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## com.jgoodies.binding
Class PresentationModel<B>

    java.lang.Object
      com.jgoodies.common.bean.AbstractBean
          com.jgoodies.binding.beans.Model
              com.jgoodies.binding.PresentationModel<B>

Type Parameters:
  `B` - the type of the bean managed by this PresentationModel

All Implemented Interfaces:
  com.jgoodies.common.bean.ObservableBean, com.jgoodies.common.bean.ObservableBean2, Serializable

    public class PresentationModel<B>

extends Model

The standard base class to implement the Presentation Model pattern, that represents the state and behavior of a presentation independently of the GUI components used in the interface. This pattern is described in Martin Fowler's upcoming addition to his "Patterns of Enterprise Application Architecture". More details around this implementation of the Presentation Model pattern and a 3-tier Swing client architecture with a presentation model layer can be found in the JGoodies Binding presentation. This architecture is supported by the JGoodies Binding library.

This class minimizes the effort required to bind, edit, buffer, and observe the bound properties of an exchangeable bean. Therefore it provides five groups of features that are described below:

1. adapt bean properties,
2. change the adapted bean,
3. buffer values,
4. observe the buffering state, and
5. track changes in adapted bean properties.

Typically this class will be extended to add custom models, Actions, presentation logic, model operations and other higher-level behavior. However, in simple cases you can use this class as-is. Several methods are intended to be used as-is and a typical subclass should not modify them. For example #isChanged, #isBuffering, #getBean, #setBean, #getBeanChannel, #getModel, #getBufferedModel, #getTriggerChannel, #setTriggerChannel, #triggerCommit and #triggerFlush.

Adapting Bean Properties
The method `getModel(String)` vends ValueModels that adapt a bound bean property of an exchangeable bean. These ValueModels will be requested from an underlying BeanAdapter. To get such a model you specify the name of the bean property. All properties adapted must be read-write and must comply with the Java Bean coding conventions. In case you need to adapt a read-only or write-only property, or if the bean uses custom names for the reader and writer, use `getModel(String, String, String)`. Also note that you must not mix calls to these methods for the same property name. For details see the JavaDoc class comment in `BeanAdapter`.

Changing the Adapted Bean
The adapted bean is not stored in this PresentationModel. Instead it is held by a ValueModel, the bean channel - just as in the PropertyAdapter and BeanAdapter. This indirection enables you to manage the adapted bean outside of this PresentationModel, and it enables you to share bean channels between multiple PresentationModels, PropertyAdapters, and BeanAdapters. The bean channel is used by all adapting models created by the factory methods `#getModel`. You can get and set the current bean by means of `#getBean` and `#setBean`. Or you can set a new value to the bean channel.

PresentationModel fires three PropertyChangeEvents if the bean changes: beforeBean, bean and afterBean. This is useful when sharing a bean channel and you must perform an operation before or after other listeners handle a bean change. Since you cannot rely on the order listeners will be notified, only the beforeBean and afterBean events are guaranteed to be fired before and after the bean change is fired. Note that `#getBean()` returns the new bean before any of these three PropertyChangeEvents is fired. Therefore listeners that handle these events must use the event's old and new value to determine the old and new bean. The order of events fired during a bean change is:

1. the bean channel fires a value change,
2. this model fires a beforeBean change,
3. this model fires the bean change,
4. this model fires an afterBean change.

Buffering Values
At the core of this feature are the methods `getBufferedModel(String)` that vend BufferedValueModels that wrap an adapted bean property. The buffer can be committed or flushed using `#triggerCommit` and `#triggerFlush` respectively.

The trigger channel is provided as a bound Java bean property triggerChannel that must be a non-`null` `ValueModel` with values of type `Boolean`. Attempts to read or write other value types may be rejected with runtime exceptions. By default the trigger channel is initialized as an instance of `Trigger`. As an alternative it can be set in the constructor.

Observing the Buffering State
This class also provides support for observing the buffering state of the BufferedValueModels created with this model. The buffering state is useful for UI actions and operations that are enabled or disabled if there are pending changes, for example on OK or APPLY button. API users can request the buffering state via `#isBuffering` and can observe the bound property buffering.

Tracking Changes in the Adapted Bean
PresentationModel provides support for observing bean property changes and it tracks all changes to report the overall changed state. The latter is useful to detect whether the bean has changed at all, for example to mark the bean as dirty, so it will be updated in a database. API users can request the changed state via `#isChanged` and can observe the bound property changed. If you want to track changes of other ValueModels, bean properties, or of submodels, register them using `#observeChanged`. To reset the changed state invoke `#resetChanged`. In case you track the changed state of submodels you should override `#resetChanged` to reset the changed state in these submodels.

The changed state changes once only (from false to true). If you need instant notifications about changes in the properties of the target bean, you can register PropertyChangeListeners with this model. This is useful if you change the bean and don't want to move your listeners from one bean to the other. And it's useful if you want to observe multiple bean properties at the same time. These listeners are managed by the method set `#addBeanPropertyChangeListener` and `#removeBeanPropertyChangeListener`. Listeners registered via these methods will be removed from the old bean before the bean changes and will be re-added after the new bean has been set. Therefore these listeners will be notified about changes only if the current bean changes a property. They won't be notified if the bean changes - and in turn the property value. If you want to observes property changes caused by bean changes too, register with the adapting ValueModel as returned by `#getModel(String)`.

Instance Creation
PresentationModel can be instantiated using four different constructors: you can specify the target bean directly, or you can provide a bean channel to access the bean indirectly. In the latter case you specify a `ValueModel` that holds the bean that in turn holds the adapted property. In both cases the target bean is accessed indirectly through the bean channel. In both cases you can specify a custom trigger channel, or you can use a default trigger channel.

