Fix for MalformedParametersException #33

pom.xml

@@ -37,7 +37,9 @@ introspection of method/constructor parameter names, without having to add expli
     <!-- Generate PackageVersion.java into this directory. -->
     <packageVersion.dir>com/fasterxml/jackson/module/paramnames</packageVersion.dir>
     <packageVersion.package>${project.groupId}.paramnames</packageVersion.package>
-    <assertj-core.version>3.3.0</assertj-core.version>
+
+    <assertj-core.version>3.4.0</assertj-core.version>
+    <mockito-core.version>1.10.19</mockito-core.version>
   </properties>
 
   <dependencies>
@@ -58,6 +60,12 @@ introspection of method/constructor parameter names, without having to add expli
       <version>${assertj-core.version}</version>
       <scope>test</scope>
     </dependency>
+    <dependency>
+      <groupId>org.mockito</groupId>
+      <artifactId>mockito-core</artifactId>
+      <version>${mockito-core.version}</version>
+      <scope>test</scope>
+    </dependency>
   </dependencies>
 
   <build>

src/main/java/com/fasterxml/jackson/module/paramnames/ParameterExtractor.java

@@ -0,0 +1,11 @@
+package com.fasterxml.jackson.module.paramnames;
+
+import java.lang.reflect.Executable;
+import java.lang.reflect.Parameter;
+
+class ParameterExtractor {
+
+    public Parameter[] getParameters(Executable executable) {
+        return executable.getParameters();
+    }
+}

src/main/java/com/fasterxml/jackson/module/paramnames/ParameterNamesAnnotationIntrospector.java

@@ -4,7 +4,8 @@
 import com.fasterxml.jackson.databind.AnnotationIntrospector;
 import com.fasterxml.jackson.databind.introspect.*;
 
-import java.lang.reflect.*;
+import java.lang.reflect.MalformedParametersException;
+import java.lang.reflect.Parameter;
 
 /**
  * Introspector that uses parameter name information provided by the Java Reflection API additions in Java 8 to
@@ -14,15 +15,16 @@
  * @see AnnotationIntrospector
  * @see Parameter
  */
-class ParameterNamesAnnotationIntrospector extends NopAnnotationIntrospector
-{
+class ParameterNamesAnnotationIntrospector extends NopAnnotationIntrospector {
     private static final long serialVersionUID = 1L;
 
     private final JsonCreator.Mode creatorBinding;
+    private final ParameterExtractor parameterExtractor;
 
-    ParameterNamesAnnotationIntrospector(JsonCreator.Mode creatorBinding) {
+    ParameterNamesAnnotationIntrospector(JsonCreator.Mode creatorBinding, ParameterExtractor parameterExtractor) {
 
         this.creatorBinding = creatorBinding;
+        this.parameterExtractor = parameterExtractor;
     }
 
     @Override
@@ -44,26 +46,28 @@ public JsonCreator.Mode findCreatorBinding(Annotated a) {
         return creatorBinding;
     }
 
-    /**
-     * Returns the parameter name, or {@code null} if it could not be determined.
-     *
-     * @param annotatedParameter containing constructor or method from which {@link Parameter} can be extracted
-     *
-     * @return name or {@code null} if parameter could not be determined
-     */
     private String findParameterName(AnnotatedParameter annotatedParameter) {
 
-        AnnotatedWithParams owner = annotatedParameter.getOwner();
         Parameter[] params;
-
-        if (owner instanceof AnnotatedConstructor) {
-            params = ((AnnotatedConstructor) owner).getAnnotated().getParameters();
-        } else if (owner instanceof AnnotatedMethod) {
-            params = ((AnnotatedMethod) owner).getAnnotated().getParameters();
-        } else {
+        try {
+            params = getParameters(annotatedParameter.getOwner());
+        } catch (MalformedParametersException e) {
             return null;
         }
+
         Parameter p = params[annotatedParameter.getIndex()];
         return p.isNamePresent() ? p.getName() : null;
     }
+
+    private Parameter[] getParameters(AnnotatedWithParams owner) {
+        if (owner instanceof AnnotatedConstructor) {
+            return parameterExtractor.getParameters(((AnnotatedConstructor) owner).getAnnotated());
+        }
+
+        if (owner instanceof AnnotatedMethod) {
+            return parameterExtractor.getParameters(((AnnotatedMethod) owner).getAnnotated());
+        }
+
+        return null;
+    }
 }

src/main/java/com/fasterxml/jackson/module/paramnames/ParameterNamesModule.java

@@ -22,7 +22,7 @@ public ParameterNamesModule() {
     @Override
     public void setupModule(SetupContext context) {
         super.setupModule(context);
-        context.insertAnnotationIntrospector(new ParameterNamesAnnotationIntrospector(creatorBinding));
+        context.insertAnnotationIntrospector(new ParameterNamesAnnotationIntrospector(creatorBinding, new ParameterExtractor()));
     }
 
