Introduce support to create domain objects via factory methods.

Issue #2476.

src/main/java/org/springframework/data/mapping/EntityCreatorMetadata.java

@@ -0,0 +1,65 @@
+/*
+ * Copyright 2021 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
+ *
+ *      https://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.mapping;
+
+import java.util.List;
+
+/**
+ * Metadata describing a mechanism to create an entity instance.
+ *
+ * @author Mark Paluch
+ * @since 3.0
+ */
+public interface EntityCreatorMetadata<P extends PersistentProperty<P>> {
+
+	/**
+	 * Check whether the given {@link PersistentProperty} is being used as creator parameter.
+	 *
+	 * @param property
+	 * @return
+	 */
+	boolean isCreatorParameter(PersistentProperty<?> property);
+
+	/**
+	 * Returns whether the given {@link Parameter} is one referring to parent value (such as an enclosing class or a
+	 * receiver parameter).
+	 *
+	 * @param parameter
+	 * @return
+	 */
+	default boolean isParentParameter(Parameter<?, P> parameter) {
+		return false;
+	}
+
+	/**
+	 * @return the number of parameters.
+	 */
+	default int getParameterCount() {
+		return getParameters().size();
+	}
+
+	/**
+	 * @return the parameters used by this creator.
+	 */
+	List<Parameter<Object, P>> getParameters();
+
+	/**
+	 * @return whether the creator accepts {@link Parameter}s.
+	 */
+	default boolean hasParameters() {
+		return !getParameters().isEmpty();
+	}
+}

src/main/java/org/springframework/data/mapping/EntityCreatorMetadataSupport.java

@@ -0,0 +1,117 @@
+/*
+ * Copyright 2022 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
+ *
+ *      https://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.mapping;
+
+import java.lang.reflect.Executable;
+import java.util.Arrays;
+import java.util.List;
+import java.util.Map;
+import java.util.concurrent.ConcurrentHashMap;
+
+import org.springframework.util.Assert;
+
+/**
+ * Value object to encapsulate the entity creation mechanism through a {@link Executable} to be used when mapping
+ * persistent data to objects.
+ *
+ * @author Mark Paluch
+ * @since 3.0
+ */
+class EntityCreatorMetadataSupport<T, P extends PersistentProperty<P>> implements EntityCreatorMetadata<P> {
+
+	private final Executable executable;
+	private final List<Parameter<Object, P>> parameters;
+	private final Map<PersistentProperty<?>, Boolean> isPropertyParameterCache = new ConcurrentHashMap<>();
+
+	/**
+	 * Creates a new {@link EntityCreatorMetadataSupport} from the given {@link Executable} and {@link Parameter}s.
+	 *
+	 * @param executable must not be {@literal null}.
+	 * @param parameters must not be {@literal null}.
+	 */
+	@SafeVarargs
+	public EntityCreatorMetadataSupport(Executable executable, Parameter<Object, P>... parameters) {
+
+		Assert.notNull(executable, "Executable must not be null!");
+		Assert.notNull(parameters, "Parameters must not be null!");
+
+		this.executable = executable;
+		this.parameters = Arrays.asList(parameters);
+	}
+
+	/**
+	 * Returns the underlying {@link Executable} that can be invoked reflectively.
+	 *
+	 * @return
+	 */
+	Executable getExecutable() {
+		return executable;
+	}
+
+	/**
+	 * Returns the {@link Parameter}s of the executable.
+	 *
+	 * @return
+	 */
+	public List<Parameter<Object, P>> getParameters() {
+		return parameters;
+	}
+
+	/**
+	 * Returns whether the given {@link PersistentProperty} is referenced in a creator argument of the
+	 * {@link PersistentEntity} backing this {@link EntityCreatorMetadataSupport}.
+	 * <p>
+	 * Results of this call are cached and reused on the next invocation. Calling this method for a
+	 * {@link PersistentProperty} that was not yet added to its owning {@link PersistentEntity} will capture that state
+	 * and return the same result after adding {@link PersistentProperty} to its entity.
+	 *
+	 * @param property must not be {@literal null}.
+	 * @return {@literal true} if the {@link PersistentProperty} is used in the creator.
+	 */
+	@Override
+	public boolean isCreatorParameter(PersistentProperty<?> property) {
+
+		Assert.notNull(property, "Property must not be null!");
+
+		var cached = isPropertyParameterCache.get(property);
+
+		if (cached != null) {
+			return cached;
+		}
+
+		var result = doGetIsCreatorParameter(property);
+
+		isPropertyParameterCache.put(property, result);
+
+		return result;
+	}
+
+	@Override
+	public String toString() {
+		return executable.toString();
+	}
+
+	private boolean doGetIsCreatorParameter(PersistentProperty<?> property) {
+
+		for (Parameter<?, P> parameter : parameters) {
+			if (parameter.maps(property)) {
+				return true;
+			}
+		}
+
+		return false;
+	}
+}

src/main/java/org/springframework/data/mapping/FactoryMethod.java

@@ -0,0 +1,53 @@
+/*
+ * Copyright 2011-2021 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
+ *
+ *      https://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.mapping;
+
+import java.lang.reflect.Constructor;
+import java.lang.reflect.Method;
+
+import org.springframework.util.ReflectionUtils;
+
+/**
+ * Value object to encapsulate the factory method to be used when mapping persistent data to objects.
+ *
+ * @author Mark Paluch
+ * @since 3.0
+ */
+public final class FactoryMethod<T, P extends PersistentProperty<P>> extends EntityCreatorMetadataSupport<T, P> {
+
+	/**
+	 * Creates a new {@link FactoryMethod} from the given {@link Constructor} and {@link Parameter}s.
+	 *
+	 * @param factoryMethod must not be {@literal null}.
+	 * @param parameters must not be {@literal null}.
+	 */
+	@SafeVarargs
+	public FactoryMethod(Method factoryMethod, Parameter<Object, P>... parameters) {
+
+		super(factoryMethod, parameters);
+		ReflectionUtils.makeAccessible(factoryMethod);
+	}
+
+	/**
+	 * Returns the underlying {@link Constructor}.
+	 *
+	 * @return
+	 */
+	public Method getFactoryMethod() {
+		return (Method) getExecutable();
+	}
+
+}