Note: This PresentationModel provides bound bean properties and you can register and unregister PropertyChangeListers as usual using `#addPropertyChangeListener` and `#removePropertyChangeListener`. Do not mix up the model listeners with the listeners registered with the bean.

Warning: PresentationModels register a PropertyChangeListener with the target bean. Hence, a bean has a reference to all PresentationModels that hold it as target bean. To avoid memory leaks it is recommended to remove this listener if the bean lives much longer than the PresentationModel, enabling the garbage collector to remove the PresentationModel. Setting a PresentationModel's target bean to null removes this listener, which in turn clears the reference from the bean to the PresentationModel. To do so, you can call `setBean(null)` or set the bean channel's value to null. As an alternative you can use event listener lists in your beans that implement references with `WeakReference`. Setting the bean to null has side effects, which is fine in most cases. However, you can release all listeners by calling `#release`.

TODO: Further improve the class comment.

TODO: Consider adding a feature to ensure that update notifications are performed in the event dispatch thread. In case the adapted bean is changed in a thread other than the event dispatch thread, such a feature would help complying with Swing's single thread rule. The feature could be implemented by an extended PropertyChangeSupport.

TODO: I plan to improve the support for adapting beans that do not fire PropertyChangeEvents. This affects the classes PropertyAdapter, BeanAdapter, and PresentationModel. Basically the PropertyAdapter and the BeanAdapter's internal SimplePropertyAdapter's shall be able to optionally self-fire a PropertyChangeEvent in case the bean does not. There are several downsides with self-firing events compared to bound bean properties. See Issue 49 for more information about the downsides.

The observeChanges constructor parameter shall be replaced by a more fine-grained choice to not observe (former observeChanges=false), to observe bound properties (former observeChanges=true), and a new setting for self-firing PropertyChangeEvents if a value is set. The latter case may be further split up to specify how the self-fired PropertyChangeEvent is created:

1. oldValue=null, newValue=null
2. oldValue=null, newValue=the value set
3. oldValue=value read before the set, newValue=the value set
4. oldValue=value read before the set, newValue=value read after the set

Version:
  $Revision: 1.26 $
Author:
  Karsten Lentzsch
See Also:
  `BeanAdapter`, `ValueModel`, `PropertyAdapter`, `Trigger`, Serialized Form

Field Summary
`static String` | `PROPERTYNAME_AFTER_BEAN` The property name used in the PropertyChangeEvent that is fired after the bean property fires its PropertyChangeEvent.
`static String` | `PROPERTYNAME_BEAN` The name of the read-write bound property that holds the target bean.
`static String` | `PROPERTYNAME_BEFORE_BEAN` The property name used in the PropertyChangeEvent that is fired before the bean property fires its PropertyChangeEvent.
`static String` | `PROPERTYNAME_BUFFERING` The name of the read-only bound bean property that indicates whether one of the buffered models is buffering.
`static String` | `PROPERTYNAME_CHANGED` The name of the read-only bound bean property that indicates whether one of the observed models has changed.
`static String` | `PROPERTYNAME_TRIGGERCHANNEL` The name of the read-write bound bean property for the trigger channel that is shared by all PropertyAdapters that are created via `#getBufferedModel`.

Fields inherited from class com.jgoodies.common.bean.AbstractBean
`changeSupport`

Constructor Summary
`PresentationModel(B bean)` Constructs a PresentationModel that adapts properties of the given bean.
`PresentationModel(B bean, ValueModel triggerChannel)` Constructs a PresentationModel on the given bean using the given trigger channel.
`PresentationModel(ValueModel beanChannel)` Constructs a PresentationModel on the given bean channel.
`PresentationModel(ValueModel beanChannel, ValueModel triggerChannel)` Constructs a PresentationModel on the given bean channel using the given trigger channel.

