under the License is distributed on an "AS IS" BASIS,
   * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
   * See the License for the specific language governing permissions and
   * limitations under the License.
   */
  package org.activiti.validation.validator.impl;
  
  import jakarta.el.ExpressionFactory;
  import java.util.List;
  import org.activiti.bpmn.model.BpmnModel;
  import org.activiti.bpmn.model.FlowElement;
  import org.activiti.bpmn.model.FlowElementsContainer;
  import org.activiti.bpmn.model.Process;
  import org.activiti.bpmn.model.SequenceFlow;
  import org.activiti.core.el.juel.util.SimpleContext;
  import org.activiti.validation.ValidationError;
  import org.activiti.validation.validator.Problems;
  import org.activiti.validation.validator.ProcessLevelValidator;
  import org.apache.commons.lang3.StringUtils;
  
  /**
   *
   */
  public class SequenceflowValidator extends ProcessLevelValidator {
  
      @Override
      protected void executeValidation(BpmnModel bpmnModel, Process process, List<ValidationError> errors) {
          List<SequenceFlow> sequenceFlows = process.findFlowElementsOfType(SequenceFlow.class);
          for (SequenceFlow sequenceFlow : sequenceFlows) {
              String sourceRef = sequenceFlow.getSourceRef();
              String targetRef = sequenceFlow.getTargetRef();
  
              if (StringUtils.isEmpty(sourceRef)) {
                  addError(errors, Problems.SEQ_FLOW_INVALID_SRC, process, sequenceFlow);
              }
              if (StringUtils.isEmpty(targetRef)) {
                  addError(errors, Problems.SEQ_FLOW_INVALID_TARGET, process, sequenceFlow);
              }
  
              // Implicit check: sequence flow cannot cross (sub) process
              // boundaries, hence we check the parent and not the process
              // (could be subprocess for example)
              FlowElement source = process.getFlowElement(sourceRef, true);
              FlowElement target = process.getFlowElement(targetRef, true);
  
              // Src and target validation
              if (source == null) {
                  addError(errors, Problems.SEQ_FLOW_INVALID_SRC, process, sequenceFlow);
              }
              if (target == null) {
                  addError(errors, Problems.SEQ_FLOW_INVALID_TARGET, process, sequenceFlow);
              }
  
              if (source != null && target != null) {
                  FlowElementsContainer sourceContainer = process.getFlowElementsContainer(source.getId());
                  FlowElementsContainer targetContainer = process.getFlowElementsContainer(target.getId());
  
                  if (sourceContainer == null) {
                      addError(errors, Problems.SEQ_FLOW_INVALID_SRC, process, sequenceFlow);
                  }
                  if (targetContainer == null) {
                      addError(errors, Problems.SEQ_FLOW_INVALID_TARGET, process, sequenceFlow);
                  }
                  if (sourceContainer != null && targetContainer != null && !sourceContainer.equals(targetContainer)) {
                      addError(errors, Problems.SEQ_FLOW_INVALID_TARGET_DIFFERENT_SCOPE, process, sequenceFlow);
                  }
              }
  
              String conditionExpression = sequenceFlow.getConditionExpression();
  
              if (conditionExpression != null) {
                  try {
                      ExpressionFactory.newInstance().createValueExpression(
                          new SimpleContext(),
                          conditionExpression.trim(),
                          Object.class
                      );
                  } catch (Exception e) {
                      addError(errors, Problems.SEQ_FLOW_INVALID_CONDITIONAL_EXPRESSION, process, sequenceFlow);
                  }
              }
          }
      }
  }
  