====== Use event gateways with caution ======

{{tag>gateway parallel_gateway event_gateway}}

Event gateway immediately interrupts all catching events when any single one occurs.
For more versatile logic consider the combination of parallel gateway and terminating event.

===== ✔ How to =====

<bpmnio type="bpmn">
<?xml version="1.0" encoding="UTF-8"?>
<definitions xmlns="http://www.omg.org/spec/BPMN/20100524/MODEL" xmlns:bpmndi="http://www.omg.org/spec/BPMN/20100524/DI" xmlns:omgdi="http://www.omg.org/spec/DD/20100524/DI" xmlns:omgdc="http://www.omg.org/spec/DD/20100524/DC" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" id="sid-38422fae-e03e-43a3-bef4-bd33b32041b2" targetNamespace="http://bpmn.io/bpmn" exporter="http://bpmn.io" exporterVersion="0.10.1">
  <process id="Process_0kf0077">
    <startEvent id="Event_13ec10q">
      <outgoing>Flow_1v91670</outgoing>
    </startEvent>
    <parallelGateway id="Gateway_08peucq">
      <incoming>Flow_1v91670</incoming>
      <outgoing>Flow_1bmuvfd</outgoing>
      <outgoing>Flow_1omf6ox</outgoing>
    </parallelGateway>
    <endEvent id="Event_1k1tn88" name="Paid">
      <incoming>Flow_1x386gx</incoming>
      <terminateEventDefinition id="TerminateEventDefinition_0ku242o" />
    </endEvent>
    <sequenceFlow id="Flow_1v91670" sourceRef="Event_13ec10q" targetRef="Gateway_08peucq" />
    <sequenceFlow id="Flow_1bmuvfd" sourceRef="Gateway_08peucq" targetRef="Event_1hlib99" />
    <intermediateCatchEvent id="Event_0r0tew3" name="Payment due date">
      <incoming>Flow_0tjh6sh</incoming>
      <outgoing>Flow_0vj1spf</outgoing>
      <timerEventDefinition id="TimerEventDefinition_1a77cp0" />
    </intermediateCatchEvent>
    <exclusiveGateway id="Gateway_1jxup79">
      <incoming>Flow_1fpmuu7</incoming>
      <incoming>Flow_1omf6ox</incoming>
      <outgoing>Flow_0tjh6sh</outgoing>
    </exclusiveGateway>
    <task id="Activity_12mr8cn" name="Clarify delay with the client">
      <incoming>Flow_0vj1spf</incoming>
      <outgoing>Flow_0v7giyt</outgoing>
    </task>
    <exclusiveGateway id="Gateway_0gfb7mo" name="Wait more?">
      <incoming>Flow_0v7giyt</incoming>
      <outgoing>Flow_0xssdyb</outgoing>
      <outgoing>Flow_1fpmuu7</outgoing>
    </exclusiveGateway>
    <endEvent id="Event_04k06ga" name="Not paid">
      <incoming>Flow_0xssdyb</incoming>
      <terminateEventDefinition id="TerminateEventDefinition_0jd5cs4" />
    </endEvent>
    <sequenceFlow id="Flow_0tjh6sh" sourceRef="Gateway_1jxup79" targetRef="Event_0r0tew3" />
    <sequenceFlow id="Flow_0vj1spf" sourceRef="Event_0r0tew3" targetRef="Activity_12mr8cn" />
    <sequenceFlow id="Flow_1fpmuu7" name="yes" sourceRef="Gateway_0gfb7mo" targetRef="Gateway_1jxup79" />
    <sequenceFlow id="Flow_0v7giyt" sourceRef="Activity_12mr8cn" targetRef="Gateway_0gfb7mo" />
    <sequenceFlow id="Flow_0xssdyb" name="no" sourceRef="Gateway_0gfb7mo" targetRef="Event_04k06ga" />
    <sequenceFlow id="Flow_1omf6ox" sourceRef="Gateway_08peucq" targetRef="Gateway_1jxup79" />
    <intermediateCatchEvent id="Event_1hlib99" name="Payment obtained">
      <incoming>Flow_1bmuvfd</incoming>
      <outgoing>Flow_1x386gx</outgoing>
      <messageEventDefinition id="MessageEventDefinition_0gm96fa" />
    </intermediateCatchEvent>
    <sequenceFlow id="Flow_1x386gx" sourceRef="Event_1hlib99" targetRef="Event_1k1tn88" />
  </process>
  <bpmndi:BPMNDiagram id="BpmnDiagram_1">
    <bpmndi:BPMNPlane id="BpmnPlane_1" bpmnElement="Process_0kf0077">
      <bpmndi:BPMNShape id="Event_13ec10q_di" bpmnElement="Event_13ec10q">
        <omgdc:Bounds x="302" y="-178" width="36" height="36" />
      </bpmndi:BPMNShape>
      <bpmndi:BPMNShape id="Gateway_1ay1ssw_di" bpmnElement="Gateway_08peucq">
        <omgdc:Bounds x="375" y="-185" width="50" height="50" />
      </bpmndi:BPMNShape>
      <bpmndi:BPMNShape id="Event_1f2yzhy_di" bpmnElement="Event_0r0tew3">