src/main/java/org/springframework/data/mapping/Parameter.java

@@ -0,0 +1,208 @@
+/*
+ * Copyright 2021 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
+ *
+ *      https://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.mapping;
+
+import java.lang.annotation.Annotation;
+
+import org.springframework.beans.factory.annotation.Value;
+import org.springframework.core.annotation.MergedAnnotations;
+import org.springframework.data.util.Lazy;
+import org.springframework.data.util.TypeInformation;
+import org.springframework.lang.Nullable;
+import org.springframework.util.Assert;
+import org.springframework.util.ObjectUtils;
+import org.springframework.util.StringUtils;
+
+/**
+ * Value object to represent constructor parameters.
+ *
+ * @param <T> the type of the parameter
+ * @author Oliver Gierke
+ */
+public class Parameter<T, P extends PersistentProperty<P>> {
+
+	private final @Nullable String name;
+	private final TypeInformation<T> type;
+	private final MergedAnnotations annotations;
+	private final String key;
+	private final @Nullable PersistentEntity<T, P> entity;
+
+	private final Lazy<Boolean> enclosingClassCache;
+	private final Lazy<Boolean> hasSpelExpression;
+
+	/**
+	 * Creates a new {@link Parameter} with the given name, {@link TypeInformation} as well as an array of
+	 * {@link Annotation}s. Will inspect the annotations for an {@link Value} annotation to lookup a key or an SpEL
+	 * expression to be evaluated.
+	 *
+	 * @param name the name of the parameter, can be {@literal null}
+	 * @param type must not be {@literal null}
+	 * @param annotations must not be {@literal null} but can be empty
+	 * @param entity must not be {@literal null}.
+	 */
+	public Parameter(@Nullable String name, TypeInformation<T> type, Annotation[] annotations,
+			@Nullable PersistentEntity<T, P> entity) {
+
+		Assert.notNull(type, "Type must not be null!");
+		Assert.notNull(annotations, "Annotations must not be null!");
+
+		this.name = name;
+		this.type = type;
+		this.annotations = MergedAnnotations.from(annotations);
+		this.key = getValue(this.annotations);
+		this.entity = entity;
+
+		this.enclosingClassCache = Lazy.of(() -> {
+
+			if (entity == null) {
+				throw new IllegalStateException();
+			}
+
+			var owningType = entity.getType();
+			return owningType.isMemberClass() && type.getType().equals(owningType.getEnclosingClass());
+		});
+
+		this.hasSpelExpression = Lazy.of(() -> StringUtils.hasText(getSpelExpression()));
+	}
+
+	@Nullable
+	private static String getValue(MergedAnnotations annotations) {
+
+		return annotations.get(Value.class) //
+				.getValue("value", String.class) //
+				.filter(StringUtils::hasText) //
+				.orElse(null);
+	}
+
+	/**
+	 * Returns the name of the parameter.
+	 *
+	 * @return
+	 */
+	@Nullable
+	public String getName() {
+		return name;
+	}
+
+	/**
+	 * Returns the {@link TypeInformation} of the parameter.
+	 *
+	 * @return
+	 */
+	public TypeInformation<T> getType() {
+		return type;
+	}
+
+	/**
+	 * Merged annotations that this parameter is annotated with.
+	 *
+	 * @return
+	 * @since 2.5
+	 */
+	public MergedAnnotations getAnnotations() {
+		return annotations;
+	}
+
+	/**
+	 * Returns the raw resolved type of the parameter.
+	 *
+	 * @return
+	 */
+	public Class<T> getRawType() {
+		return type.getType();
+	}
+
+	/**
+	 * Returns the key to be used when looking up a source data structure to populate the actual parameter value.
+	 *
+	 * @return
+	 */
+	public String getSpelExpression() {
+		return key;
+	}
+
+	/**
+	 * Returns whether the constructor parameter is equipped with a SpEL expression.
+	 *
+	 * @return
+	 */
+	public boolean hasSpelExpression() {
+		return this.hasSpelExpression.get();
+	}
+
+	/*
+	 * (non-Javadoc)
+	 * @see java.lang.Object#equals(java.lang.Object)
+	 */
+	@Override
+	public boolean equals(Object o) {
+
+		if (this == o) {
+			return true;
+		}
+
+		if (!(o instanceof Parameter<?, ?> parameter)) {
+			return false;
+		}
+
+		if (!ObjectUtils.nullSafeEquals(name, parameter.name)) {
+			return false;
+		}
+
+		if (!ObjectUtils.nullSafeEquals(type, parameter.type)) {
+			return false;
+		}
+
+		if (!ObjectUtils.nullSafeEquals(key, parameter.key)) {
+			return false;
+		}
+
+		return ObjectUtils.nullSafeEquals(entity, parameter.entity);
+	}
+
+	/*
+	 * (non-Javadoc)
+	 * @see java.lang.Object#hashCode()
+	 */
+	@Override
+	public int hashCode() {
+		var result = ObjectUtils.nullSafeHashCode(name);
+		result = 31 * result + ObjectUtils.nullSafeHashCode(type);
+		result = 31 * result + ObjectUtils.nullSafeHashCode(key);
+		result = 31 * result + ObjectUtils.nullSafeHashCode(entity);
+		return result;
+	}
+
+	/**
+	 * Returns whether the {@link Parameter} maps the given {@link PersistentProperty}.
+	 *
+	 * @param property
+	 * @return
+	 */
+	boolean maps(PersistentProperty<?> property) {
+
+		var entity = this.entity;
+		var name = this.name;
+
+		var referencedProperty = entity == null ? null : name == null ? null : entity.getPersistentProperty(name);
+
+		return property.equals(referencedProperty);
+	}
+
+	boolean isEnclosingClassParameter() {
+		return enclosingClassCache.get();
+	}
+}

src/main/java/org/springframework/data/mapping/PersistentEntity.java

@@ -49,10 +49,24 @@ public interface PersistentEntity<T, P extends PersistentProperty<P>> extends It
 	 *         indicates that the instantiation of the object of that persistent entity is done through either a customer
 	 *         {@link org.springframework.data.mapping.model.EntityInstantiator} or handled by custom conversion
 	 *         mechanisms entirely.
+	 * @deprecated since 3.0, use {@link #getEntityCreator()}.
 	 */
 	@Nullable
+	@Deprecated
 	PreferredConstructor<T, P> getPersistenceConstructor();
 
+	/**
+	 * Returns the {@link EntityCreatorMetadata} to be used to instantiate objects of this {@link PersistentEntity}.
+	 *
+	 * @return {@literal null} in case no suitable creation mechanism for automatic construction can be found. This
+	 *         usually indicates that the instantiation of the object of that persistent entity is done through either a
+	 *         customer {@link org.springframework.data.mapping.model.EntityInstantiator} or handled by custom conversion
+	 *         mechanisms entirely.
+	 * @since 3.0
+	 */
+	@Nullable
+	EntityCreatorMetadata<P> getEntityCreator();
+
 	/**
 	 * Returns whether the given {@link PersistentProperty} is referred to by a constructor argument of the
 	 * {@link PersistentEntity}.
@@ -60,8 +74,22 @@ public interface PersistentEntity<T, P extends PersistentProperty<P>> extends It
 	 * @param property can be {@literal null}.
 	 * @return true if the given {@link PersistentProperty} is referred to by a constructor argument or {@literal false}
 	 *         if not or {@literal null}.
+	 * @deprecated since 3.0, use {@link #isCreatorArgument(PersistentProperty)} instead.
 	 */
-	boolean isConstructorArgument(PersistentProperty<?> property);
+	@Deprecated
+	default boolean isConstructorArgument(PersistentProperty<?> property) {
+		return isCreatorArgument(property);
+	}
+
+	/**
+	 * Returns whether the given {@link PersistentProperty} is referred to by a creator argument of the
+	 * {@link PersistentEntity}.
+	 *
+	 * @param property can be {@literal null}.
+	 * @return true if the given {@link PersistentProperty} is referred to by a creator argument or {@literal false} if
+	 *         not or {@literal null}.
+	 */
+	boolean isCreatorArgument(PersistentProperty<?> property);
 
 	/**
 	 * Returns whether the given {@link PersistentProperty} is the id property of the entity.

src/main/java/org/springframework/data/mapping/PreferredConstructor.java

@@ -15,25 +15,14 @@
  */
 package org.springframework.data.mapping;
 
-import java.lang.annotation.Annotation;
 import java.lang.reflect.Constructor;
 import java.util.Arrays;
 import java.util.List;
-import java.util.Map;
-import java.util.concurrent.ConcurrentHashMap;
 
-import org.springframework.beans.factory.annotation.Value;
-import org.springframework.core.annotation.AnnotationUtils;
 import org.springframework.core.annotation.MergedAnnotations;
 import org.springframework.data.annotation.PersistenceConstructor;
-import org.springframework.data.convert.WritingConverter;
-import org.springframework.data.util.Lazy;
-import org.springframework.data.util.TypeInformation;
-import org.springframework.lang.Nullable;
 import org.springframework.util.Assert;
-import org.springframework.util.ObjectUtils;
 import org.springframework.util.ReflectionUtils;
-import org.springframework.util.StringUtils;
 
 /**
  * Value object to encapsulate the constructor to be used when mapping persistent data to objects.
@@ -46,11 +35,9 @@ import org.springframework.util.StringUtils;
  * @author Myeonghyeon Lee
  * @author Xeno Amess
  */
-public class PreferredConstructor<T, P extends PersistentProperty<P>> {
+public final class PreferredConstructor<T, P extends PersistentProperty<P>> extends EntityCreatorMetadataSupport<T, P> {
 
-	private final Constructor<T> constructor;
 	private final List<Parameter<Object, P>> parameters;
-	private final Map<PersistentProperty<?>, Boolean> isPropertyParameterCache = new ConcurrentHashMap<>();
 
 	/**
 	 * Creates a new {@link PreferredConstructor} from the given {@link Constructor} and {@link Parameter}s.
@@ -61,11 +48,9 @@ public class PreferredConstructor<T, P extends PersistentProperty<P>> {
 	@SafeVarargs
 	public PreferredConstructor(Constructor<T> constructor, Parameter<Object, P>... parameters) {
 
-		Assert.notNull(constructor, "Constructor must not be null!");
-		Assert.notNull(parameters, "Parameters must not be null!");
+		super(constructor, parameters);
 
 		ReflectionUtils.makeAccessible(constructor);
-		this.constructor = constructor;
 		this.parameters = Arrays.asList(parameters);
 	}
 
@@ -75,27 +60,9 @@ public class PreferredConstructor<T, P extends PersistentProperty<P>> {
 	 * @return
 	 */
 	public Constructor<T> getConstructor() {
-		return constructor;
+		return (Constructor<T>) getExecutable();
 	}
 
-	/**
-	 * Returns the {@link Parameter}s of the constructor.
-	 *
-	 * @return
-	 */
-	public List<Parameter<Object, P>> getParameters() {
-		return parameters;
-	}
-
-	/**
-	 * Returns whether the constructor has {@link Parameter}s.
-	 *
-	 * @see #isNoArgConstructor()
-	 * @return
-	 */
-	public boolean hasParameters() {
-		return !parameters.isEmpty();
-	}
 
 	/**
 	 * Returns whether the constructor does not have any arguments.
@@ -104,7 +71,7 @@ public class PreferredConstructor<T, P extends PersistentProperty<P>> {
 	 * @return
 	 */
 	public boolean isNoArgConstructor() {
-		return parameters.isEmpty();
+		return !hasParameters();
 	}
 
