DATACMNS-867 - First draft.

src/main/java/org/springframework/data/querydsl/QuerydslRepositoryInvokerAdapter.java

@@ -17,7 +17,6 @@ package org.springframework.data.querydsl;
 
 import java.io.Serializable;
 import java.lang.reflect.Method;
-import java.util.Map;
 
 import org.springframework.data.domain.Pageable;
 import org.springframework.data.domain.Sort;
@@ -130,15 +129,6 @@ public class QuerydslRepositoryInvokerAdapter implements RepositoryInvoker {
 		return delegate.invokeFindOne(id);
 	}
 
-	/* 
-	 * (non-Javadoc)
-	 * @see org.springframework.data.repository.support.RepositoryInvoker#invokeQueryMethod(java.lang.reflect.Method, java.util.Map, org.springframework.data.domain.Pageable, org.springframework.data.domain.Sort)
-	 */
-	@Override
-	public Object invokeQueryMethod(Method method, Map<String, String[]> parameters, Pageable pageable, Sort sort) {
-		return delegate.invokeQueryMethod(method, parameters, pageable, sort);
-	}
-
 	/* 
 	 * (non-Javadoc)
 	 * @see org.springframework.data.repository.support.RepositoryInvoker#invokeQueryMethod(java.lang.reflect.Method, org.springframework.util.MultiValueMap, org.springframework.data.domain.Pageable, org.springframework.data.domain.Sort)

src/main/java/org/springframework/data/querydsl/binding/MultiValueBinding.java

@@ -16,6 +16,7 @@
 package org.springframework.data.querydsl.binding;
 
 import java.util.Collection;
+import java.util.Optional;
 
 import com.querydsl.core.types.Path;
 import com.querydsl.core.types.Predicate;
@@ -40,5 +41,5 @@ public interface MultiValueBinding<T extends Path<? extends S>, S> {
 	 * @return can be {@literal null}, in which case the binding will not be incorporated in the overall {@link Predicate}
 	 *         .
 	 */
-	Predicate bind(T path, Collection<? extends S> value);
+	Optional<Predicate> bind(T path, Collection<? extends S> value);
 }

src/main/java/org/springframework/data/querydsl/binding/OptionalValueBinding.java

@@ -0,0 +1,44 @@
+/*
+ * Copyright 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.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+package org.springframework.data.querydsl.binding;
+
+import java.util.Optional;
+
+import com.querydsl.core.types.Path;
+import com.querydsl.core.types.Predicate;
+
+/**
+ * {@link OptionalValueBinding} creates a {@link Predicate} out of given {@link Path} and value. Used for specific
+ * parameter treatment in {@link QuerydslBindings}.
+ * 
+ * @author Christoph Strobl
+ * @author Oliver Gierke
+ * @since 1.11
+ */
+@FunctionalInterface
+public interface OptionalValueBinding<T extends Path<? extends S>, S> {
+
+	/**
+	 * Returns the predicate to be applied to the given {@link Path} for the given value. The given value will be the
+	 * first the first one provided for the given path and converted into the expected type.
+	 * 
+	 * @param path {@link Path} to the property. Will not be {@literal null}.
+	 * @param value the value that should be bound. Will not be {@literal null}.
+	 * @return can be {@literal null}, in which case the binding will not be incorporated in the overall {@link Predicate}
+	 *         .
+	 */
+	Optional<Predicate> bind(T path, Optional<? extends S> value);
+}

src/main/java/org/springframework/data/querydsl/binding/QuerydslBindings.java

@@ -15,8 +15,6 @@
  */
 package org.springframework.data.querydsl.binding;
 
-import static org.springframework.data.querydsl.QueryDslUtils.*;
-
 import lombok.NonNull;
 import lombok.RequiredArgsConstructor;
 import lombok.Value;
@@ -24,15 +22,16 @@ import lombok.Value;
 import java.util.Arrays;
 import java.util.Collection;
 import java.util.HashSet;
-import java.util.Iterator;
 import java.util.LinkedHashMap;
 import java.util.List;
 import java.util.Map;
+import java.util.Optional;
 import java.util.Set;
 
 import org.springframework.data.mapping.PropertyPath;
 import org.springframework.data.mapping.PropertyReferenceException;
 import org.springframework.data.util.ClassTypeInformation;
+import org.springframework.data.util.Optionals;
 import org.springframework.data.util.TypeInformation;
 import org.springframework.util.Assert;
 import org.springframework.util.StringUtils;
@@ -42,7 +41,7 @@ import com.querydsl.core.types.Predicate;
 
