org.apache.commons.configuration2.event

Class ConfigurationEvent

java.lang.Object

java.util.EventObject

org.apache.commons.configuration2.event.Event

org.apache.commons.configuration2.event.ConfigurationEvent

All Implemented Interfaces:

Serializable

public class ConfigurationEvent
extends Event

An event class for reporting updates on a configuration object.

Event objects of this type are used for "raw" events, i.e. unfiltered modifications of any kind. A level with semantically higher events (e.g. for property changes) may be built on top of this fundamental event mechanism.

Each event can contain the following data:

• A source object, which is usually the configuration object that was modified.
• The event's type. This is an object that corresponds to constant declarations in specific event classes. It describes what exactly has happened.
• If available, the name of the property whose modification caused the event.
• If available, the value of the property that caused this event.
• A flag whether this event was generated before or after the update of the source configuration. A modification of a configuration typically causes two events: one event before and one event after the modification is performed. This allows event listeners to react at the correct point of time.

The following standard events are generated by typical configuration implementations (the constants for the event types are defined in this class:

ADD_PROPERTY

This event is triggered for each call of the addProperty() method of a configuration object. It contains the name of the property, to which new data is added, and the value object that is added to this property (this may be an array or a list if multiple values are added).

SET_PROPERTY

Calling the setProperty() method triggers this event. The event object stores the name of the affected property and its new value.

CLEAR_PROPERTY

If a property is removed from a configuration (by calling the clearProperty() method), an event of this type is fired. In this case the event object only stores the name of the removed property, the value is null.

CLEAR

This event is fired when the whole configuration is cleared. The corresponding event object contains no additional data.

Since:

1.3

See Also:

Serialized Form

Field Summary

Fields

Modifier and Type	Field and Description
static EventType<ConfigurationEvent>	ADD_NODES Constant for the event type for an add nodes operation.
static EventType<ConfigurationEvent>	ADD_PROPERTY Constant for the event type for an add property operation.
static EventType<ConfigurationEvent>	ANY Constant for the common super type of all configuration update events.
static EventType<ConfigurationEvent>	ANY_HIERARCHICAL Constant for the common base event type for all hierarchical update events.
static EventType<ConfigurationEvent>	CLEAR Constant for the event type for a clear operation.
static EventType<ConfigurationEvent>	CLEAR_PROPERTY Constant for the event type for a clear property operation.
static EventType<ConfigurationEvent>	CLEAR_TREE Constant for the event type for a clear tree operation.
static EventType<ConfigurationEvent>	SET_PROPERTY Constant for the event type for a set property operation.
static EventType<ConfigurationEvent>	SUBNODE_CHANGED Constant for the event type indicating a change on a sub configuration.

Fields inherited from class java.util.EventObject

source

Constructor Summary

Constructors

Constructor and Description
ConfigurationEvent(Object source, EventType<? extends ConfigurationEvent> type, String propertyName, Object propertyValue, boolean beforeUpdate) Creates a new instance of ConfigurationEvent and initializes it.

Method Summary

Modifier and Type	Method and Description
String	getPropertyName() Returns the name of the affected property.
Object	getPropertyValue() Returns the value of the affected property if available.
boolean	isBeforeUpdate() Returns a flag if this event was generated before or after an update.

Methods inherited from class org.apache.commons.configuration2.event.Event

appendPropertyRepresentation, getEventType, toString

Methods inherited from class java.util.EventObject

getSource

Methods inherited from class java.lang.Object

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

Field Detail

ANY

public static final EventType<ConfigurationEvent> ANY

Constant for the common super type of all configuration update events.

Since:

2.0

ADD_PROPERTY

public static final EventType<ConfigurationEvent> ADD_PROPERTY

Constant for the event type for an add property operation.

Since:

2.0

SET_PROPERTY

public static final EventType<ConfigurationEvent> SET_PROPERTY

Constant for the event type for a set property operation.

Since:

2.0

CLEAR_PROPERTY

public static final EventType<ConfigurationEvent> CLEAR_PROPERTY

Constant for the event type for a clear property operation.

Since:

2.0

CLEAR

public static final EventType<ConfigurationEvent> CLEAR

Constant for the event type for a clear operation.

Since:

2.0

ANY_HIERARCHICAL

public static final EventType<ConfigurationEvent> ANY_HIERARCHICAL

Constant for the common base event type for all hierarchical update events. Events derived from this type are generated by some specific methods of hierarchical configurations.

Since:

2.0

ADD_NODES

public static final EventType<ConfigurationEvent> ADD_NODES

Constant for the event type for an add nodes operation.

Since:

2.0

CLEAR_TREE

public static final EventType<ConfigurationEvent> CLEAR_TREE

Constant for the event type for a clear tree operation.

Since:

2.0

SUBNODE_CHANGED

public static final EventType<ConfigurationEvent> SUBNODE_CHANGED

Constant for the event type indicating a change on a sub configuration.

Since:

2.0

Constructor Detail

ConfigurationEvent

public ConfigurationEvent(Object source,
                          EventType<? extends ConfigurationEvent> type,
                          String propertyName,
                          Object propertyValue,
                          boolean beforeUpdate)

Creates a new instance of ConfigurationEvent and initializes it.

Parameters:

source - the event source

type - the event's type

propertyName - the name of the affected property

propertyValue - the value of the affected property

beforeUpdate - the before update flag

Method Detail

getPropertyName

public String getPropertyName()

Returns the name of the affected property. This can be null if no property change has lead to this event.

Returns:

the name of the property

getPropertyValue

public Object getPropertyValue()

Returns the value of the affected property if available.

Returns:

the value of the property; can be null

isBeforeUpdate

public boolean isBeforeUpdate()

Returns a flag if this event was generated before or after an update.

Returns:

true if this event was generated before an update; false otherwise