 	/**
@@ -113,41 +80,22 @@ public class PreferredConstructor<T, P extends PersistentProperty<P>> {
 	 * @return
 	 */
 	public boolean isExplicitlyAnnotated() {
-		return AnnotationUtils.findAnnotation(constructor, PersistenceConstructor.class) != null;
+		return MergedAnnotations.from(getExecutable()).isPresent(PersistenceConstructor.class);
 	}
 
 	/**
-	 * Returns whether the given {@link PersistentProperty} is referenced in a constructor argument of the
-	 * {@link PersistentEntity} backing this {@link PreferredConstructor}.
-	 * <p>
-	 * Results of this call are cached and reused on the next invocation. Calling this method for a
-	 * {@link PersistentProperty} that was not yet added to its owning {@link PersistentEntity} will capture that state
-	 * and return the same result after adding {@link PersistentProperty} to its entity.
-	 *
-	 * @param property must not be {@literal null}.
-	 * @return {@literal true} if the {@link PersistentProperty} is used in the constructor.
+	 * @param property
+	 * @return
+	 * @deprecated since 3.0, use {@link #isCreatorParameter(PersistentProperty)} instead.
 	 */
+	@Deprecated
 	public boolean isConstructorParameter(PersistentProperty<?> property) {
+		return isCreatorParameter(property);
+	}
 
-		Assert.notNull(property, "Property must not be null!");
-
-		var cached = isPropertyParameterCache.get(property);
-
-		if (cached != null) {
-			return cached;
-		}
-
-		var result = false;
-		for (Parameter<?, P> parameter : parameters) {
-			if (parameter.maps(property)) {
-				result = true;
-				break;
-			}
-		}
-
-		isPropertyParameterCache.put(property, result);
-
-		return result;
+	@Override
+	public boolean isParentParameter(Parameter<?, P> parameter) {
+		return isEnclosingClassParameter(parameter);
 	}
 
 	/**
@@ -169,176 +117,4 @@ public class PreferredConstructor<T, P extends PersistentProperty<P>> {
 		return parameters.get(0).equals(parameter);
 	}
 
-	/**
-	 * Value object to represent constructor parameters.
-	 *
-	 * @param <T> the type of the parameter
-	 * @author Oliver Gierke
-	 */
-	public static class Parameter<T, P extends PersistentProperty<P>> {
-
-		private final @Nullable String name;
-		private final TypeInformation<T> type;
-		private final MergedAnnotations annotations;
-		private final String key;
-		private final @Nullable PersistentEntity<T, P> entity;
-
-		private final Lazy<Boolean> enclosingClassCache;
-		private final Lazy<Boolean> hasSpelExpression;
-
-		/**
-		 * Creates a new {@link Parameter} with the given name, {@link TypeInformation} as well as an array of
-		 * {@link Annotation}s. Will inspect the annotations for an {@link Value} annotation to lookup a key or an SpEL
-		 * expression to be evaluated.
-		 *
-		 * @param name the name of the parameter, can be {@literal null}
-		 * @param type must not be {@literal null}
-		 * @param annotations must not be {@literal null} but can be empty
-		 * @param entity must not be {@literal null}.
-		 */
-		public Parameter(@Nullable String name, TypeInformation<T> type, Annotation[] annotations,
-				@Nullable PersistentEntity<T, P> entity) {
-
-			Assert.notNull(type, "Type must not be null!");
-			Assert.notNull(annotations, "Annotations must not be null!");
-
-			this.name = name;
-			this.type = type;
-			this.annotations = MergedAnnotations.from(annotations);
-			this.key = getValue(this.annotations);
-			this.entity = entity;
-
-			this.enclosingClassCache = Lazy.of(() -> {
-
-				if (entity == null) {
-					throw new IllegalStateException();
-				}
-
-				var owningType = entity.getType();
-				return owningType.isMemberClass() && type.getType().equals(owningType.getEnclosingClass());
-			});
-
-			this.hasSpelExpression = Lazy.of(() -> StringUtils.hasText(getSpelExpression()));
-		}
-
-		@Nullable
-		private static String getValue(MergedAnnotations annotations) {
-
-			return annotations.get(Value.class) //
-					.getValue("value", String.class) //
-					.filter(StringUtils::hasText) //
-					.orElse(null);
-		}
-
-		/**
-		 * Returns the name of the parameter.
-		 *
-		 * @return
-		 */
-		@Nullable
-		public String getName() {
-			return name;
-		}
-
-		/**
-		 * Returns the {@link TypeInformation} of the parameter.
-		 *
-		 * @return
-		 */
-		public TypeInformation<T> getType() {
-			return type;
-		}
-
-		/**
-		 * Merged annotations that this parameter is annotated with.
-		 *
-		 * @return
-		 * @since 2.5
-		 */
-		public MergedAnnotations getAnnotations() {
-			return annotations;
-		}
-
-		/**
-		 * Returns the raw resolved type of the parameter.
-		 *
-		 * @return
-		 */
-		public Class<T> getRawType() {
-			return type.getType();
-		}
-
-		/**
-		 * Returns the key to be used when looking up a source data structure to populate the actual parameter value.
-		 *
-		 * @return
-		 */
-		public String getSpelExpression() {
-			return key;
-		}
-
-		/**
-		 * Returns whether the constructor parameter is equipped with a SpEL expression.
-		 *
-		 * @return
-		 */
-		public boolean hasSpelExpression() {
-			return this.hasSpelExpression.get();
-		}
-
-		@Override
-		public boolean equals(Object o) {
-
-			if (this == o) {
-				return true;
-			}
-
-			if (!(o instanceof Parameter<?, ?> parameter)) {
-				return false;
-			}
-
-			if (!ObjectUtils.nullSafeEquals(name, parameter.name)) {
-				return false;
-			}
-
-			if (!ObjectUtils.nullSafeEquals(type, parameter.type)) {
-				return false;
-			}
-
-			if (!ObjectUtils.nullSafeEquals(key, parameter.key)) {
-				return false;
-			}
-
-			return ObjectUtils.nullSafeEquals(entity, parameter.entity);
-		}
-
-		@Override
-		public int hashCode() {
-			var result = ObjectUtils.nullSafeHashCode(name);
-			result = 31 * result + ObjectUtils.nullSafeHashCode(type);
-			result = 31 * result + ObjectUtils.nullSafeHashCode(key);
-			result = 31 * result + ObjectUtils.nullSafeHashCode(entity);
-			return result;
-		}
-
-		/**
-		 * Returns whether the {@link Parameter} maps the given {@link PersistentProperty}.
-		 *
-		 * @param property
-		 * @return
-		 */
-		boolean maps(PersistentProperty<?> property) {
-
-			var entity = this.entity;
-			var name = this.name;
-
-			var referencedProperty = entity == null ? null : name == null ? null : entity.getPersistentProperty(name);
-
-			return property.equals(referencedProperty);
-		}
-
-		private boolean isEnclosingClassParameter() {
-			return enclosingClassCache.get();
-		}
-	}
 }

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

@@ -63,7 +63,7 @@ public class BasicPersistentEntity<T, P extends PersistentProperty<P>> implement
 
 	private static final String TYPE_MISMATCH = "Target bean of type %s is not of type of the persistent entity (%s)!";
 
-	private final @Nullable PreferredConstructor<T, P> constructor;
+	private final @Nullable EntityCreatorMetadata<P> creator;
 	private final TypeInformation<T> information;
 	private final List<P> properties;
 	private final List<P> persistentPropertiesCache;
@@ -109,7 +109,7 @@ public class BasicPersistentEntity<T, P extends PersistentProperty<P>> implement
 		this.properties = new ArrayList<>();
 		this.persistentPropertiesCache = new ArrayList<>();
 		this.comparator = comparator;
-		this.constructor = PreferredConstructorDiscoverer.discover(this);
+		this.creator = EntityCreatorMetadataDiscoverer.discover(this);
 		this.associations = comparator == null ? new HashSet<>() : new TreeSet<>(new AssociationComparator<>(comparator));
 
 		this.propertyCache = new HashMap<>(16, 1f);
@@ -124,16 +124,23 @@ public class BasicPersistentEntity<T, P extends PersistentProperty<P>> implement
 
 		this.isImmutable = Lazy.of(() -> isAnnotationPresent(Immutable.class));
 		this.requiresPropertyPopulation = Lazy.of(() -> !isImmutable() && properties.stream() //
-				.anyMatch(it -> !(isConstructorArgument(it) || it.isTransient())));
+				.anyMatch(it -> !(isCreatorArgument(it) || it.isTransient())));
 	}
 
 	@Nullable
+	@Override
 	public PreferredConstructor<T, P> getPersistenceConstructor() {
-		return constructor;
+		return creator instanceof PreferredConstructor ? (PreferredConstructor<T, P>) creator : null;
 	}
 
