NPE in `ClassDiscoverer::handleXmlElement` about jaxb-visitor

[Warpten]

Looking at this again, if the type attribute is missing from an annotation, it's expected to be derived from the property type itself. Now, I don't know codemodel that much (and am having trouble debugging it to inspect it in greater details), but I assume this should rather be fixed like so:

            jfv.annotations().stream()
                    .filter(jau -> Utils.isXmlElements(jau.getAnnotationClass()))
                    .map(jau -> (JAnnotationArrayMember) jau.getAnnotationMembers().get("value"))
                    .flatMap(value -> value.annotations().stream())
                    .forEach(anno -> {
                        JAnnotationValue type = anno.getAnnotationMembers().get("type");
                        if (type != null) {
                            handleXmlElement(outline, directClasses, type);
                        } else {
                            if (jfv.type().elementType() != null) { // Adapt this for List<T>. This only works for T[].
                                handleXmlElement(outline, directClasses, jfv.type().elementType());
                            }
                        }
                    });

And changing the final argument to handleXmlElement to a JGenerable

[massfords]

@Warpten thanks for reporting this. Can you provide a full example so I can add it as a test case?

I'm wondering if the else should invoke the addIfDirectClass helper like so:

JClass elementType = (JClass) jfv.type().elementType();
List<JClass> typeParameters = elementType.getTypeParameters();
if (typeParameters != null && typeParameters.get(0) != null) {
   addIfDirectClass(directClasses, typeParameters.get(0));
} else {
   addIfDirectClass(directClasses, elementType);
}

It would help to have some schemas and different settings to test with.

[Warpten]

Sorry, I forgot about this.

A test case should be as simple as reusing the codehaus unit test with the sample XSD file I provided (it's self sufficient). Alternatively, I think this triggers as soon as the base type in an inheritance layout is prsent in a <xs:choice>'s possible value types:

<?xml version="1.0" encoding="UTF-8" standalone="yes"?>
<xs:schema xmlns:xs="http://www.w3.org/2001/XMLSchema">
    <xs:element name="DerivedA" type="DerivedA"/>
    <xs:element name="BaseType" type="BaseType"/>

    <xs:element name="TypeList" type="TypeList"/>

    <xs:element name="DerivedD" type="DerivedD" />

    <xs:complexType name="TypeList">
        <xs:sequence>
            <xs:choice minOccurs="0" maxOccurs="unbounded">
                <xs:element ref="DerivedA"/>
                <xs:element ref="BaseType"/>
                <xs:element ref="DerivedD"/>
            </xs:choice>
        </xs:sequence>
    </xs:complexType>

    <xs:complexType name="BaseType" />

    <xs:complexType name="DerivedA">
        <xs:complexContent>
            <xs:extension base="BaseType">
                <xs:sequence />
            </xs:extension>
        </xs:complexContent>
    </xs:complexType>

    <xs:complexType name="DerivedD">
        <xs:complexContent>
            <xs:extension base="BaseType">
                <xs:sequence />
            </xs:extension>
        </xs:complexContent>
    </xs:complexType>
</xs:schema>

This is enough to trigger the NPE when used with the basic-codehaus test.

As far as fixing this goes, I also tried this approach:

            jfv.annotations().stream()
                    .filter(jau -> Utils.isXmlElements(jau.getAnnotationClass()))
                    .map(jau -> (JAnnotationArrayMember) jau.getAnnotationMembers().get("value"))
                    .flatMap(value -> value.annotations().stream())
                    .forEach(anno -> {
                        JAnnotationValue type = anno.getAnnotationMembers().get("type");
                        if (type != null) {
                            handleXmlElement(outline, directClasses, type);
                        } else {
                            JClass jcs = (JClass) jfv.type();
                            if (Objects.equals(outline.getCodeModel().ref(List.class), jcs.erasure())) {
                                JClass elementType = jcs.getTypeParameters().get(0);
                                handleXmlElement(outline, directClasses, elementType);
                            } else {
                               handleXmlElement(outline, directClasses, jcs);
                            }
                        }
                    });

But I don't know that it is correct.

[massfords]

@Warpten I added your schema as a test case and took the simple approach of checking for the type and then handling an array or collection. Thanks for the report and suggestions.