I'm not sure whether the example given is indicative of all of your use
cases, but calling* setExcludeNullValues(true)* would accomplish your above
goal.
On Wed, Jul 7, 2021 at 6:57 PM Daniel Augusto Veronezi Salvador <
dvsalvador...@gmail.com> wrote:
> Thanks for the reply Rob,
>
> To examplify what I mean:
>
> We have a class with 7 attributes: a, b, c, d, e, f.
>
> Example example...
> example.setA("test");
> example.setB(1);
> ...
> example.setE(false);
> ...
>
> We need to print only "a", "b" and "e"; According with your suggestion,
> it would be:
>
> ToStringBuilder toStringBuilder = new ToStringBuilder(example,
> ToStringStyle.JSON_STYLE);
> toStringBuilder.append("a", example.getA());
> toStringBuilder.append("b", example.getB());
> toStringBuilder.append("e", example.isE());
> System.out.println(toStringBuilder.build());
>
> It works, but I see some negative points:
> - We instance the ToStringBuilder with the object, but it's meaningless
> to this situation;
> - We can put whatever we want as attribute name and value, therefore
> it's not related to the object we want to print;
> - It's verbose; The more attributes we want to print, more calls to
> append we need;
>
>
> The way I want to propose (I already have some code in my fork -
>
> https://github.com/GutoVeronezi/commons-lang/tree/create-methods-on-reflectiontostringbuilder-to-select-fields)
>
> would work like a intersection between excludeFields and selectedFields.
> It would have some methods to set the selected fields (like exclude
> fields has) and a validation in the method "accept":
>
> protected boolean accept(final Field field) {
> ...
> if (this.excludeFieldNames != null
> && Arrays.binarySearch(this.excludeFieldNames, field.getName())
> >= 0) {
> // Reject fields from the getExcludeFieldNames list.
> return false;
> }
> if (this.selectedFieldNames != null) {
> // Only accept fields that were selected on
> getSelectedFieldNames list.
> return Arrays.binarySearch(this.selectedFieldNames,
> field.getName()) >= 0;
> }
> return !field.isAnnotationPresent(ToStringExclude.class);
> }
>
>
> Then, to use the proposed solution, we would have the following code
> snippet:
>
>
> ReflectionToStringBuilder reflectionToStringBuilder = new
> ReflectionToStringBuilder(example, ToStringStyle.JSON_STYLE);
> reflectionToStringBuilder.setSelectedFieldNames("a", "b", "e");
> System.out.println(reflectionToStringBuilder.build());
>
>
>
> Both ways would generate the result:
> {"a":"test","b":1,"e":false}
>
> However, selecting the fields, as I am proposing, is less verbose and
> more intuitive as it relates directly the fields we want with the object
> that we are targeting to generate the `toString` to.
>
> Best Regards,
> Daniel Salvador
>
> > If you know the fields, why use ReflectionToStringBuilder? Why not use a
>
> > regular ToStringBuilder? That allows you to append each field you want.
> > Yes, you have to type each field name twice (for the name and the
> > value), but is that so much more work that it would require complicating
> > the ReflectiontoStringBuilder API?
> >
> >
> > On 02/07/2021 20:06, Daniel Augusto Veronezi Salvador wrote:
> > > Hello,
> > >
> > > This is my first interaction with this community, so I may commit some
> > > mistakes 😠.
> > >
> > > *ReflectionToStringBuilder* has methods to exclude fields from
> > > *toString*; If we have an object with several fields and want to
> reflect
> > > only a some, we have to list all the fields that we don't want to
> > > reflect and pass to *excludeFieldNames*. I did this trick locally,
> but I
> > > was wondering if it would be valid to implement a way to pass the
> fields
> > > that we want and reflect only the selected fields in
> > > *ReflectionToStringBuilder*.
> > >
> > > As the contributing documentation guide, I submitted an issue on Jira
> > > too (https://issues.apache.org/jira/browse/LANG-1662).
> > >
> > >
> > > Best regards,
> > >
> > > Daniel Salvador
>
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