 /**
  * {@link QuerydslBindings} allows definition of path specific bindings.
- * 
+ *
  * <pre>
  * <code>
  * new QuerydslBindings() {
@@ -53,7 +52,7 @@ import com.querydsl.core.types.Predicate;
  * }
  * </code>
  * </pre>
- * 
+ *
  * The bindings can either handle a single - see {@link PathBinder#first(SingleValueBinding)} - (the first in case
  * multiple ones are supplied) or multiple - see {@link PathBinder#all(MultiValueBinding)} - value binding. If exactly
  * one path is deployed, an {@link AliasingPathBinder} is returned which - as the name suggests - allows aliasing of
@@ -61,7 +60,7 @@ import com.querydsl.core.types.Predicate;
  * <p>
  * {@link QuerydslBindings} are usually manipulated using a {@link QuerydslBinderCustomizer}, either implemented
  * directly or using a default method on a Spring Data repository.
- * 
+ *
  * @author Christoph Strobl
  * @author Oliver Gierke
  * @since 1.11
@@ -90,7 +89,7 @@ public class QuerydslBindings {
 
 	/**
 	 * Returns an {@link AliasingPathBinder} for the given {@link Path} to define bindings for them.
-	 * 
+	 *
 	 * @param path must not be {@literal null}.
 	 * @return
 	 */
@@ -100,17 +99,18 @@ public class QuerydslBindings {
 
 	/**
 	 * Returns a new {@link PathBinder} for the given {@link Path}s to define bindings for them.
-	 * 
+	 *
 	 * @param paths must not be {@literal null} or empty.
 	 * @return
 	 */
+	@SafeVarargs
 	public final <T extends Path<S>, S> PathBinder<T, S> bind(T... paths) {
 		return new PathBinder<T, S>(paths);
 	}
 
 	/**
 	 * Returns a new {@link TypeBinder} for the given type.
-	 * 
+	 *
 	 * @param type must not be {@literal null}.
 	 * @return
 	 */
@@ -121,7 +121,7 @@ public class QuerydslBindings {
 	/**
 	 * Exclude properties from binding. Exclusion of all properties of a nested type can be done by exclusion on a higher
 	 * level. E.g. {@code address} would exclude both {@code address.city} and {@code address.street}.
-	 * 
+	 *
 	 * @param paths must not be {@literal null} or empty.
 	 */
 	public final void excluding(Path<?>... paths) {
@@ -129,13 +129,13 @@ public class QuerydslBindings {
 		Assert.notEmpty(paths, "At least one path has to be provided!");
 
 		for (Path<?> path : paths) {
-			this.blackList.add(toDotPath(path));
+			this.blackList.add(toDotPath(Optional.of(path)));
 		}
 	}
 
 	/**
 	 * Include properties for binding. Include the property considered a binding candidate.
-	 * 
+	 *
 	 * @param properties must not be {@literal null} or empty.
 	 */
 	public final void including(Path<?>... paths) {
@@ -143,7 +143,7 @@ public class QuerydslBindings {
 		Assert.notEmpty(paths, "At least one path has to be provided!");
 
 		for (Path<?> path : paths) {
-			this.whiteList.add(toDotPath(path));
+			this.whiteList.add(toDotPath(Optional.of(path)));
 		}
 	}
 
@@ -151,7 +151,7 @@ public class QuerydslBindings {
 	 * Returns whether to exclude all properties for which no explicit binding has been defined or it has been explicitly
 	 * white-listed. This defaults to {@literal false} which means that for properties without an explicitly defined
 	 * binding a type specific default binding will be applied.
-	 * 
+	 *
 	 * @param excludeUnlistedProperties
 	 * @return
 	 * @see #including(String...)
@@ -165,7 +165,7 @@ public class QuerydslBindings {
 