Method Summary
`void` | `addBeanPropertyChangeListener(PropertyChangeListener listener)` Adds a PropertyChangeListener to the list of bean listeners.
`void` | `addBeanPropertyChangeListener(String propertyName, PropertyChangeListener listener)` Adds a PropertyChangeListener to the list of bean listeners for a specific property.
`void` | `afterBeanChange(B oldBean, B newBean)` The underlying BeanAdapter has changed the target bean.
`void` | `beforeBeanChange(B oldBean, B newBean)` The underlying BeanAdapter is about to change the bean.
`protected BeanAdapter<B>` | `createBeanAdapter(ValueModel beanChannel)` Creates and returns a BeanAdapter for the given bean channel.
`B` | `getBean()` Returns the bean that holds the adapted properties.
`ValueModel` | `getBeanChannel()` Returns the ValueModel that holds the bean that in turn holds the adapted properties.
`PropertyChangeListener[]` | `getBeanPropertyChangeListeners()` Returns an array of all the property change listeners registered on this component.
`PropertyChangeListener[]` | `getBeanPropertyChangeListeners(String propertyName)` Returns an array of all the listeners which have been associated with the named property.
`AbstractWrappedValueModel` | `getBufferedComponentModel(String propertyName)` Looks up or creates a buffered component adapter to the read-write property with the given name on this PresentationModel's bean channel.
`BufferedValueModel` | `getBufferedModel(String propertyName)` Looks up or creates a buffered adapter to the read-write property with the given name on this PresentationModel's bean channel.
`BufferedValueModel` | `getBufferedModel(String propertyName, String getterName, String setterName)` Looks up or creates a buffered adapter to the read-write property with the given name on this PresentationModel's bean channel using the specified getter and setter name to read and write values.
`Object` | `getBufferedValue(String propertyName)` Returns the value of specified buffered bean property.
`AbstractWrappedValueModel` | `getComponentModel(String propertyName)` Looks up and lazily creates a ComponentValueModel that adapts the bound property with the specified name.
`AbstractValueModel` | `getModel(String propertyName)` Looks up and lazily creates a ValueModel that adapts the bound property with the specified name.
`AbstractValueModel` | `getModel(String propertyName, String getterName, String setterName)` Looks up and lazily creates a ValueModel that adapts the bound property with the given name.
`ValueModel` | `getTriggerChannel()` Returns a ValueModel that can be shared and used to trigger commit and flush events in BufferedValueModels.
`Object` | `getValue(String propertyName)` Returns the value of specified bean property, `null` if the current bean is `null`.
`boolean` | `isBuffering()` Answers whether any of the buffered models is buffering.
`boolean` | `isChanged()` Answers whether one of the registered ValueModels has changed since the changed state has been reset last time.
`void` | `observeChanged(Object bean, String propertyName)` Observes the specified readable bound bean property in the given bean.
`void` | `observeChanged(ValueModel valueModel)` Observes value changes in the given ValueModel.
`void` | `release()` Removes the PropertyChangeHandler from the observed bean, if the bean is not `null`.
`void` | `removeBeanPropertyChangeListener(PropertyChangeListener listener)` Removes a PropertyChangeListener from the list of bean listeners.
`void` | `removeBeanPropertyChangeListener(String propertyName, PropertyChangeListener listener)` Removes a PropertyChangeListener from the listener list for a specific property.
`void` | `resetChanged()` Resets this model's changed state to `false`.
`void` | `retractInterestFor(Object bean, String propertyName)` Retracts interest for the specified readable bound bean property in the given bean.
`void` | `retractInterestFor(ValueModel valueModel)` Retracts interest for value changes in the given ValueModel.
`void` | `setBean(B newBean)` Sets a new bean as content of the bean channel.
`void` | `setBufferedValue(String propertyName, Object newValue)` Buffers the given value for the specified bean property.
`protected void` | `setChanged(boolean newValue)`
`void` | `setTriggerChannel(ValueModel newTriggerChannel)` Sets the given ValueModel as this model's new trigger channel.
`void` | `setValue(String propertyName, Object newValue)` Sets the given new value for the specified bean property.
`void` | `setVetoableValue(String propertyName, Object newValue)` Sets a new value for the specified bean property.
`void` | `triggerCommit()` Sets the trigger channel to true which in turn triggers commit events in all BufferedValueModels that share this trigger.
`void` | `triggerFlush()` Sets the trigger channel to false which in turn triggers flush events in all BufferedValueModels that share this trigger.

Methods inherited from class com.jgoodies.binding.beans.Model
`createPropertyChangeSupport, firePropertyChange`

Methods inherited from class com.jgoodies.common.bean.AbstractBean
`addPropertyChangeListener, addPropertyChangeListener, addVetoableChangeListener, addVetoableChangeListener, fireIndexedPropertyChange, fireIndexedPropertyChange, fireIndexedPropertyChange, fireMultiplePropertiesChanged, firePropertyChange, firePropertyChange, firePropertyChange, firePropertyChange, firePropertyChange, firePropertyChange, firePropertyChange, fireVetoableChange, fireVetoableChange, fireVetoableChange, fireVetoableChange, fireVetoableChange, fireVetoableChange, fireVetoableChange, getPropertyChangeListeners, getPropertyChangeListeners, getVetoableChangeListeners, getVetoableChangeListeners, removePropertyChangeListener, removePropertyChangeListener, removeVetoableChangeListener, removeVetoableChangeListener`

Methods inherited from class java.lang.Object
`clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait`

Field Detail

### PROPERTYNAME_BEFORE_BEAN

    public static final String PROPERTYNAME_BEFORE_BEAN

  The property name used in the PropertyChangeEvent that is fired before the bean property fires its PropertyChangeEvent. Useful to perform an operation before listeners that handle the bean change are notified. See also the class comment.

  See Also:
    Constant Field Values

### PROPERTYNAME_BEAN

    public static final String PROPERTYNAME_BEAN

  The name of the read-write bound property that holds the target bean.

  See Also:
    `getBean()`, `setBean(Object)`, Constant Field Values

### PROPERTYNAME_AFTER_BEAN

    public static final String PROPERTYNAME_AFTER_BEAN

  The property name used in the PropertyChangeEvent that is fired after the bean property fires its PropertyChangeEvent. Useful to perform an operation after listeners that handle the bean change are notified. See also the class comment.

  See Also:
    Constant Field Values

### PROPERTYNAME_TRIGGERCHANNEL

    public static final String PROPERTYNAME_TRIGGERCHANNEL

  The name of the read-write bound bean property for the trigger channel that is shared by all PropertyAdapters that are created via `#getBufferedModel`.

  See Also:
    `getTriggerChannel()`, `setTriggerChannel(ValueModel)`, `getBufferedModel(String)`, Constant Field Values

### PROPERTYNAME_BUFFERING

    public static final String PROPERTYNAME_BUFFERING

  The name of the read-only bound bean property that indicates whether one of the buffered models is buffering.

  See Also:
    `isBuffering()`, `getBufferedModel(String)`, Constant Field Values

### PROPERTYNAME_CHANGED

    public static final String PROPERTYNAME_CHANGED

  The name of the read-only bound bean property that indicates whether one of the observed models has changed.

  See Also:
    `isChanged()`, `resetChanged()`, `observeChanged(ValueModel)`, `observeChanged(Object, String)`, Constant Field Values

Constructor Detail

### PresentationModel

    public PresentationModel(B bean)

  Constructs a PresentationModel that adapts properties of the given bean.

  Installs a default bean channel that checks the identity not equity to ensure that listeners are unregistered properly if the old and new bean are equal but not the same.

  Installs a Trigger as initial trigger channel.

