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/*
* Copyright (c) 2002-2013 JGoodies Software GmbH. All Rights Reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions are met:
*
* o Redistributions of source code must retain the above copyright notice,
* this list of conditions and the following disclaimer.
*
* o Redistributions in binary form must reproduce the above copyright notice,
* this list of conditions and the following disclaimer in the documentation
* and/or other materials provided with the distribution.
*
* o Neither the name of JGoodies Software GmbH nor the names of
* its contributors may be used to endorse or promote products derived
* from this software without specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
* AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO,
* THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
* PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR
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* EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
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package com.jgoodies.binding.beans;
import static com.jgoodies.common.base.Preconditions.checkNotBlank;
import static com.jgoodies.common.internal.Messages.MUST_NOT_BE_BLANK;
import java.beans.PropertyChangeEvent;
import java.beans.PropertyChangeListener;
import java.beans.PropertyDescriptor;
import java.beans.PropertyVetoException;
import java.lang.reflect.Method;
import com.jgoodies.binding.value.AbstractValueModel;
import com.jgoodies.binding.value.ValueHolder;
import com.jgoodies.binding.value.ValueModel;
/**
* Converts a single Java Bean property into the generic ValueModel interface.
* The bean property must be a single value as described by the
* Java
* Bean Specification. See below for a comparison with the more frequently
* used BeanAdapter and PresentationModel classes.
*
* The constructors accept either a property name or a triple of
* (property name, getter name, setter name). If you just specify the
* property name, the adapter uses the standard Java Bean introspection
* to lookup the available properties and how to read and write the
* property value. In case of custom readers and writers you may
* specify a custom BeanInfo class, or as a shortcut use the constructors
* that accept the optional getter and setter name. If these are specified,
* introspection will be bypassed and a PropertyDescriptor will be
* created for the given property name, getter and setter name.
*
* Optionally the PropertyAdapter can observe changes in bound
* properties as described in section 7.4 of the Bean specification.
* You can enable this feature by setting the constructor parameter
* {@code observeChanges} to {@code true}.
* If the adapter observes changes, it will fire value change events,
* i.e. PropertyChangeEvents for the property {@code "value"}.
* Even if you ignore property changes, you can access the adapted
* property value via {@code #getValue()}.
* It's just that you won't be notified about changes.
*
* The PropertyAdapter provides two access styles to the target bean
* that holds the adapted property: you can specify a bean directly,
* or you can use a bean channel to access the bean indirectly.
* In the latter case you specify a {@code ValueModel}
* that holds the bean that in turn holds the adapted property.
*
* If the adapted bean is {@code null} the PropertyAdapter can
* neither read nor set a value. In this case {@code #getValue}
* returns {@code null} and {@code #setValue} will silently
* ignore the new value.
*
* This adapter throws 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 {@code #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:
* - this adapter's bean channel fires a value change,
*
- this adapter fires a beforeBean change,
*
- this adapter fires the bean change,
*
- this adapter fires an afterBean change.
*
*
* Note:
* PropertyAdapters that observe changes have a PropertyChangeListener
* registered with the target bean. Hence, a bean has a reference
* to any PropertyAdapter that observes it. To avoid memory leaks
* it is recommended to remove this listener if the bean lives much longer than
* the PropertyAdapter, enabling the garbage collector to remove the adapter.
* To do so, you can call {@code 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 {@code WeakReference}.
*
* Setting the bean to null has side-effects, for example the adapter fires
* a change event for the bound property bean and other properties.
* And the adpter's value 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 adapter.
* Another way to clear the reference from the target bean is
* to call {@code #release}. It has no side-effects, but the adapter
* must not be used anymore once #release has been called.
*
* Constraints: If property changes shall be observed,
* the bean class must support bound properties, i. e. it must provide
* the following pair of methods for registration of multicast property
* change event listeners:
*
* public void addPropertyChangeListener(PropertyChangeListener x);
* public void removePropertyChangeListener(PropertyChangeListener x);
*
*
* PropertyAdapter vs. BeanAdapter vs. PresentationModel
* If you adapt multiple properties of the same bean, you better use
* a {@link com.jgoodies.binding.beans.BeanAdapter}. The BeanAdapter
* registers only a single PropertyChangeListener with the bean,
* where multiple PropertyAdapters would register multiple listeners.