 	/**
 	 * Returns whether the given path is available on the given type.
-	 * 
+	 *
 	 * @param path must not be {@literal null}.
 	 * @param type must not be {@literal null}.
 	 * @return
@@ -180,7 +180,7 @@ public class QuerydslBindings {
 
 	/**
 	 * Returns whether the given path is available on the given type.
-	 * 
+	 *
 	 * @param path must not be {@literal null}.
 	 * @param type
 	 * @return
@@ -196,12 +196,12 @@ public class QuerydslBindings {
 	/**
 	 * Returns the {@link SingleValueBinding} for the given {@link PropertyPath}. Prefers a path configured for the
 	 * specific path but falls back to the builder registered for a given type.
-	 * 
+	 *
 	 * @param path must not be {@literal null}.
 	 * @return can be {@literal null}.
 	 */
 	@SuppressWarnings("unchecked")
-	public <S extends Path<? extends T>, T> MultiValueBinding<S, T> getBindingForPath(PathInformation path) {
+	public <S extends Path<? extends T>, T> Optional<MultiValueBinding<S, T>> getBindingForPath(PathInformation path) {
 
 		Assert.notNull(path, "PropertyPath must not be null!");
 
@@ -209,30 +209,29 @@ public class QuerydslBindings {
 
 		if (pathAndBinding != null) {
 
-			MultiValueBinding<S, T> binding = pathAndBinding.getBinding();
+			Optional<MultiValueBinding<S, T>> binding = pathAndBinding.getBinding();
 
-			if (binding != null) {
-				return pathAndBinding.getBinding();
+			if (binding.isPresent()) {
+				return binding;
 			}
 		}
 
 		pathAndBinding = (PathAndBinding<S, T>) typeSpecs.get(path.getLeafType());
 
-		return pathAndBinding == null ? null : pathAndBinding.getBinding();
+		return pathAndBinding == null ? Optional.empty() : pathAndBinding.getBinding();
 	}
 
 	/**
 	 * Returns a {@link Path} for the {@link PropertyPath} instance.
-	 * 
+	 *
 	 * @param path must not be {@literal null}.
 	 * @return
 	 */
-	Path<?> getExistingPath(PathInformation path) {
+	Optional<Path<?>> getExistingPath(PathInformation path) {
 
 		Assert.notNull(path, "PropertyPath must not be null!");
 
-		PathAndBinding<?, ?> pathAndBuilder = pathSpecs.get(path.toDotPath());
-		return pathAndBuilder == null ? null : pathAndBuilder.getPath();
+		return Optional.ofNullable(pathSpecs.get(path.toDotPath())).flatMap(it -> it.getPath());
 	}
 
 	/**
@@ -252,7 +251,9 @@ public class QuerydslBindings {
 		}
 
 		if (pathSpecs.containsKey(path)) {
-			return QuerydslPathInformation.of(pathSpecs.get(path).getPath());
+			return pathSpecs.get(path).getPath()//
+					.map(it -> QuerydslPathInformation.of(it))//
+					.orElse(null);
 		}
 
 		try {
@@ -265,7 +266,7 @@ public class QuerydslBindings {
 
 	/**
 	 * Checks if a given {@link PropertyPath} should be visible for binding values.
-	 * 
+	 *
 	 * @param path
 	 * @return
 	 */
@@ -292,7 +293,7 @@ public class QuerydslBindings {
 	/**
 	 * Returns whether the given path is visible, which means either an alias and not explicitly blacklisted, explicitly
 	 * white listed or not on the black list if no white list configured.
-	 * 
+	 *
 	 * @param path must not be {@literal null}.
 	 * @return
 	 */
@@ -310,6 +311,17 @@ public class QuerydslBindings {
 		return whiteList.contains(path);
 	}
 
+	/**
+	 * Returns the property path for the given {@link Path}.
+	 *
+	 * @param path can be {@literal null}.
+	 * @return
+	 */
+	private static String toDotPath(Optional<Path<?>> path) {
+		return path.map(it -> it.toString().substring(it.getMetadata().getRootPath().getMetadata().getName().length() + 1))
+				.orElse("");
+	}
+
 	/**
 	 * A binder for {@link Path}s.
 	 *
@@ -321,9 +333,10 @@ public class QuerydslBindings {
 