        <omgdc:Bounds x="492" y="-298" width="36" height="36" />
        <bpmndi:BPMNLabel>
          <omgdc:Bounds x="465" y="-255" width="90" height="14" />
        </bpmndi:BPMNLabel>
      </bpmndi:BPMNShape>
      <bpmndi:BPMNShape id="Gateway_1jxup79_di" bpmnElement="Gateway_1jxup79" isMarkerVisible="true">
        <omgdc:Bounds x="375" y="-305" width="50" height="50" />
      </bpmndi:BPMNShape>
      <bpmndi:BPMNShape id="Activity_12mr8cn_di" bpmnElement="Activity_12mr8cn">
        <omgdc:Bounds x="590" y="-320" width="100" height="80" />
        <bpmndi:BPMNLabel />
      </bpmndi:BPMNShape>
      <bpmndi:BPMNShape id="Gateway_0gfb7mo_di" bpmnElement="Gateway_0gfb7mo" isMarkerVisible="true">
        <omgdc:Bounds x="735" y="-305" width="50" height="50" />
        <bpmndi:BPMNLabel>
          <omgdc:Bounds x="732" y="-248" width="56" height="14" />
        </bpmndi:BPMNLabel>
      </bpmndi:BPMNShape>
      <bpmndi:BPMNShape id="Event_1kp0poi_di" bpmnElement="Event_04k06ga">
        <omgdc:Bounds x="822" y="-298" width="36" height="36" />
        <bpmndi:BPMNLabel>
          <omgdc:Bounds x="819" y="-255" width="42" height="14" />
        </bpmndi:BPMNLabel>
      </bpmndi:BPMNShape>
      <bpmndi:BPMNShape id="Event_07hur9k_di" bpmnElement="Event_1hlib99">
        <omgdc:Bounds x="492" y="-178" width="36" height="36" />
        <bpmndi:BPMNLabel>
          <omgdc:Bounds x="466" y="-135" width="89" height="14" />
        </bpmndi:BPMNLabel>
      </bpmndi:BPMNShape>
      <bpmndi:BPMNShape id="Event_0s7eoii_di" bpmnElement="Event_1k1tn88">
        <omgdc:Bounds x="622" y="-178" width="36" height="36" />
        <bpmndi:BPMNLabel>
          <omgdc:Bounds x="629" y="-135" width="23" height="14" />
        </bpmndi:BPMNLabel>
      </bpmndi:BPMNShape>
      <bpmndi:BPMNEdge id="Flow_1v91670_di" bpmnElement="Flow_1v91670">
        <omgdi:waypoint x="338" y="-160" />
        <omgdi:waypoint x="375" y="-160" />
      </bpmndi:BPMNEdge>
      <bpmndi:BPMNEdge id="Flow_1bmuvfd_di" bpmnElement="Flow_1bmuvfd">
        <omgdi:waypoint x="425" y="-160" />
        <omgdi:waypoint x="492" y="-160" />
      </bpmndi:BPMNEdge>
      <bpmndi:BPMNEdge id="Flow_0tjh6sh_di" bpmnElement="Flow_0tjh6sh">
        <omgdi:waypoint x="425" y="-280" />
        <omgdi:waypoint x="492" y="-280" />
      </bpmndi:BPMNEdge>
      <bpmndi:BPMNEdge id="Flow_0vj1spf_di" bpmnElement="Flow_0vj1spf">
        <omgdi:waypoint x="528" y="-280" />
        <omgdi:waypoint x="590" y="-280" />
      </bpmndi:BPMNEdge>
      <bpmndi:BPMNEdge id="Flow_1fpmuu7_di" bpmnElement="Flow_1fpmuu7">
        <omgdi:waypoint x="760" y="-305" />
        <omgdi:waypoint x="760" y="-370" />
        <omgdi:waypoint x="400" y="-370" />
        <omgdi:waypoint x="400" y="-305" />
        <bpmndi:BPMNLabel>
          <omgdc:Bounds x="572" y="-388" width="17" height="14" />
        </bpmndi:BPMNLabel>
      </bpmndi:BPMNEdge>
      <bpmndi:BPMNEdge id="Flow_0v7giyt_di" bpmnElement="Flow_0v7giyt">
        <omgdi:waypoint x="690" y="-280" />
        <omgdi:waypoint x="735" y="-280" />
      </bpmndi:BPMNEdge>
      <bpmndi:BPMNEdge id="Flow_0xssdyb_di" bpmnElement="Flow_0xssdyb">
        <omgdi:waypoint x="785" y="-280" />
        <omgdi:waypoint x="822" y="-280" />
        <bpmndi:BPMNLabel>
          <omgdc:Bounds x="797" y="-298" width="13" height="14" />
        </bpmndi:BPMNLabel>
      </bpmndi:BPMNEdge>
      <bpmndi:BPMNEdge id="Flow_1omf6ox_di" bpmnElement="Flow_1omf6ox">
        <omgdi:waypoint x="400" y="-185" />
        <omgdi:waypoint x="400" y="-255" />
      </bpmndi:BPMNEdge>
      <bpmndi:BPMNEdge id="Flow_1x386gx_di" bpmnElement="Flow_1x386gx">
        <omgdi:waypoint x="528" y="-160" />
        <omgdi:waypoint x="622" y="-160" />
      </bpmndi:BPMNEdge>
    </bpmndi:BPMNPlane>
  </bpmndi:BPMNDiagram>
</definitions>
</bpmnio>

