Flowable源码注释（五十二）事件解析处理器（上）

最新推荐文章于 2024-09-26 19:17:15 发布

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原文链接：https://github.com/flowable/flowable-engine

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#flowable #源码注释 #流程引擎

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本文介绍了Flowable流程引擎中事件解析处理器的实现，包括补偿事件、消息事件和信号事件的定义解析处理器。这些处理器在解析BPMN模型时，为不同类型的事件设置行为，如中间抛出补偿事件、边界事件等。同时，还提到了发送事件服务任务的处理器。源码分析有助于理解Flowable引擎如何处理各类事件。

Flowable源码地址：https://github.com/flowable/flowable-engine

Flowable-6.7.2 源码注释地址：https://github.com/solojin/flowable-6.7.2-annotated

事件解析处理器，包路径：org.flowable.engine.impl.bpmn.parser.handler

CompensateEventDefinitionParseHandler 补偿事件定义解析处理器

/**
 * 补偿事件定义解析处理器
 *
 * @author Joram Barrez
 * @author Tijs Rademakers
 */
public class CompensateEventDefinitionParseHandler extends AbstractBpmnParseHandler<CompensateEventDefinition> {

    @Override
    public Class<? extends BaseElement> getHandledType() {
        return CompensateEventDefinition.class;
    }

    @Override
    protected void executeParse(BpmnParse bpmnParse, CompensateEventDefinition eventDefinition) {

        if (bpmnParse.getCurrentFlowElement() instanceof ThrowEvent) {
            ThrowEvent throwEvent = (ThrowEvent) bpmnParse.getCurrentFlowElement();
            throwEvent.setBehavior(bpmnParse.getActivityBehaviorFactory().createIntermediateThrowCompensationEventActivityBehavior(
                    throwEvent, eventDefinition));

        } else if (bpmnParse.getCurrentFlowElement() instanceof BoundaryEvent) {
            BoundaryEvent boundaryEvent = (BoundaryEvent) bpmnParse.getCurrentFlowElement();
            boundaryEvent.setBehavior(bpmnParse.getActivityBehaviorFactory().createBoundaryCompensateEventActivityBehavior(boundaryEvent,
                    eventDefinition, boundaryEvent.isCancelActivity()));

        } else {

            // What to do?

        }

    }

}

MessageEventDefinitionParseHandler 消息事件定义解析处理器

/**
 * 消息事件定义解析处理器
 *
 * @author Joram Barrez
 * @author Tijs Rademakers
 */
public class MessageEventDefinitionParseHandler extends AbstractBpmnParseHandler<MessageEventDefinition> {

    @Override
    public Class<? extends BaseElement> getHandledType() {
        return MessageEventDefinition.class;
    }

    @Override
    protected void executeParse(BpmnParse bpmnParse, MessageEventDefinition messageDefinition) {
        BpmnModel bpmnModel = bpmnParse.getBpmnModel();
        String messageRef = messageDefinition.getMessageRef();
        if (bpmnModel.containsMessageId(messageRef)) {
            Message message = bpmnModel.getMessage(messageRef);
            messageDefinition.setMessageRef(message.getName());

            for(List<ExtensionElement> extensionElementList : message.getExtensionElements().values()) {
                for(ExtensionElement extensionElement : extensionElementList) {
                    messageDefinition.addExtensionElement(extensionElement);
                }
            }
        }

        if (bpmnParse.getCurrentFlowElement() instanceof IntermediateCatchEvent) {
            IntermediateCatchEvent intermediateCatchEvent = (IntermediateCatchEvent) bpmnParse.getCurrentFlowElement();
            intermediateCatchEvent.setBehavior(bpmnParse.getActivityBehaviorFactory().createIntermediateCatchMessageEventActivityBehavior(intermediateCatchEvent, messageDefinition));

        } else if (bpmnParse.getCurrentFlowElement() instanceof BoundaryEvent) {
            BoundaryEvent boundaryEvent = (BoundaryEvent) bpmnParse.getCurrentFlowElement();
            boundaryEvent.setBehavior(bpmnParse.getActivityBehaviorFactory().createBoundaryMessageEventActivityBehavior(boundaryEvent, messageDefinition, boundaryEvent.isCancelActivity()));
        }

        else {
            // What to do here?
        }

    }

}

SignalEventDefinitionParseHandler 信号事件定义解析处理器

/**
 * 信号事件定义解析处理器
 *
 * @author Joram Barrez
 * @author Tijs Rademakers
 */
public class SignalEventDefinitionParseHandler extends AbstractBpmnParseHandler<SignalEventDefinition> {

    @Override
    public Class<? extends BaseElement> getHandledType() {
        return SignalEventDefinition.class;
    }

