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Element with Default Value [message #711806]

Sat, 06 August 2011 17:13

Kamesh Sampath

Messages: 213
Registered: July 2009

Senior Member

I added the Default value annotation for a Property and i see the radio buttons appearing for it and default value being selected, but in my XML model i dont see the element created though i gave the @Required and @MustExist annotation. Unless and until i click on the element it does no create the element

Is there any way for adding the element tag automatically and populating it with DEFAULT value.

~Kamesh

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Re: Element with Default Value [message #713606 is a reply to message #711806]

Mon, 08 August 2011 16:36

Konstantin Komissarchik

Messages: 1077
Registered: July 2009

Senior Member

The @DefaultValue, @Required and @MustExist annotations do not operate at the level of XML binding.

@DefaultValue - Specifies the property value if a null was read from the underlying store (XML file, etc.).

@Required - Specifies that it should be a validation error if the property value is null. Does not make sense in conjunction with @DefaultValue.

@MustExist - Used with properties that name an external resource such as a file or a Java type to signify that the referenced entity has to exist or it's a validation error.

Getting back to your scenario, there are no declarative facilities to make sure that new elements are created with pre-populated content, but you can achieve this by implementing a custom binding for your list property. See @CustomXmlListBinding, StandardXmlListBindingImpl (the addUnderlyingObject method in particular).

- Konstantin

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Re: Element with Default Value [message #713781 is a reply to message #713606]

Tue, 09 August 2011 03:36

Kamesh Sampath

Messages: 213
Registered: July 2009

Senior Member

Thanks for the info Konstantin, I have implemented a class DefaultXmlBinding following StandardXmlListBindingImpl for this purpose. I feel that we can add an Annotation @Mandatory and make this implementation there. Right now this supported only for Non-list types, may be we could extend it for other types too.
Attaching the code here so that it might be useful for some one.

~Kamesh

Attachment: DefaultXmlBinding.java
(Size: 7.92KB, Downloaded 235 times)

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Re: Element with Default Value [message #714028 is a reply to message #713781]

Tue, 09 August 2011 16:21

Konstantin Komissarchik

Messages: 1077
Registered: July 2009

Senior Member

I am certainly open to devising a way to incorporate this scenario into the framework. Go ahead an open an enhancement request and we can discuss this further there.

BTW, in your custom binding implementation, you are modifying the DOM tree during a read, which you shouldn't be doing. Applying the initial values should happen in the createUnderlyingObject method.

- Konstantin

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