invoke "values" coming from getAllEnums

[FranGomezVenegas]

Hi,
I'm refactoring my code in the way to not have to add to my 'declared enums documentation' method the enums one by one any time my code requires one new enum.
The idea is to get them by reflection and it works fine by using getAllEnums therefore I can document all enum names.
My problem comes when I need to get all enum entries, what I'm trying to do is to call the enum 'values' method due to I need to document the enum names and its entries.
I tried by this way. method=getMine.getClass().getMethod(methName, paramTypes), but it raises one Exception.
Then found this alternative way, Field f = getMine.getClass().getDeclaredField("$VALUES"), but did not works, it seems to not be compatible with the ClassInfo object in some way.

Anybody tried to do something similar? How to apply reflection for both, get the enum names (this works for me) and its entries (this is where I'm stuck).

Thanks in advance

[lukehutch]

Which exception is thrown?

For enums, the enum constants are available as methods, if I rember correctly. List methods and fields for an enum, and you should find what you need.

If it's methods, not fields, then maybe ClassGraph should add a ClassInfo.getEnumConstants() method that strips out hashCode(), equals(), etc. -- feel free to submit a pull request for that!

[FranGomezVenegas]

Thanks Luke for your quick answer

It gives NoSuchFieldException.
See below the code I'm trying to run, LpPlatformBusinessRules is one of my Enums which is not a simple enum, it contains some attributes therefore had to add one enum construction in it.

by ClassInfoList allEnums = scanResult.getAllEnums(); I get all those enums and then through a for loop I try to get all values per each one so getMine variable should get one by one each enum.
The hasMethod method returns true then it seems like values is a method other than a field but I'm a bit lost in this part ..

The code:
ClassInfo getMine = classesImplementing.get(i);
out.println(classesImplementing.get(i).getName());
String methName="values";
out.println("has method "+methName+"? "+getMine.hasMethod(methName));
Class [] carr = new Class[]{};
Method method = (Method) getMine.getClass().getMethod("values").invoke(null);

if I run the values by using the enum directly in this way below then it works fine.
LPPlatform.LpPlatformBusinessRules[] lpPlatformBusinessRules=LPPlatform.LpPlatformBusinessRules.values();

If you want me to create the pull request then let me know, I wanted to share the detail before adding the pull request. Just let me know and I will create it if so.

Thanks again

[lukehutch]

Hi,

The enum constants can be listed by looking at the fields, as I mentioned:

public class EnumTest {
    private static enum MyEnum {
        A, B, C;
    }

    public static void main(String[] args) throws Exception {
        try (ScanResult scanResult = new ClassGraph().acceptClasses(MyEnum.class.getName()).enableAllInfo()
                .scan()) {
            final ClassInfo myEnum = scanResult.getAllEnums().get(0);
            for (FieldInfo fi : myEnum.getFieldInfo()) {
                System.out.println(fi);
            }
        }
    }
}

This prints:

public static final test.EnumTest.MyEnum A
public static final test.EnumTest.MyEnum B
public static final test.EnumTest.MyEnum C
private static final synthetic test.EnumTest.MyEnum[] ENUM$VALUES

Just skip the one synthetic field by testing fi.isSynthetic().

[FranGomezVenegas]

Yes, I tested this and works fine.
My enum is more than a constants sequence ... see below one example having only one entry. What I need to do for each entry is to run the getters to get the info as to be written in the repository. In some way, I want my code to document its own business rules and then don't bother the developer with those business needs even keep this documentation up to date by daily running this logic.

public enum LpPlatformBusinessRules implements EnumIntBusinessRules {
PROCEDURE_ACTIONS("procedureActions", GlobalVariables.Schemas.PROCEDURE.getName(), null, null, '|', false)
;
private LpPlatformBusinessRules(String tgName, String areaNm, JSONArray valuesList, Boolean allowMulti, char separator, Boolean opt){
this.tagName=tgName;
this.areaName=areaNm;
this.valuesList=valuesList;
this.allowMultiValue=allowMulti;
this.multiValueSeparator=separator;
this.isOptional=opt;

    }       
    public String getTagName(){return this.tagName;}
    public String getAreaName(){return this.areaName;}
    public JSONArray getValuesList(){return this.valuesList;}
    public Boolean getAllowMultiValue(){return this.allowMultiValue;}
    public char getMultiValueSeparator(){return this.multiValueSeparator;}
    public Boolean getIsOptional(){return this.isOptional;}

    private final String tagName;
    private final String areaName;
    private final JSONArray valuesList;  
    private final Boolean allowMultiValue;
    private final char multiValueSeparator;  
    private final Boolean isOptional;
}

[lukehutch]

I added a method to return these enum constants. It will be in the next release (but it's not worth pushing out a release just for this). You can see the code here:

ce52201

[FranGomezVenegas]

Is it compatible with the kind of enum I posted above? I mean, I need to invoke any of those methods like getTagName or getValuesList for each enum entry.
By now I have to do it in the regular way that we use enums in the code, not by reference ....then I need to repeat the same for loop per each enum that belongs to this family (implements interface) that is what I want to replace by reflection

[lukehutch]

@FranGomezVenegas Ah, I see the problem. You need not just the names of the enum constants, but also the enum constant objects themselves.

The only way to do that is by loading the enum class, then using reflection to access each enum constant by name (since enum constants are stored as static fields of enum classes).

I implemented a method to accomplish this: ClassInfo.getEnumConstantObjects(). You can see how I accomplished this here: 04223e8 You can see how this can be used in this test: 1c8adca

I released this change in version 4.8.138: https://github.com/classgraph/classgraph/releases/tag/classgraph-4.8.138

[FranGomezVenegas]

Great!!!
I will try to find the way for adding this to my project

Thank you very much

[lukehutch]

You're welcome! Sorry for the delayed responses, I have been traveling.

[FranGomezVenegas]

@lukehutch Yes!!! It worked! As All enums are 'grouped' by Interface then I can use the Interface as reference to the list object provided by getEnumConstantObjects()
Thanks a lot, it will reduce tones of lines due to without reflection I had to add the same repetitive 'loop' just due to I had to add reference for every single enum. Even I had to manually add this loop for every single new enum and then if I miss to add it to the list then it is not considered by the logic I need to perform, right now I can catch the enums by reflection search so any new enum will not be 'engage'.
Thank you so much!

[lukehutch]

That's great! I'm glad it's working for you! Thanks for letting me know.