DATACMNS-1224 - Polishing of nullability annotations.

Refactored code to properly check for null fields in Eclipse. Added warning suppressions where suitable.

Author: odrotbohm

src/main/java/org/springframework/data/domain/AbstractAggregateRoot.java

@@ -75,6 +75,7 @@ protected Collection<Object> domainEvents() {
 	 * @param aggregate must not be {@literal null}.
 	 * @return the aggregate
 	 */
+	@SuppressWarnings("unchecked")
 	protected final A andEventsFrom(A aggregate) {
 
 		Assert.notNull(aggregate, "Aggregate must not be null!");
@@ -92,6 +93,7 @@ protected final A andEventsFrom(A aggregate) {
 	 * @return the aggregate
 	 * @see #registerEvent(Object)
 	 */
+	@SuppressWarnings("unchecked")
 	protected final A andEvent(Object event) {
 
 		registerEvent(event);

src/main/java/org/springframework/data/mapping/model/AbstractPersistentProperty.java

@@ -56,6 +56,7 @@ public abstract class AbstractPersistentProperty<P extends PersistentProperty<P>
 	private final Lazy<Association<P>> association;
 	private final @Getter PersistentEntity<?, P> owner;
 
+	@SuppressWarnings("null") //
 	private final @Getter(value = AccessLevel.PROTECTED, onMethod = @__(@SuppressWarnings("null"))) Property property;
 	private final Lazy<Integer> hashCode;
 	private final Lazy<Boolean> usePropertyAccess;

src/main/java/org/springframework/data/projection/DefaultMethodInvokingMethodInterceptor.java

@@ -133,8 +133,8 @@ MethodHandle lookup(Method method) throws ReflectiveOperationException {
 
 				MethodType methodType = MethodType.methodType(method.getReturnType(), method.getParameterTypes());
 
-				return getLookup(method.getDeclaringClass()).findSpecial(method.getDeclaringClass(), method.getName(),
-						methodType, method.getDeclaringClass());
+				return getLookup(method.getDeclaringClass(), privateLookupIn).findSpecial(method.getDeclaringClass(),
+						method.getName(), methodType, method.getDeclaringClass());
 			}
 
 			/*
@@ -146,14 +146,14 @@ boolean isAvailable() {
 				return true;
 			}
 
-			private Lookup getLookup(Class<?> declaringClass) {
-
-				Lookup lookup = MethodHandles.lookup();
+			private Lookup getLookup(Class<?> declaringClass, @Nullable Method privateLookupIn) {
 
 				if (privateLookupIn == null) {
-					return lookup;
+					return MethodHandles.lookup();
 				}
 
+				Lookup lookup = MethodHandles.lookup();
+
 				try {
 					return (Lookup) privateLookupIn.invoke(MethodHandles.class, declaringClass, lookup);
 				} catch (ReflectiveOperationException e) {

src/main/java/org/springframework/data/repository/core/support/MethodInvocationValidator.java

@@ -70,7 +70,7 @@ public static boolean supports(Class<?> repositoryInterface) {
 	 */
 	@Nullable
 	@Override
-	public Object invoke(MethodInvocation invocation) throws Throwable {
+	public Object invoke(@SuppressWarnings("null") MethodInvocation invocation) throws Throwable {
 
 		Method method = invocation.getMethod();
 		Nullability nullability = nullabilityCache.get(method);

src/main/java/org/springframework/data/repository/init/AbstractRepositoryPopulatorFactoryBean.java

@@ -15,6 +15,8 @@
  */
 package org.springframework.data.repository.init;
 
+import javax.annotation.Nonnull;
+
 import org.springframework.beans.factory.FactoryBean;
 import org.springframework.beans.factory.config.AbstractFactoryBean;
 import org.springframework.context.ApplicationContext;
@@ -37,7 +39,7 @@ public abstract class AbstractRepositoryPopulatorFactoryBean
 		extends AbstractFactoryBean<ResourceReaderRepositoryPopulator>
 		implements ApplicationListener<ContextRefreshedEvent>, ApplicationContextAware {
 