* If you adapt bean properties for an editor, you will typically use the
* {@link com.jgoodies.binding.PresentationModel}. The PresentationModel is
* more powerful than the BeanAdapter. It adds support for buffered models,
* and provides an extensible mechanism for observing the change state
* of the bean and related objects.
*
* Basic Examples:
*
* // Direct access, ignores changes
* Address address = new Address()
* PropertyAdapter adapter = new PropertyAdapter(address, "street");
* adapter.setValue("Broadway");
* System.out.println(address.getStreet()); // Prints "Broadway"
* address.setStreet("Franz-Josef-Strasse");
* System.out.println(adapter.getValue()); // Prints "Franz-Josef-Strasse"
*
*
* //Direct access, observes changes
* PropertyAdapter adapter = new PropertyAdapter(address, "street", true);
*
*
* // Indirect access, ignores changes
* ValueHolder addressHolder = new ValueHolder(address1);
* PropertyAdapter adapter = new PropertyAdapter(addressHolder, "street");
* adapter.setValue("Broadway"); // Sets the street in address1
* System.out.println(address1.getValue()); // Prints "Broadway"
* adapter.setBean(address2);
* adapter.setValue("Robert-Koch-Strasse"); // Sets the street in address2
* System.out.println(address2.getValue()); // Prints "Robert-Koch-Strasse"
*
*
* // Indirect access, observes changes
* ValueHolder addressHolder = new ValueHolder();
* PropertyAdapter adapter = new PropertyAdapter(addressHolder, "street", true);
* addressHolder.setValue(address1);
* address1.setStreet("Broadway");
* System.out.println(adapter.getValue()); // Prints "Broadway"
*
*
* Adapter Chain Example:
*
Builds an adapter chain from a domain model to the presentation layer.
*
* Country country = new Country();
* country.setName("Germany");
* country.setEuMember(true);
*
* JTextField nameField = new JTextField();
* nameField.setDocument(new DocumentAdapter(
* new PropertyAdapter(country, "name", true)));
*
* JCheckBox euMemberBox = new JCheckBox("Is EU Member");
* euMemberBox.setModel(new ToggleButtonAdapter(
* new PropertyAdapter(country, "euMember", true)));
*
* // Using factory methods
* JTextField nameField = Factory.createTextField(country, "name");
* JCheckBox euMemberBox = Factory.createCheckBox (country, "euMember");
* euMemberBox.setText("Is EU Member");
*
*
* 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 splitted up to specify how the
* self-fired PropertyChangeEvent is created:
*
* - oldValue=null, newValue=null
*
- oldValue=null, newValue=the value set
*
- oldValue=value read before the set, newValue=the value set
*
- oldValue=value read before the set, newValue=value read after the set
*
*
* @author Karsten Lentzsch
* @version $Revision: 1.24 $
*
* @see com.jgoodies.binding.beans.BeanAdapter
* @see ValueModel
* @see ValueModel#getValue()
* @see ValueModel#setValue(Object)
* @see PropertyChangeEvent
* @see PropertyChangeListener
* @see java.beans.Introspector
* @see java.beans.BeanInfo
* @see PropertyDescriptor
*
* @param the type of the adapted bean
*/
public final class PropertyAdapter extends AbstractValueModel {
// Property Names *********************************************************
/**
* 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.
*/
public static final String PROPERTY_BEFORE_BEAN = "beforeBean";
/**
* The name of the read-write bound property that holds the target bean.
*
* @see #getBean()
* @see #setBean(Object)
*/
public static final String PROPERTY_BEAN = "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.
*/
public static final String PROPERTY_AFTER_BEAN = "afterBean";
/**
* The name of the read-only bound bean property that
* indicates whether one of the observed properties has changed.
*
* @see #isChanged()
*/
public static final String PROPERTY_CHANGED = "changed";
// Fields *****************************************************************
/**
* Holds a {@code ValueModel} that holds the bean, that in turn
* holds the adapted property.
*
* @see #getBean()
* @see #setBean(Object)
*/
private final ValueModel beanChannel;
/**
* Holds the name of the adapted property.
