Many-To-Many relationship between Implementations and Algorithms

org.planqk.atlas.core/src/main/java/org/planqk/atlas/core/model/Algorithm.java

@@ -149,10 +149,10 @@ public class Algorithm extends KnowledgeArtifact {
     @NotAudited
     private Set<Tag> tags = new HashSet<>();
 
-    @OneToMany(mappedBy = "implementedAlgorithm",
-               fetch = FetchType.LAZY,
-               cascade = CascadeType.ALL,
-               orphanRemoval = true)
+    @ManyToMany(cascade = {CascadeType.PERSIST, CascadeType.MERGE})
+    @JoinTable(name = "algorithm_implementation",
+            joinColumns = @JoinColumn(name = "algorithm_id"),
+            inverseJoinColumns = @JoinColumn(name = "implementation_id"))
     @EqualsAndHashCode.Exclude
     @ToString.Exclude
     @NotAudited
@@ -297,4 +297,20 @@ public void removeLearningMethod(@NonNull LearningMethod learningMethod) {
         learningMethods.remove(learningMethod);
         learningMethod.getAlgorithms().remove(this);
     }
+
+    public void addImplementation(@NonNull Implementation implementation) {
+        if (implementations.contains(implementation)) {
+            return;
+        }
+        implementations.add(implementation);
+        implementation.getImplementedAlgorithms().add(this);
+    }
+
+    public void removeImplementation(@NonNull Implementation implementation) {
+        if (!implementations.contains(implementation)) {
+            return;
+        }
+        implementations.remove(implementation);
+        implementation.getImplementedAlgorithms().remove(this);
+    }
 }

org.planqk.atlas.core/src/main/java/org/planqk/atlas/core/model/Implementation.java

@@ -27,7 +27,6 @@
 import javax.persistence.JoinColumn;
 import javax.persistence.JoinTable;
 import javax.persistence.ManyToMany;
-import javax.persistence.ManyToOne;
 import javax.persistence.OneToMany;
 
 import org.hibernate.envers.AuditTable;
@@ -89,10 +88,11 @@ public class Implementation extends KnowledgeArtifact {
     @NotAudited
     private Set<Publication> publications = new HashSet<>();
 
-    @ManyToOne
+    @ManyToMany(mappedBy = "implementations", cascade = {CascadeType.PERSIST, CascadeType.MERGE})
     @EqualsAndHashCode.Exclude
     @ToString.Exclude
-    private Algorithm implementedAlgorithm;
+    @NotAudited
+    private Set<Algorithm> implementedAlgorithms = new HashSet<>();
 
     @ManyToMany(cascade = {CascadeType.PERSIST, CascadeType.MERGE})
     @JoinTable(name = "implementation_tag",
@@ -192,4 +192,20 @@ public void removeImplementationPackage(@NonNull ImplementationPackage implement
         this.implementationPackages.remove(implementationPackage);
         implementationPackage.setImplementation(null);
     }
+
+    public void addAlgorithm(@NonNull Algorithm algorithm) {
+        if (implementedAlgorithms.contains(algorithm)) {
+            return;
+        }
+        implementedAlgorithms.add(algorithm);
+        algorithm.getImplementations().add(this);
+    }
+
+    public void removeAlgorithm(@NonNull Algorithm algorithm) {
+        if (!implementedAlgorithms.contains(algorithm)) {
+            return;
+        }
+        implementedAlgorithms.remove(algorithm);
+        algorithm.getImplementations().remove(this);
+    }
 }

org.planqk.atlas.core/src/main/java/org/planqk/atlas/core/repository/ImplementationRepository.java

@@ -39,7 +39,11 @@
 @RepositoryRestResource(exported = false)
 public interface ImplementationRepository extends RevisionRepository<Implementation, UUID, Integer>, JpaRepository<Implementation, UUID> {
 
-    Page<Implementation> findByImplementedAlgorithmId(UUID implementedAlgorithmId, Pageable pageable);
+    @Query("SELECT impl " +
+                   "FROM Implementation impl " +
+                   "JOIN impl.implementedAlgorithms alg " +
+                   "WHERE  alg.id = :algId")
+    Page<Implementation> findByImplementedAlgorithmId(@Param("algId") UUID implementedAlgorithmId, Pageable pageable);
 
     @Query("SELECT impl " +
                    "FROM Implementation impl " +

org.planqk.atlas.core/src/main/java/org/planqk/atlas/core/services/AlgorithmServiceImpl.java

