org.apache.wicket.core.util.lang

Class PropertyResolver

java.lang.Object

org.apache.wicket.core.util.lang.PropertyResolver

public final class PropertyResolver
extends Object

This class parses expressions to lookup or set a value on the object that is given.
The supported expressions are:

"property"

This could be a bean property with getter and setter. Or if a map is given as an object it will be lookup with the expression as a key when there is not getter for that property.

"property1.property2"

Both properties are looked up as described above. If property1 evaluates to null then if there is a setter (or if it is a map) and the Class of the property has a default constructor then the object will be constructed and set on the object.

"method()"

The corresponding method is invoked.

"property.index" or "property[index]"

If the property is a List or Array then the following expression can be a index on that list like: 'mylist.0'. The list will grow automatically if the index is greater than the size.

This expression will also map on indexed properties, i.e. getProperty(index) and setProperty(index,value) methods.

"property.key" or "property[key]"

If the property is a Map then the following expression can be a key in that map like: 'myMap.key'.

Note that the PropertyResolver.DefaultPropertyLocator by default provides access to private members and methods. If guaranteeing encapsulation of the target objects is a big concern, you should consider using an alternative implementation.

Note: If a property evaluates to an instance of IModel then the expression should use '.object' to work with its value.

Author:

jcompagner, svenmeier

Nested Class Summary

Nested Classes

Modifier and Type	Class and Description
static class	PropertyResolver.AbstractGetAndSet
static class	PropertyResolver.CachingPropertyLocator A wrapper for another PropertyResolver.IPropertyLocator that caches results of PropertyResolver.CachingPropertyLocator.get(Class, String).
static class	PropertyResolver.DefaultPropertyLocator Default locator supporting Java Beans properties, maps, lists and method invocations.
static interface	PropertyResolver.IGetAndSet A property to get and set.
static interface	PropertyResolver.IPropertyLocator A locator of properties.

Method Summary

Modifier and Type	Method and Description
static void	destroy(Application application) Clean up cache for this app.
static PropertyResolver.IPropertyLocator	getLocator() Get the current PropertyResolver.IPropertyLocator.
static <T> Class<T>	getPropertyClass(String expression, Class<?> clz)
static Class<?>	getPropertyClass(String expression, Object object)
static Field	getPropertyField(String expression, Object object)
static Method	getPropertyGetter(String expression, Object object)
static Method	getPropertySetter(String expression, Object object)
static Object	getValue(String expression, Object object) Looks up the value from the object with the given expression.
static void	setLocator(Application application, PropertyResolver.IPropertyLocator locator) Set a locator for the given application.
static void	setValue(String expression, Object object, Object value, PropertyResolverConverter converter) Set the value on the object with the given expression.

Methods inherited from class java.lang.Object

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

Method Detail

getValue

public static Object getValue(String expression,
                              Object object)

Looks up the value from the object with the given expression. If the expression, the object itself or one property evaluates to null then a null will be returned.

Parameters:

expression - The expression string with the property to be lookup.

object - The object which is evaluated.

Returns:

The value that is evaluated. Null something in the expression evaluated to null.

setValue

public static void setValue(String expression,
                            Object object,
                            Object value,
                            PropertyResolverConverter converter)

Set the value on the object with the given expression. If the expression can't be evaluated then a WicketRuntimeException will be thrown. If a null object is encountered then it will try to generate it by calling the default constructor and set it on the object. The value will be tried to convert to the right type with the given converter.

Parameters:

expression - The expression string with the property to be set.

object - The object which is evaluated to set the value on.

value - The value to set.

converter - The converter to convert the value if needed to the right type.

Throws:

WicketRuntimeException

getPropertyClass

public static Class<?> getPropertyClass(String expression,
                                        Object object)

Parameters:

expression -

object -

Returns:

class of the target property object

Throws:

WicketRuntimeException - if the cannot be resolved

getPropertyClass

public static <T> Class<T> getPropertyClass(String expression,
                                            Class<?> clz)

Type Parameters:

T -

Parameters:

expression -

clz -

Returns:

class of the target Class property expression

Throws:

WicketRuntimeException - if class cannot be resolved

getPropertyField

public static Field getPropertyField(String expression,
                                     Object object)

Parameters:

expression -

object -

Returns:

Field for the property expression

Throws:

WicketRuntimeException - if there is no such field

getPropertyGetter

public static Method getPropertyGetter(String expression,
                                       Object object)

Parameters:

expression -

object -

Returns:

Getter method for the property expression

Throws:

WicketRuntimeException - if there is no getter method

getPropertySetter

public static Method getPropertySetter(String expression,
                                       Object object)

Parameters:

expression -

object -

Returns:

Setter method for the property expression

Throws:

WicketRuntimeException - if there is no setter method

destroy

public static void destroy(Application application)

Clean up cache for this app.

Parameters:

application -

getLocator

public static PropertyResolver.IPropertyLocator getLocator()

Get the current PropertyResolver.IPropertyLocator.

Returns:

locator for the current Application or a general one if no current application is present

See Also:

Application.get()

setLocator

public static void setLocator(Application application,
                              PropertyResolver.IPropertyLocator locator)

Set a locator for the given application.

Parameters:

application - application, may be null

locator - locator