*
* @see #getPropertyName()
*/
private final String propertyName;
/**
* Holds the optional name of the property's getter.
*/
private final String getterName;
/**
* Holds the optional name of the property's setter.
*/
private final String setterName;
/**
* Specifies whether we observe property changes and in turn
* fire state changes.
*
* @see #getObserveChanges()
*/
private final boolean observeChanges;
/**
* Refers to the old bean. Used as old value if the bean changes.
* Updated after a bean change in the BeanChangeHandler.
*/
private B storedOldBean;
/**
* Indicates whether a property in the current target been has changed.
* Will be reset to {@code false} every time the target bean changes.
*
* @see #isChanged()
* @see #setBean(Object)
*/
private boolean changed = false;
/**
* The {@code PropertyChangeListener} used to handle changes
* in the adapted bean property. A new instance is created every time
* the target bean changes.
*/
private PropertyChangeListener propertyChangeHandler;
/**
* Describes the property access; basically a getter and setter.
*/
private transient PropertyAccessor cachedPropertyAccessor;
/**
* Holds the bean class associated with the cached property descriptor.
*/
private Class cachedBeanClass;
// Instance creation ****************************************************
/**
* Constructs a {@code PropertyAdapter} for the given
* bean and property name; does not observe changes.
*
* @param bean the bean that owns the property
* @param propertyName the name of the adapted property
* @throws NullPointerException if {@code propertyName} is {@code null}
* @throws IllegalArgumentException if {@code propertyName} is empty
*/
public PropertyAdapter(B bean, String propertyName) {
this(bean, propertyName, false);
}
/**
* Constructs a {@code PropertyAdapter} for the given
* bean and property name; observes changes if specified.
*
* @param bean the bean that owns the property
* @param propertyName the name of the adapted property
* @param observeChanges {@code true} to observe changes of bound
* or constrained properties, {@code false} to ignore changes
* @throws NullPointerException if {@code propertyName} is {@code null}
* @throws IllegalArgumentException if {@code propertyName} is empty
* @throws PropertyUnboundException if {@code observeChanges}
* is true but the property is unbound, i. e. the {@code bean}
* does not provide a pair of methods to register a multicast
* PropertyChangeListener
*/
public PropertyAdapter(
B bean,
String propertyName,
boolean observeChanges) {
this(bean, propertyName, null, null, observeChanges);
}
/**
* Constructs a {@code PropertyAdapter} for the given bean,
* property name, getter and setter name; does not observe changes.
*
* @param bean the bean that owns the property
* @param propertyName the name of the adapted property
* @param getterName the optional name of the property reader
* @param setterName the optional name of the property writer
* @throws NullPointerException if {@code propertyName} is {@code null}
* @throws IllegalArgumentException if {@code propertyName} is empty
*/
public PropertyAdapter(B bean, String propertyName, String getterName, String setterName) {
this(bean, propertyName, getterName, setterName, false);
}
/**
* Constructs a {@code PropertyAdapter} for the given bean,
* property name, getter and setter name; observes changes if specified.
*
* @param bean the bean that owns the property
* @param propertyName the name of the adapted property
* @param getterName the optional name of the property reader
* @param setterName the optional name of the property writer
* @param observeChanges {@code true} to observe changes of bound
* or constrained properties, {@code false} to ignore changes
* @throws NullPointerException if {@code propertyName} is {@code null}
* @throws IllegalArgumentException if {@code propertyName} is empty
* @throws PropertyUnboundException if {@code observeChanges}
* is true but the property is unbound, i. e. the {@code bean}
* does not provide a pair of methods to register a multicast
* PropertyChangeListener
*/
public PropertyAdapter(
B bean,
String propertyName,
String getterName,
String setterName,
boolean observeChanges) {
this(new ValueHolder(bean, true), propertyName, getterName, setterName, observeChanges);
}
/**
* Constructs a {@code PropertyAdapter} for the given
* bean channel and property name; does not observe changes.
*
* @param beanChannel the {@code ValueModel} that holds the bean
* @param propertyName the name of the adapted property
* @throws NullPointerException if {@code beanChannel} or
* {@code propertyName} is {@code null}
* @throws IllegalArgumentException if {@code propertyName} is empty
*/
public PropertyAdapter(ValueModel beanChannel, String propertyName) {
this(beanChannel, propertyName, false);
}
/**
* Constructs a {@code PropertyAdapter} for the given
* bean channel and property name; observes changes if specified.
