Eclipse content assist not working for Java objects within Groovy files

Question

I found this question Eclipse Groovy and autocompletion and am experiencing the same issue, however, it is almost three years hence and I am using the current version of the Groovy Eclipse plugin, and there do not appear to be any syntax errors that would be confusing ANTLR.

I also tried using the Groovy/Grails Tool Suite, and got the same results.

I have mocked up a simple test case under which the content assist works for Groovy objects' methods, and for Java objects' static members, but not Java objects' methods.

The Groovy class:

package test_groovy

import test_groovy.FooJava

class FooGroovy
{
    def fooJava = [2, "baz"] as FooJava

    def x = 4

    def FooGroovy()
    {
        // empty constructor    
    }

    def useFooJava()
    {
        // only displays Groovy methods, not the java ones
        def str = fooJava.getStr()
        println "str: ${str}"

        // static members like this *can* be found via content assist
        def str2 = FooJava.FOO_STR
        println "str2: ${str2}"

        // This is also not found via content assist
        def str3 = fooJava.dumpToStr()
        println "str3: ${str3}"
    }

    def fooBar()
    {
        return x + 3
    }

    static void main(def args)
    {
        def fooGroovy = [] as FooGroovy

        // Groovy object methods can be found via content assist
        def res = fooGroovy.fooBar()
        println "res: ${res}"

        fooGroovy.useFooJava()
    }
}

The Java class:

package test_groovy;

public class FooJava
{
    private long bar;
    private String str;

    public static final String FOO_STR = "foo";

    public FooJava(long bar, String str)
    {
        super();
        this.bar = bar;
        this.str = str;
    }

    public long getBar()
    {
        return bar;
    }

    public void setBar(long bar)
    {
        this.bar = bar;
    }

    public String getStr()
    {
        return str;
    }

    public void setStr(String str)
    {
        this.str = str;
    }

    public String dumpToStr()
    {
        return new String("Str: " + str + ", bar: " + bar);
    }

}

I am using Eclipse Kepler Service Release 2, Groovy compiler 2.0.7 and Groovy Eclipse plugin version 2.8.0.xx-20130703-1600-e43-RELEASE.

Under the Java > Editor > Content Assist > Advanced preferences menu, I have made sure all the Java options are checked off in addition to Groovy Content (Java Non-Type, Java, Java type Proposals).

Since this does seem to work in general for some, I am wondering what I could be missing here that would allow content assist to work for Java object methods. Thanks.

Answer 1

I was continuing to think about this, and had a thought which I just tested out which allows content-assist to work, albeit under less-Groovy conditions:

It appears that the root of the problem is that Groovy Eclipse can't do auto-complete on Java objects if they are declared in a Groovy way using def, i.e.:

def fooJava = [2, "baz"] as FooJava
def fooJava2 = new FooJava(3, "bar")

even though in both of these cases, the type is known at compile time. I suspect it has something to do with the fact that def is essentially an alias for Object, and even though the type is technically known, it is probably treated as Object, and so that's the type on which the content-assist operates.

If I declare it in the traditional Java way, i.e.:

FooJava fooJava3 = new FooJava(4, "foo")

Content assist then allows me to find the members, methods, etc. of the FooJava object.

So, I can certainly do this in the future to work around the issue, but I do wonder if there is any way to essentially have my cake and eat it too.

i.e. Has anyone found a way to get content assist to work on Java objects declared via the def syntax, so long as the type is known?