Package opendap.servers

Class AbstractClause

java.lang.Object
opendap.servers.AbstractClause
All Implemented Interfaces:
Clause
Direct Known Subclasses:
BoolFunctionClause, BTFunctionClause, DereferenceClause, RelOpClause, ValueClause
public abstract class AbstractClause extends Object implements Clause
Provides default implementations for the Clause interface methods. This eliminates redundant code and provides a starting point for new implementations of Clause.

Note that every Clause object is expected to implement either SubClause or TopLevelClause. No default implementations are provided for the methods of these subinterfaces

Also note that it is not necessary to use this class to create your own implementations, it's just a convenience.

The class has no abstract methods, but is declared abstract because it should not be directly instantiated.

  • Field Summary

    Fields
    Modifier and Type
    Field
    Description
    protected List
    children
    A list of SubClause objects representing the sub-clauses of this clause.
    protected boolean
    constant
    Value to be returned by isConstant().
    protected boolean
    defined
    Value to be returned by isDefined().

  • Constructor Summary

    Constructors
    Constructor
    Description
    AbstractClause()
     

  • Method Summary

    Modifier and Type
    Method
    Description
    List
    getChildren()
    Returns an ordered list of this clause's sub-clauses.
    boolean
    isConstant()
    A clause is considered "constant" iff it and its subclauses do not refer to data values from the dataset being constrained.
    boolean
    isDefined()
    Returns whether or not the clause has a defined value.

    Methods inherited from class java.lang.Object

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

    Methods inherited from interface opendap.servers.Clause

    printConstraint

  • Field Details

    • constant

      protected boolean constant
      Value to be returned by isConstant(). Should not change for the lifetime of the object.

    • defined

      protected boolean defined
      Value to be returned by isDefined(). May change during the lifetime of the object.

    • children

      protected List children
      A list of SubClause objects representing the sub-clauses of this clause. Use caution when modifying this list other than at the point of creation, since methods such as evaluate() depend on it.

  • Constructor Details

    • AbstractClause

      public AbstractClause()

  • Method Details

    • getChildren

      public List getChildren()
      Description copied from interface: Clause
      Returns an ordered list of this clause's sub-clauses. If the clause has no sub-clauses, an empty list will be returned.
      Specified by:
      getChildren in interface Clause

    • isConstant

      public boolean isConstant()
      Description copied from interface: Clause
      A clause is considered "constant" iff it and its subclauses do not refer to data values from the dataset being constrained. A constant clause is defined as soon as it is created, and is guaranteed not to change its value during its lifetime.
      Specified by:
      isConstant in interface Clause

    • isDefined

      public boolean isDefined()
      Description copied from interface: Clause
      Returns whether or not the clause has a defined value. Non-constant clauses do not have a defined value until they are evaluated for the first time. Methods for evaluating are found in the TopLevelClause and SubClause interfaces.
      Specified by:
      isDefined in interface Clause