*
* @param beanChannel the {@code ValueModel} that holds the bean
* @param propertyName the name of the adapted property
* @param observeChanges {@code true} to observe changes of bound
* or constrained properties, {@code false} to ignore changes
* @throws NullPointerException if {@code beanChannel} or
* {@code propertyName} is {@code null}
* @throws IllegalArgumentException if {@code propertyName} is empty
* @throws PropertyUnboundException if {@code observeChanges}
* is true but the property is unbound, i. e. the {@code bean}
* does not provide a pair of methods to register a multicast
* PropertyChangeListener
* @throws PropertyAccessException if the {@code beanChannel}'s value
* does not provide a property descriptor for {@code propertyName}
*/
public PropertyAdapter(
ValueModel beanChannel,
String propertyName,
boolean observeChanges) {
this(beanChannel, propertyName, null, null, observeChanges);
}
/**
* Constructs a {@code PropertyAdapter} for the given bean channel,
* property name, getter and setter name; does not observe changes.
*
* @param beanChannel the {@code ValueModel} that holds the bean
* @param propertyName the name of the adapted property
* @param getterName the optional name of the property reader
* @param setterName the optional name of the property writer
* @throws NullPointerException if {@code beanChannel} or
* {@code propertyName} is {@code null}
* @throws IllegalArgumentException if {@code propertyName} is empty
*/
public PropertyAdapter(ValueModel beanChannel, String propertyName, String getterName, String setterName) {
this(beanChannel, propertyName, getterName, setterName, false);
}
/**
* Constructs a {@code PropertyAdapter} for the given bean channel,
* property name, getter and setter name; observes changes if specified.
*
* @param beanChannel the {@code ValueModel} that holds the bean
* @param propertyName the name of the adapted property
* @param getterName the optional name of the property reader
* @param setterName the optional name of the property writer
* @param observeChanges {@code true} to observe changes of bound
* or constrained properties, {@code false} to ignore changes
*
* @throws NullPointerException if {@code propertyName} is {@code null}
* @throws IllegalArgumentException if {@code propertyName} is empty
* @throws IllegalArgumentException if the bean channel is a ValueHolder
* that has the identityCheck feature disabled
* @throws PropertyUnboundException if {@code observeChanges}
* is true but the property is unbound, i. e. the {@code bean}
* does not provide a pair of methods to register a multicast
* PropertyChangeListener
* @throws PropertyAccessException if the {@code beanChannel}'s value
* does not provide a property descriptor for {@code propertyName}
*/
public PropertyAdapter(
ValueModel beanChannel,
String propertyName,
String getterName,
String setterName,
boolean observeChanges) {
this.beanChannel = beanChannel != null
? beanChannel
: new ValueHolder(null, true);
this.propertyName = propertyName;
this.getterName = getterName;
this.setterName = setterName;
this.observeChanges = observeChanges;
checkNotBlank(propertyName, MUST_NOT_BE_BLANK, "property name");
checkBeanChannelIdentityCheck(beanChannel);
this.beanChannel.addValueChangeListener(new BeanChangeHandler());
B initialBean = getBean();
// Eagerly check the existence of the property to adapt.
if (initialBean != null) {
getPropertyAccessor(initialBean);
addChangeHandlerTo(initialBean);
}
storedOldBean = initialBean;
}
// Accessors ************************************************************
/**
* Returns the Java Bean that holds the adapted property.
*
* @return the Bean that holds the adapted property
*
* @see #setBean(Object)
*/
public B getBean() {
return (B) beanChannel.getValue();
}
/**
* Sets a new Java Bean as holder of the adapted property.
* Notifies any registered value listeners if the value has changed.
* Also notifies listeners that have been registered with this adapter
* to observe the bound property bean.
*
* @param newBean the new holder of the property
*
* @see #getBean()
*/
public void setBean(B newBean) {
beanChannel.setValue(newBean);
}
/**
* Returns the name of the adapted Java Bean property.
