DATACMNS-1005 - Polishing.

Simplified type check by using Set as method signature to avoid unnecessary manual array wrapping. Simplification in the test assertions. A bit of Javadoc, corrected imports and author tags.

Original pull request: #200.

src/main/java/org/springframework/data/repository/query/QueryMethod.java

@@ -1,5 +1,5 @@
 /*
- * Copyright 2008-2015 the original author or authors.
+ * Copyright 2008-2017 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.
@@ -18,7 +18,6 @@ package org.springframework.data.repository.query;
 import static org.springframework.data.repository.util.ClassUtils.*;
 
 import java.lang.reflect.Method;
-import java.util.Arrays;
 import java.util.Set;
 
 import org.springframework.data.domain.Page;
@@ -40,6 +39,7 @@ import org.springframework.util.Assert;
  * 
  * @author Oliver Gierke
  * @author Thomas Darimont
+ * @author Maciek Opała
  */
 public class QueryMethod {
 
@@ -80,8 +80,7 @@ public class QueryMethod {
 		if (hasParameterOfType(method, Pageable.class)) {
 
 			if (!isStreamQuery()) {
-				final Set<Class<?>> allowedPageableTypes = QueryExecutionConverters.getAllowedPageableTypes();
-				assertReturnTypeAssignable(method, allowedPageableTypes.toArray(new Class<?>[allowedPageableTypes.size()]));
+				assertReturnTypeAssignable(method, QueryExecutionConverters.getAllowedPageableTypes());
 			}
 
 			if (hasParameterOfType(method, Sort.class)) {
@@ -90,7 +89,8 @@ public class QueryMethod {
 			}
 		}
 
-		Assert.notNull(this.parameters, String.format("Parameters extracted from method '%s' must not be null!", method.getName()));
+		Assert.notNull(this.parameters,
+				String.format("Parameters extracted from method '%s' must not be null!", method.getName()));
 
 		if (isPageQuery()) {
 			Assert.isTrue(this.parameters.hasPageableParameter(),
@@ -279,13 +279,14 @@ public class QueryMethod {
 		return method.getReturnType();
 	}
 
-	private static void assertReturnTypeAssignable(Method method, Class<?>... types) {
+	private static void assertReturnTypeAssignable(Method method, Set<Class<?>> types) {
 
 		Assert.notNull(method, "Method must not be null!");
 		Assert.notEmpty(types, "Types must not be null or empty!");
 
 		TypeInformation<?> returnType = ClassTypeInformation.fromReturnTypeOf(method);
-		returnType = QueryExecutionConverters.isSingleValue(returnType.getType()) ? returnType.getComponentType() : returnType;
+		returnType = QueryExecutionConverters.isSingleValue(returnType.getType()) ? returnType.getComponentType()
+				: returnType;
 
 		for (Class<?> type : types) {
 			if (type.isAssignableFrom(returnType.getType())) {
@@ -293,6 +294,6 @@ public class QueryMethod {
 			}
 		}
 
-		throw new IllegalStateException("Method has to have one of the following return types! " + Arrays.toString(types));
+		throw new IllegalStateException("Method has to have one of the following return types! " + types.toString());
 	}
-}
+}

src/main/java/org/springframework/data/repository/util/QueryExecutionConverters.java

@@ -1,5 +1,5 @@
 /*
- * Copyright 2014-2016 the original author or authors.
+ * Copyright 2014-2017 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.
@@ -21,8 +21,6 @@ import lombok.AccessLevel;
 import lombok.Getter;
 import lombok.RequiredArgsConstructor;
 import lombok.Value;
-import org.springframework.data.domain.Page;
-import org.springframework.data.domain.Slice;
 import scala.Function0;
 import scala.Option;
 import scala.runtime.AbstractFunction0;
@@ -43,6 +41,8 @@ import org.springframework.core.convert.TypeDescriptor;
 import org.springframework.core.convert.converter.Converter;
 import org.springframework.core.convert.converter.GenericConverter;
 import org.springframework.core.convert.support.ConfigurableConversionService;
+import org.springframework.data.domain.Page;
+import org.springframework.data.domain.Slice;
 import org.springframework.scheduling.annotation.AsyncResult;
 import org.springframework.util.Assert;
 import org.springframework.util.ClassUtils;
@@ -62,11 +62,14 @@ import com.google.common.base.Optional;
  * <li>{@code java.util.concurrent.CompletableFuture}</li>
  * <li>{@code org.springframework.util.concurrent.ListenableFuture<}</li>
  * <li>{@code javaslang.control.Option} - as of 1.13</li>
+ * <li>{@code javaslang.collection.Seq}, {@code javaslang.collection.Map}, {@code javaslang.collection.Set} - as of
  * <li>Reactive wrappers supported by {@link ReactiveWrappers}</li>
+ * 1.13</li>
  * </ul>
  * 
  * @author Oliver Gierke
  * @author Mark Paluch
+ * @author Maciek Opała
  * @since 1.8
  * @see ReactiveWrappers
  */
@@ -191,6 +194,12 @@ public abstract class QueryExecutionConverters {
 		return false;
 	}
 
+	/**
+	 * Returns the types that are supported on paginating query methods. Will include custom collection types of e.g.
+	 * Javaslang.
+	 * 
+	 * @return
+	 */
 	public static Set<Class<?>> getAllowedPageableTypes() {
 		return Collections.unmodifiableSet(ALLOWED_PAGEABLE_TYPES);
 	}