-	public boolean isConstructorArgument(PersistentProperty<?> property) {
-		return constructor != null && constructor.isConstructorParameter(property);
+	@Override
+	public EntityCreatorMetadata<P> getEntityCreator() {
+		return creator;
+	}
+
+	@Override
+	public boolean isCreatorArgument(PersistentProperty<?> property) {
+		return creator != null && creator.isCreatorParameter(property);
 	}
 
 	public boolean isIdProperty(PersistentProperty<?> property) {

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

@@ -33,19 +33,22 @@ import org.springframework.asm.Type;
 import org.springframework.beans.BeanInstantiationException;
 import org.springframework.cglib.core.ReflectUtils;
 import org.springframework.core.NativeDetector;
+import org.springframework.data.mapping.EntityCreatorMetadata;
+import org.springframework.data.mapping.FactoryMethod;
+import org.springframework.data.mapping.Parameter;
 import org.springframework.data.mapping.PersistentEntity;
 import org.springframework.data.mapping.PersistentProperty;
 import org.springframework.data.mapping.PreferredConstructor;
-import org.springframework.data.mapping.PreferredConstructor.Parameter;
 import org.springframework.data.util.TypeInformation;
 import org.springframework.lang.Nullable;
+import org.springframework.util.Assert;
 import org.springframework.util.ClassUtils;
 
 /**
  * An {@link EntityInstantiator} that can generate byte code to speed-up dynamic object instantiation. Uses the
  * {@link PersistentEntity}'s {@link PreferredConstructor} to instantiate an instance of the entity by dynamically
  * generating factory methods with appropriate constructor invocations via ASM. If we cannot generate byte code for a
- * type, we gracefully fall-back to the {@link ReflectionEntityInstantiator}.
+ * type, we gracefully fallback to the {@link ReflectionEntityInstantiator}.
  *
  * @author Thomas Darimont
  * @author Oliver Gierke
@@ -64,11 +67,21 @@ class ClassGeneratingEntityInstantiator implements EntityInstantiator {
 
 	private volatile Map<TypeInformation<?>, EntityInstantiator> entityInstantiators = new HashMap<>(32);
 
+	private final boolean fallbackToReflectionOnError;
+
 	/**
 	 * Creates a new {@link ClassGeneratingEntityInstantiator}.
 	 */
 	public ClassGeneratingEntityInstantiator() {
+		this(true);
+	}
+
+	/**
+	 * Creates a new {@link ClassGeneratingEntityInstantiator}.
+	 */
+	ClassGeneratingEntityInstantiator(boolean fallbackToReflectionOnError) {
 		this.generator = new ObjectInstantiatorClassGenerator();
+		this.fallbackToReflectionOnError = fallbackToReflectionOnError;
 	}
 
 	@Override
@@ -122,18 +135,22 @@ class ClassGeneratingEntityInstantiator implements EntityInstantiator {
 			return MappingInstantiationExceptionEntityInstantiator.create(entity.getType());
 		}
 
-		try {
-			return doCreateEntityInstantiator(entity);
-		} catch (Throwable ex) {
+		if (fallbackToReflectionOnError) {
+			try {
+				return doCreateEntityInstantiator(entity);
+			} catch (Throwable ex) {
 
-			if (LOGGER.isDebugEnabled()) {
-				LOGGER.debug(
-						String.format("Cannot create entity instantiator for %s. Falling back to ReflectionEntityInstantiator.",
-								entity.getName()),
-						ex);
+				if (LOGGER.isDebugEnabled()) {
+					LOGGER.debug(
+							String.format("Cannot create entity instantiator for %s. Falling back to ReflectionEntityInstantiator.",
+									entity.getName()),
+							ex);
+				}
+				return ReflectionEntityInstantiator.INSTANCE;
 			}
-			return ReflectionEntityInstantiator.INSTANCE;
 		}
+
+		return doCreateEntityInstantiator(entity);
 	}
 
 	/**
@@ -141,7 +158,8 @@ class ClassGeneratingEntityInstantiator implements EntityInstantiator {
 	 * @return
 	 */
 	protected EntityInstantiator doCreateEntityInstantiator(PersistentEntity<?, ?> entity) {
-		return new EntityInstantiatorAdapter(createObjectInstantiator(entity, entity.getPersistenceConstructor()));
+		return new EntityInstantiatorAdapter(
+				createObjectInstantiator(entity, entity.getEntityCreator()));
 	}
 
 	/**
@@ -169,11 +187,26 @@ class ClassGeneratingEntityInstantiator implements EntityInstantiator {
 			return true;
 		}
 
-		var persistenceConstructor = entity.getPersistenceConstructor();
-		if (persistenceConstructor == null || Modifier.isPrivate(persistenceConstructor.getConstructor().getModifiers())) {
+		var entityCreator = entity.getEntityCreator();
+
+		if (entityCreator == null) {
 			return true;
 		}
 
+		if (entityCreator instanceof PreferredConstructor<?, ?> persistenceConstructor) {
+
+			if (Modifier.isPrivate(persistenceConstructor.getConstructor().getModifiers())) {
+				return true;
+			}
+		}
+
+		if (entityCreator instanceof FactoryMethod<?, ?> factoryMethod) {
+
+			if (Modifier.isPrivate(factoryMethod.getFactoryMethod().getModifiers())) {
+				return true;
+			}
+		}
+
 		if (!ClassUtils.isPresent(ObjectInstantiator.class.getName(), type.getClassLoader())) {
 			return true;
 		}
@@ -194,7 +227,7 @@ class ClassGeneratingEntityInstantiator implements EntityInstantiator {
 
 	/**
 	 * Creates a dynamically generated {@link ObjectInstantiator} for the given {@link PersistentEntity} and
-	 * {@link PreferredConstructor}. There will always be exactly one {@link ObjectInstantiator} instance per
+	 * {@link EntityCreatorMetadata}. There will always be exactly one {@link ObjectInstantiator} instance per
 	 * {@link PersistentEntity}.
 	 *
 	 * @param entity
@@ -202,7 +235,7 @@ class ClassGeneratingEntityInstantiator implements EntityInstantiator {
 	 * @return
 	 */
 	ObjectInstantiator createObjectInstantiator(PersistentEntity<?, ?> entity,
-			@Nullable PreferredConstructor<?, ?> constructor) {
+			@Nullable EntityCreatorMetadata<?> constructor) {
 
 		try {
 			return (ObjectInstantiator) this.generator.generateCustomInstantiatorClass(entity, constructor).newInstance();
@@ -236,7 +269,7 @@ class ClassGeneratingEntityInstantiator implements EntityInstantiator {
 		public <T, E extends PersistentEntity<? extends T, P>, P extends PersistentProperty<P>> T createInstance(E entity,
 				ParameterValueProvider<P> provider) {
 
-			var params = extractInvocationArguments(entity.getPersistenceConstructor(), provider);
+			var params = extractInvocationArguments(entity.getEntityCreator(), provider);
 
 			try {
 				return (T) instantiator.newInstance(params);
@@ -254,13 +287,13 @@ class ClassGeneratingEntityInstantiator implements EntityInstantiator {
 	 * @return
 	 */
 	static <P extends PersistentProperty<P>, T> Object[] extractInvocationArguments(
-			@Nullable PreferredConstructor<? extends T, P> constructor, ParameterValueProvider<P> provider) {
+			@Nullable EntityCreatorMetadata<P> constructor, ParameterValueProvider<P> provider) {
 
 		if (constructor == null || !constructor.hasParameters()) {
 			return allocateArguments(0);
 		}
 
-		var params = allocateArguments(constructor.getConstructor().getParameterCount());
+		var params = allocateArguments(constructor.getParameterCount());
 
 		var index = 0;
 		for (Parameter<?, P> parameter : constructor.getParameters()) {
@@ -303,7 +336,7 @@ class ClassGeneratingEntityInstantiator implements EntityInstantiator {
 		public <T, E extends PersistentEntity<? extends T, P>, P extends PersistentProperty<P>> T createInstance(E entity,
 				ParameterValueProvider<P> provider) {
 
-			var params = extractInvocationArguments(entity.getPersistenceConstructor(), provider);
+			var params = extractInvocationArguments(entity.getEntityCreator(), provider);
 
 			throw new MappingInstantiationException(entity, Arrays.asList(params),
 					new BeanInstantiationException(typeToCreate, "Class is abstract"));
@@ -353,7 +386,7 @@ class ClassGeneratingEntityInstantiator implements EntityInstantiator {
 
 		private static final String INIT = "<init>";
 		private static final String TAG = "_Instantiator_";
-		private static final String JAVA_LANG_OBJECT = "java/lang/Object";
+		private static final String JAVA_LANG_OBJECT = Type.getInternalName(Object.class);
 		private static final String CREATE_METHOD_NAME = "newInstance";
 
 		private static final String[] IMPLEMENTED_INTERFACES = new String[] {
@@ -367,7 +400,7 @@ class ClassGeneratingEntityInstantiator implements EntityInstantiator {
 		 * @return
 		 */
 		public Class<?> generateCustomInstantiatorClass(PersistentEntity<?, ?> entity,
-				@Nullable PreferredConstructor<?, ?> constructor) {
+				@Nullable EntityCreatorMetadata<?> constructor) {
 
 			var className = generateClassName(entity);
 			var type = entity.getType();
@@ -404,11 +437,11 @@ class ClassGeneratingEntityInstantiator implements EntityInstantiator {
 		 *
 		 * @param internalClassName
 		 * @param entity
-		 * @param constructor
+		 * @param entityCreator
 		 * @return
 		 */
 		public byte[] generateBytecode(String internalClassName, PersistentEntity<?, ?> entity,
-				@Nullable PreferredConstructor<?, ?> constructor) {
+				@Nullable EntityCreatorMetadata<?> entityCreator) {
 
 			var cw = new ClassWriter(ClassWriter.COMPUTE_MAXS);
 