===== ✘ How NOT to =====

<bpmnio type="bpmn">
<?xml version="1.0" encoding="UTF-8"?>
<definitions xmlns="http://www.omg.org/spec/BPMN/20100524/MODEL" xmlns:bpmndi="http://www.omg.org/spec/BPMN/20100524/DI" xmlns:omgdi="http://www.omg.org/spec/DD/20100524/DI" xmlns:omgdc="http://www.omg.org/spec/DD/20100524/DC" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" id="sid-38422fae-e03e-43a3-bef4-bd33b32041b2" targetNamespace="http://bpmn.io/bpmn" exporter="http://bpmn.io" exporterVersion="0.10.1">
  <process id="Process_0kf0077">
    <intermediateCatchEvent id="Event_0r0tew3" name="Payment due date">
      <incoming>Flow_0opoyid</incoming>
      <outgoing>Flow_1tv5ius</outgoing>
      <timerEventDefinition id="TimerEventDefinition_1a77cp0" />
    </intermediateCatchEvent>
    <intermediateCatchEvent id="Event_09tpike" name="Payment obtained">
      <incoming>Flow_11x2rmj</incoming>
      <outgoing>Flow_1j4cmln</outgoing>
      <messageEventDefinition id="MessageEventDefinition_0j2tmjq" />
    </intermediateCatchEvent>
    <eventBasedGateway id="Gateway_0qwge4c">
      <incoming>Flow_1elj1ik</incoming>
      <outgoing>Flow_11x2rmj</outgoing>
      <outgoing>Flow_0opoyid</outgoing>
    </eventBasedGateway>
    <sequenceFlow id="Flow_11x2rmj" sourceRef="Gateway_0qwge4c" targetRef="Event_09tpike" />
    <sequenceFlow id="Flow_0opoyid" sourceRef="Gateway_0qwge4c" targetRef="Event_0r0tew3" />
    <startEvent id="Event_01ljcuy">
      <outgoing>Flow_104xfj6</outgoing>
    </startEvent>
    <sequenceFlow id="Flow_1j4cmln" sourceRef="Event_09tpike" targetRef="Event_1k1tn88" />
    <task id="Activity_12mr8cn" name="Clarify delay with the client">
      <incoming>Flow_1tv5ius</incoming>
      <outgoing>Flow_06rckk1</outgoing>
    </task>
    <sequenceFlow id="Flow_1tv5ius" sourceRef="Event_0r0tew3" targetRef="Activity_12mr8cn" />
    <exclusiveGateway id="Gateway_0gfb7mo" name="Wait more?">
      <incoming>Flow_06rckk1</incoming>
      <outgoing>Flow_0eyb0h5</outgoing>
      <outgoing>Flow_083x67t</outgoing>
    </exclusiveGateway>
    <sequenceFlow id="Flow_06rckk1" sourceRef="Activity_12mr8cn" targetRef="Gateway_0gfb7mo" />
    <sequenceFlow id="Flow_0eyb0h5" name="no" sourceRef="Gateway_0gfb7mo" targetRef="Event_04k06ga" />
    <endEvent id="Event_1k1tn88" name="Paid">
      <incoming>Flow_1j4cmln</incoming>
    </endEvent>
    <endEvent id="Event_04k06ga" name="Not paid">
      <incoming>Flow_0eyb0h5</incoming>
    </endEvent>
    <exclusiveGateway id="Gateway_057c6r5">
      <incoming>Flow_104xfj6</incoming>
      <incoming>Flow_083x67t</incoming>
      <outgoing>Flow_1elj1ik</outgoing>