*
* @return the name of the adapted property
*/
public String getPropertyName() {
return propertyName;
}
/**
* Answers whether this adapter observes changes in the
* adapted Bean property.
*
* @return true if this adapter observes changes, false if not
*/
public boolean getObserveChanges() {
return observeChanges;
}
/*
* Sets whether changes in the adapted Bean property shall be observed.
* As a requirement the property must be bound.
*
* @param newValue true to observe changes, false to ignore them
public void setObserveChanges(boolean newValue) {
if (newValue == getObserveChanges())
return;
observeChanges = newValue;
Object bean = getBean();
removePropertyChangeHandler(bean);
addPropertyChangeHandler(bean);
}
*/
// ValueModel Implementation ********************************************
/**
* Returns the value of the bean's adapted property, {@code null}
* if the current bean is {@code null}.
*
* If the adapted bean property is write-only, this adapter is write-only
* too, and this operation is not supported and throws an exception.
*
* @return the value of the adapted bean property, null if the bean is null
* @throws UnsupportedOperationException if the property is write-only
* @throws PropertyNotFoundException if the property could not be found
* @throws PropertyAccessException if the value could not be read
*/
@Override
public Object getValue() {
return getValue0(getBean());
}
/**
* Sets the given object as new value of the adapted bean property.
* Does nothing if the bean is {@code null}. If the bean setter
* throws a PropertyVetoException, it is silently ignored.
* This write operation is supported only for writable bean properties.
*
* Notifies any registered value 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.
*
* @param newValue the value to set
*
* @throws UnsupportedOperationException if the property is read-only
* @throws PropertyNotFoundException if the property could not be found
* @throws PropertyAccessException if the new value could not be set
*/
@Override
public void setValue(Object newValue) {
B bean = getBean();
if (bean == null) {
return;
}
try {
setValue0(bean, newValue);
} catch (PropertyVetoException e) {
// Silently ignore this situation.
}
}
/**
* Sets the given object as new value of the adapted bean property.
* Does nothing if the bean is {@code null}. If the bean setter
* throws a PropertyVetoExeption, this method throws the same exception.
* This write operation is supported only for writable bean properties.
*
* Notifies any registered value 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.
*
* @param newValue the value to set
*
* @throws UnsupportedOperationException if the property is read-only
* @throws PropertyNotFoundException if the property could not be found
* @throws PropertyAccessException if the new value could not be set
* @throws PropertyVetoException if the invoked bean setter
* throws a PropertyVetoException
*
* @since 1.1
*/
public void setVetoableValue(Object newValue) throws PropertyVetoException {
B bean = getBean();
if (bean == null) {
return;
}
setValue0(getBean(), newValue);
}
// Accessing the Changed State ********************************************
/**
* Answers whether a bean property has changed since the changed state
* has been reset. The changed state is implicitly reset every time
* the target bean changes.
*
* @return true if a property of the current target bean
* has changed since the last reset
*/
public boolean isChanged() {
return changed;
}
/**
* Resets this tracker's changed state to {@code false}.
*/
public void resetChanged() {
setChanged(false);
}
/**
* Sets the changed state to the given value. Invoked by the global
* PropertyChangeHandler that observes all bean changes. Also invoked
* by {@code #resetChanged}.
*
* @param newValue the new changed state
*/
private void setChanged(boolean newValue) {
boolean oldValue = isChanged();
changed = newValue;
firePropertyChange(PROPERTY_CHANGED, oldValue, newValue);
}
// Releasing PropertyChangeListeners **************************************
/**
* Removes the PropertyChangeHandler from the observed bean, if the bean
* is not {@code null} and if property changes are observed.
*
* PropertyAdapters that observe changes have a PropertyChangeListener
* registered with the target bean. Hence, a bean has a reference to all
* PropertyAdapters that observe it. To avoid memory leaks it is recommended
* to remove this listener if the bean lives much longer than the
* PropertyAdapter, enabling the garbage collector to remove the adapter.
* To do so, you can call {@code 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 {@code WeakReference}.
*
* Setting the bean to null has side-effects, for example
* this adapter fires a change event for the bound property bean
* and other properties. And this adpter's value 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 adapter.
* Another way to clear the reference from the target bean is
* to call {@code #release}. It has no side-effects, but the adapter
* must not be used anymore once #release has been called.
