import org.activiti.engine.impl.pvm.delegate.SignallableActivityBehavior; //导入依赖的package包/类
@Override
public void signal(ActivityExecution execution, String signalName, Object signalData) throws Exception {
    if (activityBehaviorInstance == null) {
        activityBehaviorInstance = getActivityBehaviorInstance(execution);
    }

    if (activityBehaviorInstance instanceof SignallableActivityBehavior) {
        ((SignallableActivityBehavior) activityBehaviorInstance).signal(execution, signalName, signalData);
    } else {
        throw new ActivitiException("signal() can only be called on a " + SignallableActivityBehavior.class.getName() + " instance");
    }
}
 

import org.activiti.engine.impl.pvm.delegate.SignallableActivityBehavior; //导入依赖的package包/类
@Override
public void signal(ActivityExecution execution, String signalName, Object signalData) throws Exception {
    Object delegate = DelegateExpressionUtil.resolveDelegateExpression(expression, execution, fieldDeclarations);
    if (delegate instanceof SignallableActivityBehavior) {
        ((SignallableActivityBehavior) delegate).signal(execution, signalName, signalData);
    }
}
 

import org.activiti.engine.impl.pvm.delegate.SignallableActivityBehavior; //导入依赖的package包/类
public void signal(ActivityExecution execution, String signalName, Object signalData) throws Exception {
  if (activityBehaviorInstance == null) {
    activityBehaviorInstance = getActivityBehaviorInstance(execution);
  }
  
  if (activityBehaviorInstance instanceof SignallableActivityBehavior) {
    ((SignallableActivityBehavior) activityBehaviorInstance).signal(execution, signalName, signalData);
  } else {
    throw new ActivitiException("signal() can only be called on a " + SignallableActivityBehavior.class.getName() + " instance");
  }
}
 

import org.activiti.engine.impl.pvm.delegate.SignallableActivityBehavior; //导入依赖的package包/类
@Override
public void signal(ActivityExecution execution, String signalName, Object signalData) throws Exception {
  Object delegate = expression.getValue(execution);
  if( delegate instanceof SignallableActivityBehavior){
    ((SignallableActivityBehavior) delegate).signal( execution , signalName , signalData);
  }
}