DATAJPA-652 - Added support for REF_CURSOR output parameters for procedures.

We now support detecting output parameters for stored-procedures with ParameterMode.REF_CURSOR. Previously we only considered parameters with OUT or INOUT mode as output parameters.

Note that since it is a bit tricky to setup a proper test case with hsql / eclipselink, I had to verify this with a standalone spring boot app:
https://gist.github.com/thomasdarimont/129bc15d0ccc459610c2
A proper test case will follow.

Original pull request: #130.

Author: Thomas Darimont

src/main/java/org/springframework/data/jpa/repository/query/StoredProcedureAttributeSource.java

@@ -1,5 +1,5 @@
 /*
- * Copyright 2014 the original author or authors.
+ * Copyright 2014-2015 the original author or authors.
  *
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
@@ -57,7 +57,7 @@ public StoredProcedureAttributes createFrom(Method method, JpaEntityMetadata<?>
 				procedure);
 
 		if (namedStoredProc != null) {
-			return newProcedureAttributesFrom(method, namedStoredProc);
+			return newProcedureAttributesFrom(method, namedStoredProc, procedure);
 		}
 
 		String procedureName = deriveProcedureNameFrom(method, procedure);
@@ -90,43 +90,61 @@ private String deriveProcedureNameFrom(Method method, Procedure procedure) {
 	/**
 	 * @param method
 	 * @param namedStoredProc
+	 * @param procedure
 	 * @return
 	 */
-	private StoredProcedureAttributes newProcedureAttributesFrom(Method method, NamedStoredProcedureQuery namedStoredProc) {
+	private StoredProcedureAttributes newProcedureAttributesFrom(Method method,
+			NamedStoredProcedureQuery namedStoredProc, Procedure procedure) {
 
 		String outputParameterName = null;
 		Class<?> outputParameterType = null;
 
-		int outputParameterCount = 0;
+		if (!procedure.outputParameterName().isEmpty()) {
+
+			// we give the output parameter definition from the @Procedure annotation precedence
+			outputParameterName = procedure.outputParameterName();
+		} else {
+
+			// try to discover the output parameter
+			List<StoredProcedureParameter> outputParameters = extractOutputParametersFrom(namedStoredProc);
+
+			if (outputParameters.size() != 1) {
+				throw new IllegalStateException(String.format(
+						"Could not create ProcedureAttributes from %s. We currently support exactly one output parameter!", method));
+			}
+
+			StoredProcedureParameter outputParameter = outputParameters.get(0);
+			outputParameterName = outputParameter.name();
+			outputParameterType = outputParameter.type();
+		}
+
+		if (outputParameterType == null || Object.class.equals(outputParameterType)
+				|| void.class.equals(outputParameterType)) {
+			outputParameterType = method.getReturnType();
+		}
+
+		return new StoredProcedureAttributes(namedStoredProc.name(), outputParameterName, outputParameterType, true);
+	}
+
+	private List<StoredProcedureParameter> extractOutputParametersFrom(NamedStoredProcedureQuery namedStoredProc) {
+
+		List<StoredProcedureParameter> outputParameters = new ArrayList<StoredProcedureParameter>();
 
 		for (StoredProcedureParameter param : namedStoredProc.parameters()) {
+
 			switch (param.mode()) {
 				case OUT:
 				case INOUT:
-
-					if (outputParameterCount > 0) {
-						throw new IllegalStateException(
-								String.format(
-										"Could not create ProcedureAttributes from %s. We currently support only one output parameter!",
-										method));
-					}
-
-					outputParameterName = param.name();
-					outputParameterType = param.type();
-
-					outputParameterCount++;
+				case REF_CURSOR:
+					outputParameters.add(param);
 					break;
 				case IN:
 				default:
 					continue;
 			}
 		}
 
-		if (outputParameterType == null) {
-			outputParameterType = method.getReturnType();
-		}
-
-		return new StoredProcedureAttributes(namedStoredProc.name(), outputParameterName, outputParameterType, true);
+		return outputParameters;
 	}
 
 	/**