Module de.haumacher.msgbuf

Package de.haumacher.msgbuf.observer

Interface Listener

All Known Implementing Classes:

DefaultScope, Listener.MultiplexListener

public interface Listener

A listener observing an Observable object.

Nested Class Summary

Nested Classes

Modifier and Type	Interface	Description
static class	Listener.MultiplexListener	Listener that multiplexes events to a list of potentially multiple target Listeners.

Field Summary

Fields

Modifier and Type	Field	Description
static Listener	NONE	A Listener ignoring all events.

Method Summary

Modifier and Type	Method	Description
default void	afterRemove(Observable obj, String property, int index, Object element)	Informs this Listener that an element was removed from a repeated property with the given name.
default void	afterRemove(Observable obj, String property, Object index, Object element)	Informs this Listener that an element was removed from a map property with the given name.
default void	beforeAdd(Observable obj, String property, int index, Object element)	Informs this Listener that an element will be added to the repeated property with the given name.
default void	beforeAdd(Observable obj, String property, Object index, Object element)	Informs this Listener that an element will be added to the map property with the given name.
void	beforeSet(Observable obj, String property, Object value)	Informs this Listener that the value of the given property is to be modified.
static Listener	register(Listener current, Listener added)	Utility to use a single field of type Listener as storage for potentially multiple attached Listeners.
static Listener	unregister(Listener current, Listener removed)	Utility to remove a Listener from a listener list stored in a single field of type Listener.

Field Detail

NONE

static final Listener NONE

A Listener ignoring all events.

Method Detail

beforeSet

void beforeSet(Observable obj,
               String property,
               Object value)

Informs this Listener that the value of the given property is to be modified.

Parameters:

obj - The Observable object.

property - The name of the property to be modified.

value - The new value that is being set to the given property.

beforeAdd

default void beforeAdd(Observable obj,
                       String property,
                       int index,
                       Object element)

Informs this Listener that an element will be added to the repeated property with the given name.

Parameters:

obj - The Observable object.

property - The name of the property to be modified.

index - The index where the new element will be added if the property is ordered, -1 otherwise.

element - The new element that is being added to the given property.

beforeAdd

default void beforeAdd(Observable obj,
                       String property,
                       Object index,
                       Object element)

Informs this Listener that an element will be added to the map property with the given name.

Parameters:

obj - The Observable object.

property - The name of the property to be modified.

index - The index where the new element will be added if the property is ordered, -1 otherwise.

element - The new element that is being added to the given property.

afterRemove

default void afterRemove(Observable obj,
                         String property,
                         int index,
                         Object element)

Informs this Listener that an element was removed from a repeated property with the given name.

Parameters:

obj - The Observable object.

property - The name of the property to be modified.

index - The index where the element was removed if the property is ordered, -1 otherwise.

element - The element that was removed from the given property.

afterRemove

default void afterRemove(Observable obj,
                         String property,
                         Object index,
                         Object element)

Informs this Listener that an element was removed from a map property with the given name.

Parameters:

obj - The Observable object.

property - The name of the property to be modified.

index - The index where the element was removed if the property is ordered, -1 otherwise.

element - The element that was removed from the given property.

register

static Listener register(Listener current,
                         Listener added)

Utility to use a single field of type Listener as storage for potentially multiple attached Listeners.

To be used in the following way: _listener = Listener.register(_listener, newListener);

Parameters:

current - The current value of the the listener field.

added - The new Listener to add.

Returns:

The new value to store in the listener field.

unregister

static Listener unregister(Listener current,
                           Listener removed)

Utility to remove a Listener from a listener list stored in a single field of type Listener.

Parameters:

current - The current value of the the listener field.

removed - The Listener to remove.

Returns:

The new value to store in the listener field.

See Also:

register(Listener, Listener)