  Parameters:
    `bean` - the bean that holds the properties to adapt
  Throws:
    `PropertyUnboundException` - if the `bean` does not provide a pair of methods to register a PropertyChangeListener

### PresentationModel

    public PresentationModel(B bean,
                             ValueModel triggerChannel)

  Constructs a PresentationModel on the given bean using the given trigger channel. The bean provides the properties to adapt.

  Installs a default bean channel that checks the identity not equity to ensure that listeners are unregistered properly if the old and new bean are equal but not the same.

  The trigger channel is shared by all buffered models that are created using `#getBufferedModel`. It can be replaced by any other Boolean ValueModel later. Note that PresentationModel observes trigger value changes, not value state. Therefore you must ensure that customer triggers report value changes when asked to commit or flush. See the Trigger implementation for an example.

  Parameters:
    `bean` - the bean that holds the properties to adapt
    `triggerChannel` - the ValueModel that triggers commit and flush events

### PresentationModel

    public PresentationModel(ValueModel beanChannel)

  Constructs a PresentationModel on the given bean channel. This channel holds a bean that in turn holds the properties to adapt.

  It is strongly recommended that the bean channel checks the identity not equity. This ensures that listeners are unregistered properly if the old and new bean are equal but not the same.

  The trigger channel is initialized as a `Trigger`. It may be replaced by any other Boolean ValueModel later. Note that PresentationModel observes trigger value changes, not value state. Therefore you must ensure that customer triggers report value changes when asked to commit or flush. See the Trigger implementation for an example.

  Parameters:
    `beanChannel` - the ValueModel that holds the bean
  Throws:
    `PropertyUnboundException` - if the `bean` does not provide a pair of methods to register a PropertyChangeListener

### PresentationModel

    public PresentationModel(ValueModel beanChannel,
                             ValueModel triggerChannel)

  Constructs a PresentationModel on the given bean channel using the given trigger channel. The bean channel holds a bean that in turn holds the properties to adapt.

  It is strongly recommended that the bean channel checks the identity not equity. This ensures that listeners are unregistered properly if the old and new bean are equal but not the same.

  The trigger channel is shared by all buffered models that are created using `#buffer`. It can be replaced by any other Boolean ValueModel later. Note that PresentationModel observes trigger value changes, not value state. Therefore you must ensure that customer triggers report value changes when asked to commit or flush. See the Trigger implementation for an example.

  Parameters:
    `beanChannel` - the ValueModel that holds the bean
    `triggerChannel` - the ValueModel that triggers commit and flush events

Method Detail

### createBeanAdapter

    protected BeanAdapter<B> createBeanAdapter(ValueModel beanChannel)

  Creates and returns a BeanAdapter for the given bean channel. For compatibility with the 1.0.x, 1.1.x, and 1.2.x series, this default implementation creates a BeanAdapter that always observes the bean. Subclasses may override to observe only observable beans.

  Here's an example code for a custom implementation:

        boolean observe =
              (beanChannel == null)
           || (beanChannel.getValue() == null)
           || BeanUtils.supportsBoundProperties((beanChannel.getValue().getClass());
        return new BeanAdapter(beanChannel, observe);

  A future implementation shall return a BeanAdapter-like interface, not a BeanAdapter.

  Parameters:
    `beanChannel` - the ValueModel that holds the bean
  Returns:
    the created bean adapter
  Since:
    1.3

### getBeanChannel

    public ValueModel getBeanChannel()

  Returns the ValueModel that holds the bean that in turn holds the adapted properties. This bean channel is shared by the PropertyAdapters created by the factory methods `#getModel` and `#getBufferedModel`.

  Returns:
    the ValueModel that holds the bean that in turn holds the adapted properties
  See Also:
    `getBean()`, `setBean(Object)`

### getBean

    public B getBean()

  Returns the bean that holds the adapted properties. This bean is the bean channel's content.

  Returns:
    the bean that holds the adapted properties
  See Also:
    `setBean(Object)`, `getBeanChannel()`

### setBean

    public void setBean(B newBean)

  Sets a new bean as content of the bean channel. All adapted properties will reflect this change.

  Parameters:
    `newBean` - the new bean
  See Also:
    `getBean()`, `getBeanChannel()`

### beforeBeanChange

    public void beforeBeanChange(B oldBean,
                                 B newBean)

  The underlying BeanAdapter is about to change the bean. Allows to perform actions before the bean change happens. For example you can remove listeners that shall not be notified if adapted properties change just because of the bean change. Or you can reset values, set fields to `null` etc.

  The default behavior fires a PropertyChangeEvent for property `#PROPERTYNAME_BEFORE_BEAN`. Note: Subclasses that override this method must invoke super or perform the same behavior.

  This method is invoked by the BeanChangeHandler listening to the beforeBean non-readable property of the BeanAdapter.

  Parameters:
    `oldBean` - the bean before the change
    `newBean` - the bean that will be adapted after the change
  See Also:
    `afterBeanChange(Object, Object)`, `PROPERTYNAME_BEFORE_BEAN`, `PROPERTYNAME_BEAN`, `PROPERTYNAME_AFTER_BEAN`, `BeanAdapter`

### afterBeanChange

    public void afterBeanChange(B oldBean,
                                B newBean)

  The underlying BeanAdapter has changed the target bean. Allows to perform actions after the bean changed. For example you can re-add listeners that were removed in `#beforeBeanChange`. Or you can reset values, reset custom changed state, set fields to `null` etc.

  The default behavior resets the change tracker's changed state and fires a PropertyChangeEvent for the property `#PROPERTYNAME_AFTER_BEAN`. Note: Subclasses that override this method must invoke super or perform the same behavior.

  This method is invoked by the BeanChangeHandler listening to the afterBean non-readable property of the BeanAdapter.

