Issue: TNG#60

I worked on adding theClass(String className) to the ArchRuleDefinition class so that users can easily select a specifc class to test

Signed-off-by: Michael Sherman <msherman32@gatech.edu>

archunit/src/main/java/com/tngtech/archunit/lang/syntax/ArchRuleDefinition.java

@@ -15,17 +15,24 @@
  */
 package com.tngtech.archunit.lang.syntax;
 
+import java.util.Collections;
+
 import com.tngtech.archunit.PublicAPI;
 import com.tngtech.archunit.base.Function;
+import com.tngtech.archunit.base.Function.Functions;
 import com.tngtech.archunit.core.domain.JavaClass;
 import com.tngtech.archunit.core.domain.JavaClasses;
 import com.tngtech.archunit.core.importer.ClassFileImporter;
+import com.tngtech.archunit.lang.AbstractClassesTransformer;
 import com.tngtech.archunit.lang.ArchCondition;
 import com.tngtech.archunit.lang.ArchRule;
 import com.tngtech.archunit.lang.ClassesTransformer;
 import com.tngtech.archunit.lang.Priority;
+import com.tngtech.archunit.lang.syntax.elements.GivenClass;
 import com.tngtech.archunit.lang.syntax.elements.GivenClasses;
+import com.tngtech.archunit.lang.syntax.elements.GivenClassesConjunction;
 import com.tngtech.archunit.lang.syntax.elements.GivenObjects;
+import com.tngtech.archunit.lang.syntax.GivenClassesThatInternal;
 
 import static com.tngtech.archunit.PublicAPI.Usage.ACCESS;
 import static com.tngtech.archunit.lang.Priority.MEDIUM;
@@ -66,6 +73,10 @@ public static GivenClasses noClasses() {
         return priority(MEDIUM).noClasses();
     }
 
+    public static GivenClass theClass(Class<?> clazz) {
+        return priority(MEDIUM).theClass(clazz);
+    }
+
     public static final class Creator {
         private final Priority priority;
 
@@ -110,6 +121,37 @@ public <TYPE> GivenObjects<TYPE> no(ClassesTransformer<TYPE> classesTransformer)
                     classesTransformer.as("no " + classesTransformer.getDescription()),
                     ArchRuleDefinition.<TYPE>negateCondition());
         }
+
+        public GivenClass theClass(final Class<?> clazz) {
+            ClassesTransformer<JavaClass> theClass = new AbstractClassesTransformer<JavaClass>("the class " + clazz.getName()) {
+                @Override
+                public Iterable<JavaClass> doTransform(JavaClasses classes) {
+                    return Collections.singleton(classes.get(clazz));
+                }
+            };
+            return new GivenClassInternal(priority, theClass, Functions.<ArchCondition<JavaClass>>identity());
+        }
+
+        public GivenClass theClass(final String className) {
+            ArchCondition<JavaClass> nameCondition = getConditionFrom(className);
+
+            return new GivenClassInternal(Priority.LOW, classesTransformer, prepareCondition);
+
+
+
+            //need to get to haveFullyQualifiedName in ArchConditions
+        }
+
+        private ArchCondition<JavaClass> getConditionFrom(String className) {
+            GivenClassesInternal givenClasses =  new GivenClassesInternal(priority, ClassesIdentityTransformer.classes());
+            PredicateAggregator<JavaClass> predicateAggregator = new PredicateAggregator<JavaClass>();
+
+            GivenClassesThatInternal theClassThat = new GivenClassesThatInternal(givenClasses, predicateAggregator);
+            GivenClassesConjunction conjunction = theClassThat.haveFullyQualifiedName(className);
+            //            or().haveSimpleName(className);
+
+            return conjunction;
+        }
     }
 
     private static <T> Function<ArchCondition<T>, ArchCondition<T>> negateCondition() {