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PropertyDescriptor (Java 2 Platform SE v1.4.1) - JDK 5 Documentation v1.4.1, Java 2 SDK 英文文档

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java.beans
Class PropertyDescriptor

java.lang.Object
  |
  +--java.beans.FeatureDescriptor
        |
        +--java.beans.PropertyDescriptor

Direct Known Subclasses:

IndexedPropertyDescriptor

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public class PropertyDescriptor

extends FeatureDescriptor

A PropertyDescriptor describes one property that a Java Bean exports via a pair of accessor methods.

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Constructor Summary

PropertyDescriptor(String propertyName, Class beanClass)           Constructs a PropertyDescriptor for a property that follows the standard Java convention by having getFoo and setFoo accessor methods.

PropertyDescriptor(String propertyName, Class beanClass, String getterName, String setterName)           This constructor takes the name of a simple property, and method names for reading and writing the property.

PropertyDescriptor(String propertyName, Method getter, Method setter)           This constructor takes the name of a simple property, and Method objects for reading and writing the property.

 

Method Summary
boolean	equals(Object obj)           Compares this PropertyDescriptor against the specified object.
Class	getPropertyEditorClass()           Gets any explicit PropertyEditor Class that has been registered for this property.
Class	getPropertyType()           Gets the Class object for the property.
Method	getReadMethod()           Gets the method that should be used to read the property value.
Method	getWriteMethod()           Gets the method that should be used to write the property value.
boolean	isBound()           Updates to "bound" properties will cause a "PropertyChange" event to get fired when the property is changed.
boolean	isConstrained()           Attempted updates to "Constrained" properties will cause a "VetoableChange" event to get fired when the property is changed.
void	setBound(boolean bound)           Updates to "bound" properties will cause a "PropertyChange" event to get fired when the property is changed.
void	setConstrained(boolean constrained)           Attempted updates to "Constrained" properties will cause a "VetoableChange" event to get fired when the property is changed.
void	setPropertyEditorClass(Class propertyEditorClass)           Normally PropertyEditors will be found using the PropertyEditorManager.
void	setReadMethod(Method getter)           Sets the method that should be used to read the property value.
void	setWriteMethod(Method setter)           Sets the method that should be used to write the property value.

 

Methods inherited from class java.beans.FeatureDescriptor

attributeNames, getDisplayName, getName, getShortDescription, getValue, isExpert, isHidden, isPreferred, setDisplayName, setExpert, setHidden, setName, setPreferred, setShortDescription, setValue

 

Methods inherited from class java.lang.Object

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

 

Constructor Detail

PropertyDescriptor

public PropertyDescriptor(String propertyName,
                          Class beanClass)
                   throws IntrospectionException

Constructs a PropertyDescriptor for a property that follows the standard Java convention by having getFoo and setFoo accessor methods. Thus if the argument name is "fred", it will assume that the writer method is "setFred" and the reader method is "getFred" (or "isFred" for a boolean property). Note that the property name should start with a lower case character, which will be capitalized in the method names.

Parameters:

propertyName - The programmatic name of the property.

beanClass - The Class object for the target bean. For example sun.beans.OurButton.class.

Throws:

IntrospectionException - if an exception occurs during introspection.

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PropertyDescriptor

public PropertyDescriptor(String propertyName,
                          Class beanClass,
                          String getterName,
                          String setterName)
                   throws IntrospectionException

This constructor takes the name of a simple property, and method names for reading and writing the property.

Parameters:

propertyName - The programmatic name of the property.

beanClass - The Class object for the target bean. For example sun.beans.OurButton.class.

getterName - The name of the method used for reading the property value. May be null if the property is write-only.

setterName - The name of the method used for writing the property value. May be null if the property is read-only.

Throws:

IntrospectionException - if an exception occurs during introspection.

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PropertyDescriptor

public PropertyDescriptor(String propertyName,
                          Method getter,
                          Method setter)
                   throws IntrospectionException

This constructor takes the name of a simple property, and Method objects for reading and writing the property.

Parameters:

propertyName - The programmatic name of the property.

getter - The method used for reading the property value. May be null if the property is write-only.

setter - The method used for writing the property value. May be null if the property is read-only.

Throws:

IntrospectionException - if an exception occurs during introspection.

Method Detail

getPropertyType

public Class getPropertyType()

Gets the Class object for the property.

Returns:

The Java type info for the property. Note that the "Class" object may describe a built-in Java type such as "int". The result may be "null" if this is an indexed property that does not support non-indexed access.

This is the type that will be returned by the ReadMethod.

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getReadMethod

public Method getReadMethod()

Gets the method that should be used to read the property value.

Returns:

The method that should be used to read the property value. May return null if the property can't be read.

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setReadMethod

public void setReadMethod(Method getter)
                   throws IntrospectionException

Sets the method that should be used to read the property value.

Parameters:

getter - The new getter method.

IntrospectionException

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getWriteMethod

public Method getWriteMethod()

Gets the method that should be used to write the property value.

Returns:

The method that should be used to write the property value. May return null if the property can't be written.

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setWriteMethod

public void setWriteMethod(Method setter)
                    throws IntrospectionException

Sets the method that should be used to write the property value.

Parameters:

setter - The new setter method.

IntrospectionException

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isBound

public boolean isBound()

Updates to "bound" properties will cause a "PropertyChange" event to get fired when the property is changed.

Returns:

True if this is a bound property.

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setBound

public void setBound(boolean bound)

Updates to "bound" properties will cause a "PropertyChange" event to get fired when the property is changed.

Parameters:

bound - True if this is a bound property.

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isConstrained

public boolean isConstrained()

Attempted updates to "Constrained" properties will cause a "VetoableChange" event to get fired when the property is changed.

Returns:

True if this is a constrained property.

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setConstrained

public void setConstrained(boolean constrained)

Attempted updates to "Constrained" properties will cause a "VetoableChange" event to get fired when the property is changed.

Parameters:

constrained - True if this is a constrained property.

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setPropertyEditorClass

public void setPropertyEditorClass(Class propertyEditorClass)

Normally PropertyEditors will be found using the PropertyEditorManager. However if for some reason you want to associate a particular PropertyEditor with a given property, then you can do it with this method.

Parameters:

propertyEditorClass - The Class for the desired PropertyEditor.

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getPropertyEditorClass

public Class getPropertyEditorClass()

Gets any explicit PropertyEditor Class that has been registered for this property.

Returns:

Any explicit PropertyEditor Class that has been registered for this property. Normally this will return "null", indicating that no special editor has been registered, so the PropertyEditorManager should be used to locate a suitable PropertyEditor.

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equals

public boolean equals(Object obj)

Compares this PropertyDescriptor against the specified object. Returns true if the objects are the same. Two PropertyDescriptors are the same if the read, write, property types, property editor and flags are equivalent.

Overrides:

equals in class Object

Parameters:

obj - the reference object with which to compare.

Returns:

true if this object is the same as the obj argument; false otherwise.

Since:

1.4

See Also:

Object.hashCode(), Hashtable

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For further API reference and developer documentation, see Java 2 SDK SE Developer Documentation. That documentation contains more detailed, developer-targeted descriptions, with conceptual overviews, definitions of terms, workarounds, and working code examples.

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