@@ -417,7 +450,7 @@ class ClassGeneratingEntityInstantiator implements EntityInstantiator {
 
 			visitDefaultConstructor(cw);
 
-			visitCreateMethod(cw, entity, constructor);
+			visitCreateMethod(cw, entity, entityCreator);
 
 			cw.visitEnd();
 
@@ -440,49 +473,79 @@ class ClassGeneratingEntityInstantiator implements EntityInstantiator {
 		 *
 		 * @param cw
 		 * @param entity
-		 * @param constructor
+		 * @param entityCreator
 		 */
 		private void visitCreateMethod(ClassWriter cw, PersistentEntity<?, ?> entity,
-				@Nullable PreferredConstructor<?, ?> constructor) {
+				@Nullable EntityCreatorMetadata<?> entityCreator) {
 
 			var entityTypeResourcePath = Type.getInternalName(entity.getType());
 
 			var mv = cw.visitMethod(ACC_PUBLIC + ACC_VARARGS, CREATE_METHOD_NAME,
-					"([Ljava/lang/Object;)Ljava/lang/Object;", null, null);
+					"([" + BytecodeUtil.referenceName(Object.class) + ")" + BytecodeUtil.referenceName(Object.class),
+					null, null);
 			mv.visitCode();
 			mv.visitTypeInsn(NEW, entityTypeResourcePath);
 			mv.visitInsn(DUP);
 
-			if (constructor != null) {
+			if (entityCreator instanceof PreferredConstructor<?, ?> constructor) {
+				visitConstructorCreation(constructor, mv, entityTypeResourcePath);
+			}
 
-				var ctor = constructor.getConstructor();
-				var parameterTypes = ctor.getParameterTypes();
-				List<? extends Parameter<Object, ?>> parameters = constructor.getParameters();
+			if (entityCreator instanceof FactoryMethod<?, ?> factoryMethod) {
+				visitFactoryMethodCreation(factoryMethod, mv, entityTypeResourcePath);
+			}
 
-				for (var i = 0; i < parameterTypes.length; i++) {
+			mv.visitInsn(ARETURN);
+			mv.visitMaxs(0, 0); // (0, 0) = computed via ClassWriter.COMPUTE_MAXS
+			mv.visitEnd();
+		}
 
-					mv.visitVarInsn(ALOAD, 1);
+		private static void visitConstructorCreation(PreferredConstructor<?, ?> constructor, MethodVisitor mv,
+				String entityTypeResourcePath) {
 
-					visitArrayIndex(mv, i);
+			var ctor = constructor.getConstructor();
+			var parameterTypes = ctor.getParameterTypes();
+			List<? extends Parameter<Object, ?>> parameters = constructor.getParameters();
 
-					mv.visitInsn(AALOAD);
+			visitParameterTypes(mv, parameterTypes, parameters);
 
-					if (parameterTypes[i].isPrimitive()) {
+			mv.visitMethodInsn(INVOKESPECIAL, entityTypeResourcePath, INIT, Type.getConstructorDescriptor(ctor), false);
+		}
 
-						mv.visitInsn(DUP);
-						var parameterName = parameters.size() > i ? parameters.get(i).getName() : null;
+		private static void visitFactoryMethodCreation(FactoryMethod<?, ?> factoryMethod, MethodVisitor mv,
+				String entityTypeResourcePath) {
 
-						insertAssertNotNull(mv, parameterName == null ? String.format("at index %d", i) : parameterName);
-						insertUnboxInsns(mv, Type.getType(parameterTypes[i]).toString().charAt(0), "");
-					} else {
-						mv.visitTypeInsn(CHECKCAST, Type.getInternalName(parameterTypes[i]));
-					}
+			var method = factoryMethod.getFactoryMethod();
+			var parameterTypes = method.getParameterTypes();
+			List<? extends Parameter<Object, ?>> parameters = factoryMethod.getParameters();
+
+			visitParameterTypes(mv, parameterTypes, parameters);
+
+			mv.visitMethodInsn(INVOKESTATIC, entityTypeResourcePath, method.getName(), Type.getMethodDescriptor(method),
+					false);
+		}
+
+		private static void visitParameterTypes(MethodVisitor mv, Class<?>[] parameterTypes,
+				List<? extends Parameter<Object, ?>> parameters) {
+
+			for (var i = 0; i < parameterTypes.length; i++) {
+
+				mv.visitVarInsn(ALOAD, 1);
+
+				visitArrayIndex(mv, i);
+
+				mv.visitInsn(AALOAD);
+
+				if (parameterTypes[i].isPrimitive()) {
+
+					mv.visitInsn(DUP);
+					var parameterName = parameters.size() > i ? parameters.get(i).getName() : null;
+
+					insertAssertNotNull(mv, parameterName == null ? String.format("at index %d", i) : parameterName);
+					insertUnboxInsns(mv, Type.getType(parameterTypes[i]).toString().charAt(0), "");
+				} else {
+					mv.visitTypeInsn(CHECKCAST, Type.getInternalName(parameterTypes[i]));
 				}
-
-				mv.visitMethodInsn(INVOKESPECIAL, entityTypeResourcePath, INIT, Type.getConstructorDescriptor(ctor), false);
-				mv.visitInsn(ARETURN);
-				mv.visitMaxs(0, 0); // (0, 0) = computed via ClassWriter.COMPUTE_MAXS
-				mv.visitEnd();
 			}
 		}
 
@@ -512,8 +575,8 @@ class ClassGeneratingEntityInstantiator implements EntityInstantiator {
 
 			// Assert.notNull(property)
 			mv.visitLdcInsn(String.format("Parameter %s must not be null!", parameterName));
-			mv.visitMethodInsn(INVOKESTATIC, "org/springframework/util/Assert", "notNull",
-					String.format("(%s%s)V", String.format("L%s;", JAVA_LANG_OBJECT), "Ljava/lang/String;"), false);
+			mv.visitMethodInsn(INVOKESTATIC, Type.getInternalName(Assert.class), "notNull", String.format("(%s%s)V",
+					BytecodeUtil.referenceName(JAVA_LANG_OBJECT), BytecodeUtil.referenceName(String.class)), false);
 		}
 
 		/**
@@ -529,52 +592,52 @@ class ClassGeneratingEntityInstantiator implements EntityInstantiator {
 