  Parameters:
    `oldBean` - the bean that was adapted before the change
    `newBean` - the bean that is already the new target bean
  See Also:
    `beforeBeanChange(Object, Object)`, `PROPERTYNAME_BEFORE_BEAN`, `PROPERTYNAME_BEAN`, `PROPERTYNAME_AFTER_BEAN`, `BeanAdapter`

### getValue

    public Object getValue(String propertyName)

  Returns the value of specified bean property, `null` if the current bean is `null`.

  This operation is supported only for readable bean properties.

  Parameters:
    `propertyName` - the name of the property to be read
  Returns:
    the value of the adapted bean property, null if the bean is null
  Throws:
    `NullPointerException` - if the property name is null
    `UnsupportedOperationException` - if the property is write-only
    `PropertyNotFoundException` - if the property could not be found
    `PropertyAccessException` - if the value could not be read
  Since:
    1.1

### setValue

    public void setValue(String propertyName,
                         Object newValue)

  Sets the given new value for the specified bean property. Does nothing if this adapter's bean is `null`. If the setter associated with the propertyName throws a PropertyVetoException, it is silently ignored.

  Notifies the associated value change listeners if the bean reports a property change. Note that a bean may suppress PropertyChangeEvents if the old and new value are the same, or if the old and new value are equal.

  This operation is supported only for writable bean properties.

  Parameters:
    `propertyName` - the name of the property to set
    `newValue` - the value to set
  Throws:
    `NullPointerException` - if the property name is null
    `UnsupportedOperationException` - if the property is read-only
    `PropertyNotFoundException` - if the property could not be found
    `PropertyAccessException` - if the new value could not be set
  Since:
    1.1

### setVetoableValue

    public void setVetoableValue(String propertyName,
                                 Object newValue)
                          throws PropertyVetoException

  Sets a new value for the specified bean property. Does nothing if the bean is `null`. If the setter associated with the propertyName throws a PropertyVetoException, this methods throws the same exception.

  Notifies the associated value change listeners if the bean reports a property change. Note that a bean may suppress PropertyChangeEvents if the old and new value are the same, or if the old and new value are equal.

  This operation is supported only for writable bean properties.

  Parameters:
    `propertyName` - the name of the property to set
    `newValue` - the value to set
  Throws:
    `NullPointerException` - if the property name is null
    `UnsupportedOperationException` - if the property is read-only
    `PropertyNotFoundException` - if the property could not be found
    `PropertyAccessException` - if the new value could not be set
    `PropertyVetoException` - if the bean setter throws a PropertyVetoException
  Since:
    1.1

### getBufferedValue

    public Object getBufferedValue(String propertyName)

  Returns the value of specified buffered bean property. It is a shorthand for writing

      getBufferedModel(propertyName).getValue()

  As a side-effect, this method may create a buffered model.

  Parameters:
    `propertyName` - the name of the property to be read
  Returns:
    the value of the adapted bean property, null if the bean is null
  Throws:
    `NullPointerException` - if the property name is null
    `UnsupportedOperationException` - if the property is write-only
    `PropertyNotFoundException` - if the property could not be found
    `PropertyAccessException` - if the value could not be read
  Since:
    1.1

### setBufferedValue

    public void setBufferedValue(String propertyName,
                                 Object newValue)

  Buffers the given value for the specified bean property. It is a shorthand for writing

      getBufferedModel(propertyName).setValue(newValue)

  As a side-effect, this method may create a buffered model.

  Parameters:
    `propertyName` - the name of the property to set
    `newValue` - the value to set
  Throws:
    `NullPointerException` - if the property name is null
    `PropertyNotFoundException` - if the property could not be found
    `PropertyAccessException` - if the new value could not be set
  Since:
    1.1

### getModel

    public AbstractValueModel getModel(String propertyName)

  Looks up and lazily creates a ValueModel that adapts the bound property with the specified name. Uses the Bean introspection to look up the getter and setter names.

  Subsequent calls to this method with the same property name return the same ValueModel.

  To prevent potential runtime errors it eagerly looks up the associated PropertyDescriptor if the target bean is not null.

  For each property name all calls to this method and to `#getModel(String, String, String)` must use the same getter and setter names. Attempts to violate this constraint will be rejected with an IllegalArgumentException. Especially once you've called this method you must not call `#getModel(String, String, String)` with a non-null getter or setter name. And vice versa, once you've called the latter method with a non-null getter or setter name, you must not call this method.

  This method uses a return type of AbstractValueModel, not a ValueModel. This makes the AbstractValueModel convenience type converters available, which can significantly shrink the source code necessary to read and write values from/to these models.

  Parameters:
    `propertyName` - the name of the property to adapt
  Returns:
    a ValueModel that adapts the property with the specified name
  Throws:
    `NullPointerException` - if the property name is null
    `PropertyNotFoundException` - if the property could not be found
    `IllegalArgumentException` - if `#getModel(String, String, String)` has been called before with the same property name and a non-null getter or setter name
  See Also:
    `AbstractValueModel`, `BeanAdapter`, `getModel(String, String, String)`, `getBufferedModel(String)`

### getModel

    public AbstractValueModel getModel(String propertyName,
                                       String getterName,
                                       String setterName)

  Looks up and lazily creates a ValueModel that adapts the bound property with the given name. Unlike `#getModel(String)` this method bypasses the Bean Introspection and uses the given getter and setter names to setup the access to the adapted Bean property.

  Subsequent calls to this method with the same parameters will return the same ValueModel.

  To prevent potential runtime errors this method eagerly looks up the associated PropertyDescriptor if the target bean is not null.

  For each property name all calls to this method and to `#getModel(String)` must use the same getter and setter names. Attempts to violate this constraint will be rejected with an IllegalArgumentException. Especially once you've called this method with a non-null getter or setter name, you must not call `#getModel(String)`. And vice versa, once you've called the latter method you must not call this method with a non-null getter or setter name.