    @Override
    protected void executeParse(BpmnParse bpmnParse, SignalEventDefinition signalDefinition) {

        Signal signal = null;
        if (bpmnParse.getBpmnModel().containsSignalId(signalDefinition.getSignalRef())) {
            signal = bpmnParse.getBpmnModel().getSignal(signalDefinition.getSignalRef());
        }

        if (bpmnParse.getCurrentFlowElement() instanceof IntermediateCatchEvent) {
            IntermediateCatchEvent intermediateCatchEvent = (IntermediateCatchEvent) bpmnParse.getCurrentFlowElement();
            intermediateCatchEvent.setBehavior(bpmnParse.getActivityBehaviorFactory().createIntermediateCatchSignalEventActivityBehavior(intermediateCatchEvent, signalDefinition, signal));

        } else if (bpmnParse.getCurrentFlowElement() instanceof BoundaryEvent) {
            BoundaryEvent boundaryEvent = (BoundaryEvent) bpmnParse.getCurrentFlowElement();
            boundaryEvent.setBehavior(bpmnParse.getActivityBehaviorFactory().createBoundarySignalEventActivityBehavior(boundaryEvent, signalDefinition, signal, boundaryEvent.isCancelActivity()));
        }
    }
}

SendEventServiceTaskParseHandler 发送事件解析处理器

/**
 * 发送事件解析处理器
 *
 * @author Tijs Rademakers
 */
public class SendEventServiceTaskParseHandler extends AbstractActivityBpmnParseHandler<SendEventServiceTask> {

    @Override
    public Class<? extends BaseElement> getHandledType() {
        return SendEventServiceTask.class;
    }

    @Override
    protected void executeParse(BpmnParse bpmnParse, SendEventServiceTask sendEventServiceTask) {
        sendEventServiceTask.setBehavior(bpmnParse.getActivityBehaviorFactory().createSendEventTaskBehavior(sendEventServiceTask));
    }

}

BoundaryEventParseHandler 边界事件解析处理器

/**
 * 边界事件解析处理器
 *
 * @author Joram Barrez
 * @author Tijs Rademakers
 */
public class BoundaryEventParseHandler extends AbstractFlowNodeBpmnParseHandler<BoundaryEvent> {

    private static final Logger LOGGER = LoggerFactory.getLogger(BoundaryEventParseHandler.class);

    @Override
    public Class<? extends BaseElement> getHandledType() {
        return BoundaryEvent.class;
    }

    @Override
    protected void executeParse(BpmnParse bpmnParse, BoundaryEvent boundaryEvent) {

        if (boundaryEvent.getAttachedToRef() == null) {
            // 边界事件中的引用无效。确保引用的活动与边界事件{}定义在同一范围内
            LOGGER.warn("Invalid reference in boundary event. Make sure that the referenced activity is defined in the same scope as the boundary event {}", boundaryEvent.getId());
            return;
        }

        EventDefinition eventDefinition = null;
        if (boundaryEvent.getEventDefinitions().size() > 0) {
            eventDefinition = boundaryEvent.getEventDefinitions().get(0);
        }

        if (eventDefinition instanceof TimerEventDefinition || 
                eventDefinition instanceof ErrorEventDefinition || 
                eventDefinition instanceof SignalEventDefinition || 
                eventDefinition instanceof CancelEventDefinition || 
                eventDefinition instanceof ConditionalEventDefinition || 
                eventDefinition instanceof MessageEventDefinition || 
                eventDefinition instanceof EscalationEventDefinition || 
                eventDefinition instanceof CompensateEventDefinition ||
                eventDefinition instanceof VariableListenerEventDefinition) {

            bpmnParse.getBpmnParserHandlers().parseElement(bpmnParse, eventDefinition);
            return;
            
        } else if (!boundaryEvent.getExtensionElements().isEmpty()) {
            List<ExtensionElement> eventTypeExtensionElements = boundaryEvent.getExtensionElements().get(BpmnXMLConstants.ELEMENT_EVENT_TYPE);
            if (eventTypeExtensionElements != null && !eventTypeExtensionElements.isEmpty()) {
                String eventTypeValue = eventTypeExtensionElements.get(0).getElementText();
                if (StringUtils.isNotEmpty(eventTypeValue)) {
                    boundaryEvent.setBehavior(bpmnParse.getActivityBehaviorFactory().createBoundaryEventRegistryEventActivityBehavior(
                                    boundaryEvent, eventTypeValue, boundaryEvent.isCancelActivity()));
                    return;
                }
            }

        } 
        
        // 应该已经在部署时由process validator获取，所以这只是为了确定
        LOGGER.warn("Unsupported boundary event type for boundary event {}", boundaryEvent.getId());
    }

}