 			switch (ch) {
 				case 'Z':
-					if (!stackDescriptor.equals("Ljava/lang/Boolean")) {
-						mv.visitTypeInsn(CHECKCAST, "java/lang/Boolean");
+					if (!stackDescriptor.equals(BytecodeUtil.referenceName(Boolean.class))) {
+						mv.visitTypeInsn(CHECKCAST, Type.getInternalName(Boolean.class));
 					}
-					mv.visitMethodInsn(INVOKEVIRTUAL, "java/lang/Boolean", "booleanValue", "()Z", false);
+					mv.visitMethodInsn(INVOKEVIRTUAL, Type.getInternalName(Boolean.class), "booleanValue", "()Z", false);
 					break;
 				case 'B':
-					if (!stackDescriptor.equals("Ljava/lang/Byte")) {
-						mv.visitTypeInsn(CHECKCAST, "java/lang/Byte");
+					if (!stackDescriptor.equals(BytecodeUtil.referenceName(Byte.class))) {
+						mv.visitTypeInsn(CHECKCAST, Type.getInternalName(Byte.class));
 					}
-					mv.visitMethodInsn(INVOKEVIRTUAL, "java/lang/Byte", "byteValue", "()B", false);
+					mv.visitMethodInsn(INVOKEVIRTUAL, Type.getInternalName(Byte.class), "byteValue", "()B", false);
 					break;
 				case 'C':
-					if (!stackDescriptor.equals("Ljava/lang/Character")) {
-						mv.visitTypeInsn(CHECKCAST, "java/lang/Character");
+					if (!stackDescriptor.equals(BytecodeUtil.referenceName(Character.class))) {
+						mv.visitTypeInsn(CHECKCAST, Type.getInternalName(Character.class));
 					}
-					mv.visitMethodInsn(INVOKEVIRTUAL, "java/lang/Character", "charValue", "()C", false);
+					mv.visitMethodInsn(INVOKEVIRTUAL, Type.getInternalName(Character.class), "charValue", "()C", false);
 					break;
 				case 'D':
-					if (!stackDescriptor.equals("Ljava/lang/Double")) {
-						mv.visitTypeInsn(CHECKCAST, "java/lang/Double");
+					if (!stackDescriptor.equals(BytecodeUtil.referenceName(Double.class))) {
+						mv.visitTypeInsn(CHECKCAST, Type.getInternalName(Double.class));
 					}
-					mv.visitMethodInsn(INVOKEVIRTUAL, "java/lang/Double", "doubleValue", "()D", false);
+					mv.visitMethodInsn(INVOKEVIRTUAL, Type.getInternalName(Double.class), "doubleValue", "()D", false);
 					break;
 				case 'F':
-					if (!stackDescriptor.equals("Ljava/lang/Float")) {
-						mv.visitTypeInsn(CHECKCAST, "java/lang/Float");
+					if (!stackDescriptor.equals(BytecodeUtil.referenceName(Float.class))) {
+						mv.visitTypeInsn(CHECKCAST, Type.getInternalName(Float.class));
 					}
-					mv.visitMethodInsn(INVOKEVIRTUAL, "java/lang/Float", "floatValue", "()F", false);
+					mv.visitMethodInsn(INVOKEVIRTUAL, Type.getInternalName(Float.class), "floatValue", "()F", false);
 					break;
 				case 'I':
-					if (!stackDescriptor.equals("Ljava/lang/Integer")) {
-						mv.visitTypeInsn(CHECKCAST, "java/lang/Integer");
+					if (!stackDescriptor.equals(BytecodeUtil.referenceName(Integer.class))) {
+						mv.visitTypeInsn(CHECKCAST, Type.getInternalName(Integer.class));
 					}
-					mv.visitMethodInsn(INVOKEVIRTUAL, "java/lang/Integer", "intValue", "()I", false);
+					mv.visitMethodInsn(INVOKEVIRTUAL, Type.getInternalName(Integer.class), "intValue", "()I", false);
 					break;
 				case 'J':
-					if (!stackDescriptor.equals("Ljava/lang/Long")) {
-						mv.visitTypeInsn(CHECKCAST, "java/lang/Long");
+					if (!stackDescriptor.equals(BytecodeUtil.referenceName(Long.class))) {
+						mv.visitTypeInsn(CHECKCAST, Type.getInternalName(Long.class));
 					}
-					mv.visitMethodInsn(INVOKEVIRTUAL, "java/lang/Long", "longValue", "()J", false);
+					mv.visitMethodInsn(INVOKEVIRTUAL, Type.getInternalName(Long.class), "longValue", "()J", false);
 					break;
 				case 'S':
-					if (!stackDescriptor.equals("Ljava/lang/Short")) {
-						mv.visitTypeInsn(CHECKCAST, "java/lang/Short");
+					if (!stackDescriptor.equals(BytecodeUtil.referenceName(Short.class))) {
+						mv.visitTypeInsn(CHECKCAST, Type.getInternalName(Short.class));
 					}
-					mv.visitMethodInsn(INVOKEVIRTUAL, "java/lang/Short", "shortValue", "()S", false);
+					mv.visitMethodInsn(INVOKEVIRTUAL, Type.getInternalName(Short.class), "shortValue", "()S", false);
 					break;
 				default:
 					throw new IllegalArgumentException("Unboxing should not be attempted for descriptor '" + ch + "'");

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

@@ -16,7 +16,7 @@
 
 package org.springframework.data.mapping.model;
 
-import org.springframework.data.mapping.PreferredConstructor.Parameter;
+import org.springframework.data.mapping.Parameter;
 import org.springframework.expression.EvaluationContext;
 import org.springframework.expression.spel.standard.SpelExpressionParser;
 import org.springframework.lang.Nullable;

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

@@ -0,0 +1,161 @@
+/*
+ * Copyright 2021 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
+ *
+ *      https://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.mapping.model;
+
+import java.lang.annotation.Annotation;
+import java.lang.reflect.AnnotatedElement;
+import java.lang.reflect.Method;
+import java.lang.reflect.Modifier;
+import java.util.ArrayList;
+import java.util.List;
+
+import org.springframework.core.DefaultParameterNameDiscoverer;
+import org.springframework.core.ParameterNameDiscoverer;
+import org.springframework.core.annotation.MergedAnnotations;
+import org.springframework.data.annotation.EntityCreatorAnnotation;
+import org.springframework.data.mapping.EntityCreatorMetadata;
+import org.springframework.data.mapping.FactoryMethod;
+import org.springframework.data.mapping.MappingException;
+import org.springframework.data.mapping.Parameter;
+import org.springframework.data.mapping.PersistentEntity;
+import org.springframework.data.mapping.PersistentProperty;
+import org.springframework.lang.Nullable;
+
+/**
+ * Discoverer for factory methods and persistence constructors.
+ *
+ * @author Mark Paluch
+ * @since 3.0
+ */
+class EntityCreatorMetadataDiscoverer {
+
+	private static final ParameterNameDiscoverer PARAMETER_NAME_DISCOVERER = new DefaultParameterNameDiscoverer();
+
+	/**
+	 * Discover an entity creator
+	 *
+	 * @param entity
+	 * @param <T>
+	 * @param <P>
+	 * @return
+	 */
+	@Nullable
+	public static <T, P extends PersistentProperty<P>> EntityCreatorMetadata<P> discover(PersistentEntity<T, P> entity) {
+
+		var declaredConstructors = entity.getType().getDeclaredConstructors();
+		var declaredMethods = entity.getType().getDeclaredMethods();
+
+		var hasAnnotatedFactoryMethod = findAnnotation(EntityCreatorAnnotation.class, declaredMethods);
+		var hasAnnotatedConstructor = findAnnotation(EntityCreatorAnnotation.class, declaredConstructors);
+
+		if (hasAnnotatedConstructor && hasAnnotatedFactoryMethod) {
+			throw new MappingException(
+					"Invalid usage of @Factory and @PersistenceConstructor on %s. Only one annotation type permitted to indicate how entity instances should be created."
+							.formatted(entity.getType().getName()));
+		}
+
+		if (hasAnnotatedFactoryMethod) {
+
+			var candidates = discoverFactoryMethods(entity, declaredMethods);
+
+			if (candidates.size() == 1) {
+				return getFactoryMethod(entity, candidates.get(0));
+			}
+		}
+
+		return PreferredConstructorDiscoverer.discover(entity);
+	}
+
+	private static <T, P extends PersistentProperty<P>> List<Method> discoverFactoryMethods(PersistentEntity<T, P> entity,
+			Method[] declaredMethods) {
+
+		List<Method> candidates = new ArrayList<>();
+
+		for (var method : declaredMethods) {
+
+			validateMethod(method);
+
+			if (!isFactoryMethod(method, entity.getType())) {
+				continue;
+			}
+
+			if (findAnnotation(EntityCreatorAnnotation.class, method)) {
+				candidates.add(method);
+			}
+		}
+
+		return candidates;
+	}
+
+	@SuppressWarnings({ "unchecked", "rawtypes" })
+	private static <T, P extends PersistentProperty<P>> FactoryMethod<Object, P> getFactoryMethod(
+			PersistentEntity<T, P> entity, Method method) {
+
+		Parameter<Object, P>[] parameters = new Parameter[method.getParameterCount()];
+		var parameterAnnotations = method.getParameterAnnotations();
+		var types = entity.getTypeInformation().getParameterTypes(method);
+
+		var parameterNames = PARAMETER_NAME_DISCOVERER.getParameterNames(method);
+
+		for (var i = 0; i < parameters.length; i++) {
+
+			var name = parameterNames == null || parameterNames.length <= i ? null : parameterNames[i];
+			var type = types.get(i);
+			var annotations = parameterAnnotations[i];
+
+			parameters[i] = new Parameter(name, type, annotations, entity);
+		}
+
+		return new FactoryMethod<>(method, parameters);
+	}
+
+	private static void validateMethod(Method method) {
+
+		if (MergedAnnotations.from(method).isPresent(EntityCreatorAnnotation.class)) {
+
+			if (!Modifier.isStatic(method.getModifiers())) {
+				throw new MappingException(
+						"@Factory can only be used on static methods. Offending method: %s".formatted(method));
+			}
+		}
+	}
+
+	private static <T> boolean isFactoryMethod(Method method, Class<T> type) {
+
+		// private methods not supported
+		if (Modifier.isPrivate(method.getModifiers())) {
+			return false;
+		}
+
+		// synthetic methods not supported
+		if (method.isSynthetic()) {
+			return false;
+		}
+
+		return Modifier.isStatic(method.getModifiers()) && method.getReturnType().isAssignableFrom(type);
+	}
+
+	private static boolean findAnnotation(Class<? extends Annotation> annotationType, AnnotatedElement... elements) {
+
+		for (var element : elements) {
+			if (MergedAnnotations.from(element).isPresent(annotationType)) {
+				return true;
+			}
+		}
+
+		return false;
+	}
+}

