Package com.inductiveautomation.ignition.gateway.tags.managed

Interface WriteHandler

All Known Subinterfaces:
SecureWriteHandler
public interface WriteHandler
Note: it is recommended to extend the SecureWriteHandler instead of the WriteHandler directly. The original WriteHandler interface did not take SecurityContext into account. An overload was later added so that SecurityContext could be passed along with the write request, though due to backwards-compatibility reasons, the default implementation of the overload ignores the SecurityContext and delegates to the original overload without the SecurityContext, effectively ignoring the SecurityContext. SecureWriteHandler reverses this paradigm so that the overload without SecurityContext has a default implementation which delegates to the overload with SecurityContext by passing SecurityContext.emptyContext() and the overload with SecurityContext is overridden so that it remains abstract, compelling implementations to override only the overload with SecurityContext.

  • Method Summary

    Modifier and Type
    Method
    Description
    QualityCode
    write(TagPath target, Object value)
    Should write the value to the given target, and return a quality code of success or failure.
    Important: A return value of Good_WritePending means that this handler does not want to handle the write (or will not execute it, exactly) and the write should be handled by the underlying tag implementation.
    default QualityCode
    write(TagPath target, Object value, SecurityContext securityContext)
    Same as write(TagPath, Object) except a SecurityContext may be passed in case permissions need to be checked for the write request.

  • Method Details

    • write

      QualityCode write(TagPath target, Object value)
      Should write the value to the given target, and return a quality code of success or failure.
      Important: A return value of Good_WritePending means that this handler does not want to handle the write (or will not execute it, exactly) and the write should be handled by the underlying tag implementation.

    • write

      default QualityCode write(TagPath target, Object value, SecurityContext securityContext)
      Same as write(TagPath, Object) except a SecurityContext may be passed in case permissions need to be checked for the write request. By default, this overload delegates to the aforementioned overload, effectively ignoring the SecurityContext, for backwards-compatibility reasons.