     @Override

src/test/java/com/fasterxml/jackson/module/paramnames/ParameterNamesAnnotationIntrospectorTest.java

@@ -4,47 +4,86 @@
 import com.fasterxml.jackson.databind.introspect.AnnotatedConstructor;
 import com.fasterxml.jackson.databind.introspect.AnnotatedMethod;
 import com.fasterxml.jackson.databind.introspect.AnnotatedParameter;
-
+import org.junit.Before;
 import org.junit.Test;
+import org.junit.runner.RunWith;
+import org.mockito.BDDMockito;
+import org.mockito.Mock;
+import org.mockito.runners.MockitoJUnitRunner;
 
 import java.lang.reflect.Constructor;
+import java.lang.reflect.MalformedParametersException;
 import java.lang.reflect.Method;
+import java.lang.reflect.Parameter;
 
-import static org.junit.Assert.assertEquals;
+import static org.assertj.core.api.BDDAssertions.then;
+import static org.mockito.BDDMockito.given;
+import static org.mockito.Matchers.any;
 
 /**
  * @author Lovro Pandzic
  */
+@RunWith(MockitoJUnitRunner.class)
 public class ParameterNamesAnnotationIntrospectorTest {
 
-    private final ParameterNamesAnnotationIntrospector PN_AI = new ParameterNamesAnnotationIntrospector(JsonCreator.Mode.DEFAULT);
+    @Mock
+    private ParameterExtractor parameterExtractor;
+
+    private ParameterNamesAnnotationIntrospector introspector;
+
+    @Before
+    public void setUp() throws Exception {
+        introspector = new ParameterNamesAnnotationIntrospector(JsonCreator.Mode.DEFAULT, parameterExtractor);
+    }
 
     @Test
     public void shouldFindParameterNameFromConstructorForLegalIndex() throws Exception {
-        Constructor<?> ctor = ImmutableBean.class.getConstructor(String.class, Integer.class);
-
-        assertEquals("name", ctor.getParameters()[0].getName());
 
-        AnnotatedConstructor owner = new AnnotatedConstructor(null, ctor, null, null);
+        // given
+        Constructor<?> givenConstructor = ImmutableBean.class.getConstructor(String.class, Integer.class);
+        Parameter[] givenParameters = givenConstructor.getParameters();
+        AnnotatedConstructor owner = new AnnotatedConstructor(null, givenConstructor, null, null);
         AnnotatedParameter annotatedParameter = new AnnotatedParameter(owner, null, null, 0);
-
-        String propertyName = PN_AI.findImplicitPropertyName(annotatedParameter);
+        given(parameterExtractor.getParameters(any())).willReturn(givenParameters);
+
+        // when
+        String actual = introspector.findImplicitPropertyName(annotatedParameter);
 
-        assertEquals("name", propertyName);
+        then(actual).isEqualTo("name");
+        BDDMockito.then(parameterExtractor).should().getParameters(givenConstructor);
     }
 
     @Test
     public void shouldFindParameterNameFromMethodForLegalIndex() throws Exception {
 
-        Method method  = ImmutableBeanWithStaticFactory.class.getMethod("of", String.class, Integer.class);
+        // given
+        Method givenMethod = ImmutableBeanWithStaticFactory.class.getMethod("of", String.class, Integer.class);
+        Parameter[] givenParameters = givenMethod.getParameters();
+        AnnotatedMethod owner = new AnnotatedMethod(null, givenMethod, null, null);
+        AnnotatedParameter annotatedParameter = new AnnotatedParameter(owner, null, null, 0);
+        given(parameterExtractor.getParameters(any())).willReturn(givenParameters);
+
+        // when
+        String actual = introspector.findImplicitPropertyName(annotatedParameter);
+
+        // then
+        then(actual).isEqualTo("name");
+        BDDMockito.then(parameterExtractor).should().getParameters(givenMethod);
+    }
+
+    @Test
+    public void shouldReturnNullForMalformedParametersException() throws Exception {
 
-        assertEquals("name", method.getParameters()[0].getName());
-
-        AnnotatedMethod owner = new AnnotatedMethod(null, method, null, null);
+        // given
+        Constructor<?> givenConstructor = ImmutableBean.class.getConstructor(String.class, Integer.class);
+        AnnotatedConstructor owner = new AnnotatedConstructor(null, givenConstructor, null, null);
         AnnotatedParameter annotatedParameter = new AnnotatedParameter(owner, null, null, 0);
+        given(parameterExtractor.getParameters(any())).willThrow(new MalformedParametersException());
 
-        String propertyName = PN_AI.findImplicitPropertyName(annotatedParameter);
+        // when
+        String actual = introspector.findImplicitPropertyName(annotatedParameter);
 
-        assertEquals("name", propertyName);
+        then(actual).isNull();
+        BDDMockito.then(parameterExtractor).should().getParameters(givenConstructor);
     }
 }