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

@@ -19,9 +19,9 @@ import java.util.function.Function;
 
 import org.springframework.core.KotlinDetector;
 import org.springframework.data.annotation.PersistenceConstructor;
+import org.springframework.data.mapping.Parameter;
 import org.springframework.data.mapping.PersistentProperty;
 import org.springframework.data.mapping.PersistentPropertyAccessor;
-import org.springframework.data.mapping.PreferredConstructor.Parameter;
 import org.springframework.lang.Nullable;
 import org.springframework.util.Assert;
 
@@ -81,22 +81,22 @@ public class InstantiationAwarePropertyAccessor<T> implements PersistentProperty
 			return;
 		}
 
-		var constructor = owner.getPersistenceConstructor();
+		var creator = owner.getEntityCreator();
 
-		if (constructor == null) {
+		if (creator == null) {
 			throw new IllegalStateException(String.format(NO_SETTER_OR_CONSTRUCTOR, property.getName(), owner.getType()));
 		}
 
-		if (!constructor.isConstructorParameter(property)) {
+		if (!creator.isCreatorParameter(property)) {
 			throw new IllegalStateException(
-					String.format(NO_CONSTRUCTOR_PARAMETER, property.getName(), constructor.getConstructor()));
+					String.format(NO_CONSTRUCTOR_PARAMETER, property.getName(), creator));
 		}
 
-		constructor.getParameters().forEach(it -> {
+		creator.getParameters().forEach(it -> {
 
 			if (it.getName() == null) {
 				throw new IllegalStateException(
-						String.format("Cannot detect parameter names of copy constructor of %s!", owner.getType()));
+						String.format("Cannot detect parameter names of copy creator of %s!", owner.getType()));
 			}
 		});
 

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

@@ -24,10 +24,11 @@ import java.util.Arrays;
 import java.util.List;
 import java.util.stream.IntStream;
 
+import org.springframework.data.mapping.EntityCreatorMetadata;
+import org.springframework.data.mapping.Parameter;
 import org.springframework.data.mapping.PersistentEntity;
 import org.springframework.data.mapping.PersistentProperty;
 import org.springframework.data.mapping.PreferredConstructor;
-import org.springframework.data.mapping.PreferredConstructor.Parameter;
 import org.springframework.data.util.KotlinReflectionUtils;
 import org.springframework.data.util.ReflectionUtils;
 import org.springframework.lang.Nullable;
@@ -45,9 +46,10 @@ class KotlinClassGeneratingEntityInstantiator extends ClassGeneratingEntityInsta
 	@Override
 	protected EntityInstantiator doCreateEntityInstantiator(PersistentEntity<?, ?> entity) {
 
-		var constructor = entity.getPersistenceConstructor();
+		var creator = entity.getEntityCreator();
 
-		if (KotlinReflectionUtils.isSupportedKotlinClass(entity.getType()) && constructor != null) {
+		if (KotlinReflectionUtils.isSupportedKotlinClass(entity.getType())
+				&& creator instanceof PreferredConstructor<?, ?> constructor) {
 
 			var defaultConstructor = new DefaultingKotlinConstructorResolver(entity)
 					.getDefaultConstructor();
@@ -78,9 +80,9 @@ class KotlinClassGeneratingEntityInstantiator extends ClassGeneratingEntityInsta
 		DefaultingKotlinConstructorResolver(PersistentEntity<?, ?> entity) {
 
 			var hit = resolveDefaultConstructor(entity);
-			var persistenceConstructor = entity.getPersistenceConstructor();
+			var creator = entity.getEntityCreator();
 
-			if (hit != null && persistenceConstructor != null) {
+			if (hit != null && creator instanceof PreferredConstructor<?, ?> persistenceConstructor) {
 				this.defaultConstructor = new PreferredConstructor<>(hit,
 						persistenceConstructor.getParameters().toArray(new Parameter[0]));
 			} else {
@@ -91,9 +93,7 @@ class KotlinClassGeneratingEntityInstantiator extends ClassGeneratingEntityInsta
 		@Nullable
 		private static Constructor<?> resolveDefaultConstructor(PersistentEntity<?, ?> entity) {
 
-			var persistenceConstructor = entity.getPersistenceConstructor();
-
-			if (persistenceConstructor == null) {
+			if (!(entity.getEntityCreator()instanceof PreferredConstructor<?, ?> persistenceConstructor)) {
 				return null;
 			}
 
@@ -191,7 +191,7 @@ class KotlinClassGeneratingEntityInstantiator extends ClassGeneratingEntityInsta
 		public <T, E extends PersistentEntity<? extends T, P>, P extends PersistentProperty<P>> T createInstance(E entity,
 				ParameterValueProvider<P> provider) {
 
-			var params = extractInvocationArguments(entity.getPersistenceConstructor(), provider);
+			var params = extractInvocationArguments(entity.getEntityCreator(), provider);
 
 			try {
 				return (T) instantiator.newInstance(params);
@@ -201,17 +201,17 @@ class KotlinClassGeneratingEntityInstantiator extends ClassGeneratingEntityInsta
 		}
 
 		private <P extends PersistentProperty<P>, T> Object[] extractInvocationArguments(
-				@Nullable PreferredConstructor<? extends T, P> preferredConstructor, ParameterValueProvider<P> provider) {
+				@Nullable EntityCreatorMetadata<P> entityCreator, ParameterValueProvider<P> provider) {
 
-			if (preferredConstructor == null) {
-				throw new IllegalArgumentException("PreferredConstructor must not be null!");
+			if (entityCreator == null) {
+				throw new IllegalArgumentException("EntityCreator must not be null!");
 			}
 
 			var params = allocateArguments(synthetic.getParameterCount()
 					+ KotlinDefaultMask.getMaskCount(synthetic.getParameterCount()) + /* DefaultConstructorMarker */1);
 			var userParameterCount = kParameters.size();
 
-			var parameters = preferredConstructor.getParameters();
+			var parameters = entityCreator.getParameters();
 
 			// Prepare user-space arguments
 			for (var i = 0; i < userParameterCount; i++) {

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

@@ -22,6 +22,8 @@ import java.util.ArrayList;
 import java.util.List;
 import java.util.Optional;
 
+import org.springframework.data.mapping.EntityCreatorMetadata;
+import org.springframework.data.mapping.FactoryMethod;
 import org.springframework.data.mapping.PersistentEntity;
 import org.springframework.data.mapping.PreferredConstructor;
 import org.springframework.data.util.KotlinReflectionUtils;
@@ -42,7 +44,7 @@ public class MappingInstantiationException extends RuntimeException {
 	private static final String TEXT_TEMPLATE = "Failed to instantiate %s using constructor %s with arguments %s";
 
 	private final Class<?> entityType;
-	private final Constructor<?> constructor;
+	private final EntityCreatorMetadata<?> entityCreator;
 	private final List<Object> constructorArguments;
 
 	/**
@@ -73,8 +75,7 @@ public class MappingInstantiationException extends RuntimeException {
 		super(buildExceptionMessage(entity, arguments, message), cause);
 
 		this.entityType = entity.map(PersistentEntity::getType).orElse(null);
-		this.constructor = entity.map(PersistentEntity::getPersistenceConstructor).map(PreferredConstructor::getConstructor)
-				.orElse(null);
+		this.entityCreator = entity.map(PersistentEntity::getEntityCreator).orElse(null);
 		this.constructorArguments = arguments;
 	}
 
@@ -83,7 +84,7 @@ public class MappingInstantiationException extends RuntimeException {
 
 		return entity.map(it -> {
 
-			Optional<? extends PreferredConstructor<?, ?>> constructor = Optional.ofNullable(it.getPersistenceConstructor());
+			Optional<? extends EntityCreatorMetadata<?>> constructor = Optional.ofNullable(it.getEntityCreator());
 			List<String> toStringArgs = new ArrayList<>(arguments.size());
 
 			for (var o : arguments) {
@@ -97,6 +98,19 @@ public class MappingInstantiationException extends RuntimeException {
 		}).orElse(defaultMessage);
 	}
 
+	private static String toString(EntityCreatorMetadata<?> creator) {
+
+		if (creator instanceof PreferredConstructor<?, ?> c) {
+			return toString(c);
+		}
+
+		if (creator instanceof FactoryMethod<?, ?> m) {
+			return toString(m);
+		}
+
+		return creator.toString();
+	}
+
 	private static String toString(PreferredConstructor<?, ?> preferredConstructor) {
 
 		var constructor = preferredConstructor.getConstructor();
@@ -113,6 +127,22 @@ public class MappingInstantiationException extends RuntimeException {
 		return constructor.toString();
 	}
 