 		/**
 		 * Creates a new {@link PathBinder} for the given {@link Path}s.
-		 * 
+		 *
 		 * @param paths must not be {@literal null} or empty.
 		 */
+		@SafeVarargs
 		PathBinder(P... paths) {
 
 			Assert.notEmpty(paths, "At least one path has to be provided!");
@@ -332,20 +345,26 @@ public class QuerydslBindings {
 
 		/**
 		 * Defines the given {@link SingleValueBinding} to be used for the paths.
-		 * 
+		 *
 		 * @param binding must not be {@literal null}.
 		 * @return
 		 */
-		public void first(SingleValueBinding<P, T> binding) {
+		public void firstOptional(OptionalValueBinding<P, T> binding) {
 
 			Assert.notNull(binding, "Binding must not be null!");
 
-			all(new MultiValueBindingAdapter<P, T>(binding));
+			all((path, value) -> binding.bind(path, Optionals.next(value.iterator())));
+		}
+
+		public void first(SingleValueBinding<P, T> binding) {
+
+			Assert.notNull(binding, "Binding must not be null!");
+			all((path, value) -> Optionals.next(value.iterator()).flatMap(t -> binding.bind(path, t)));
 		}
 
 		/**
 		 * Defines the given {@link MultiValueBinding} to be used for the paths.
-		 * 
+		 *
 		 * @param binding must not be {@literal null}.
 		 * @return
 		 */
@@ -353,9 +372,7 @@ public class QuerydslBindings {
 
 			Assert.notNull(binding, "Binding must not be null!");
 
-			for (P path : paths) {
-				registerBinding(new PathAndBinding<P, T>(path, binding));
-			}
+			paths.forEach(path -> registerBinding(PathAndBinding.withPath(path).with(binding)));
 		}
 
 		protected void registerBinding(PathAndBinding<P, T> binding) {
@@ -376,7 +393,7 @@ public class QuerydslBindings {
 
 		/**
 		 * Creates a new {@link AliasingPathBinder} for the given {@link Path}.
-		 * 
+		 *
 		 * @param paths must not be {@literal null}.
 		 */
 		AliasingPathBinder(P path) {
@@ -385,11 +402,10 @@ public class QuerydslBindings {
 
 		/**
 		 * Creates a new {@link AliasingPathBinder} using the given alias and {@link Path}.
-		 * 
+		 *
 		 * @param alias can be {@literal null}.
 		 * @param path must not be {@literal null}.
 		 */
-		@SuppressWarnings("unchecked")
 		private AliasingPathBinder(String alias, P path) {
 
 			super(path);
@@ -404,7 +420,7 @@ public class QuerydslBindings {
 		 * Aliases the current binding to be available under the given path. By default, the binding path will be
 		 * blacklisted so that aliasing effectively hides the original path. If you want to keep the original path around,
 		 * include it in an explicit whitelist.
-		 * 
+		 *
 		 * @param alias must not be {@literal null}.
 		 * @return will never be {@literal null}.
 		 */
@@ -418,10 +434,10 @@ public class QuerydslBindings {
 		 * Registers the current aliased binding to use the default binding.
 		 */
 		public void withDefaultBinding() {
-			registerBinding(new PathAndBinding<P, T>(path, null));
+			registerBinding(PathAndBinding.withPath(path));
 		}
 
-		/* 
+		/*
 		 * (non-Javadoc)
 		 * @see org.springframework.data.querydsl.binding.QuerydslBindings.PathBinder#registerBinding(org.springframework.data.querydsl.binding.QuerydslBindings.PathAndBinding)
 		 */
@@ -450,60 +466,69 @@ public class QuerydslBindings {
 
 		/**
 		 * Configures the given {@link SingleValueBinding} to be used for the current type.
-		 * 
+		 *
 		 * @param binding must not be {@literal null}.
 		 */
+		public <P extends Path<T>> void firstOptional(OptionalValueBinding<P, T> binding) {
+
+			Assert.notNull(binding, "Binding must not be null!");
+			all(new MultiValueBinding<P, T>() {
+
+				@Override
+				public Optional<Predicate> bind(P path, Collection<? extends T> value) {
+					return binding.bind(path, Optionals.next(value.iterator()));
+				}
+			});
+		}
+
 		public <P extends Path<T>> void first(SingleValueBinding<P, T> binding) {
 