  This method uses a return type of AbstractValueModel, not a ValueModel. This makes the AbstractValueModel convenience type converters available, which can significantly shrink the source code necessary to read and write values from/to these models.

  Parameters:
    `propertyName` - the name of the property to adapt
    `getterName` - the name of the method that reads the value
    `setterName` - the name of the method that sets the value
  Returns:
    a ValueModel that adapts the property with the specified name
  Throws:
    `NullPointerException` - if the property name is null
    `PropertyNotFoundException` - if the property could not be found
    `IllegalArgumentException` - if this method has been called before with the same property name and different getter or setter names
  See Also:
    `AbstractValueModel`, `BeanAdapter`, `getModel(String, String, String)`, `getBufferedModel(String)`

### getComponentModel

    public AbstractWrappedValueModel getComponentModel(String propertyName)

  Looks up and lazily creates a ComponentValueModel that adapts the bound property with the specified name. Uses the standard Bean introspection to look up the getter and setter names.

  Subsequent calls to this method with the same property name return the same ComponentValueModel.

  To prevent potential runtime errors it eagerly looks up the associated PropertyDescriptor if the target bean is not null.

  For each property name all calls to this method and to `#getModel(String, String, String)` must use the same getter and setter names. Attempts to violate this constraint will be rejected with an IllegalArgumentException. Especially once you've called this method you must not call `#getModel(String, String, String)` with a non-null getter or setter name. And vice versa, once you've called the latter method with a non-null getter or setter name, you must not call this method.

  This returned ComponentValueModel provides convenience type converter method from AbstractValueModel and allows to modify GUI state such as enabled, visible, and editable in this presentation model. This can significantly shrink the source code necessary to handle GUI state changes.

  Parameters:
    `propertyName` - the name of the property to adapt
  Returns:
    a ValueModel that adapts the property with the specified name
  Throws:
    `NullPointerException` - if the property name is null
    `PropertyNotFoundException` - if the property could not be found
    `IllegalArgumentException` - if `#getModel(String, String, String)` has been called before with the same property name and a non-null getter or setter name
  Since:
    1.1
  See Also:
    `ComponentValueModel`, `AbstractValueModel`, `BeanAdapter`, `getModel(String, String, String)`, `getBufferedModel(String)`, `Bindings.addComponentPropertyHandler(JComponent, ValueModel)`

### getBufferedModel

    public BufferedValueModel getBufferedModel(String propertyName)

  Looks up or creates a buffered adapter to the read-write property with the given name on this PresentationModel's bean channel. Creates a BufferedValueModel that wraps a ValueModel that adapts the bean property with the specified name. The buffered model uses this PresentationModel's trigger channel to listen for commit and flush events.

  The created BufferedValueModel is stored in a Map. Hence subsequent calls to this method with the same property name return the same BufferedValueModel.

  To prevent potential runtime errors this method eagerly looks up the associated PropertyDescriptor if the target bean is not null.

  For each property name all calls to this method and to `#getBufferedModel(String, String, String)` must use the same getter and setter names. Attempts to violate this constraint will be rejected with an IllegalArgumentException. Especially once you've called this method you must not call `#getBufferedModel(String, String, String)` with a non-null getter or setter name. And vice versa, once you've called the latter method with a non-null getter or setter name, you must not call this method.

  Parameters:
    `propertyName` - the name of the read-write property to adapt
  Returns:
    a buffered adapter to the property with the given name on this model's bean channel using this model's trigger channel
  Throws:
    `NullPointerException` - if the property name is null
    `PropertyNotFoundException` - if the property could not be found
    `IllegalArgumentException` - if `#getBufferedModel(String, String, String)` has been called before with the same property name and a non-null getter or setter name
  See Also:
    `BufferedValueModel`, `ValueModel`, `Trigger`, `BeanAdapter`, `getModel(String)`, `getBufferedModel(String, String, String)`

### getBufferedModel

    public BufferedValueModel getBufferedModel(String propertyName,
                                               String getterName,
                                               String setterName)

  Looks up or creates a buffered adapter to the read-write property with the given name on this PresentationModel's bean channel using the specified getter and setter name to read and write values. Creates a `BufferedValueModel` that wraps a `ValueModel` that adapts the bean property with the specified name. The buffered model uses this PresentationModel's trigger channel to listen for commit and flush events.

  The created BufferedValueModel is stored in a Map so it can be looked up if it is requested multiple times.

  To prevent potential runtime errors this method eagerly looks up the associated PropertyDescriptor if the target bean is not null.

  For each property name all calls to this method and to `#getBufferedModel(String)` must use the same getter and setter names. Attempts to violate this constraint will be rejected with an IllegalArgumentException. Especially once you've called this method with a non-null getter or setter name, you must not call `#getBufferedModel(String)`. And vice versa, once you've called the latter method you must not call this method with a non-null getter or setter name.

  Parameters:
    `propertyName` - the name of the property to adapt
    `getterName` - the name of the method that reads the value
    `setterName` - the name of the method that sets the value
  Returns:
    a buffered adapter to the property with the given name on this model's bean channel using this model's trigger channel
  Throws:
    `NullPointerException` - if the property name is null
    `PropertyNotFoundException` - if the property could not be found
    `IllegalArgumentException` - if this method has been called before with the same property name and different getter or setter names
  See Also:
    `BufferedValueModel`, `ValueModel`, `Trigger`, `BeanAdapter`, `getModel(String)`, `getBufferedModel(String)`

### getBufferedComponentModel

    public AbstractWrappedValueModel getBufferedComponentModel(String propertyName)

  Looks up or creates a buffered component adapter to the read-write property with the given name on this PresentationModel's bean channel. Creates a ComponentValueModel that wraps a BufferedValueModel that in turn wraps a ValueModel that adapts the bean property with the specified name. The buffered model uses this PresentationModel's trigger channel to listen for commit and flush events. The ComponentValueModel allows to set component state in this presentation model.

