Class Expression

  extended by java.util.Observable
      extended by jimm.datavision.Expression
All Implemented Interfaces:
java.util.Observer, Draggable, Identity, Nameable, Writeable
Direct Known Subclasses:
Formula, UserColumn

public abstract class Expression
extends java.util.Observable
implements Identity, Nameable, Writeable, Draggable, java.util.Observer

The abstract superclass of objects that are evaluated, such as formulas and user columns. An expression contains text that is evaluated. The text may contain database column values, formulas, special values, or other types of objects.

Before being evaluated, the following substitutions are made withing the evaluation string: