org.jfree.report.function
Class ElementVisibilitySwitchFunction

java.lang.Object
  org.jfree.report.function.AbstractFunction
      org.jfree.report.function.ElementVisibilitySwitchFunction

All Implemented Interfaces:

java.lang.Cloneable, java.util.EventListener, Expression, Function, PageEventListener, ReportListener, java.io.Serializable

public class ElementVisibilitySwitchFunction

extends AbstractFunction

implements java.io.Serializable, PageEventListener

A function that alternates between true and false for each item within a group. The functions value affects a defined elements visibility. If the function evaluates to true, the named element is visible, else the element is invisible.

Elements in JFreeReport do not define their own background color attribute. To create a background, you would place a rectangle shape element behind the element.

The ElementVisibilitySwitchFunction is used to trigger the visibility of an named element. If the element is your background, you will get the alternating effect.

The ElementVisibilitySwitchFunction defines two parameters:

• element

  The name of the element in the itemband that should be modified. The element must be named using the "name" attribute, only the first occurence of that named element will be modfied.

• initial-state

  The initial state of the function. (true or false) defaults to false. This is the revers of the element's visiblity (set to false to start with an visible element, set to true to hide the element in the first itemrow).

Author:

Thomas Morgner

See Also:

Serialized Form

Field Summary

static java.lang.String	ELEMENT_PROPERTY the Property key for the name of the ItemBand element.
static java.lang.String	INITIAL_STATE_PROPERTY The initial state property key.

Fields inherited from interface org.jfree.report.function.Expression

AUTOACTIVATE_PROPERTY

Constructor Summary

ElementVisibilitySwitchFunction()
Default constructor.

Method Summary

java.lang.String	getElement() Returns the element name.
boolean	getInitialTriggerValue() Gets the initial value for the visible trigger, either "true" or "false".
java.lang.Object	getValue() Returns the defined visibility of the element.
void	initialize() Checks that the function has been correctly initialized.
void	itemsAdvanced(ReportEvent event) Triggers the visibility of an element.
void	itemsStarted(ReportEvent event) Receives notification that the items are being processed.
void	pageCanceled(ReportEvent event) Receives notification that a page was canceled by the ReportProcessor.
void	pageFinished(ReportEvent event) Receives notification that a page is completed.
void	pageStarted(ReportEvent event) Receives notification that a page has started.
void	setElement(java.lang.String name) Sets the element name.

Methods inherited from class org.jfree.report.function.AbstractFunction

clone, getDataRow, getDependencyLevel, getInstance, getName, getProperties, getProperty, getProperty, groupFinished, groupStarted, isActive, itemsFinished, reportDone, reportFinished, reportInitialized, reportStarted, setDataRow, setDependencyLevel, setName, setProperties, setProperty

Methods inherited from class java.lang.Object

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

Field Detail

ELEMENT_PROPERTY

public static final java.lang.String ELEMENT_PROPERTY

the Property key for the name of the ItemBand element.

See Also:

Constant Field Values

INITIAL_STATE_PROPERTY

public static final java.lang.String INITIAL_STATE_PROPERTY

The initial state property key.

See Also:

Constant Field Values

Constructor Detail

ElementVisibilitySwitchFunction

public ElementVisibilitySwitchFunction()

Default constructor.

Method Detail

pageStarted

public void pageStarted(ReportEvent event)

Receives notification that a page has started.

Specified by:

pageStarted in interface PageEventListener

Parameters:

event - the event.

pageCanceled

public void pageCanceled(ReportEvent event)

Receives notification that a page was canceled by the ReportProcessor. This method is called, when a page was removed from the report after it was generated.

Specified by:

pageCanceled in interface PageEventListener

Parameters:

event - The event.

pageFinished

public void pageFinished(ReportEvent event)

Receives notification that a page is completed.

Specified by:

pageFinished in interface PageEventListener

Parameters:

event - The event.

itemsStarted

public void itemsStarted(ReportEvent event)

Receives notification that the items are being processed. Sets the function value to false.

Following this event, there will be a sequence of itemsAdvanced events until the itemsFinished event is raised.

Specified by:

itemsStarted in interface ReportListener

Overrides:

itemsStarted in class AbstractFunction

Parameters:

event - Information about the event.

itemsAdvanced

public void itemsAdvanced(ReportEvent event)

Triggers the visibility of an element. If the named element was visible at the last itemsAdvanced call, it gets now invisible and vice versa. This creates the effect, that an element is printed every other line.

Specified by:

itemsAdvanced in interface ReportListener

Overrides:

itemsAdvanced in class AbstractFunction

Parameters:

event - the report event.

initialize

public void initialize()
                throws FunctionInitializeException

Checks that the function has been correctly initialized. The functions name or the elements name have not been set, and FunctionInitializeException is thrown.

Specified by:

initialize in interface Expression

Overrides:

initialize in class AbstractFunction

Throws:

FunctionInitializeException - if required parameters were missing and initialisation cannot be performed.

getInitialTriggerValue

public boolean getInitialTriggerValue()

Gets the initial value for the visible trigger, either "true" or "false".

Returns:

the initial value for the trigger.

setElement

public void setElement(java.lang.String name)

Sets the element name. The name denotes an element within the item band. The element will be retrieved using the getElement(String) function.

Parameters:

name - The element name.

See Also:

Band.getElement(String)

getElement

public java.lang.String getElement()

Returns the element name.

Returns:

The element name.

getValue

public java.lang.Object getValue()

Returns the defined visibility of the element. Returns either true or false as java.lang.Boolean.

Specified by:

getValue in interface Expression

Returns:

the visibility of the element, either Boolean.TRUE or Boolean.FALSE.