| com.opensymphony.xwork.util.XWorkConverter
| XWorkConverter | | public class XWorkConverter extends DefaultTypeConverter (Code) | | XWorkConverter is a singleton used by many of the WebWork's Ognl extention points,
such as InstantiatingNullHandler, XWorkListPropertyAccessor etc to do object
conversion.
Type conversion is great for situations where you need to turn a String in to a more complex object. Because the web
is type-agnostic (everything is a string in HTTP), WebWork's type conversion features are very useful. For instance,
if you were prompting a user to enter in coordinates in the form of a string (such as "3, 22"), you could have
WebWork do the conversion both from String to Point and from Point to String.
Using this "point" example, if your action (or another compound object in which you are setting properties on)
has a corresponding ClassName-conversion.properties file, WebWork will use the configured type converters for
conversion to and from strings. So turning "3, 22" in to new Point(3, 22) is done by merely adding the following
entry to ClassName-conversion.properties (Note that the PointConverter should impl the ognl.TypeConverter
interface):
point = com.acme.PointConverter
Your type converter should be sure to check what class type it is being requested to convert. Because it is used
for both to and from strings, you will need to split the conversion method in to two parts: one that turns Strings in
to Points, and one that turns Points in to Strings.
After this is done, you can now reference your point (using <ww:property value="post"/> in JSP or ${point}
in FreeMarker) and it will be printed as "3, 22" again. As such, if you submit this back to an action, it will be
converted back to a Point once again.
In some situations you may wish to apply a type converter globally. This can be done by editing the file
xwork-conversion.properties in the root of your class path (typically WEB-INF/classes) and providing a
property in the form of the class name of the object you wish to convert on the left hand side and the class name of
the type converter on the right hand side. For example, providing a type converter for all Point objects would mean
adding the following entry:
com.acme.Point = com.acme.PointConverter
Type conversion should not be used as a substitute for i18n. It is not recommended to use this feature to print out
properly formatted dates. Rather, you should use the i18n features of WebWork (and consult the JavaDocs for JDK's
MessageFormat object) to see how a properly formatted date should be displayed.
Any error that occurs during type conversion may or may not wish to be reported. For example, reporting that the
input "abc" could not be converted to a number might be important. On the other hand, reporting that an empty string,
"", cannot be converted to a number might not be important - especially in a web environment where it is hard to
distinguish between a user not entering a value vs. entering a blank value.
By default, all conversion errors are reported using the generic i18n key xwork.default.invalid.fieldvalue,
which you can override (the default text is Invalid field value for field "xxx", where xxx is the field name)
in your global i18n resource bundle.
However, sometimes you may wish to override this message on a per-field basis. You can do this by adding an i18n
key associated with just your action (Action.properties) using the pattern invalid.fieldvalue.xxx, where xxx
is the field name.
It is important to know that none of these errors are actually reported directly. Rather, they are added to a map
called conversionErrors in the ActionContext. There are several ways this map can then be accessed and the
errors can be reported accordingly.
author:
Pat Lightbody
author:
Rainer Hermanns
author:
Alexandru Popescu
See Also: XWorkBasicConverter |
| Method Summary | |
| void | addConverterMapping(Map mapping, Class clazz)
Looks for converter mappings for the specified class and adds it to an existing map. | | public static String | buildConverterFilename(Class clazz)
| | public Object | convertValue(Map map, Object o, Class aClass)
| | public Object | convertValue(Map context, Object target, Member member, String property, Object value, Class toClass)
Convert value from one form to another. | | TypeConverter | createTypeConverter(String className)
| | public static String | getConversionErrorMessage(String propertyName, OgnlValueStack stack)
| | protected Object | getConverter(Class clazz, String property)
| | public static XWorkConverter | getInstance()
| | public ObjectTypeDeterminer | getObjectTypeDeterminer()
| | protected void | handleConversionException(Map context, String property, Object value, Object object)
| | public void | loadConversionProperties(String propsName)
| | public TypeConverter | lookup(String className)
Looks for a TypeConverter in the default mappings. | | public TypeConverter | lookup(Class clazz)
Looks for a TypeConverter in the default mappings. | | TypeConverter | lookupSuper(Class clazz)
Recurses through a class' interfaces and class hierarchy looking for a TypeConverter in the default mapping that
can handle the specified class. | | public synchronized void | registerConverter(String className, TypeConverter converter)
| | public synchronized void | registerConverterNotFound(String className)
| | public static void | resetInstance()
| | public void | setDefaultConverter(TypeConverter defaultTypeConverter)
| | public static void | setInstance(XWorkConverter instance)
| | public void | setObjectTypeDeterminer(ObjectTypeDeterminer determiner)
|
| CONVERSION_COLLECTION_PREFIX | | final public static String CONVERSION_COLLECTION_PREFIX(Code) | | |
| CONVERSION_ERROR_PROPERTY_PREFIX | | final public static String CONVERSION_ERROR_PROPERTY_PREFIX(Code) | | |
| CONVERSION_PROPERTY_FULLNAME | | final public static String CONVERSION_PROPERTY_FULLNAME(Code) | | |
| LAST_BEAN_CLASS_ACCESSED | | final public static String LAST_BEAN_CLASS_ACCESSED(Code) | | |
| LAST_BEAN_PROPERTY_ACCESSED | | final public static String LAST_BEAN_PROPERTY_ACCESSED(Code) | | |
| LOG | | final protected static Log LOG(Code) | | |
| REPORT_CONVERSION_ERRORS | | final public static String REPORT_CONVERSION_ERRORS(Code) | | |
| defaultTypeConverter | | TypeConverter defaultTypeConverter(Code) | | |
| XWorkConverter | | protected XWorkConverter()(Code) | | |
| addConverterMapping | | void addConverterMapping(Map mapping, Class clazz)(Code) | | Looks for converter mappings for the specified class and adds it to an existing map. Only new converters are
added. If a converter is defined on a key that already exists, the converter is ignored.
Parameters:
mapping - an existing map to add new converter mappings to
Parameters:
clazz - class to look for converter mappings for |
| convertValue | | public Object convertValue(Map context, Object target, Member member, String property, Object value, Class toClass)(Code) | | Convert value from one form to another.
Minimum requirement of arguments:
- supplying context, toClass and value
- supplying context, target and value.
See Also: ognl.TypeConverter.convertValue(java.util.Mapjava.lang.Objectjava.lang.reflect.Memberjava.lang.Stringjava.lang.Objectjava.lang.Class) |
| lookup | | public TypeConverter lookup(String className)(Code) | | Looks for a TypeConverter in the default mappings.
Parameters:
className - name of the class the TypeConverter must handle a TypeConverter to handle the specified class or null if none can be found |
| lookup | | public TypeConverter lookup(Class clazz)(Code) | | Looks for a TypeConverter in the default mappings.
Parameters:
clazz - the class the TypeConverter must handle a TypeConverter to handle the specified class or null if none can be found |
| lookupSuper | | TypeConverter lookupSuper(Class clazz)(Code) | | Recurses through a class' interfaces and class hierarchy looking for a TypeConverter in the default mapping that
can handle the specified class.
Parameters:
clazz - the class the TypeConverter must handle a TypeConverter to handle the specified class or null if none can be found |
| registerConverter | | public synchronized void registerConverter(String className, TypeConverter converter)(Code) | | |
| registerConverterNotFound | | public synchronized void registerConverterNotFound(String className)(Code) | | |
| resetInstance | | public static void resetInstance()(Code) | | |
| setDefaultConverter | | public void setDefaultConverter(TypeConverter defaultTypeConverter)(Code) | | |
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