-	private @Nullable Resource[] resources;
+	private Resource[] resources = new Resource[0];
 	private @Nullable RepositoryPopulator populator;
 	private @Nullable ApplicationContext context;
 
@@ -64,6 +66,7 @@ public void setApplicationContext(ApplicationContext applicationContext) {
 	 * (non-Javadoc)
 	 * @see org.springframework.beans.factory.config.AbstractFactoryBean#getObjectType()
 	 */
+	@Nonnull
 	@Override
 	public Class<?> getObjectType() {
 		return ResourceReaderRepositoryPopulator.class;
@@ -78,7 +81,10 @@ protected ResourceReaderRepositoryPopulator createInstance() {
 
 		ResourceReaderRepositoryPopulator initializer = new ResourceReaderRepositoryPopulator(getResourceReader());
 		initializer.setResources(resources);
-		initializer.setApplicationEventPublisher(context);
+
+		if (context != null) {
+			initializer.setApplicationEventPublisher(context);
+		}
 
 		this.populator = initializer;
 
@@ -91,14 +97,25 @@ protected ResourceReaderRepositoryPopulator createInstance() {
 	 */
 	public void onApplicationEvent(ContextRefreshedEvent event) {
 
+		RepositoryPopulator populator = this.populator;
+
+		if (populator == null) {
+			throw new IllegalStateException("RepositoryPopulator was not properly initialized!");
+		}
+
 		if (event.getApplicationContext().equals(context)) {
+
 			Repositories repositories = new Repositories(event.getApplicationContext());
 			populator.populate(repositories);
 		}
 	}
 
 	protected abstract ResourceReader getResourceReader();
 
+	/*
+	 * (non-Javadoc)
+	 * @see org.springframework.beans.factory.config.AbstractFactoryBean#afterPropertiesSet()
+	 */
 	@Override
 	public void afterPropertiesSet() throws Exception {
 

src/main/java/org/springframework/data/repository/init/UnmarshallerRepositoryPopulatorFactoryBean.java

@@ -44,6 +44,13 @@ public void setUnmarshaller(Unmarshaller unmarshaller) {
 	 */
 	@Override
 	protected ResourceReader getResourceReader() {
+
+		Unmarshaller unmarshaller = this.unmarshaller;
+
+		if (unmarshaller == null) {
+			throw new IllegalStateException("No Unmarshaller configured!");
+		}
+
 		return new UnmarshallingResourceReader(unmarshaller);
 	}
 

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

@@ -290,7 +290,6 @@ public List<String> getInputProperties() {
 			return inputProperties;
 		}
 
-		@SuppressWarnings({ "unchecked", "rawtypes" })
 		private List<String> detectConstructorParameterNames(Class<?> type) {
 
 			if (!isDto()) {

src/main/java/org/springframework/data/repository/query/parser/AbstractQueryCreator.java

@@ -23,6 +23,7 @@
 import org.springframework.data.repository.query.ParameterAccessor;
 import org.springframework.data.repository.query.ParametersParameterAccessor;
 import org.springframework.data.repository.query.parser.PartTree.OrPart;
+import org.springframework.lang.Nullable;
 import org.springframework.util.Assert;
 
 /**
@@ -101,18 +102,24 @@ public T createQuery(Sort dynamicSort) {
 	 * @param tree must not be {@literal null}.
 	 * @return
 	 */
+	@Nullable
 	private S createCriteria(PartTree tree) {
 
 		S base = null;
 		Iterator<Object> iterator = parameters.map(ParameterAccessor::iterator).orElse(Collections.emptyIterator());
 
 		for (OrPart node : tree) {
 
-			S criteria = null;
+			Iterator<Part> parts = node.iterator();
 
-			for (Part part : node) {
+			if (!parts.hasNext()) {
+				throw new IllegalStateException(String.format("No part found in PartTree %s!", tree));
+			}
+
+			S criteria = create(parts.next(), iterator);
 
