TopLevelClause (opendap-servlet 5.1 API)

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:

SubClause, CEEvaluator, ClauseFactory

Method Summary

All Methods Instance Methods Abstract Methods
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 Detail
  - 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.