 			Assert.notNull(binding, "Binding must not be null!");
-			all(new MultiValueBindingAdapter<P, T>(binding));
+			all(new MultiValueBinding<P, T>() {
+
+				@Override
+				public Optional<Predicate> bind(P path, Collection<? extends T> value) {
+					return Optionals.next(value.iterator()).flatMap(t -> binding.bind(path, t));
+				}
+			});
 		}
 
 		/**
 		 * Configures the given {@link MultiValueBinding} to be used for the current type.
-		 * 
+		 *
 		 * @param binding must not be {@literal null}.
 		 */
 		public <P extends Path<T>> void all(MultiValueBinding<P, T> binding) {
 
 			Assert.notNull(binding, "Binding must not be null!");
-			QuerydslBindings.this.typeSpecs.put(type, new PathAndBinding<P, T>(null, binding));
+
+			QuerydslBindings.this.typeSpecs.put(type, PathAndBinding.<T, P> withoutPath().with(binding));
 		}
 	}
 
 	/**
 	 * A pair of a {@link Path} and the registered {@link MultiValueBinding}.
-	 * 
+	 *
 	 * @author Christoph Strobl
 	 * @author Oliver Gierke
 	 * @since 1.11
 	 */
 	@Value
-	private static class PathAndBinding<S extends Path<? extends T>, T> {
+	private static class PathAndBinding<P extends Path<? extends T>, T> {
 
-		Path<?> path;
-		MultiValueBinding<S, T> binding;
-	}
+		@NonNull Optional<Path<?>> path;
+		@NonNull Optional<MultiValueBinding<P, T>> binding;
 
-	/**
-	 * {@link MultiValueBinding} that forwards the first value of the collection values to the delegate
-	 * {@link SingleValueBinding}.
-	 * 
-	 * @author Oliver Gierke
-	 */
-	@RequiredArgsConstructor
-	static class MultiValueBindingAdapter<P extends Path<? extends T>, T> implements MultiValueBinding<P, T> {
+		public static <T, P extends Path<? extends T>> PathAndBinding<P, T> withPath(P path) {
+			return new PathAndBinding<P, T>(Optional.of(path), Optional.empty());
+		}
 
-		private final @NonNull SingleValueBinding<P, T> delegate;
+		public static <T, S extends Path<? extends T>> PathAndBinding<S, T> withoutPath() {
+			return new PathAndBinding<S, T>(Optional.empty(), Optional.empty());
+		}
 
-		/* 
-		 * (non-Javadoc)
-		 * @see org.springframework.data.web.querydsl.MultiValueBinding#bind(com.mysema.query.types.Path, java.util.Collection)
-		 */
-		@Override
-		public Predicate bind(P path, Collection<? extends T> value) {
-			Iterator<? extends T> iterator = value.iterator();
-			return delegate.bind(path, iterator.hasNext() ? iterator.next() : null);
+		public PathAndBinding<P, T> with(MultiValueBinding<P, T> binding) {
+			return new PathAndBinding<P, T>(path, Optional.of(binding));
 		}
 	}
 }

src/main/java/org/springframework/data/querydsl/binding/QuerydslBindingsFactory.java

@@ -16,6 +16,7 @@
 package org.springframework.data.querydsl.binding;
 
 import java.util.Map;
+import java.util.Optional;
 
 import org.springframework.beans.BeanUtils;
 import org.springframework.beans.BeansException;
@@ -44,8 +45,8 @@ public class QuerydslBindingsFactory implements ApplicationContextAware {
 	private final EntityPathResolver entityPathResolver;
 	private final Map<TypeInformation<?>, EntityPath<?>> entityPaths;
 
-	private AutowireCapableBeanFactory beanFactory;
-	private Repositories repositories;
+	private Optional<AutowireCapableBeanFactory> beanFactory;
+	private Optional<Repositories> repositories;
 
