BeanContextChild

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java.beans.beancontext
Interface BeanContextChild

All Known Subinterfaces:: BeanContext, BeanContextServices

All Known Implementing Classes:: BeanContextChildSupport, BeanContextServicesSupport, BeanContextSupport

public interface BeanContextChild

Beans implement this to get information about the execution environment and its services and to be placed in the hierarchy.

The difference between a BeanContext and a BeanContextChild, mainly, is that a BeanContext may be a parent.

BeanContextChild instances will be serialized at some point in their life, but you need to make sure your bean context does not contain a serializable reference (directly or indirectly) to the parent BeanContext, to any of the other BeanContexts in the tree, or to any resources obtained via the BeanContextServices interface. One way to do this is to mark any fields that contain such references as transient. Another way is to use a custom serializer.

If you do not do this, when the BeanContext is serialized, all the other BeanContexts and other unnecessary things will be serialized along with it.

Before dying, a BeanContextChild should call getBeanContext().remove(this) to detach from the hierarchy and exit cleanly.

Since:: JDK1.2

Method Summary

void addPropertyChangeListener(java.lang.String prop, java.beans.PropertyChangeListener listener)
          Add a listener that will be notified when a specific property changes.

void addVetoableChangeListener(java.lang.String prop, java.beans.VetoableChangeListener listener)
          Add a listener that will be notified when a specific property change is requested (a PropertyVetoException may be thrown) as well as after the change is successfully made.

BeanContext getBeanContext()
          Get the parent BeanContext.

void removePropertyChangeListener(java.lang.String prop, java.beans.PropertyChangeListener listener)
          Remove a listener to a certain property.

void removeVetoableChangeListener(java.lang.String prop, java.beans.VetoableChangeListener listener)
          Remove a listener to a certain property.

void setBeanContext(BeanContext parent)
          Set the parent BeanContext.

Method Detail

setBeanContext

public void setBeanContext(BeanContext parent)
                    throws java.beans.PropertyVetoException

Set the parent BeanContext.

This method is called from BeanContext.add() and should not be called directly.

When this Object is being added to a new BeanContext or moved from an old one, a non-null value will be passed in.

When this Object is being removed from the current BeanContext, setBeanContext() will receive the parameter null.

When being removed from the current BeanContext, it is the BeanContextChild's responsibility to release all services it has obtained.

This change should generate PropertyChangeEvent and VetoableChangeEvents with the property name "beanContext". If the change is vetoed, it must re-throw the exception and not change anything. In this way, the parent BeanContextChild, who has registered himself with you, will have a chance to remove this child from its collection.

If the Bean does not wish to change the parent or be removed from one, it may throw the PropertyVetoException. If you veto a setBeanContext(null) call, then you should try your hardest to remedy whatever problem is keeping you from being removed from the BeanContext so that you can not veto it the next time. Otherwise, nasty pathological recursion stuff could occur in certain situations.

If you do veto the change, you must first back out any changes you made prior to the veto. Best not to make any such changes prior to the veto in the first place.

This method is called from BeanContext.add() and should not be called directly.

getBeanContext

public BeanContext getBeanContext()

Get the parent BeanContext.

addPropertyChangeListener

public void addPropertyChangeListener(java.lang.String prop,
                                      java.beans.PropertyChangeListener listener)

Add a listener that will be notified when a specific property changes.

removePropertyChangeListener

public void removePropertyChangeListener(java.lang.String prop,
                                         java.beans.PropertyChangeListener listener)

Remove a listener to a certain property.

addVetoableChangeListener

public void addVetoableChangeListener(java.lang.String prop,
                                      java.beans.VetoableChangeListener listener)

Add a listener that will be notified when a specific property change is requested (a PropertyVetoException may be thrown) as well as after the change is successfully made.

removeVetoableChangeListener

public void removeVetoableChangeListener(java.lang.String prop,
                                         java.beans.VetoableChangeListener listener)