-				criteria = criteria == null ? create(part, iterator) : and(part, criteria, iterator);
+			while (parts.hasNext()) {
+				criteria = and(parts.next(), criteria, iterator);
 			}
 
 			base = base == null ? criteria : or(base, criteria);
@@ -152,9 +159,9 @@ private S createCriteria(PartTree tree) {
 	/**
 	 * Actually creates the query object applying the given criteria object and {@link Sort} definition.
 	 *
-	 * @param criteria will never be {@literal null}.
+	 * @param criteria can be {@literal null}.
 	 * @param sort must not be {@literal null}.
 	 * @return
 	 */
-	protected abstract T complete(S criteria, Sort sort);
+	protected abstract T complete(@Nullable S criteria, Sort sort);
 }

src/main/java/org/springframework/data/repository/query/parser/Part.java

@@ -235,10 +235,6 @@ public Collection<String> getKeywords() {
 		 */
 		protected boolean supports(String property) {
 
-			if (keywords == null) {
-				return true;
-			}
-
 			for (String keyword : keywords) {
 				if (property.endsWith(keyword)) {
 					return true;

src/main/java/org/springframework/data/repository/query/spi/EvaluationContextExtension.java

@@ -19,6 +19,7 @@
 
 import org.springframework.data.repository.query.ExtensionAwareEvaluationContextProvider;
 import org.springframework.expression.EvaluationContext;
+import org.springframework.lang.Nullable;
 
 /**
  * SPI to allow adding a set of properties and function definitions accessible via the root of an
@@ -59,5 +60,6 @@ public interface EvaluationContextExtension {
 	 * 
 	 * @return
 	 */
+	@Nullable
 	Object getRootObject();
 }

src/main/java/org/springframework/data/repository/query/spi/EvaluationContextExtensionSupport.java

@@ -18,6 +18,8 @@
 import java.util.Collections;
 import java.util.Map;
 
+import org.springframework.lang.Nullable;
+
 /**
  * A base class for {@link EvaluationContextExtension}s.
  * 
@@ -49,6 +51,7 @@ public Map<String, Function> getFunctions() {
 	 * (non-Javadoc)
 	 * @see org.springframework.data.repository.query.spi.EvaluationContextExtension#getRootObject()
 	 */
+	@Nullable
 	@Override
 	public Object getRootObject() {
 		return null;

src/main/java/org/springframework/data/repository/query/spi/Function.java

@@ -21,6 +21,7 @@
 import java.util.List;
 
 import org.springframework.core.convert.TypeDescriptor;
+import org.springframework.lang.Nullable;
 import org.springframework.util.Assert;
 import org.springframework.util.TypeUtils;
 
@@ -36,7 +37,7 @@
 public class Function {
 
 	private final Method method;
-	private final Object target;
+	private final @Nullable Object target;
 
 	/**
 	 * Creates a new {@link Function} to statically invoke the given {@link Method}.
@@ -56,7 +57,7 @@ public Function(Method method) {
 	 * @param method must not be {@literal null}.
 	 * @param target can be {@literal null}, if so, the method
 	 */
-	public Function(Method method, Object target) {
+	public Function(Method method, @Nullable Object target) {
 
 		Assert.notNull(method, "Method must not be null!");
 		Assert.isTrue(target != null || Modifier.isStatic(method.getModifiers()),
@@ -154,7 +155,6 @@ public boolean supportsExact(List<TypeDescriptor> argumentTypes) {
 	 * Checks wether this {@code Function} has the same signature as another {@code Function}.
 	 *
 	 * @param other the {@code Function} to compare {@code this} with.
-	 *
 	 * @return {@code true} iff name and argument list are the same.
 	 */
 	public boolean isSignatureEqual(Function other) {

src/main/java/org/springframework/data/transaction/ChainedTransactionManager.java

