Offer a way to retrieve the component type of a JavaClass that is an array.

Issue: #187

Signed-off-by: Alexander Fedorenchik <alexander.fedorenchik@gmail.com>

Author: alexfedorenchik

archunit/src/main/java/com/tngtech/archunit/core/domain/ImportContext.java

@@ -56,4 +56,6 @@ public interface ImportContext {
     Set<JavaConstructor> getConstructorsWithParameterOfType(JavaClass javaClass);
 
     Set<ThrowsDeclaration<JavaConstructor>> getConstructorThrowsDeclarationsOfType(JavaClass javaClass);
+
+    Optional<JavaClass> resolveComponentType(JavaType type);
 }

archunit/src/main/java/com/tngtech/archunit/core/domain/JavaClass.java

@@ -81,6 +81,7 @@ public class JavaClass implements HasName.AndFullName, HasAnnotations, HasModifi
     private final Set<JavaClass> interfaces = new HashSet<>();
     private final Set<JavaClass> subClasses = new HashSet<>();
     private Optional<JavaClass> enclosingClass = Optional.absent();
+    private Optional<JavaClass> componentType = Optional.absent();
     private Supplier<Map<String, JavaAnnotation>> annotations =
             Suppliers.ofInstance(Collections.<String, JavaAnnotation>emptyMap());
     private Supplier<Set<JavaMethod>> allMethods;
@@ -186,6 +187,11 @@ public boolean isArray() {
         return javaType.isArray();
     }
 
+    @PublicAPI(usage = ACCESS)
+    Optional<JavaClass> tryGetComponentType() {
+        return componentType;
+    }
+
     /**
      * @return Returns true if this class is declared within another class.
      *         Returns false for top-level classes.
@@ -841,6 +847,7 @@ public Map<String, JavaAnnotation> get() {
     }
 
     CompletionProcess completeFrom(ImportContext context) {
+        componentType = context.resolveComponentType(javaType);
         enclosingClass = context.createEnclosingClass(this);
         memberDependenciesOnClass = new MemberDependenciesOnClass(
                 context.getFieldsOfType(this),

archunit/src/main/java/com/tngtech/archunit/core/importer/ClassGraphCreator.java

@@ -40,6 +40,7 @@
 import com.tngtech.archunit.core.domain.JavaMethod;
 import com.tngtech.archunit.core.domain.JavaMethodCall;
 import com.tngtech.archunit.core.domain.JavaStaticInitializer;
+import com.tngtech.archunit.core.domain.JavaType;
 import com.tngtech.archunit.core.domain.ThrowsDeclaration;
 import com.tngtech.archunit.core.importer.AccessRecord.FieldAccessRecord;
 import com.tngtech.archunit.core.importer.DomainBuilders.JavaConstructorCallBuilder;
@@ -275,6 +276,16 @@ public Optional<JavaClass> createEnclosingClass(JavaClass owner) {
                 Optional.<JavaClass>absent();
     }
 
+    @Override
+    public Optional<JavaClass> resolveComponentType(JavaType array) {
+        return array.tryGetComponentType().transform(new Function<JavaType, JavaClass>() {
+            @Override
+            public JavaClass apply(JavaType input) {
+                return classes.getOrResolve(input.getName());
+            }
+        });
+    }
+
     private static class MemberDependenciesByTarget {
         private final SetMultimap<JavaClass, JavaField> fieldTypeDependencies = HashMultimap.create();
         private final SetMultimap<JavaClass, JavaMethod> methodParameterTypeDependencies = HashMultimap.create();

archunit/src/test/java/com/tngtech/archunit/core/domain/JavaClassTest.java

@@ -23,6 +23,9 @@
 import com.tngtech.archunit.core.domain.testobjects.IsArrayTestClass;
 import com.tngtech.archunit.core.domain.testobjects.SuperA;
 import com.tngtech.archunit.core.importer.ClassFileImporter;
+import com.tngtech.archunit.core.importer.testexamples.arrays.ClassAccessingOneDimensionalArray;
+import com.tngtech.archunit.core.importer.testexamples.arrays.ClassAccessingTwoDimensionalArray;
+import com.tngtech.archunit.core.importer.testexamples.arrays.ClassUsedInArray;
 import com.tngtech.java.junit.dataprovider.DataProvider;
 import com.tngtech.java.junit.dataprovider.DataProviderRunner;
 import com.tngtech.java.junit.dataprovider.UseDataProvider;
@@ -80,13 +83,28 @@ public void finds_array_type() {
         JavaMethod method = importClassWithContext(IsArrayTestClass.class).getMethod("anArray");
 
         assertThat(method.getRawReturnType().isArray()).isTrue();
+        assertThat(method.getRawReturnType().tryGetComponentType().get().getName()).isEqualTo("java.lang.Object");
     }
 
     @Test
     public void finds_non_array_type() {
         JavaMethod method = importClassWithContext(IsArrayTestClass.class).getMethod("notAnArray");
 
         assertThat(method.getRawReturnType().isArray()).isFalse();
+        assertThat(method.getRawReturnType().tryGetComponentType().isPresent()).isFalse();
+    }
+
+    @Test
+    public void finds_multidimensional_array_type() {
+        JavaClasses classes = importClassesWithContext(ClassUsedInArray.class, ClassAccessingOneDimensionalArray.class, ClassAccessingTwoDimensionalArray.class);
+        JavaClass type = classes.get(ClassUsedInArray.class);
+        JavaClass oneDimArray = classes.get(ClassAccessingOneDimensionalArray.class).getField("array").getRawType();
+        JavaClass twoDimArray = classes.get(ClassAccessingTwoDimensionalArray.class).getField("array").getRawType();
+
+        assertThat(oneDimArray.isArray()).isTrue();
+        assertThat(oneDimArray.tryGetComponentType().get()).isEqualTo(type);
+        assertThat(twoDimArray.isArray()).isTrue();
+        assertThat(twoDimArray.tryGetComponentType().get()).isEqualTo(oneDimArray);
     }
 
     @Test

archunit/src/test/java/com/tngtech/archunit/core/importer/ImportTestUtils.java

@@ -428,5 +428,10 @@ public Set<JavaConstructor> getConstructorsWithParameterOfType(JavaClass javaCla
         public Set<ThrowsDeclaration<JavaConstructor>> getConstructorThrowsDeclarationsOfType(JavaClass javaClass) {
             return Collections.emptySet();
         }
+
+        @Override
+        public Optional<JavaClass> resolveComponentType(JavaType type) {
+            return Optional.absent();
+        }
     }
 }