  The created ComponentValueModel is stored in a Map. Hence subsequent calls to this method with the same property name return the same ComponentValueModel.

  To prevent potential runtime errors this method eagerly looks up the associated PropertyDescriptor if the target bean is not null.

  For each property name all calls to this method and to `#getBufferedModel(String, String, String)` must use the same getter and setter names. Attempts to violate this constraint will be rejected with an IllegalArgumentException. Especially once you've called this method you must not call `#getBufferedModel(String, String, String)` with a non-null getter or setter name. And vice versa, once you've called the latter method with a non-null getter or setter name, you must not call this method.

  Parameters:
    `propertyName` - the name of the read-write property to adapt
  Returns:
    a ComponentValueModel that wraps a buffered adapter to the property with the given name on this model's bean channel using this model's trigger channel
  Throws:
    `NullPointerException` - if the property name is null
    `PropertyNotFoundException` - if the property could not be found
    `IllegalArgumentException` - if `#getBufferedModel(String, String, String)` has been called before with the same property name and a non-null getter or setter name
  Since:
    1.1
  See Also:
    `ComponentValueModel`, `BufferedValueModel`, `ValueModel`, `Trigger`, `BeanAdapter`, `getModel(String)`, `getBufferedModel(String)`, `getComponentModel(String)`, `Bindings.addComponentPropertyHandler(JComponent, ValueModel)`

### getTriggerChannel

    public ValueModel getTriggerChannel()

  Returns a ValueModel that can be shared and used to trigger commit and flush events in BufferedValueModels. The trigger channel's value changes to true in `#triggerCommit` and it changes to false in `#triggerFlush`.

  This trigger channel is used to commit and flush values in the BufferedValueModels returned by `#getBufferedModel`.

  Returns:
    this model's trigger channel
  See Also:
    `BufferedValueModel`, `ValueModel`, `setTriggerChannel(ValueModel)`

### setTriggerChannel

    public void setTriggerChannel(ValueModel newTriggerChannel)

  Sets the given ValueModel as this model's new trigger channel. Sets the new trigger channel in all existing BufferedValueModels that have been created using `#getBufferedModel`. Subsequent invocations of `#triggerCommit` and `#triggerFlush` will trigger commit and flush events using the new trigger channel.

  Parameters:
    `newTriggerChannel` - the ValueModel to be set as this model's new trigger channel
  Throws:
    `NullPointerException` - if the new trigger channel is `null`
  See Also:
    `BufferedValueModel`, `ValueModel`, `getTriggerChannel()`

### triggerCommit

    public void triggerCommit()

  Sets the trigger channel to true which in turn triggers commit events in all BufferedValueModels that share this trigger.

  See Also:
    `triggerFlush()`

### triggerFlush

    public void triggerFlush()

  Sets the trigger channel to false which in turn triggers flush events in all BufferedValueModels that share this trigger.

  See Also:
    `triggerCommit()`

### isBuffering

    public boolean isBuffering()

  Answers whether any of the buffered models is buffering. Useful to enable and disable UI actions and operations that depend on the buffering state.

  Returns:
    true if any of the buffered models is buffering, false, if all buffered models write-through

### isChanged

    public boolean isChanged()

  Answers whether one of the registered ValueModels has changed since the changed state has been reset last time.

  Note: Unlike `#resetChanged` this method is not intended to be overridden by subclasses. If you want to track changes of other ValueModels, bean properties, or of submodels, register them by means of `#observeChanged`. Overriding `#isChanged` to include the changed state of submodels would return the correct changed value, but it would bypass the change notification from submodels to this model. Therefore submodels must be observed, which can be achieve using `#observeChanged`.

  To reset the changed state invoke `#resetChanged`. In case you track the changed state of submodels override `#resetChanged` to reset the changed state in these submodels too.

  Returns:
    true if an observed property has changed since the last reset
  See Also:
    `observeChanged(ValueModel)`, `observeChanged(Object, String)`, `resetChanged()`

### resetChanged

    public void resetChanged()

  Resets this model's changed state to `false`. Therefore it resets the changed states of the change tracker and the underlying bean adapter.

  Subclasses may override this method to reset the changed state of submodels. The overriding method must invoke this super behavior. For example if you have a MainModel that is composed of two submodels Submodel1 and Submodel2, you may write:

       public void resetChanged() {
           super.resetChanged();
           getSubmodel1().resetChanged();
           getSubmodel2().resetChanged();
       }

  See Also:
    `isChanged()`, `observeChanged(ValueModel)`, `observeChanged(Object, String)`

### setChanged

    protected void setChanged(boolean newValue)

### observeChanged

    public void observeChanged(Object bean,
                               String propertyName)

  Observes the specified readable bound bean property in the given bean.

  Parameters:
    `bean` - the bean to be observed
    `propertyName` - the name of the readable bound bean property
  Throws:
    `NullPointerException` - if the bean or propertyName is null
    `PropertyNotBindableException` - if this class can't add the PropertyChangeListener from the bean
  See Also:
    `retractInterestFor(Object, String)`, `observeChanged(ValueModel)`

### observeChanged

    public void observeChanged(ValueModel valueModel)

  Observes value changes in the given ValueModel.

  Parameters:
    `valueModel` - the ValueModel to observe
  Throws:
    `NullPointerException` - if the valueModel is null
  See Also:
    `retractInterestFor(ValueModel)`, `observeChanged(Object, String)`

### retractInterestFor

    public void retractInterestFor(Object bean,
                                   String propertyName)

  Retracts interest for the specified readable bound bean property in the given bean.

