Path: csiph.com!eternal-september.org!feeder.eternal-september.org!reader02.eternal-september.org!.POSTED!not-for-mail
From: Eric Sosman <esosman@comcast-dot-net.invalid>
Newsgroups: comp.lang.java.programmer
Subject: Re: getting generic type parameter in method
Date: Wed, 21 Oct 2020 08:43:06 -0400
Organization: A noiseless patient Spider
Lines: 23
Message-ID: <rmpact$irl$1@dont-email.me>
References: <7e2c11ae-85bd-42cd-a7a7-27313edb9178n@googlegroups.com>
Mime-Version: 1.0
Content-Type: text/plain; charset=utf-8; format=flowed
Content-Transfer-Encoding: 7bit
Injection-Date: Wed, 21 Oct 2020 12:43:09 -0000 (UTC)
Injection-Info: reader02.eternal-september.org; posting-host="6895006881a8baa16a6b4a7db70f0207"; logging-data="19317"; mail-complaints-to="abuse@eternal-september.org";	posting-account="U2FsdGVkX19bZFfvbwT5y/SjI0MiTEcV"
User-Agent: Mozilla/5.0 (Windows NT 10.0; Win64; x64; rv:78.0) Gecko/20100101 Thunderbird/78.3.3
Cancel-Lock: sha1:aiLo614ymsfELUlBXUcYyy4xy2o=
In-Reply-To: <7e2c11ae-85bd-42cd-a7a7-27313edb9178n@googlegroups.com>
Content-Language: en-US
Xref: csiph.com comp.lang.java.programmer:39629

On 10/21/2020 7:38 AM, Philipp Kraus wrote:
> Hello,
> 
> I'm implementing an interface of a library, which I can use for deserialization a byte array into my own datastructures. The method is:
> 
> public <T> T fromData( @Nonnull final byte[] p_bytes, @Nonnull final Class<T> p_class, @Nonnull final Type p_type ) throws DataConverterException
> [...]
> I have taken a look into Google Guava and Apache Commons with the ReflectUtils / TypeUtils, but I don't know How I get get from my p_class Variable the details auf T during runtime.

     I'm not up to speed on all the latest developments, but I think
you're out of luck at least through Java 15.  JLS 4.7 describes which
types are "reifiable," and includes a discussion on why some types
(including most generic types) are not.  Perhaps in some future Java
things will change, but I don't believe they've changed yet.

     (However, "perhaps" I'm wrong.  I'm at Java 11 these days, and
have not fully explored the more recent releases.)

-- 
esosman@comcast-dot-net.invalid
"Total honesty is what we as citizens deserve from our president."
-- Melania Trump
Ninety-one days to go.