Setting a build dependency for the JDK

[Daniel J. Luke]

On Sep 4, 2018, at 10:50 AM, mf2k at macports.org wrote:
>> On Aug 31, 2018, at 8:32 PM, Guenael Strutt <macports at guenael.com> wrote:
>> To build lang/processing, one needs a specific version of the JDK (as specified in https://github.com/processing/processing/blob/master/build/build.xml). Question: how does one create a dependency in the Portfile to determine whether this version is present? The purpose is to 1) provide a better error message to the user and 2) prevent builds from failing https://travis-ci.org/macports/macports-ports/builds/423195489 at every update. I tried checking for the existence of this folder:  `/Library/Java/JavaVirtualMachines/jdk1.8.0_181.jdk/` but didn't get anywhere. Thanks!
> 
> Have you looked at the java-1.0 portgroup?
> 
> It is pretty simple and determines if the user has java installed and can set the JAVA_HOME directory in the environment variables. 
> 
> It probably could be enhanced to determine the actual version and type (JRE vs. JDK) of java installed. 

+1

It would be nice if it also installed a 'good' JRE/JDK or at least gave the user instructions on how/where to get it.

> Otherwise, since Java is 3rd party, we cannot have a dependency on it and expect that it will be installed by Macports. We can only check if it is installed or not. 

I haven't looked at the oracle license recently, but if it allows it, we should be providing install via port so that the normal dependency resolution stuff can work.

-- 
Daniel J. Luke