jimm.datavision.field
Class FormulaField

java.lang.Object
  java.util.Observable
      jimm.datavision.Element
          jimm.datavision.field.Field
              jimm.datavision.field.FormulaField

All Implemented Interfaces:

java.lang.Cloneable, java.util.Observer, Draggable, Identity, Writeable

public class FormulaField
extends Field
implements java.util.Observer

A formula field represents a formula calculated on-the-fly. The value of a formula field holds a Formula object. (In the XML, the formula field's value is the id of the formula.)

Author:

Jim Menard, jimm@io.com

Field Summary

protected Formula

formula

Fields inherited from class jimm.datavision.field.Field

border, bounds, cache, DEFAULT_HEIGHT, DEFAULT_WIDTH, format, id, maxIdSeen, value

Fields inherited from class jimm.datavision.Element

report, section, visible

Constructor Summary

FormulaField(java.lang.Long id, Report report, Section section, java.lang.Object value, boolean visible)
Constructs a formula field with the specified id in the specified report section whose Formula's id is value.

Method Summary

boolean	canBeAggregated() This override returns true if this formula is in a detail section.
java.util.Collection	columnsUsed() Returns a collection of the columns used in the formula.
java.lang.String	designLabel() Returns a string representing the field in the GUI during report design.
java.lang.String	dragString() Not really used; we drag formulas, not formula fields.
protected void	finalize()
java.lang.String	formulaString() Returns a string representing the field as it appears in a formula.
Formula	getFormula() Returns the formula.
java.lang.Object	getValue() Returns the value of this field.
FieldWidget	makeWidget(SectionWidget sw) Returns a new widget of the appropriate FieldWidget subclass for this field.
boolean	refersTo(Field f) Returns true if this field contains a reference to the specified field.
boolean	refersTo(Formula f) Returns true if this field contains a reference to the specified formula.
boolean	refersTo(Parameter p) Returns true if this field contains a reference to the specified parameter.
boolean	refersTo(UserColumn uc) Returns true if this field contains a reference to the specified user column.
void	setFormula(Formula newFormula) Sets the formula.
java.lang.String	typeString() Returns the string that specifies this field's type in the report XML.
void	update(java.util.Observable o, java.lang.Object arg)
java.util.Collection	userColumnsUsed() Returns a collection of the user columns used in the formula.

Methods inherited from class jimm.datavision.field.Field

clone, create, createFromDragString, getBorder, getBorderOrDefault, getBounds, getFormat, getId, getOutputHeight, setBorder, setBounds, setFormat, setValue, toString, writeFieldGuts, writeXML

Methods inherited from class jimm.datavision.Element

getReport, getSection, isVisible, setSection, setVisible

Methods inherited from class java.util.Observable

addObserver, clearChanged, countObservers, deleteObserver, deleteObservers, hasChanged, notifyObservers, notifyObservers, setChanged

Methods inherited from class java.lang.Object

equals, getClass, hashCode, notify, notifyAll, wait, wait, wait

Field Detail

formula

protected Formula formula

Constructor Detail

FormulaField

public FormulaField(java.lang.Long id,
                    Report report,
                    Section section,
                    java.lang.Object value,
                    boolean visible)

Constructs a formula field with the specified id in the specified report section whose Formula's id is value.

Parameters:

id - the new field's id

report - the report containing this element

section - the report section in which the field resides

value - the id of a formula

visible - show/hide flag

Method Detail

finalize

protected void finalize()
                 throws java.lang.Throwable

Overrides:

finalize in class Field

Throws:

java.lang.Throwable

update

public void update(java.util.Observable o,
                   java.lang.Object arg)

Specified by:

update in interface java.util.Observer

Overrides:

update in class Field

makeWidget

public FieldWidget makeWidget(SectionWidget sw)

Description copied from class: Field

Returns a new widget of the appropriate FieldWidget subclass for this field. Subclasses override this method to return different types of widgets.

Overrides:

makeWidget in class Field

Parameters:

sw - a field widget

dragString

public java.lang.String dragString()

Not really used; we drag formulas, not formula fields.

Specified by:

dragString in interface Draggable

Specified by:

dragString in class Field

Returns:

the string used to identify the field when dragging

getFormula

public Formula getFormula()

Returns the formula.

Returns:

the formula

setFormula

public void setFormula(Formula newFormula)

Sets the formula.

Parameters:

newFormula - the new formula

typeString

public java.lang.String typeString()

Description copied from class: Field

Returns the string that specifies this field's type in the report XML.

Specified by:

typeString in class Field

Returns:

a string representing this field's type; used in XML files

designLabel

public java.lang.String designLabel()

Description copied from class: Field

Returns a string representing the field in the GUI during report design.

Overrides:

designLabel in class Field

Returns:

a string useful for display in the design GUI

formulaString

public java.lang.String formulaString()

Description copied from class: Field

Returns a string representing the field as it appears in a formula.

Specified by:

formulaString in class Field

Returns:

a string useful in a formula

refersTo

public boolean refersTo(Field f)

Description copied from class: Field

Returns true if this field contains a reference to the specified field. Most fields return false; only a AggregateField or FormulaField would return true.

Overrides:

refersTo in class Field

Parameters:

f - a field

Returns:

true if this field contains a reference to the specified field

refersTo

public boolean refersTo(Formula f)

Description copied from class: Field

Returns true if this field contains a reference to the specified formula. Most fields return false; only a AggregateField or FormulaField would return true.

Overrides:

refersTo in class Field

Parameters:

f - a formula

Returns:

true if this field contains a reference to the specified field

refersTo

public boolean refersTo(UserColumn uc)

Description copied from class: Field

Returns true if this field contains a reference to the specified user column. Most fields return false; only a AggregateField, UserColumnField, or FormulaField would return true.

Overrides:

refersTo in class Field

Parameters:

uc - a user column

Returns:

true if this field contains a reference to the specified user column

refersTo

public boolean refersTo(Parameter p)

Description copied from class: Field

Returns true if this field contains a reference to the specified parameter. Most fields return false; only a AggregateField or FormulaField would return true.

Overrides:

refersTo in class Field

Parameters:

p - a parameter

Returns:

true if this field contains a reference to the specified field

canBeAggregated

public boolean canBeAggregated()

This override returns true if this formula is in a detail section. We don't really know that this formula returns a number, so we'll err on the side of allowing aggregation.

Overrides:

canBeAggregated in class Field

Returns:

true if this field can be aggregated

getValue

public java.lang.Object getValue()

Returns the value of this field. For formula fields, this is the value generated by evaluating the Formula.

Overrides:

getValue in class Field

Returns:

the result of evaluating the formula

columnsUsed

public java.util.Collection columnsUsed()

Returns a collection of the columns used in the formula. This is used by the report's query when it is figuring out what columns and tables are used by the report. Calls Expression.columnsUsed().

Returns:

a possibly empty collection of database columns

See Also:

Query.findSelectablesUsed()

userColumnsUsed

public java.util.Collection userColumnsUsed()

Returns a collection of the user columns used in the formula. This is used by the report's query when it is figuring out what columns, tables, and user columns are used by the report. Calls Expression.userColumnsUsed().

Returns:

a possibly empty collection of user columns

See Also:

Query.findSelectablesUsed()