#194 generics support for annotated helpers

Adds a dependency to `spring-generics`, and uses it to resolve the generics
of method parameters in introspected helper classes.

With this change, it is also possible to do away with the clunky @blockchain
generics handling, where the user had to provide the generic type of the
`AtomicReference` class. The Spring tools are able to handle this, and so the
annotation parameter has been removed. (BREAKING CHANGE)

Author: UnquietCode

pom.xml

@@ -210,6 +210,11 @@
 			<artifactId>codemodel</artifactId>
 			<version>1.0.2</version>
 		</dependency>
+		<dependency>
+			<groupId>com.unquietcode.tools.spring</groupId>
+			<artifactId>spring-generics</artifactId>
+			<version>4.1.4</version>
+		</dependency>
 		<dependency>
 			<groupId>com.google.guava</groupId>
 			<artifactId>guava</artifactId>

src/main/java/unquietcode/tools/flapi/IntrospectorSupport.java

@@ -17,6 +17,8 @@
 package unquietcode.tools.flapi;
 
 import unquietcode.tools.flapi.annotations.BlockChain;
+import unquietcode.tools.spring.generics.MethodParameter;
+import unquietcode.tools.spring.generics.ResolvableType;
 
 import java.lang.annotation.Annotation;
 import java.lang.reflect.Method;
@@ -89,7 +91,27 @@ else if (parameterType.isArray()) {
 				typeName = parameterType.getName();
 			}
 
-			signature.append(typeName).append(" p").append(i);
+			// raw type
+			signature.append(typeName);
+
+			// generics
+			Class<?>[] generics = ResolvableType.forMethodParameter(MethodParameter.forMethodOrConstructor(method, i)).resolveGenerics();
+
+			if (generics != null && generics.length > 0) {
+				signature.append("<");
+
+				for (int p = 0; p < generics.length; ++p) {
+					if (p != 0) { signature.append(", "); }
+
+					Class<?> generic = generics[p];
+					signature.append(generic.getName());
+				}
+
+				signature.append("> ");
+			}
+
+			// parameter name
+			signature.append(" p").append(i);
 		}
 
 		signature.append(")");

src/main/java/unquietcode/tools/flapi/annotations/AnnotationIntrospector.java

@@ -29,6 +29,8 @@
 import unquietcode.tools.flapi.outline.DescriptorOutline;
 import unquietcode.tools.flapi.outline.MethodOutline;
 import unquietcode.tools.flapi.runtime.SpringMethodUtils;
+import unquietcode.tools.spring.generics.MethodParameter;
+import unquietcode.tools.spring.generics.ResolvableType;
 
 import java.lang.annotation.Annotation;
 import java.lang.reflect.AnnotatedElement;
@@ -242,7 +244,11 @@ private void handleMethod(MethodOutline methodOutline, Method method) {
 					throw new DescriptorBuilderException("@BlockChain parameters must be of type AtomicReference");
 				}
 
-				BlockOutline blockOutline = handleClass(blockChain.value());
+				// get the generic type of the reference
+				Class<?> generic = ResolvableType.forMethodParameter(MethodParameter.forMethodOrConstructor(method, i)).resolveGeneric();
+
+				// handle the reference type
+				BlockOutline blockOutline = handleClass(generic);
 				methodOutline.getBlockChain().add(blockOutline);
 				methodOutline.getChainParameterPositions().add(i);
 			}

src/main/java/unquietcode/tools/flapi/annotations/BlockChain.java

@@ -24,18 +24,12 @@
 /**
  * Specifies a method parameter that is to be used for building
  * a block chain around the method. The parameter must be of
- * type {@link java.util.concurrent.atomic.AtomicReference},
- * and the provided {@link #value()} class must match the
- * generic type of the reference object. A mismatch will not
- * be discovered until runtime, at which point you will receive
- * a ClassCastException.
+ * type {@link java.util.concurrent.atomic.AtomicReference}.
  *
  * @author Ben Fagin
  * @version 2014-08-03
  */
 @FlapiAnnotation
 @Target(ElementType.PARAMETER)
 @Retention(RetentionPolicy.RUNTIME)
-public @interface BlockChain {
-	Class<?> value();
-}
+public @interface BlockChain { }

src/test/java/unquietcode/tools/flapi/examples/calculator/Calculator.java

@@ -19,5 +19,5 @@
 public interface Calculator {
 
 	@Last
-	void $(int startingValue, @BlockChain(Calculation.class) AtomicReference<Calculation> helper);
+	void $(int startingValue, @BlockChain AtomicReference<Calculation> helper);
 }