Custom extensions are a standardized way to extend the DMN model.The Camunda extension attrributes are fully implemented in the DMN model API.

    Every DMN Decision element can have the attributes historyTimeToLive and versionTag.To access the extension attributes, you have to call the Decision#getCamundaHistoryTimeToLiveString() andDecision#getVersionTag() methods.

    1. String historyTimeToLive = decision.getCamundaHistoryTimeToLiveString();
    2. String versionTag = decision.getVersionTag();

    To set attributes, use Decision#setCamundaHistoryTimeToLiveString() and Decision#setVersionTag()

    1. decision.setCamundaHistoryTimeToLiveString("1000");
    2. decision.setVersionTag("1.0.0");

    Every Input element can have an inputVariable attribute.This attribute specifies the variable name which can be used to access the result of the input expression in an input entry expression.It can be set and fetched similarly, calling Input#setCamundaInputVariable() and Input#getCamundaInputVariable():

    1. input.setCamundaInputVariable("camundaInput");
    2. String camundaInput = input.getCamundaInputVariable();

    原文: https://docs.camunda.org/manual/7.9/user-guide/model-api/dmn-model-api/extension-attributes/