CODEWITHSUNDEEP
javajvm-argumentsannotation-processing
yash6
yash6

Reputation: 141

accessing VM arguments during compile time

I have problem in accessing VM arguments in My program. I am writing an annotation processor in which i want to access some VM arguments. I am Using NETBeans IDE. I create the jar file of the annotation processor and then use it in another project which has java files with the annotations.

Now in my annotation processor project, In IDE i set the VM arguments as follows

-Dname="hello from VM"

and in the process() function of the annotation processor when i try to access it 

String property = System.getProperty("name");

System.out.println(property);

It prints null. Can we access these VM arguments during compile time As both the annotation processor and the annotated class run in the same VM ? Thanks

Upvotes: 1

Views: 1302

Answers (3)

Atorian
Atorian

Reputation: 817

This works for me in Netbeans 8.0 under Windows 8.1 x64 with Java 1.8.0_05. I can only presume its been fixed lately.

    Messager cm = processingEnv.getMessager();
    ByteArrayOutputStream baos = new ByteArrayOutputStream();
    try {
        System.getProperties().storeToXML(baos, "System Properties");
    }
    catch (IOException ex) {
        cm.printMessage(Kind.ERROR, "Exception while getting System properties as XML: " + ex.getMessage());
    }
    cm.printMessage(Kind.NOTE, "\System.properties XML:\n" + baos.toString());

This will give me

<?xml version="1.0" encoding="UTF-8" standalone="no"?>
<!DOCTYPE properties SYSTEM "http://java.sun.com/dtd/properties.dtd">
<properties>
<comment>System Properties</comment>
<entry key="java.runtime.name">Java(TM) SE Runtime Environment</entry>
<entry key="java.vm.vendor">Sun Microsystems Inc.</entry>
...
</properties>

The anwser of jbunting (i.e using processingEnv.getOptions()) is definitely more correct for cleanly passing key-value pairs to your annotation processor.

Upvotes: 0

Ian Roberts
Ian Roberts

Reputation: 122364

You can pass options to the JVM that runs javac using -J, so

-J-Dname="hello from VM"

may possibly do what you require.

Upvotes: 0

jbunting
jbunting

Reputation: 901

I do not know of a way to access system properties from the annotation processor, but I think that the annotation processor options would support your use case. Essentially you would want to implement getSupportedOptions in your processor, access the options via processingEnv.getOptions, and pass the options on the command line with -Aname=value. Supported options may also be specified via the @SupportedOptions annotation.

Upvotes: 1

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