  Parameters:
    `bean` - the bean to be observed
    `propertyName` - the name of the readable bound bean property
  Throws:
    `NullPointerException` - if the bean or propertyName is null
    `PropertyNotBindableException` - if this class can't remove the PropertyChangeListener from the bean
  See Also:
    `observeChanged(Object, String)`, `retractInterestFor(ValueModel)`

### retractInterestFor

    public void retractInterestFor(ValueModel valueModel)

  Retracts interest for value changes in the given ValueModel.

  Parameters:
    `valueModel` - the ValueModel to observe
  Throws:
    `NullPointerException` - if the valueModel is null
  See Also:
    `observeChanged(ValueModel)`, `retractInterestFor(Object, String)`

### addBeanPropertyChangeListener

    public void addBeanPropertyChangeListener(PropertyChangeListener listener)

  Adds a PropertyChangeListener to the list of bean listeners. The listener is registered for all bound properties of the target bean.

  The listener will be notified if and only if this BeanAdapter's current bean changes a property. It'll not be notified if the bean changes.

  If listener is `null`, no exception is thrown and no action is performed.

  Parameters:
    `listener` - the PropertyChangeListener to be added
  See Also:
    `removeBeanPropertyChangeListener(PropertyChangeListener)`, `removeBeanPropertyChangeListener(String, PropertyChangeListener)`, `addBeanPropertyChangeListener(String, PropertyChangeListener)`, `getBeanPropertyChangeListeners()`

### removeBeanPropertyChangeListener

    public void removeBeanPropertyChangeListener(PropertyChangeListener listener)

  Removes a PropertyChangeListener from the list of bean listeners. This method should be used to remove PropertyChangeListeners that were registered for all bound properties of the target bean.

  If listener is `null`, no exception is thrown and no action is performed.

  Parameters:
    `listener` - the PropertyChangeListener to be removed
  See Also:
    `addBeanPropertyChangeListener(PropertyChangeListener)`, `addBeanPropertyChangeListener(String, PropertyChangeListener)`, `removeBeanPropertyChangeListener(String, PropertyChangeListener)`, `getBeanPropertyChangeListeners()`

### addBeanPropertyChangeListener

    public void addBeanPropertyChangeListener(String propertyName,
                                              PropertyChangeListener listener)

  Adds a PropertyChangeListener to the list of bean listeners for a specific property. The specified property may be user-defined.

  The listener will be notified if and only if this BeanAdapter's current bean changes the specified property. It'll not be notified if the bean changes. If you want to observe property changes and bean changes, you may observe the ValueModel that adapts this property - as returned by `#getModel(String)`.

  Note that if the bean is inheriting a bound property, then no event will be fired in response to a change in the inherited property.

  If listener is `null`, no exception is thrown and no action is performed.

  Parameters:
    `propertyName` - one of the property names listed above
    `listener` - the PropertyChangeListener to be added
  See Also:
    `removeBeanPropertyChangeListener(String, PropertyChangeListener)`, `addBeanPropertyChangeListener(String, PropertyChangeListener)`, `getBeanPropertyChangeListeners(String)`

### removeBeanPropertyChangeListener

    public void removeBeanPropertyChangeListener(String propertyName,
                                                 PropertyChangeListener listener)

  Removes a PropertyChangeListener from the listener list for a specific property. This method should be used to remove PropertyChangeListeners that were registered for a specific bound property.

  If listener is `null`, no exception is thrown and no action is performed.

  Parameters:
    `propertyName` - a valid property name
    `listener` - the PropertyChangeListener to be removed
  See Also:
    `addBeanPropertyChangeListener(String, PropertyChangeListener)`, `removeBeanPropertyChangeListener(PropertyChangeListener)`, `getBeanPropertyChangeListeners(String)`

### getBeanPropertyChangeListeners

    public PropertyChangeListener[] getBeanPropertyChangeListeners()

  Returns an array of all the property change listeners registered on this component.

  Returns:
    all of this component's `PropertyChangeListener`s or an empty array if no property change listeners are currently registered
  See Also:
    `addBeanPropertyChangeListener(PropertyChangeListener)`, `removeBeanPropertyChangeListener(PropertyChangeListener)`, `getBeanPropertyChangeListeners(String)`, `PropertyChangeSupport.getPropertyChangeListeners()`

### getBeanPropertyChangeListeners

    public PropertyChangeListener[] getBeanPropertyChangeListeners(String propertyName)

  Returns an array of all the listeners which have been associated with the named property.

  Parameters:
    `propertyName` - the name of the property to lookup listeners
  Returns:
    all of the `PropertyChangeListeners` associated with the named property or an empty array if no listeners have been added
  See Also:
    `addBeanPropertyChangeListener(String, PropertyChangeListener)`, `removeBeanPropertyChangeListener(String, PropertyChangeListener)`, `getBeanPropertyChangeListeners()`

### release

    public void release()

  Removes the PropertyChangeHandler from the observed bean, if the bean is not `null`. Also removes all listeners from the bean that have been registered with `#addBeanPropertyChangeListener` before.

  PresentationModels have a PropertyChangeListener registered with the target bean. Hence, a bean has a reference to all PresentationModels that hold it as bean. To avoid memory leaks it is recommended to remove this listener, if the bean lives much longer than the PresentationModel, enabling the garbage collector to remove the PresentationModel. To do so, you can call `setBean(null)` or set the bean channel's value to null. As an alternative you can use event listener lists in your beans that implement references with `WeakReference`.

  Setting the bean to null has side-effects, for example the model fires a change event for the bound property bean and other properties. And the value of ValueModel's vent by this model may change. However, typically this is fine and setting the bean to null is the first choice for removing the reference from the bean to the PresentationModel. Another way to clear the reference from the target bean is to call this `#release` method; it has no side-effects.

  Since version 2.0.4 it is safe to call this method multiple times, however, the PresentationModel must not be used anymore once #release has been called.

  Since:
    1.2
  See Also:
    `setBean(Object)`, `WeakReference`

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