    </exclusiveGateway>
    <sequenceFlow id="Flow_104xfj6" sourceRef="Event_01ljcuy" targetRef="Gateway_057c6r5" />
    <sequenceFlow id="Flow_1elj1ik" sourceRef="Gateway_057c6r5" targetRef="Gateway_0qwge4c" />
    <sequenceFlow id="Flow_083x67t" name="yes" sourceRef="Gateway_0gfb7mo" targetRef="Gateway_057c6r5" />
  </process>
  <bpmndi:BPMNDiagram id="BpmnDiagram_1">
    <bpmndi:BPMNPlane id="BpmnPlane_1" bpmnElement="Process_0kf0077">
      <bpmndi:BPMNShape id="Gateway_182m8yn_di" bpmnElement="Gateway_0qwge4c">
        <omgdc:Bounds x="395" y="-145" width="50" height="50" />
      </bpmndi:BPMNShape>
      <bpmndi:BPMNShape id="Event_0lccgc3_di" bpmnElement="Event_09tpike">
        <omgdc:Bounds x="512" y="-138" width="36" height="36" />
        <bpmndi:BPMNLabel>
          <omgdc:Bounds x="486" y="-95" width="89" height="14" />
        </bpmndi:BPMNLabel>
      </bpmndi:BPMNShape>
      <bpmndi:BPMNShape id="Event_1f2yzhy_di" bpmnElement="Event_0r0tew3">
        <omgdc:Bounds x="512" y="-258" width="36" height="36" />
        <bpmndi:BPMNLabel>
          <omgdc:Bounds x="485" y="-215" width="90" height="14" />
        </bpmndi:BPMNLabel>
      </bpmndi:BPMNShape>
      <bpmndi:BPMNShape id="Event_01ljcuy_di" bpmnElement="Event_01ljcuy">
        <omgdc:Bounds x="212" y="-138" width="36" height="36" />
      </bpmndi:BPMNShape>
      <bpmndi:BPMNShape id="Activity_12mr8cn_di" bpmnElement="Activity_12mr8cn">
        <omgdc:Bounds x="600" y="-280" width="100" height="80" />
        <bpmndi:BPMNLabel />
      </bpmndi:BPMNShape>
      <bpmndi:BPMNShape id="Gateway_0gfb7mo_di" bpmnElement="Gateway_0gfb7mo" isMarkerVisible="true">
        <omgdc:Bounds x="755" y="-265" width="50" height="50" />
        <bpmndi:BPMNLabel>
          <omgdc:Bounds x="752" y="-205" width="56" height="14" />
        </bpmndi:BPMNLabel>
      </bpmndi:BPMNShape>
      <bpmndi:BPMNShape id="Event_081tn46_di" bpmnElement="Event_1k1tn88">
        <omgdc:Bounds x="632" y="-138" width="36" height="36" />
        <bpmndi:BPMNLabel>
          <omgdc:Bounds x="639" y="-95" width="23" height="14" />
        </bpmndi:BPMNLabel>
      </bpmndi:BPMNShape>
      <bpmndi:BPMNShape id="Gateway_057c6r5_di" bpmnElement="Gateway_057c6r5" isMarkerVisible="true">
        <omgdc:Bounds x="295" y="-145" width="50" height="50" />
      </bpmndi:BPMNShape>
      <bpmndi:BPMNShape id="Event_1odkgr3_di" bpmnElement="Event_04k06ga">
        <omgdc:Bounds x="852" y="-258" width="36" height="36" />
        <bpmndi:BPMNLabel>
          <omgdc:Bounds x="849" y="-215" width="42" height="14" />
        </bpmndi:BPMNLabel>