 	/**
 	 * Creates a new {@link QuerydslBindingsFactory} using the given {@link EntityPathResolver}.
@@ -58,6 +59,8 @@ public class QuerydslBindingsFactory implements ApplicationContextAware {
 
 		this.entityPathResolver = entityPathResolver;
 		this.entityPaths = new ConcurrentReferenceHashMap<TypeInformation<?>, EntityPath<?>>();
+		this.beanFactory = Optional.empty();
+		this.repositories = Optional.empty();
 	}
 
 	/* 
@@ -67,8 +70,8 @@ public class QuerydslBindingsFactory implements ApplicationContextAware {
 	@Override
 	public void setApplicationContext(ApplicationContext applicationContext) throws BeansException {
 
-		this.beanFactory = applicationContext.getAutowireCapableBeanFactory();
-		this.repositories = new Repositories(applicationContext);
+		this.beanFactory = Optional.of(applicationContext.getAutowireCapableBeanFactory());
+		this.repositories = Optional.of(new Repositories(applicationContext));
 	}
 
 	/**
@@ -84,14 +87,15 @@ public class QuerydslBindingsFactory implements ApplicationContextAware {
 	 * Creates the {@link QuerydslBindings} to be used using for the given domain type and a pre-defined
 	 * {@link QuerydslBinderCustomizer}. If no customizer is given, auto-detection will be applied.
 	 * 
-	 * @param customizer the {@link QuerydslBinderCustomizer} to use. If {@literal null} is given customizer detection for
-	 *          the given domain type will be applied.
 	 * @param domainType must not be {@literal null}.
+	 * @param customizer the {@link QuerydslBinderCustomizer} to use. If an empty {@link Optional} is given customizer
+	 *          detection for the given domain type will be applied.
 	 * @return
 	 */
-	public QuerydslBindings createBindingsFor(Class<? extends QuerydslBinderCustomizer<?>> customizer,
-			TypeInformation<?> domainType) {
+	public QuerydslBindings createBindingsFor(TypeInformation<?> domainType,
+			Optional<Class<? extends QuerydslBinderCustomizer<?>>> customizer) {
 
+		Assert.notNull(customizer, "Customizer must not be null!");
 		Assert.notNull(domainType, "Domain type must not be null!");
 
 		EntityPath<?> path = verifyEntityPathPresent(domainType);
@@ -111,23 +115,15 @@ public class QuerydslBindingsFactory implements ApplicationContextAware {
 	 */
 	private EntityPath<?> verifyEntityPathPresent(TypeInformation<?> candidate) {
 
-		EntityPath<?> path = entityPaths.get(candidate);
+		return entityPaths.computeIfAbsent(candidate, key -> {
 
-		if (path != null) {
-			return path;
-		}
-
-		Class<?> type = candidate.getType();
-
-		try {
-			path = entityPathResolver.createPath(type);
-		} catch (IllegalArgumentException o_O) {
-			throw new IllegalStateException(
-					String.format(INVALID_DOMAIN_TYPE, candidate.getType(), QuerydslPredicate.class.getSimpleName()), o_O);
-		}
-
-		entityPaths.put(candidate, path);
-		return path;
+			try {
+				return entityPathResolver.createPath(key.getType());
+			} catch (IllegalArgumentException o_O) {
+				throw new IllegalStateException(
+						String.format(INVALID_DOMAIN_TYPE, key.getType(), QuerydslPredicate.class.getSimpleName()), o_O);
+			}
+		});
 	}
 
 	/**
@@ -140,22 +136,16 @@ public class QuerydslBindingsFactory implements ApplicationContextAware {
 	 */
 	@SuppressWarnings({ "unchecked", "rawtypes" })
 	private QuerydslBinderCustomizer<EntityPath<?>> findCustomizerForDomainType(
-			Class<? extends QuerydslBinderCustomizer> customizer, Class<?> domainType) {
+			Optional<? extends Class<? extends QuerydslBinderCustomizer>> customizer, Class<?> domainType) {
 