*
* @see #setBean(Object)
* @see java.lang.ref.WeakReference
*/
public void release() {
removeChangeHandlerFrom(getBean());
}
// Overriding Superclass Behavior *****************************************
@Override
protected String paramString() {
B bean = getBean();
String beanType = null;
Object value = getValue();
String valueType = null;
String propertyAccessorName = null;
String propertyType = null;
Method propertySetter = null;
if (bean != null) {
beanType = bean.getClass().getName();
valueType = value == null ? null : value.getClass().getName();
PropertyAccessor propertyAccessor = getPropertyAccessor(bean);
propertyAccessorName = propertyAccessor.getPropertyName();
propertyType = propertyAccessor.getPropertyType().getName();
propertySetter = propertyAccessor.getWriteMethod();
}
return
"bean="
+ bean
+ "; bean type="
+ beanType
+ "; value="
+ value
+ "; value type="
+ valueType
+ "; property name="
+ propertyAccessorName
+ "; property type="
+ propertyType
+ "; property setter="
+ propertySetter;
}
// Changing the Bean & Adding and Removing the PropertyChangeHandler ******
private void setBean0(B oldBean, B newBean) {
firePropertyChange(PROPERTY_BEFORE_BEAN, oldBean, newBean, true);
removeChangeHandlerFrom(oldBean);
forwardAdaptedValueChanged(oldBean, newBean);
resetChanged();
addChangeHandlerTo(newBean);
firePropertyChange(PROPERTY_BEAN, oldBean, newBean, true);
firePropertyChange(PROPERTY_AFTER_BEAN, oldBean, newBean, true);
}
private void forwardAdaptedValueChanged(B oldBean, B newBean) {
Object oldValue = oldBean == null || isWriteOnlyProperty(oldBean)
? null
: getValue0(oldBean);
Object newValue = newBean == null || isWriteOnlyProperty(newBean)
? null
: getValue0(newBean);
if (oldValue != null || newValue != null) {
fireValueChange(oldValue, newValue, true);
}
}
private void forwardAdaptedValueChanged(B newBean) {
Object newValue = newBean == null || isWriteOnlyProperty(newBean)
? null
: getValue0(newBean);
fireValueChange(null, newValue);
}
/**
* Adds a property change listener to the given bean if we observe changes
* and the bean is not null. First checks whether the bean class
* supports bound properties, i.e. it provides a pair of methods
* to register multicast property change event listeners;
* see section 7.4.1 of the Java Beans specification for details.
*
* @param bean the bean to add a property change handler.
* @throws PropertyUnboundException
* if the bean does not support bound properties
* @throws PropertyNotBindableException
* if the property change handler cannot be added successfully
*
* @see #removeChangeHandlerFrom(Object)
*/
private void addChangeHandlerTo(B bean) {
if (!observeChanges || bean == null) {
return;
}
propertyChangeHandler = new PropertyChangeHandler();
BeanUtils.addPropertyChangeListener(bean, getBeanClass(bean), propertyChangeHandler);
}
/**
* Removes the formerly added property change handler from the given bean
* if we observe changes and the bean is not null and we haven't called
* this method before.
*
* @param bean the bean to remove the property change handler from.
* @throws PropertyUnboundException
* if the bean does not support bound properties
* @throws PropertyNotBindableException
* if the property change handler cannot be removed successfully
*
* @see #addChangeHandlerTo(Object)
*/
private void removeChangeHandlerFrom(B bean) {
if (!observeChanges || bean == null || propertyChangeHandler == null) {
return;
}
BeanUtils.removePropertyChangeListener(bean, getBeanClass(bean), propertyChangeHandler);
propertyChangeHandler = null;
}
// Helper Methods to Get and Set a Property Value *************************
/**
* Returns the Java Bean class used by this adapter.
* The current implementation just returns the given bean's class.
*
* A future version may return a type other than the concrete
* class of the given bean. This beanClass could be specified
* in a new set of constructors. This is useful if the beans
* are specified by public interfaces, and implemented by
* package private classes. In this case, the class of the given bean
* object shall be checked against the specified type.
*
* @param bean the bean that may be used to lookup the class from
* @return the Java Bean class used for this adapter.