+	private static String toString(FactoryMethod<?, ?> factoryMethod) {
+
+		var constructor = factoryMethod.getFactoryMethod();
+
+		if (KotlinReflectionUtils.isSupportedKotlinClass(constructor.getDeclaringClass())) {
+
+			var kotlinFunction = ReflectJvmMapping.getKotlinFunction(constructor);
+
+			if (kotlinFunction != null) {
+				return kotlinFunction.toString();
+			}
+		}
+
+		return constructor.toString();
+	}
+
 	/**
 	 * Returns the type of the entity that was attempted to instantiate.
 	 *
@@ -126,9 +156,22 @@ public class MappingInstantiationException extends RuntimeException {
 	 * The constructor used during the instantiation attempt.
 	 *
 	 * @return the constructor
+	 * @deprecated since 3.0, use {@link #getEntityCreator()} instead.
 	 */
+	@Deprecated
 	public Optional<Constructor<?>> getConstructor() {
-		return Optional.ofNullable(constructor);
+		return getEntityCreator().filter(PreferredConstructor.class::isInstance).map(PreferredConstructor.class::cast)
+				.map(PreferredConstructor::getConstructor);
+	}
+
+	/**
+	 * The entity creator used during the instantiation attempt.
+	 *
+	 * @return the entity creator
+	 * @since 3.0
+	 */
+	public Optional<EntityCreatorMetadata<?>> getEntityCreator() {
+		return Optional.ofNullable(entityCreator);
 	}
 
 	/**

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

@@ -15,8 +15,8 @@
  */
 package org.springframework.data.mapping.model;
 
+import org.springframework.data.mapping.Parameter;
 import org.springframework.data.mapping.PersistentProperty;
-import org.springframework.data.mapping.PreferredConstructor.Parameter;
 import org.springframework.lang.Nullable;
 
 /**

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

@@ -16,9 +16,9 @@
 package org.springframework.data.mapping.model;
 
 import org.springframework.data.mapping.MappingException;
+import org.springframework.data.mapping.Parameter;
 import org.springframework.data.mapping.PersistentEntity;
 import org.springframework.data.mapping.PersistentProperty;
-import org.springframework.data.mapping.PreferredConstructor.Parameter;
 import org.springframework.lang.Nullable;
 
 /**
@@ -47,10 +47,10 @@ public class PersistentEntityParameterValueProvider<P extends PersistentProperty
 	@SuppressWarnings("unchecked")
 	public <T> T getParameterValue(Parameter<T, P> parameter) {
 
-		var constructor = entity.getPersistenceConstructor();
+		var creator = entity.getEntityCreator();
 
-		if (constructor != null && constructor.isEnclosingClassParameter(parameter)) {
-			return (T) parent;
+		if (creator.isParentParameter(parameter)) {
+				return (T) parent;
 		}
 
 		var name = parameter.getName();

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

@@ -24,17 +24,14 @@ import java.util.ArrayList;
 import java.util.Arrays;
 import java.util.List;
 
-import javax.inject.Qualifier;
-
-import org.springframework.beans.factory.annotation.Value;
 import org.springframework.core.DefaultParameterNameDiscoverer;
 import org.springframework.core.ParameterNameDiscoverer;
 import org.springframework.core.annotation.AnnotationUtils;
-import org.springframework.data.annotation.PersistenceConstructor;
+import org.springframework.data.annotation.EntityCreatorAnnotation;
+import org.springframework.data.mapping.Parameter;
 import org.springframework.data.mapping.PersistentEntity;
 import org.springframework.data.mapping.PersistentProperty;
 import org.springframework.data.mapping.PreferredConstructor;
-import org.springframework.data.mapping.PreferredConstructor.Parameter;
 import org.springframework.data.util.ClassTypeInformation;
 import org.springframework.data.util.KotlinReflectionUtils;
 import org.springframework.data.util.TypeInformation;
@@ -114,7 +111,7 @@ public interface PreferredConstructorDiscoverer<T, P extends PersistentProperty<
 						continue;
 					}
 
-					if (AnnotationUtils.findAnnotation(candidate, PersistenceConstructor.class) != null) {
+					if (AnnotationUtils.findAnnotation(candidate, EntityCreatorAnnotation.class) != null) {
 						return buildPreferredConstructor(candidate, type, entity);
 					}
 
@@ -148,7 +145,10 @@ public interface PreferredConstructorDiscoverer<T, P extends PersistentProperty<
 
 				return Arrays.stream(rawOwningType.getDeclaredConstructors()) //
 						.filter(it -> !it.isSynthetic()) // Synthetic constructors should not be considered
-						.filter(it -> AnnotationUtils.findAnnotation(it, PersistenceConstructor.class) != null) // Explicitly defined constructor trumps
+						.filter(it -> AnnotationUtils.findAnnotation(it, EntityCreatorAnnotation.class) != null) // Explicitly
+																																																			// defined
+																																																			// constructor
+																																																			// trumps
 																																								// all
 						.map(it -> buildPreferredConstructor(it, type, entity)) //
 						.findFirst() //

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

@@ -22,10 +22,12 @@ import java.util.Collections;
 
 import org.springframework.beans.BeanInstantiationException;
 import org.springframework.beans.BeanUtils;
+import org.springframework.data.mapping.FactoryMethod;
+import org.springframework.data.mapping.Parameter;
 import org.springframework.data.mapping.PersistentEntity;
 import org.springframework.data.mapping.PersistentProperty;
 import org.springframework.data.mapping.PreferredConstructor;
-import org.springframework.data.mapping.PreferredConstructor.Parameter;
+import org.springframework.util.ReflectionUtils;
 
 /**
  * {@link EntityInstantiator} that uses the {@link PersistentEntity}'s {@link PreferredConstructor} to instantiate an
@@ -44,39 +46,58 @@ enum ReflectionEntityInstantiator implements EntityInstantiator {
 	public <T, E extends PersistentEntity<? extends T, P>, P extends PersistentProperty<P>> T createInstance(E entity,
 			ParameterValueProvider<P> provider) {
 
-		var constructor = entity.getPersistenceConstructor();
+		var creator = entity.getEntityCreator();
 
-		if (constructor == null) {
-
-			try {
-				Class<?> clazz = entity.getType();
-				if (clazz.isArray()) {
-					var ctype = clazz;
-					var dims = 0;
-					while (ctype.isArray()) {
-						ctype = ctype.getComponentType();
-						dims++;
-					}
-					return (T) Array.newInstance(clazz, dims);
-				} else {
-					return BeanUtils.instantiateClass(entity.getType());
-				}
-			} catch (BeanInstantiationException e) {
-				throw new MappingInstantiationException(entity, Collections.emptyList(), e);
-			}
+		if (creator == null) {
+			return instantiateClass(entity);
 		}
-		var parameterCount = constructor.getConstructor().getParameterCount();
+		var parameterCount = creator.getParameterCount();
 
 		var params = parameterCount == 0 ? EMPTY_ARGS : new Object[parameterCount];
 		var i = 0;
-		for (Parameter<?, P> parameter : constructor.getParameters()) {
+		for (Parameter<?, P> parameter : creator.getParameters()) {
 			params[i++] = provider.getParameterValue(parameter);
 		}
 
+		if (creator instanceof FactoryMethod method) {
+
+			try {
+				var t = (T) ReflectionUtils.invokeMethod(method.getFactoryMethod(), null, params);
+
+				if (t == null) {
+					throw new IllegalStateException("Method %s returned null!".formatted(method.getFactoryMethod()));
+				}
+				return t;
+			} catch (Exception e) {
+				throw new MappingInstantiationException(entity, new ArrayList<>(Arrays.asList(params)), e);
+			}
+		}
+
 		try {
-			return BeanUtils.instantiateClass(constructor.getConstructor(), params);
+			return BeanUtils.instantiateClass(((PreferredConstructor<T, ?>) creator).getConstructor(), params);
 		} catch (BeanInstantiationException e) {
 			throw new MappingInstantiationException(entity, new ArrayList<>(Arrays.asList(params)), e);
 		}
 	}
+
+	private <T, E extends PersistentEntity<? extends T, P>, P extends PersistentProperty<P>> T instantiateClass(
+			E entity) {
+
+		try {
+			Class<?> clazz = entity.getType();
+			if (clazz.isArray()) {
+				var ctype = clazz;
+				var dims = 0;
+				while (ctype.isArray()) {
+					ctype = ctype.getComponentType();
+					dims++;
+				}
+				return (T) Array.newInstance(clazz, dims);
+			} else {
+				return BeanUtils.instantiateClass(entity.getType());
+			}
+		} catch (BeanInstantiationException e) {
+			throw new MappingInstantiationException(entity, Collections.emptyList(), e);
+		}
+	}
 }

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

@@ -16,8 +16,8 @@
 package org.springframework.data.mapping.model;
 
 import org.springframework.core.convert.ConversionService;
+import org.springframework.data.mapping.Parameter;
 import org.springframework.data.mapping.PersistentProperty;
-import org.springframework.data.mapping.PreferredConstructor.Parameter;
 import org.springframework.lang.Nullable;
 
 /**