[BUG] Inner interface cannot be correctly parsed

[shuaiwang516]

Consider the following interface file demoInterface.java, there is a inner interface called AnotherInterface.

package org.example;

public interface demoInterface {
    interface AnotherInterface {
        void anotherMethod();
        void anotherMethod2();
        void anotherMethod3();
    }
}

Now a class implements the above interface as below:

package org.example;

public class demoTest implements demoInterface {
    public AnotherInterface fakeMethod() {
        return null;
    }
}

When QDox parses the fakeMethod(), it cannot correctly get the method infomration.
The parsing code is:

JavaProjectBuilder builder = new JavaProjectBuilder();
builder.addSourceTree(${path_to_org_example_package});
JavaClass javaClass = builder.getClassByName("org.example.demoTest");
// iterate all the methods
for (JavaMethod method : javaClass.getMethods()) {
    JavaClass returnClass = method.getReturns();
    if (returnClass != null) {
        System.out.println("Class: " + returnClass.getFullyQualifiedName());
        System.out.println("Method: " + method.getName() + " returns: " + returnClass.getFullyQualifiedName());
        System.out.println(returnClass.getMethods());
    }
}

You will see the output:

Class: AnotherInterface
Method: fakeMethod returns: AnotherInterface
[]

The expected output should be:

Class: org.example.demoInterface.AnotherInterface
Method: fakeMethod returns: org.example.demoInterface.AnotherInterface
[public void anotherMethod(), public void anotherMethod2(), public void anotherMethod3()]

[shuaiwang516]

I found that the issue only happens if the target class implements the interface.

So the below code works:

package org.example;

public class demoTest {
    public demoInterface.AnotherInterface fakeMethod() {
        return null;
    }
}

But this code does not work:

package org.example;

public class demoTest implements demoInterface {
    public AnotherInterface fakeMethod() {
        return null;
    }
}

[paul-hammant]

Any idea about a way forward with this?

[google-labs-jules]

You are currently at your limit of 3 running tasks. Either wait for a task to finish or pause a task from the dashboard, then reassign this issue. See rate limit documentation for more information.

[google-labs-jules]

Jules is on it. When finished, you will see another comment and be able to review a PR.

[paul-hammant]

Jules has quit for some reason. Here's what it was thinking for reproduction:

package com.thoughtworks.qdox;

import com.thoughtworks.qdox.model.JavaClass;
import com.thoughtworks.qdox.model.JavaMethod;
import org.junit.jupiter.api.Assertions;
import org.junit.jupiter.api.Test;

import java.io.StringReader;

public class InnerInterfaceTest {

    @Test
    public void testInnerInterfaceResolution() {
        String demoInterfaceSource = "package org.example;\n" +
                "public interface demoInterface {\n" +
                "    interface AnotherInterface {\n" +
                "        void anotherMethod();\n" +
                "        void anotherMethod2();\n" +
                "        void anotherMethod3();\n" +
                "    }\n" +
                "}";

        String demoTestSource = "package org.example;\n" +
                "public class demoTest implements demoInterface {\n" +
                "    public AnotherInterface fakeMethod() {\n" +
                "        return null;\n" +
                "    }\n" +
                "}";

        JavaProjectBuilder builder = new JavaProjectBuilder();
        builder.addSource(new StringReader(demoInterfaceSource));
        builder.addSource(new StringReader(demoTestSource));

        JavaClass javaClass = builder.getClassByName("org.example.demoTest");
        JavaMethod method = javaClass.getMethods().get(0);
        JavaClass returnClass = method.getReturns();

        Assertions.assertEquals("org.example.demoInterface.AnotherInterface", returnClass.getFullyQualifiedName());
        Assertions.assertEquals(3, returnClass.getMethods().size());
        Assertions.assertEquals("anotherMethod", returnClass.getMethods().get(0).getName());
        Assertions.assertEquals("anotherMethod2", returnClass.getMethods().get(1).getName());
        Assertions.assertEquals("anotherMethod3", returnClass.getMethods().get(2).getName());
    }
}