*/
private Class getBeanClass(B bean) {
return bean.getClass();
// The future version shall add a check like
// beanClass.isInstance(bean) if the beanClass
// has been specified in the constructor.
}
/**
* Returns the current value of the bean's property, {@code null}
* if the current bean is {@code null}.
*
* @param bean the bean to read the value from
* @return the bean's property value
*/
private Object getValue0(B bean) {
return bean == null
? null
: getPropertyAccessor(bean).getValue(bean);
}
/**
* Sets the given object as new value of the adapted bean property.
* Does nothing if the bean is {@code null}. This operation
* is unsupported if the bean property is read-only.
*
* The operation is delegated to the property accessor.
*
* @param bean the bean that holds the adapted property
* @param newValue the property value to be set
*
* @throws NullPointerException if the bean is null
* @throws PropertyVetoException if the invoked bean setter
* throws a PropertyVetoException
*/
private void setValue0(B bean, Object newValue) throws PropertyVetoException {
getPropertyAccessor(bean).setValue(bean, newValue);
}
/**
* Looks up, lazily initializes and returns a PropertyAccessor
* for the given Java Bean and name of the adapted property.
* The concrete lookup is done by the current PropertyAccessorProvider,
* which is by default a provider that uses the Java Bean introspection.
*
* The cached accessor is considered invalid, if the bean's class
* has changed. In this case we recompute the accessor.
*
* @param bean the bean that holds the property
* @return the PropertyAccessor as returned by the provider
* @throws PropertyNotFoundException if the property could not be found
*/
private PropertyAccessor getPropertyAccessor(B bean) {
Class beanClass = getBeanClass(bean);
if (cachedPropertyAccessor == null
|| beanClass != cachedBeanClass) {
cachedPropertyAccessor = PropertyAccessors.getProvider().getAccessor(
beanClass,
getPropertyName(),
getterName,
setterName);
cachedBeanClass = beanClass;
}
return cachedPropertyAccessor;
}
/**
* Answers whether the adapted property has a setter but no getter.
* In this case the PropertyAdapter doesn't check for the old value
* when you set a new bean or a new value.
*
* @param bean the bean to test for the write only state
* @return true if the property has a setter but no getter, false otherwise
*/
private boolean isWriteOnlyProperty(B bean) {
return getPropertyAccessor(bean).isWriteOnly();
}
/**
* Throws an IllegalArgumentException if the given ValueModel
* is a ValueHolder that has the identityCheck feature disabled.
*/
private static void checkBeanChannelIdentityCheck(ValueModel valueModel) {
if (!(valueModel instanceof ValueHolder)) {
return;
}
ValueHolder valueHolder = (ValueHolder) valueModel;
if (!valueHolder.isIdentityCheckEnabled()) {
throw new IllegalArgumentException(
"The bean channel must have the identity check enabled.");
}
}
// Helper Classes *********************************************************
/**
* Listens to changes of the bean.
*/
private final class BeanChangeHandler implements PropertyChangeListener {
/**
* The bean has been changed. Uses the stored old bean instead of
* the event's old value, because the latter can be null.
* If the event's new value is null, the new bean is requested
* from the bean channel.
*
* @param evt the property change event to be handled
*/
@Override
public void propertyChange(PropertyChangeEvent evt) {
B newBean = evt.getNewValue() != null
? (B) evt.getNewValue()
: getBean();
setBean0(storedOldBean, newBean);
storedOldBean = newBean;
}
}
/**
* Listens to changes of all bean properties. Fires property changes
* if the associated property or an arbitrary set of properties has changed.
*/
private final class PropertyChangeHandler implements PropertyChangeListener {
/**
* A bean property has been changed. Sets the changed state to true.
* Checks whether the observed
* property or multiple properties have changed.
* If so, notifies all registered listeners about the change.
*
* @param evt the property change event to be handled
*/
@Override
public void propertyChange(PropertyChangeEvent evt) {
setChanged(true);
if (evt.getPropertyName() == null) {
forwardAdaptedValueChanged(getBean());
} else if (evt.getPropertyName().equals(getPropertyName())) {
fireValueChange(evt.getOldValue(), evt.getNewValue(), true);
}
}
}
}