      </bpmndi:BPMNShape>
      <bpmndi:BPMNEdge id="Flow_11x2rmj_di" bpmnElement="Flow_11x2rmj">
        <omgdi:waypoint x="445" y="-120" />
        <omgdi:waypoint x="512" y="-120" />
      </bpmndi:BPMNEdge>
      <bpmndi:BPMNEdge id="Flow_0opoyid_di" bpmnElement="Flow_0opoyid">
        <omgdi:waypoint x="420" y="-145" />
        <omgdi:waypoint x="420" y="-240" />
        <omgdi:waypoint x="512" y="-240" />
      </bpmndi:BPMNEdge>
      <bpmndi:BPMNEdge id="Flow_1j4cmln_di" bpmnElement="Flow_1j4cmln">
        <omgdi:waypoint x="548" y="-120" />
        <omgdi:waypoint x="632" y="-120" />
      </bpmndi:BPMNEdge>
      <bpmndi:BPMNEdge id="Flow_1tv5ius_di" bpmnElement="Flow_1tv5ius">
        <omgdi:waypoint x="548" y="-240" />
        <omgdi:waypoint x="600" y="-240" />
      </bpmndi:BPMNEdge>
      <bpmndi:BPMNEdge id="Flow_06rckk1_di" bpmnElement="Flow_06rckk1">
        <omgdi:waypoint x="700" y="-240" />
        <omgdi:waypoint x="755" y="-240" />
      </bpmndi:BPMNEdge>
      <bpmndi:BPMNEdge id="Flow_0eyb0h5_di" bpmnElement="Flow_0eyb0h5">
        <omgdi:waypoint x="805" y="-240" />
        <omgdi:waypoint x="852" y="-240" />
        <bpmndi:BPMNLabel>
          <omgdc:Bounds x="822" y="-258" width="13" height="14" />
        </bpmndi:BPMNLabel>
      </bpmndi:BPMNEdge>
      <bpmndi:BPMNEdge id="Flow_104xfj6_di" bpmnElement="Flow_104xfj6">
        <omgdi:waypoint x="248" y="-120" />
        <omgdi:waypoint x="295" y="-120" />
      </bpmndi:BPMNEdge>
      <bpmndi:BPMNEdge id="Flow_1elj1ik_di" bpmnElement="Flow_1elj1ik">
        <omgdi:waypoint x="345" y="-120" />
        <omgdi:waypoint x="395" y="-120" />
      </bpmndi:BPMNEdge>
      <bpmndi:BPMNEdge id="Flow_083x67t_di" bpmnElement="Flow_083x67t">
        <omgdi:waypoint x="780" y="-265" />
        <omgdi:waypoint x="780" y="-330" />
        <omgdi:waypoint x="320" y="-330" />
        <omgdi:waypoint x="320" y="-145" />
        <bpmndi:BPMNLabel>
          <omgdc:Bounds x="542" y="-348" width="17" height="14" />
        </bpmndi:BPMNLabel>
      </bpmndi:BPMNEdge>
    </bpmndi:BPMNPlane>
  </bpmndi:BPMNDiagram>
</definitions>
</bpmnio>

===== Notes =====

Mind the difference between the diagrams below: while "to do" process waits for the message all the time till the end, "no to do" process interrupts when the timer triggers. If the message arrives while we are clarifying delay with the client, it won't be caught and the process will hang after returning to the event gateway.
===== See also =====

  * [[en:rule:control_branch]]
===== Автор(ы) =====

 --- //[[user:bell|Anatoly Belaychuk]] 2023-09-10 12:51//