Fix parsing of generic parameters

providing null checks.

Signed-off-by: Manoel Campos <manoelcampos@gmail.com>

Author: manoelcampos

src/main/java/com/github/markusbernhardt/xmldoclet/Parser.java

@@ -9,12 +9,11 @@
 import jdk.javadoc.doclet.DocletEnvironment;
 
 import javax.lang.model.element.*;
+import javax.lang.model.type.DeclaredType;
 import javax.lang.model.type.TypeMirror;
 import javax.lang.model.type.TypeVariable;
 import javax.lang.model.type.WildcardType;
 import javax.lang.model.util.ElementFilter;
-import java.lang.reflect.ParameterizedType;
-import java.lang.reflect.Type;
 import java.util.List;
 import java.util.Map;
 import java.util.Set;
@@ -558,11 +557,11 @@ protected TypeInfo parseTypeInfo(final TypeMirror type) {
             typeInfoNode.setWildcard(parseWildcard(wildcard));
         }
 
-        final ParameterizedType parameterized = getParameterizedType(type);
+        final DeclaredType parameterized = getParameterizedType(type);
 
         if (parameterized != null) {
-            for (final Type typeArgument : parameterized.getActualTypeArguments()) {
-                typeInfoNode.getGeneric().add(parseTypeInfo(typeUtils.getTypeMirror(typeArgument)));
+            for (final TypeMirror typeArgument : parameterized.getTypeArguments()) {
+                typeInfoNode.getGeneric().add(parseTypeInfo(typeArgument));
             }
         }
 
@@ -572,15 +571,17 @@ protected TypeInfo parseTypeInfo(final TypeMirror type) {
     protected Wildcard parseWildcard(final WildcardType wildcard) {
         final Wildcard wildcardNode = objectFactory.createWildcard();
 
-        final TypeMirror extendType = wildcard.getExtendsBound();
-        wildcardNode.getExtendsBound().add(parseTypeInfo(extendType));
-
-        final TypeMirror superType = wildcard.getSuperBound();
-        wildcardNode.getSuperBound().add(parseTypeInfo(superType));
+        addIfNotNull(wildcardNode.getExtendsBound(), wildcard.getExtendsBound());
+        addIfNotNull(wildcardNode.getSuperBound(), wildcard.getSuperBound());
 
         return wildcardNode;
     }
 
+    private void addIfNotNull(final List<TypeInfo> wildcardNode, final TypeMirror extendType) {
+        if (extendType != null)
+            wildcardNode.add(parseTypeInfo(extendType));
+    }
+
     protected TypeParameter parseTypeParameter(final TypeParameterElement typeParameter) {
         return parseTypeParameter((TypeVariable) typeParameter.asType());
     }

src/main/java/com/github/markusbernhardt/xmldoclet/TypeUtils.java

@@ -5,7 +5,6 @@
 import javax.lang.model.util.ElementFilter;
 import javax.lang.model.util.Elements;
 import javax.lang.model.util.Types;
-import java.lang.reflect.ParameterizedType;
 import java.lang.reflect.Type;
 import java.util.List;
 
@@ -27,7 +26,7 @@ public static String getMethodSignature(final ExecutableElement methodDoc) {
 
     /**
      * Checks if an element has a given modifier
-     * 
+     *
      * @param element the element to check
      * @param modifier the modifier we are looking for in the element
      * @return true if the modifier is present in the element declaration, false otherwise
@@ -38,7 +37,7 @@ public static boolean hasModifier(final Element element, final Modifier modifier
 
     /**
      * {@return the list of fields from a given class element}
-     * 
+     *
      * @param classElement the class to get its fields
      */
     public static List<VariableElement> getFields(final TypeElement classElement) {
@@ -47,7 +46,7 @@ public static List<VariableElement> getFields(final TypeElement classElement) {
 
     /**
      * {@return the list of constructors from a given class element}
-     * 
+     *
      * @param classElement the class to get its constructors
      */
     public static List<ExecutableElement> getConstructors(final TypeElement classElement) {
@@ -56,7 +55,7 @@ public static List<ExecutableElement> getConstructors(final TypeElement classEle
 
     /**
      * {@return the list of methods from a given class element}
-     * 
+     *
      * @param classElement the class to get its methods
      */
     public static List<ExecutableElement> getMethods(final TypeElement classElement) {
@@ -65,7 +64,7 @@ public static List<ExecutableElement> getMethods(final TypeElement classElement)
 
     /**
      * {@return a type as WildcardType if it is such a type, or null otherwise}
-     * 
+     *
      * @param typeMirror the type to get it as a wildcard type
      */
     public static WildcardType getWildcardType(final TypeMirror typeMirror) {
@@ -77,14 +76,14 @@ public static WildcardType getWildcardType(final TypeMirror typeMirror) {
     }
 
     /**
-     * {@return a type as ParameterizedType if it is such a type, or null otherwise}
-     * 
+     * {@return a type as DeclaredType if the typeMirror has type arguments (such a List<String>), or null otherwise}
+     *
      * @param typeMirror the type to get it as a wildcard type
      */
-    public static ParameterizedType getParameterizedType(TypeMirror typeMirror) {
+    public static DeclaredType getParameterizedType(TypeMirror typeMirror) {
         if (typeMirror instanceof DeclaredType declaredType) {
-            if (!declaredType.getTypeArguments().isEmpty() && declaredType instanceof ParameterizedType) {
-                return (ParameterizedType) declaredType;
+            if (!declaredType.getTypeArguments().isEmpty()) {
+                return declaredType;
             }
         }
 
@@ -97,7 +96,7 @@ public static boolean isArray(final TypeMirror typeMirror) {
 
     /**
      * {@return the dimension of type that represents an array, or an empty string if the type is not an array}
-     * 
+     *
      * @param typeMirror the array type to get its dimension
      */
     public static String getArrayDimension(final TypeMirror typeMirror) {
@@ -112,7 +111,7 @@ public static String getArrayDimension(final TypeMirror typeMirror) {
 
     /**
      * {@return a TypeMirror for a given Type instance}
-     * 
+     *
      * @param type the {@link Type} instance to get a {@link TypeMirror}
      */
     public TypeMirror getTypeMirror(final Type type) {