Interface Constraint

  • All Known Implementing Classes:
    DefaultKeySizeConstraint, NoDeleteConstraint, VisibilityConstraint

    public interface Constraint
    Constraint objects are used to determine if mutations will be applied to a table.

    This interface expects implementers to return violation codes. The reason codes are returned instead of arbitrary strings to encourage conciseness. Conciseness is needed because violations are aggregated. If a user sends a batch of 10,000 mutations to Accumulo, only aggregated counts about which violations occurred are returned. If the constraint implementer were allowed to return arbitrary violation strings like the following:

    Value "abc" is not a number
    Value "vbg" is not a number

    This would not aggregate very well, because the same violation is represented with two different strings.

    • Method Detail

      • getViolationDescription

        String getViolationDescription​(short violationCode)
        Gets a short, one-sentence description of what a given violation code means.
        violationCode - numeric violation code
        matching violation description
      • check

        List<Short> check​(Constraint.Environment env,
                          Mutation mutation)
        Checks a mutation for constraint violations. If the mutation contains no violations, returns null. Otherwise, returns a list of violation codes. Violation codes must be non-negative. Negative violation codes are reserved for system use.
        env - constraint environment
        mutation - mutation to check
        list of violation codes, or null if none