@@ -25,6 +25,7 @@
 
 import org.slf4j.Logger;
 import org.slf4j.LoggerFactory;
+import org.springframework.lang.Nullable;
 import org.springframework.transaction.CannotCreateTransactionException;
 import org.springframework.transaction.HeuristicCompletionException;
 import org.springframework.transaction.PlatformTransactionManager;
@@ -86,10 +87,14 @@ public ChainedTransactionManager(PlatformTransactionManager... transactionManage
 	 * (non-Javadoc)
 	 * @see org.springframework.transaction.PlatformTransactionManager#getTransaction(org.springframework.transaction.TransactionDefinition)
 	 */
-	public MultiTransactionStatus getTransaction(TransactionDefinition definition) throws TransactionException {
+	public MultiTransactionStatus getTransaction(@Nullable TransactionDefinition definition) throws TransactionException {
 
 		MultiTransactionStatus mts = new MultiTransactionStatus(transactionManagers.get(0));
 
+		if (definition == null) {
+			return mts;
+		}
+
 		if (!synchronizationManager.isSynchronizationActive()) {
 			synchronizationManager.initSynchronization();
 			mts.setNewSynchonization();

src/main/java/org/springframework/data/util/NullableUtils.java

@@ -262,7 +262,7 @@ private static Set<Class<?>> findClasses(String... classNames) {
 				.collect(Collectors.toSet());
 	}
 
-	@SuppressWarnings("unchecked")
+	@SuppressWarnings({ "unchecked", "rawtypes" })
 	private static <T> Optional<Class<T>> findClass(String className) {
 
 		try {

src/main/java/org/springframework/data/web/config/SpringDataWebConfiguration.java

@@ -141,7 +141,7 @@ public void addArgumentResolvers(List<HandlerMethodArgumentResolver> argumentRes
 		argumentResolvers.add(pageableResolver());
 
 		ProxyingHandlerMethodArgumentResolver resolver = new ProxyingHandlerMethodArgumentResolver(
-				getRequiredConversionService());
+				conversionService.getObject());
 		resolver.setBeanFactory(context);
 		forwardBeanClassLoader(resolver);
 
@@ -180,17 +180,6 @@ protected void customizeSortResolver(SortHandlerMethodArgumentResolver sortResol
 		sortResolverCustomizer.ifPresent(c -> c.customize(sortResolver));
 	}
 
-	private ConversionService getRequiredConversionService() {
-
-		ConversionService conversionService = this.conversionService.getObject();
-
-		if (conversionService == null) {
-			throw new IllegalStateException("No ConversionService configured!");
-		}
-
-		return conversionService;
-	}
-
 	private void forwardBeanClassLoader(BeanClassLoaderAware target) {
 
 		if (beanClassLoader != null) {

src/main/java/org/springframework/data/web/querydsl/QuerydslPredicateArgumentResolver.java

@@ -90,6 +90,7 @@ public boolean supportsParameter(MethodParameter parameter) {
 	 * (non-Javadoc)
 	 * @see org.springframework.web.method.support.HandlerMethodArgumentResolver#resolveArgument(org.springframework.core.MethodParameter, org.springframework.web.method.support.ModelAndViewContainer, org.springframework.web.context.request.NativeWebRequest, org.springframework.web.bind.support.WebDataBinderFactory)
 	 */
+	@Nullable
 	@Override
 	public Predicate resolveArgument(MethodParameter parameter, @Nullable ModelAndViewContainer mavContainer,
 			NativeWebRequest webRequest, @Nullable WebDataBinderFactory binderFactory) throws Exception {
@@ -149,6 +150,10 @@ private static TypeInformation<?> detectDomainType(TypeInformation<?> source) {
 
 		TypeInformation<?> actualType = source.getActualType();
 
+		if (actualType == null) {
+			throw new IllegalArgumentException(String.format("Could not determine domain type from %s!", source));
+		}
+
 		if (source != actualType) {
 			return detectDomainType(actualType);
 		}