Class BeanProperty<S,V>
- java.lang.Object
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- org.jdesktop.beansbinding.Property<S,V>
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- org.jdesktop.beansbinding.PropertyHelper<S,V>
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- org.jdesktop.beansbinding.BeanProperty<S,V>
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- Type Parameters:
S
- the type of source object that thisBeanProperty
operates onV
- the type of value that thisBeanProperty
represents
public final class BeanProperty<S,V> extends PropertyHelper<S,V>
An implementation ofProperty
that uses a simple dot-separated path syntax to address Java Beans properties of source objects. For example, to create a property representing thefirstName
property of an obect:BeanProperty.create("firstName");
Or to create a property representing the
firstName
property of an object'smother
property:BeanProperty.create("mother.firstName");
An instance of
BeanProperty
is immutable and can be used with different source objects. When aPropertyStateListener
is added to aBeanProperty
for a given source object, theBeanProperty
starts listening to all objects along the path (based on that source object) for change notification, and reflects any changes by notifying the listener associated with the property for that source object. So, in the second example above, if aPropertyStateListener
is added to the property for an objectDuke
, thePropertyStateListener
is notified when eitherDuke's
mother changes (if the new mother's name is different), orDuke's mother's firstName
changes.It is very important that any bean properties addressed via a
BeanProperty
follow the Java Beans specification, including firing property change notification; otherwise,BeanProperty
cannot respond to change. As some beans outside of your control may not follow the Java Beans specification,BeanProperty
always checks theBeanAdapterFactory
to see if a delegate provider has been registered to provide a delegate bean to take the place of an object for a given property. See the ext package level documentation for more details.When there are no
PropertyStateListeners
installed on aBeanProperty
for a given source, allProperty
methods act by traversing the entire path from the source to the end point, thereby always providing "live" information. On the contrary, when there arePropertyStateListeners
installed, the beans along the path (including the final value) are cached, and only updated upon notification of change from a bean. Again, this makes it very important that any bean property that could change along the path fires property change notification.Readability of a
BeanProperty
for a given source is defined as follows: ABeanProperty
is readable for a given source if and only if a) each bean in the path, starting with the source, defines a Java Beans getter method for the the property to be read on it AND b) each bean in the path, starting with the source and ending with the bean on which we read the final property, isnon-null
. The final value beingnull
does not affect the readability.So, in the second example given earlier, the
BeanProperty
is readable for (@code Duke} when all of the following are true:Duke
defines a Java Beans getter formother
,Duke's mother
defines a Java Beans getter forfirstName
,Duke
isnon-null
,Duke's mother
isnon-null
. TheBeanProperty
is therefore unreadable when any of the following is true:Duke
does not define a Java Beans getter formother
,Duke's mother
does not define a Java Beans getter forfirstName
,Duke
isnull
,Duke's mother
isnull
.Writeability of a
BeanProperty
for a given source is defined as follows: ABeanProperty
is writeable for a given source if and only if a) each bean in the path, starting with the source and ending with the bean on which we set the final property, defines a Java Beans getter method for the property to be read on it AND b) the bean on which we set the final property defines a Java Beans setter for the property to be set on it AND c) each bean in the path, starting with the source and ending with the bean on which we set the final property, isnon-null
. The final value beingnull
does not affect the writeability.So, in the second example given earlier, the
BeanProperty
is writeable forDuke
when all of the following are true:Duke
defines a Java Beans getter formother
,Duke's mother
defines a Java Beans setter forfirstName
,Duke
isnon-null
,Duke's mother
isnon-null
. TheBeanProperty
is therefore unreadable when any of the following is true:Duke
does not define a Java Beans getter formother
,Duke's mother
does not define a Java Beans setter forfirstName
,Duke
isnull
,Duke's mother
isnull
.In addition to working on Java Beans properties, any object in the path can be an instance of
Map
. In this case, theMap's get
method is used with the property name as the getter, and theMap's put
method is used with the property name as the setter.BeanProperty
can only respond to changes inMaps
if they are instances ofObservableMap
.Some methods in this class document that they can throw
PropertyResolutionException
if an exception occurs while trying to resolve the path. The throwing of this exception represents an abnormal condition and if listeners are installed for the given source object, leaves theBeanProperty
in an inconsistent state for that source object. ABeanProperty
should not be used again for that same source object after such an exception without first removing all listeners associated with theBeanProperty
for that source object.
