opendap.dap.Server
Class BTFunctionClause

java.lang.Object
  opendap.dap.Server.AbstractClause
      opendap.dap.Server.BTFunctionClause

All Implemented Interfaces:

Clause, SubClause

public class BTFunctionClause
extends AbstractClause
implements SubClause

Represents a clause which invokes a function that returns a BaseType.

Author:

joew

See Also:

ClauseFactory

Field Summary

protected BTFunction	function
protected Clause	parent
protected BaseType	value

Fields inherited from class opendap.dap.Server.AbstractClause

children, constant, defined

Constructor Summary

protected

BTFunctionClause(BTFunction function, java.util.List children) Creates a new BTFunctionClause.

Method Summary

BaseType	evaluate() Evaluates the clause, first calling evaluate() on any sub-clauses it contains.
BTFunction	getFunction() Returns the server-side function invoked by this clause
Clause	getParent() Returns the Clause which contains this subclause.
BaseType	getValue() Returns a BaseType containing the current value of the sub-clause.
void	setParent(Clause parent) Sets the parent of this subclause.
java.lang.String	toString() Prints the original string representation of this clause.

Methods inherited from class opendap.dap.Server.AbstractClause

getChildren, isConstant, isDefined

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, wait, wait, wait

Methods inherited from interface opendap.dap.Server.Clause

getChildren, isConstant, isDefined

Field Detail

parent

protected Clause parent

function

protected BTFunction function

value

protected BaseType value

Constructor Detail

BTFunctionClause

protected BTFunctionClause(BTFunction function,
                           java.util.List children)
                    throws DAP2ServerSideException

Creates a new BTFunctionClause.

Parameters:

function - The function invoked by the clause

children - A list of SubClauses, to be given as arguments to the function. If all the arguments are constant, the function clause will be flagged as constant, and evaluated immediately.

Throws:

DAP2ServerSideException - Thrown if either 1) the function does not accept the arguments given, or 2) the clause is constant, and the attempt to evaluate it fails.

Method Detail

getParent

public Clause getParent()

Description copied from interface: SubClause

Returns the Clause which contains this subclause. The clause returned may be a TopLevelClause or another SubClause.

Specified by:

getParent in interface SubClause

getValue

public BaseType getValue()

Description copied from interface: SubClause

Returns a BaseType containing the current value of the sub-clause. Sub-clauses that are not constant have an undefined value until the evaluate() method has been called. However, in such circumstances this method is still useful, as it indicates which class of BaseType the sub-clause will evaluate to. Implementations of this method should never return null.

Specified by:

getValue in interface SubClause

evaluate

public BaseType evaluate()
                  throws DAP2ServerSideException

Description copied from interface: SubClause

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.

Specified by:

evaluate in interface SubClause

Throws:

DAP2ServerSideException - Thrown if the evaluation fails for any reason.

setParent

public void setParent(Clause parent)

Description copied from interface: SubClause

Sets the parent of this subclause. Used during parsing.

Specified by:

setParent in interface SubClause

getFunction

public BTFunction getFunction()

Returns the server-side function invoked by this clause

toString

public java.lang.String toString()

Prints the original string representation of this clause. For use in debugging.

Overrides:

toString in class java.lang.Object