de.fraunhofer.iosb.ilt.faaast.registry.jpa.util.EntityManagerHelper Maven / Gradle / Ivy

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Relational database implementation of the FA³ST Registry.
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/*
 * Copyright (c) 2021 Fraunhofer IOSB, eine rechtlich nicht selbstaendige
 * Einrichtung der Fraunhofer-Gesellschaft zur Foerderung der angewandten
 * Forschung e.V.
 * 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 de.fraunhofer.iosb.ilt.faaast.registry.jpa.util;

import de.fraunhofer.iosb.ilt.faaast.registry.jpa.model.JpaAssetAdministrationShellDescriptor;
import de.fraunhofer.iosb.ilt.faaast.service.model.descriptor.AssetAdministrationShellDescriptor;
import jakarta.persistence.EntityManager;
import jakarta.persistence.criteria.CriteriaBuilder;
import jakarta.persistence.criteria.Predicate;
import java.util.ArrayList;
import java.util.List;
import java.util.stream.Collectors;
import org.eclipse.digitaltwin.aas4j.v3.model.AssetKind;


/**
 * Helper class for JPA objects.
 */
public class EntityManagerHelper {

    private EntityManagerHelper() {}


    /**
     * Fetches all instances of a given type from the entityManager.
     *
     * @param  the type to fetch
     * @param entityManager the entityManager to use
     * @param type the type to fetch
     * @return all instances of given type
     */
    public static  List getAll(EntityManager entityManager, Class type) {
        return getAll(entityManager, type, type);
    }


    /**
     * Fetches all instances of a given type from the entityManager as a list of a desired return type.
     *
     * @param  the return type
     * @param  the type to fetch
     * @param entityManager the entityManager to use
     * @param type the type to fetch
     * @param returnType the type to return
     * @return all instances of given type cast to return type
     */
    public static  List getAll(EntityManager entityManager, Class type, Class returnType) {
        CriteriaBuilder builder = entityManager.getCriteriaBuilder();
        var queryCriteria = builder.createQuery(type);
        queryCriteria.select(queryCriteria.from(type));
        var query = entityManager.createQuery(queryCriteria);
        return query.getResultList().stream()
                .map(returnType::cast)
                .collect(Collectors.toList());
    }


    /**
     * Fetches all instances of AssetAdministrationShellDescriptor, matching the given criteria.
     *
     * @param entityManager The entityManager to use.
     * @param assetType The desired assetType.
     * @param assetKind The desired assetKind.
     * @return All instances matching the given criteria.
     */
    public static List getAllAas(EntityManager entityManager, String assetType, AssetKind assetKind) {
        if ((assetKind == null) && (assetType == null)) {
            return getAll(entityManager, JpaAssetAdministrationShellDescriptor.class, AssetAdministrationShellDescriptor.class);
        }

        CriteriaBuilder builder = entityManager.getCriteriaBuilder();
        var queryCriteria = builder.createQuery(JpaAssetAdministrationShellDescriptor.class);
        var root = queryCriteria.from(JpaAssetAdministrationShellDescriptor.class);
        List predicates = new ArrayList<>();
        if (assetType != null) {
            predicates.add(builder.equal(root.get("assetType"), assetType));
        }
        if (assetKind != null) {
            predicates.add(builder.equal(root.get("assetKind"), assetKind));
        }
        queryCriteria.select(root).where(predicates.toArray(Predicate[]::new));
        var query = entityManager.createQuery(queryCriteria);
        return query.getResultList().stream()
                .map(AssetAdministrationShellDescriptor.class::cast)
                .toList();
    }
}