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Method Summary
All Methods Static Methods Instance Methods Concrete Methods Modifier and Type Method Description static <S,V>
BeanProperty<S,V>create(java.lang.String path)
Creates an instance ofBeanProperty
for the given path.static <S,V>
BeanProperty<S,V>create(Property<S,?> baseProperty, java.lang.String path)
Creates an instance ofBeanProperty
for the given base property and path.V
getValue(S source)
Returns the value of thisProperty
for the given source.java.lang.Class<? extends V>
getWriteType(S source)
Returns the type of object that is suitable for setting as the value of thisProperty
by calls tosetValue
.boolean
isReadable(S source)
Returns whether or not theProperty
is readable for the given source.boolean
isWriteable(S source)
Returns whether or not theProperty
is writeable for the given source.protected void
listeningStarted(S source)
Called when thisPropertyHelper
changes from having no listeners installed for the given source object to having listeners installed for the given source object.protected void
listeningStopped(S source)
Called when thisPropertyHelper
changes from having listeners installed for the given source object to having no listeners installed for the given source object.void
setValue(S source, V value)
Sets the value of thisProperty
for the given source.java.lang.String
toString()
Returns a string representation of theBeanProperty
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Methods inherited from class org.jdesktop.beansbinding.PropertyHelper
addPropertyStateListener, firePropertyStateChange, getPropertyStateListeners, isListening, removePropertyStateListener
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Method Detail
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create
public static final <S,V> BeanProperty<S,V> create(java.lang.String path)
Creates an instance ofBeanProperty
for the given path.- Parameters:
path
- the path- Returns:
- an instance of
BeanProperty
for the given path - Throws:
java.lang.IllegalArgumentException
- if the path is null, or contains no property names
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create
public static final <S,V> BeanProperty<S,V> create(Property<S,?> baseProperty, java.lang.String path)
Creates an instance ofBeanProperty
for the given base property and path. The path is relative to the value of the base property.- Parameters:
baseProperty
- the base propertypath
- the path- Returns:
- an instance of
BeanProperty
for the given base property and path - Throws:
java.lang.IllegalArgumentException
- if the path is null, or contains no property names
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getWriteType
public java.lang.Class<? extends V> getWriteType(S source)
Returns the type of object that is suitable for setting as the value of thisProperty
by calls tosetValue
.See the class level documentation for the definition of writeability.
- Specified by:
getWriteType
in classPropertyHelper<S,V>
- Parameters:
source
- the source object on which to operate- Returns:
- the type of object suitable for setting as the value
- Throws:
java.lang.UnsupportedOperationException
- if theProperty
is not writeable for the given sourcePropertyResolutionException
- if an exception occurs while resolving the path- See Also:
setValue(S, V)
,isWriteable(S)
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getValue
public V getValue(S source)
Returns the value of thisProperty
for the given source.See the class level documentation for the definition of readability.
- Specified by:
getValue
in classPropertyHelper<S,V>
- Parameters:
source
- the source object on which to operate- Returns:
- the value of this
Property
for the given source - Throws:
java.lang.UnsupportedOperationException
- if theProperty
is not readable for the given sourcePropertyResolutionException
- if an exception occurs while resolving the path- See Also:
isReadable(S)
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setValue
public void setValue(S source, V value)
Sets the value of thisProperty
for the given source.See the class level documentation for the definition of writeability.
- Specified by:
setValue
in classPropertyHelper<S,V>
- Parameters:
source
- the source object on which to operatevalue
- the new value for theProperty
- Throws:
java.lang.UnsupportedOperationException
- if theProperty
is not writeable for the given sourcePropertyResolutionException
- if an exception occurs while resolving the path- See Also:
isWriteable(S)
,getWriteType(S)
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isReadable
public boolean isReadable(S source)
Returns whether or not theProperty
is readable for the given source.See the class level documentation for the definition of readability.
- Specified by:
isReadable
in classPropertyHelper<S,V>
- Parameters:
source
- the source object on which to operate- Returns:
- whether or not the
Property
is readable for the given source. - Throws:
java.lang.UnsupportedOperationException
PropertyResolutionException
- if an exception occurs while resolving the path- See Also:
isWriteable(S)
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isWriteable
public boolean isWriteable(S source)
Returns whether or not theProperty
is writeable for the given source.See the class level documentation for the definition of writeability.
- Specified by:
isWriteable
in classPropertyHelper<S,V>
- Parameters:
source
- the source object on which to operate- Returns:
- whether or not the
Property
is writeable for the given source. - Throws:
java.lang.UnsupportedOperationException
PropertyResolutionException
- if an exception occurs while resolving the path- See Also:
isReadable(S)
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listeningStarted
protected final void listeningStarted(S source)
Description copied from class:PropertyHelper
Called when thisPropertyHelper
changes from having no listeners installed for the given source object to having listeners installed for the given source object. This is the ideal time for subclasses to install any listeners needed to track change on the source object.- Overrides:
listeningStarted
in classPropertyHelper<S,V>
- See Also:
PropertyHelper.listeningStopped(S)
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listeningStopped
protected final void listeningStopped(S source)
Description copied from class:PropertyHelper
Called when thisPropertyHelper
changes from having listeners installed for the given source object to having no listeners installed for the given source object. This is the ideal time for subclasses to remove any listeners that they've installed to track changes on the source object.- Overrides:
listeningStopped
in classPropertyHelper<S,V>
- See Also:
PropertyHelper.listeningStopped(S)
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toString
public java.lang.String toString()
Returns a string representation of theBeanProperty
. This method is intended to be used for debugging purposes only, and the content and format of the returned string may vary between implementations. The returned string may be empty but may not benull
.- Overrides:
toString
in classjava.lang.Object
- Returns:
- a string representation of this
BeanProperty
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