com.jgoodies.binding.beans
Class PropertyConnector

java.lang.Object
  extended by com.jgoodies.binding.beans.PropertyConnector

public final class PropertyConnector
extends java.lang.Object

Keeps two Java Bean properties in synch. This connector supports bound and unbound, read-only and read-write properties. Write-only properties are not supported; connecting two read-only properties won't work; connecting two unbound properties doesn't make sense.

If one of the bean properties fires a property change, this connector will set the other to the same value. If a bean property is read-only, the PropertyConnector will not listen to the other bean's property and so won't update the read-only property. And if a bean does not provide support for bound properties, it won't be observed. The properties must be single value bean properties as described by the Java Bean Secification.

Constraints: the properties must be type compatible, i. e. values returned by one reader must be accepted by the other's writer, and vice versa.

Examples: Note that the following examples are for demonstration purposes. The classes BasicComponentFactory and Bindings provide predefined connections for formatted text fields and combo boxes.

 // Connects a ValueModel and a JFormattedTextField
 JFormattedTextField textField = new JFormattedTextField();
 textField.setEditable(editable);
 PropertyConnector connector =
     PropertyConnector.connectAndUpdate(valueModel, "value", textField, "value");

 // Connects the boolean property "selectable" with a component enablement
 JComboBox comboBox = new JComboBox();
 ...
 PropertyConnector.connect(mainModel, "selectable", comboBox, "enabled");
 

Version:
$Revision: 1.23 $
Author:
Karsten Lentzsch
See Also:
PropertyChangeEvent, PropertyChangeListener, PropertyDescriptor

Method Summary
static PropertyConnector connect(java.lang.Object bean1, java.lang.String property1Name, java.lang.Object bean2, java.lang.String property2Name)
          Synchronizes the two bound bean properties as specified by the given pairs of bean and associated property name.
static void connectAndUpdate(ValueModel valueModel, java.lang.Object bean2, java.lang.String property2Name)
          Synchronizes the ValueModel with the specified bound bean property, and updates the bean immediately.
 java.lang.Object getBean1()
          Returns the Java Bean that holds the first property.
 java.lang.Object getBean2()
          Returns the Java Bean that holds the first property.
 java.lang.String getProperty1Name()
          Returns the name of the first Java Bean property.
 java.lang.String getProperty2Name()
          Returns the name of the second Java Bean property.
 void release()
          Removes the PropertyChangeHandler from the observed bean, if the bean is not null and if property changes are not observed.
 void updateProperty1()
          Reads the value of the second bean property and sets it as new value of the first bean property.
 void updateProperty2()
          Reads the value of the first bean property and sets it as new value of the second bean property.
 
Methods inherited from class java.lang.Object
clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait
 

Method Detail

connect

public static PropertyConnector connect(java.lang.Object bean1,
                                        java.lang.String property1Name,
                                        java.lang.Object bean2,
                                        java.lang.String property2Name)
Synchronizes the two bound bean properties as specified by the given pairs of bean and associated property name. If Bean1#property1Name changes it updates Bean2#property2Name and vice versa. If a bean does not provide support for bound properties, changes will not be observed. If a bean property is read-only, this connector won't listen to the other bean's property and so won't update the read-only property.

Returns the PropertyConnector that is required if one or the other property shall be updated.

Parameters:
bean1 - the bean that owns the first property
property1Name - the name of the first property
bean2 - the bean that owns the second property
property2Name - the name of the second property
Returns:
the PropertyConnector used to synchronize the properties, required if property1 or property2 shall be updated
Throws:
java.lang.NullPointerException - if a bean or property name is null
java.lang.IllegalArgumentException - if the beans are identical and the property name are equal

connectAndUpdate

public static void connectAndUpdate(ValueModel valueModel,
                                    java.lang.Object bean2,
                                    java.lang.String property2Name)
Synchronizes the ValueModel with the specified bound bean property, and updates the bean immediately. If the ValueModel changes, it updates Bean2#property2Name and vice versa. If the bean doesn't provide support for bound properties, changes will not be observed. If the bean property is read-only, this connector will not listen to the ValueModel and so won't update the read-only property.

Parameters:
valueModel - the ValueModel that provides a bound value
bean2 - the bean that owns the second property
property2Name - the name of the second property
Throws:
java.lang.NullPointerException - if the ValueModel, bean or property name is null
java.lang.IllegalArgumentException - if the bean is the ValueModel and the property name is "value"
Since:
2.0

getBean1

public java.lang.Object getBean1()
Returns the Java Bean that holds the first property.

Returns:
the Bean that holds the first property

getBean2

public java.lang.Object getBean2()
Returns the Java Bean that holds the first property.

Returns:
the Bean that holds the first property

getProperty1Name

public java.lang.String getProperty1Name()
Returns the name of the first Java Bean property.

Returns:
the name of the first property

getProperty2Name

public java.lang.String getProperty2Name()
Returns the name of the second Java Bean property.

Returns:
the name of the second property

updateProperty1

public void updateProperty1()
Reads the value of the second bean property and sets it as new value of the first bean property.

See Also:
updateProperty2()

updateProperty2

public void updateProperty2()
Reads the value of the first bean property and sets it as new value of the second bean property.

See Also:
updateProperty1()

release

public void release()
Removes the PropertyChangeHandler from the observed bean, if the bean is not null and if property changes are not observed. This connector must not be used after calling #release.

To avoid memory leaks it is recommended to invoke this method, if the connected beans live much longer than this connector.

As an alternative you may use event listener lists in the connected beans that are implemented using WeakReference.

See Also:
WeakReference


Copyright © 2002-2010 JGoodies Karsten Lentzsch. All Rights Reserved.