org.springframework.data.jpa.mapping.JpaMetamodelMappingContext.java Source code

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Here is the source code for org.springframework.data.jpa.mapping.JpaMetamodelMappingContext.java

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/*
 * Copyright 2012-2019 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.jpa.mapping;

import java.util.Set;
import java.util.function.Predicate;

import javax.persistence.metamodel.ManagedType;
import javax.persistence.metamodel.Metamodel;

import org.springframework.data.jpa.provider.PersistenceProvider;
import org.springframework.data.jpa.util.JpaMetamodel;
import org.springframework.data.mapping.PersistentPropertyPaths;
import org.springframework.data.mapping.context.AbstractMappingContext;
import org.springframework.data.mapping.context.MappingContext;
import org.springframework.data.mapping.model.Property;
import org.springframework.data.mapping.model.SimpleTypeHolder;
import org.springframework.data.util.TypeInformation;
import org.springframework.lang.Nullable;
import org.springframework.util.Assert;

/**
 * {@link MappingContext} implementation based on a Jpa {@link Metamodel}.
 *
 * @author Oliver Gierke
 * @author Christoph Strobl
 * @author Mark Paluch
 * @author David Madden
 * @since 1.3
 */
public class JpaMetamodelMappingContext
        extends AbstractMappingContext<JpaPersistentEntityImpl<?>, JpaPersistentProperty> {

    private final Metamodels models;
    private final PersistenceProvider persistenceProvider;

    /**
     * Creates a new JPA {@link Metamodel} based {@link MappingContext}.
     *
     * @param models must not be {@literal null} or empty.
     */
    public JpaMetamodelMappingContext(Set<Metamodel> models) {

        Assert.notNull(models, "JPA metamodel must not be null!");
        Assert.notEmpty(models, "JPA metamodel must not be empty!");

        this.models = new Metamodels(models);
        this.persistenceProvider = PersistenceProvider.fromMetamodel(models.iterator().next());
    }

    /*
     * (non-Javadoc)
     * @see org.springframework.data.mapping.context.AbstractMappingContext#createPersistentEntity(org.springframework.data.util.TypeInformation)
     */
    @Override
    protected <T> JpaPersistentEntityImpl<?> createPersistentEntity(TypeInformation<T> typeInformation) {
        return new JpaPersistentEntityImpl<T>(typeInformation, persistenceProvider,
                models.getMetamodel(typeInformation));
    }

    /*
     * (non-Javadoc)
     * @see org.springframework.data.mapping.context.AbstractMappingContext#createPersistentProperty(java.lang.reflect.Field, java.beans.PropertyDescriptor, org.springframework.data.mapping.model.MutablePersistentEntity, org.springframework.data.mapping.model.SimpleTypeHolder)
     */
    @Override
    protected JpaPersistentProperty createPersistentProperty(Property property, JpaPersistentEntityImpl<?> owner,
            SimpleTypeHolder simpleTypeHolder) {
        return new JpaPersistentPropertyImpl(owner.getMetamodel(), property, owner, simpleTypeHolder);
    }

    /*
     * (non-Javadoc)
     * @see org.springframework.data.mapping.context.AbstractMappingContext#shouldCreatePersistentEntityFor(org.springframework.data.util.TypeInformation)
     */
    @Override
    protected boolean shouldCreatePersistentEntityFor(TypeInformation<?> type) {
        return models.isMetamodelManagedType(type);
    }

    /**
     * We customize the lookup of {@link PersistentPropertyPaths} by also traversing properties that are embeddables.
     * 
     * @see org.springframework.data.mapping.context.AbstractMappingContext#findPersistentPropertyPaths(java.lang.Class,
     *      java.util.function.Predicate)
     */
    @Override
    public <T> PersistentPropertyPaths<T, JpaPersistentProperty> findPersistentPropertyPaths(Class<T> type,
            Predicate<? super JpaPersistentProperty> predicate) {
        return doFindPersistentPropertyPaths(type, predicate, it -> it.isEmbeddable());
    }

    /* 
     * (non-Javadoc)
     * @see org.springframework.data.mapping.context.AbstractMappingContext#hasPersistentEntityFor(java.lang.Class)
     */
    @Override
    public boolean hasPersistentEntityFor(Class<?> type) {
        return super.hasPersistentEntityFor(type) || models.isMetamodelManagedType(type);
    }

    /**
     * A wrapper for a set of JPA {@link Metamodel} instances to simplify lookups of {@link JpaMetamodel} instances and
     * managed type checks.
     *
     * @author Oliver Gierke
     */
    private static class Metamodels {

        private final Set<Metamodel> metamodels;

        private Metamodels(Set<Metamodel> metamodels) {
            this.metamodels = metamodels;
        }

        /**
         * Returns the {@link JpaMetamodel} for the given type.
         * 
         * @param type must not be {@literal null}.
         * @return
         */
        @Nullable
        public JpaMetamodel getMetamodel(TypeInformation<?> type) {

            Metamodel metamodel = getMetamodelFor(type.getType());

            return metamodel == null ? null : JpaMetamodel.of(metamodel);
        }

        /**
         * Returns whether the given type is managed by one of the underlying {@link Metamodel} instances.
         * 
         * @param type must not be {@literal null}.
         * @return
         */
        public boolean isMetamodelManagedType(TypeInformation<?> type) {
            return isMetamodelManagedType(type.getType());
        }

        /**
         * Returns whether the given type is managed by one of the underlying {@link Metamodel} instances.
         * 
         * @param type must not be {@literal null}.
         * @return
         */
        public boolean isMetamodelManagedType(Class<?> type) {
            return getMetamodelFor(type) != null;
        }

        /**
         * Returns the {@link Metamodel} aware of the given type.
         *
         * @param type must not be {@literal null}.
         * @return can be {@literal null}.
         */
        @Nullable
        private Metamodel getMetamodelFor(Class<?> type) {

            for (Metamodel model : metamodels) {

                try {
                    model.managedType(type);
                    return model;
                } catch (IllegalArgumentException o_O) {

                    // Fall back to inspect *all* managed types manually as Metamodel.managedType() only
                    // returns for entities, embeddables and managed supperclasses.

                    for (ManagedType<?> managedType : model.getManagedTypes()) {
                        if (type.equals(managedType.getJavaType())) {
                            return model;
                        }
                    }
                }
            }

            return null;
        }
    }
}