My bad, I've done the UnCompile  but forgot to remove already generated methods.

Unrelated but it's better to return a status from a generator method:

ClassMethod GenerateMethods() As %Status [ CodeMode = objectgenerator ]
{
    For i=1:1:%class.Methods.Count() {
        #dim method As %Dictionary.MethodDefinition = %class.Methods.GetAt(i)
        Continue:((method.Description["@AutoGenerated") || (method.CodeMode="objectgenerator"))
        Do %class.Methods.Insert(##class(util.TestGenerator).Generate(method.Name_"DoSomethingElse",%class.Name))
    }
    Quit %class.%Save()
}

What flags are you compiling with? For me it works on a first compilation:

USER>do $system.OBJ.UnCompile("util.*")
 
Uncompiling class util.Test
Uncompiling class util.TestGenerator
USER>do ##class(util.Test).TestOneDoSomethingElse()
 
DO ##CLASS(util.Test).TestOneDoSomethingElse()
^
<CLASS DOES NOT EXIST> *util.Test
USER>do ##class(util.TestGenerator).Generate()
 
DO ##CLASS(util.TestGenerator).Generate()
^
<CLASS DOES NOT EXIST> *util.TestGenerator
USER>do $system.OBJ.Compile("util.*")
 
Compilation started on 06/12/2018 20:13:00 with qualifiers ''
Compiling 2 classes, using 2 worker jobs
Compiling class util.TestGenerator
Compiling routine util.TestGenerator.1
Compiling class util.Test
Compiling routine util.Test.1
Compilation finished successfully in 0.012s.
 
USER>do ##class(util.Test).TestOneDoSomethingElse()
util.Test||TestOneDoSomethingElse

As you see from the log both classes don't exist, but after one compilation I can call TestOneDoSomethingElse method and it works. What's your output for:

do $system.OBJ.UnCompile("util.*")
do ##class(util.Test).TestOneDoSomethingElse()
do ##class(util.TestGenerator).Generate()
do $system.OBJ.Compile("util.*")
do ##class(util.Test).TestOneDoSomethingElse()

I tried method generators, but It only gets compiled when I compile for the second time.

Please show a sample. Compiling a class with method generators should work on a first compilation.

What's the purpose of a normal index over a text field? I assume user searches by a substring. There are two and a half ways to perform a fulltext search:

1. Define a property of %Text type and use language class. New language classes an be added fairly easily. Documentation. Removed in InterSystems IRIS and therefore not recommended.
2. Use iFind indices. They  are highly customisable.
3. Use iFind indices creatively. You can build your own indices based on iFind indices and you can write your own tokenizers, etc. Also it's possible to define your own custom index. Community article on that.

Not in  InterSystems IRIS though.

There are system implementations too:

>write $$toRoman^%bi.SWr.FolderTest(124)
CXXIV
>write $$toRoman^%bi.SWr.FolderTest(1245)
MCCXLV

If you're sure that all your keys are consecutive integers, then use $order to get the last element, which would also be a count of them:

write $order(a(""),-1)

Please share the usecase.

If you  want to connect to external database, couldn't you just provide domain name and password and authenticate with that?

Not that Count approach is while easiest, can significantly slower the query down.

Extending the adapter so you have an "after all rows" callback has speed advantage and also you wouldn't need to rewrite your queries to add Count().

Do you wan to do something specific with the last row or do you just want a callback after all rows?

If it's the later, you can subclass SQL inbound adapter:

Class Project.Ens.Adapter.SQLInbound Extends EnsLib.SQL.InboundAdapter {

Method OnTask() As %Status
{
  Set sc = ##super()
  // all rows were just processed
  // add your logic here
  Quit sc

}

}

Other approach is to UNION a dummy row to the end of your query, or add COUNT() property.