-		if (customizer != null && !QuerydslBinderCustomizer.class.equals(customizer)) {
-			return createQuerydslBinderCustomizer(customizer);
-		}
+		return customizer//
+				.filter(it -> !QuerydslBinderCustomizer.class.equals(it))//
+				.map(it -> createQuerydslBinderCustomizer(it)).orElseGet(() -> {
 
-		if (repositories != null && repositories.hasRepositoryFor(domainType)) {
-
-			Object repository = repositories.getRepositoryFor(domainType);
-
-			if (repository instanceof QuerydslBinderCustomizer) {
-				return (QuerydslBinderCustomizer<EntityPath<?>>) repository;
-			}
-		}
-
-		return NoOpCustomizer.INSTANCE;
+					return repositories.flatMap(it -> it.getRepositoryFor(domainType))//
+							.map(it -> it instanceof QuerydslBinderCustomizer ? (QuerydslBinderCustomizer<EntityPath<?>>) it : null)//
+							.orElse(NoOpCustomizer.INSTANCE);
+				});
 	}
 
 	/**
@@ -171,15 +161,14 @@ public class QuerydslBindingsFactory implements ApplicationContextAware {
 	private QuerydslBinderCustomizer<EntityPath<?>> createQuerydslBinderCustomizer(
 			Class<? extends QuerydslBinderCustomizer> type) {
 
-		if (beanFactory == null) {
-			return BeanUtils.instantiateClass(type);
-		}
+		return beanFactory.map(it -> {
 
-		try {
-			return beanFactory.getBean(type);
-		} catch (NoSuchBeanDefinitionException e) {
-			return beanFactory.createBean(type);
-		}
+			try {
+				return it.getBean(type);
+			} catch (NoSuchBeanDefinitionException e) {
+				return it.createBean(type);
+			}
+		}).orElseGet(() -> BeanUtils.instantiateClass(type));
 	}
 
 	private static enum NoOpCustomizer implements QuerydslBinderCustomizer<EntityPath<?>> {

src/main/java/org/springframework/data/querydsl/binding/QuerydslDefaultBinding.java

@@ -16,6 +16,7 @@
 package org.springframework.data.querydsl.binding;
 
 import java.util.Collection;
+import java.util.Optional;
 
 import org.springframework.util.Assert;
 
@@ -46,13 +47,13 @@ class QuerydslDefaultBinding implements MultiValueBinding<Path<? extends Object>
 	 */
 	@Override
 	@SuppressWarnings({ "unchecked", "rawtypes" })
-	public Predicate bind(Path<?> path, Collection<? extends Object> value) {
+	public Optional<Predicate> bind(Path<?> path, Collection<? extends Object> value) {
 
 		Assert.notNull(path, "Path must not be null!");
 		Assert.notNull(value, "Value must not be null!");
 
 		if (value.isEmpty()) {
-			return null;
+			return Optional.empty();
 		}
 
 		if (path instanceof CollectionPathBase) {
@@ -63,16 +64,16 @@ class QuerydslDefaultBinding implements MultiValueBinding<Path<? extends Object>
 				builder.and(((CollectionPathBase) path).contains(element));
 			}
 
-			return builder.getValue();
+			return Optional.of(builder.getValue());
 		}
 
 		if (path instanceof SimpleExpression) {
 
 			if (value.size() > 1) {
-				return ((SimpleExpression) path).in(value);
+				return Optional.of(((SimpleExpression) path).in(value));
 			}
 
-			return ((SimpleExpression) path).eq(value.iterator().next());
+			return Optional.of(((SimpleExpression) path).eq(value.iterator().next()));
 		}
 
 		throw new IllegalArgumentException(

src/main/java/org/springframework/data/querydsl/binding/QuerydslPredicate.java

@@ -38,7 +38,7 @@ public @interface QuerydslPredicate {
 	 * 
 	 * @return
 	 */
-	Class<?>root() default Object.class;
+	Class<?> root() default Object.class;
 
 	/**
 	 * To customize the way individual properties' values should be bound to the predicate a
@@ -49,5 +49,5 @@ public @interface QuerydslPredicate {
 	 * @return
 	 */
 	@SuppressWarnings("rawtypes")
-	Class<? extends QuerydslBinderCustomizer>bindings() default QuerydslBinderCustomizer.class;
+	Class<? extends QuerydslBinderCustomizer> bindings() default QuerydslBinderCustomizer.class;
 }

src/main/java/org/springframework/data/querydsl/binding/QuerydslPredicateBuilder.java

