echopoint
Class BlackHole

java.lang.Object
  nextapp.echo.Component
      nextapp.echo.Container
          echopoint.BlackHole

All Implemented Interfaces:

java.io.Serializable

public class BlackHole

extends nextapp.echo.Container

The BlackHole class is a component that will NEVER render anything. However because it is always visible, it gets a rendering peer and hence so do its visible children.

So this component will swallow other components, preventing them from from getting rendered, however it does not prevent them getting actual rendering peers. Therefore this class is most useful as a child (perhaps hidden) component of another component implementation.

You will know when you need to use this class, which is not very often.

This component works like the DevNull component, except that it is always visible and hence it children can get rendering peers.

See Also:

DevNull, Serialized Form

Field Summary

Fields inherited from class nextapp.echo.Component

BACKGROUND_CHANGED_PROPERTY, CHILDREN_CHANGED_PROPERTY, ENABLED_CHANGED_PROPERTY, FONT_CHANGED_PROPERTY, FOREGROUND_CHANGED_PROPERTY, IDENTIFIER_CHANGED_PROPERTY, listenerList, LOCALE_CHANGED_PROPERTY, MODEL_CHANGED_PROPERTY, STYLE_BACKGROUND, STYLE_FONT, STYLE_FOREGROUND, UPDATE_PROPERTY, VISIBLE_CHANGED_PROPERTY

Constructor Summary

BlackHole()
Constructs a BlackHole that is always visible and hence gets a rendering peer for itself and any of its visible children..

Method Summary

void	setVisible(boolean newValue) The BlackHole is always visible and hence does get a rendering peer for itself and any of its visible children.

Methods inherited from class nextapp.echo.Component

add, add, addHierarchyListener, addPropertyChangeListener, applyStyle, firePropertyChange, firePropertyChange, firePropertyChange, firePropertyChange, firePropertyChange, firePropertyChange, firePropertyChange, getBackground, getComponent, getComponentCount, getComponents, getEchoInstance, getFont, getForeground, getIdentifier, getLocale, getParent, indexOf, init, isAncestorOf, isEnabled, isRegistered, isShowing, isVisible, remove, remove, removeAll, removeHierarchyListener, removePropertyChangeListener, setBackground, setEnabled, setFont, setForeground, setIdentifier, setLocale, update, validate

Methods inherited from class java.lang.Object

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

Constructor Detail

BlackHole

public BlackHole()

Constructs a BlackHole that is always visible and hence gets a rendering peer for itself and any of its visible children..

Method Detail

setVisible

public void setVisible(boolean newValue)

The BlackHole is always visible and hence does get a rendering peer for itself and any of its visible children.

See Also:

Component.setVisible(boolean)