Package opendap.servers

Interface TopLevelClause

All Superinterfaces:
Clause
All Known Implementing Classes:
BoolFunctionClause, RelOpClause
public interface TopLevelClause extends Clause
Represents a top-level clause in the selection portion of a constraint expression (CE).

A top-level clause is a boolean expression preceded by "&" in the CE, such as "lat>10.0", or "function(var1,var2)". The top-level clause may contain sub-clauses which can be evaluated individually.

The parser supports several kinds of top-level clause. These are described in the ClauseFactory interface.

See SubClause for more about sub-clauses.

See CEEValuator for an explanation of how Clauses are evaluated on data.

See Also:

  • Method Summary

    Modifier and Type
    Method
    Description
    boolean
    evaluate()
    Evaluates the clause, first calling evaluate() on any sub-clauses it contains.
    boolean
    getValue()
    Returns the current value of the clause.

    Methods inherited from interface opendap.servers.Clause

    getChildren, isConstant, isDefined, printConstraint

  • Method Details

    • getValue

      boolean getValue()
      Returns the current value of the clause. The value of non-constant Clauses is undefined until the evaluate() method has been called.

    • evaluate

      boolean evaluate() throws DAP2ServerSideException
      Evaluates the clause, first calling evaluate() on any sub-clauses it contains. Implementations of this method should flag the clause as "defined" if the evaluation is successful.
      Throws:
      DAP2ServerSideException - Thrown if the evaluation fails for any reason.