@@ -23,6 +23,7 @@ import java.util.HashMap;
 import java.util.List;
 import java.util.Map;
 import java.util.Map.Entry;
+import java.util.Optional;
 
 import org.springframework.beans.PropertyValues;
 import org.springframework.core.convert.ConversionService;
@@ -50,7 +51,7 @@ import com.querydsl.core.types.Predicate;
 public class QuerydslPredicateBuilder {
 
 	private final ConversionService conversionService;
-	private final MultiValueBinding<?, ?> defaultBinding;
+	private final MultiValueBinding<Path<? extends Object>, Object> defaultBinding;
 	private final Map<PathInformation, Path<?>> paths;
 	private final EntityPathResolver resolver;
 
@@ -67,7 +68,7 @@ public class QuerydslPredicateBuilder {
 
 		this.defaultBinding = new QuerydslDefaultBinding();
 		this.conversionService = conversionService;
-		this.paths = new HashMap<PathInformation, Path<?>>();
+		this.paths = new HashMap<>();
 		this.resolver = resolver;
 	}
 
@@ -110,11 +111,9 @@ public class QuerydslPredicateBuilder {
 			}
 
 			Collection<Object> value = convertToPropertyPathSpecificType(entry.getValue(), propertyPath);
-			Predicate predicate = invokeBinding(propertyPath, bindings, value);
+			Optional<Predicate> predicate = invokeBinding(propertyPath, bindings, value);
 
-			if (predicate != null) {
-				builder.and(predicate);
-			}
+			predicate.ifPresent(it -> builder.and(it));
 		}
 
 		return builder.getValue();
@@ -128,15 +127,12 @@ public class QuerydslPredicateBuilder {
 	 * @param values must not be {@literal null}.
 	 * @return
 	 */
-	@SuppressWarnings({ "unchecked", "rawtypes" })
-	private Predicate invokeBinding(PathInformation dotPath, QuerydslBindings bindings, Collection<Object> values) {
+	private Optional<Predicate> invokeBinding(PathInformation dotPath, QuerydslBindings bindings,
+			Collection<Object> values) {
 
 		Path<?> path = getPath(dotPath, bindings);
 
-		MultiValueBinding binding = bindings.getBindingForPath(dotPath);
-		binding = binding == null ? defaultBinding : binding;
-
-		return binding.bind(path, values);
+		return bindings.getBindingForPath(dotPath).orElse(defaultBinding).bind(path, values);
 	}
 
 	/**
@@ -150,22 +146,9 @@ public class QuerydslPredicateBuilder {
 	 */
 	private Path<?> getPath(PathInformation path, QuerydslBindings bindings) {
 
-		Path<?> resolvedPath = bindings.getExistingPath(path);
+		Optional<Path<?>> resolvedPath = bindings.getExistingPath(path);
 
-		if (resolvedPath != null) {
-			return resolvedPath;
-		}
-
-		resolvedPath = paths.get(resolvedPath);
-
-		if (resolvedPath != null) {
-			return resolvedPath;
-		}
-
-		resolvedPath = path.reifyPath(resolver);
-		paths.put(path, resolvedPath);
-
-		return resolvedPath;
+		return resolvedPath.orElseGet(() -> paths.computeIfAbsent(path, it -> path.reifyPath(resolver)));
 	}
 
 	/**

src/main/java/org/springframework/data/querydsl/binding/SingleValueBinding.java

@@ -15,6 +15,8 @@
  */
 package org.springframework.data.querydsl.binding;
 
+import java.util.Optional;
+
 import com.querydsl.core.types.Path;
 import com.querydsl.core.types.Predicate;
 
@@ -38,5 +40,5 @@ public interface SingleValueBinding<T extends Path<? extends S>, S> {
 	 * @return can be {@literal null}, in which case the binding will not be incorporated in the overall {@link Predicate}
 	 *         .
 	 */
-	Predicate bind(T path, S value);
+	Optional<Predicate> bind(T path, S value);
 }