opendap.Server
Class DereferenceClause

java.lang.Object
  opendap.Server.AbstractClause
      opendap.Server.DereferenceClause

All Implemented Interfaces:

Clause, SubClause

public class DereferenceClause
extends AbstractClause
implements SubClause

Represents a sub-clause that is a URL reference to remote data. This feature is not yet supported in Java. Thus this class throws an exception in its constructor.

Author:

joew

See Also:

ClauseFactory

Field Summary

protected Clause	parent
protected String	url
protected BaseType	value

Fields inherited from class opendap.Server.AbstractClause

children, constant, defined

Constructor Summary

protected

DereferenceClause(String url) Creates a new DereferenceClause

Method Summary

BaseType	evaluate() Evaluates the clause, first calling evaluate() on any sub-clauses it contains.
Clause	getParent() Returns the Clause which contains this subclause.
String	getURL()
BaseType	getValue() Returns a BaseType containing the current value of the sub-clause.
void	printConstraint(PrintWriter os) Dump clause as in constraint form
protected BaseType	retrieve(String url)
void	setParent(Clause parent) Sets the parent of this subclause.

Methods inherited from class opendap.Server.AbstractClause

getChildren, isConstant, isDefined

Methods inherited from class java.lang.Object

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

Methods inherited from interface opendap.Server.Clause

getChildren, isConstant, isDefined

Field Detail

url

protected String url

parent

protected Clause parent

value

protected BaseType value

Constructor Detail

DereferenceClause

protected DereferenceClause(String url)
                     throws DAP2ServerSideException

Creates a new DereferenceClause

Throws:

DAP2ServerSideException

Method Detail

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()

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

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

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

getURL

public String getURL()

retrieve

protected BaseType retrieve(String url)
                     throws DAP2ServerSideException

Throws:

DAP2ServerSideException

printConstraint

public void printConstraint(PrintWriter os)

Description copied from interface: Clause

Dump clause as in constraint form

Specified by:

printConstraint in interface Clause