@@ -26,8 +26,8 @@
 import org.planqk.atlas.core.model.Algorithm;
 import org.planqk.atlas.core.model.AlgorithmRelation;
 import org.planqk.atlas.core.model.ApplicationArea;
-import org.planqk.atlas.core.model.LearningMethod;
 import org.planqk.atlas.core.model.ClassicAlgorithm;
+import org.planqk.atlas.core.model.LearningMethod;
 import org.planqk.atlas.core.model.PatternRelation;
 import org.planqk.atlas.core.model.ProblemType;
 import org.planqk.atlas.core.model.Publication;
@@ -184,9 +184,14 @@ private void removeRevisions(@NonNull Algorithm algorithm) {
     }
 
     private void removeReferences(@NonNull Algorithm algorithm) {
-        // delete related implementations
-        algorithm.getImplementations().forEach(
-                implementation -> implementationService.delete(implementation.getId()));
+
+        // remove links to implementations and remove orphans
+        CollectionUtils.forEachOnCopy(algorithm.getImplementations(),
+                implementation -> { implementation.removeAlgorithm(algorithm);
+                if (implementation.getImplementedAlgorithms().size() == 0) {
+                    implementationService.delete(implementation.getId());
+                }
+        });
 
         // delete compute resource property
         algorithm.getRequiredComputeResourceProperties().forEach(computeResourcePropertyRepository::delete);

org.planqk.atlas.core/src/main/java/org/planqk/atlas/core/services/ImplementationServiceImpl.java

@@ -20,10 +20,13 @@
 package org.planqk.atlas.core.services;
 
 import java.util.NoSuchElementException;
+import java.util.Set;
 import java.util.UUID;
+import java.util.stream.Collectors;
 
 import org.planqk.atlas.core.model.Algorithm;
 import org.planqk.atlas.core.model.ClassicImplementation;
+import org.planqk.atlas.core.model.HasId;
 import org.planqk.atlas.core.model.Implementation;
 import org.planqk.atlas.core.model.Publication;
 import org.planqk.atlas.core.model.QuantumImplementation;
@@ -71,10 +74,8 @@ public class ImplementationServiceImpl implements ImplementationService {
     @Transactional
     public Implementation create(@NonNull Implementation implementation, @NonNull UUID implementedAlgorithmId) {
         final Algorithm implementedAlgorithm = ServiceUtils.findById(implementedAlgorithmId, Algorithm.class, algorithmRepository);
-        implementation.setImplementedAlgorithm(implementedAlgorithm);
-        final Implementation savedImplementation = implementationRepository.save(implementation);
-        implementedAlgorithm.getImplementations().add(savedImplementation);
-        return savedImplementation;
+        implementation.addAlgorithm(implementedAlgorithm);
+        return implementationRepository.save(implementation);
     }
 
     @Override
@@ -166,8 +167,9 @@ private void removeRevisions(@NonNull Implementation implementation) {
     }
 
     private void removeReferences(@NonNull Implementation implementation) {
-        // Remove reference from algorithm
-        implementation.setImplementedAlgorithm(null);
+        // Remove references from algorithms
+        CollectionUtils.forEachOnCopy(implementation.getImplementedAlgorithms(),
+                algorithm -> algorithm.removeImplementation(implementation));
 
         // Delete compute resource property
         implementation.getRequiredComputeResourceProperties().forEach(computeResourcePropertyRepository::delete);
@@ -183,9 +185,10 @@ private void removeReferences(@NonNull Implementation implementation) {
 
     @Override
     public void checkIfImplementationIsOfAlgorithm(@NonNull UUID implementationId, @NonNull UUID algorithmId) {
-        final Implementation implementation = findById(implementationId);
+        final Set<UUID> implementedAlgorithmUUIDs = findById(implementationId).getImplementedAlgorithms().stream().map(HasId::getId).collect(
+                Collectors.toSet());
 
-        if (!implementation.getImplementedAlgorithm().getId().equals(algorithmId)) {
+        if (!implementedAlgorithmUUIDs.contains(algorithmId)) {
             throw new NoSuchElementException("Implementation with ID \"" + implementationId
                     + "\" of Algorithm with ID \"" + algorithmId + "\" does not exist");
         }

org.planqk.atlas.core/src/main/java/org/planqk/atlas/core/services/LinkingService.java

@@ -31,6 +31,40 @@
  */
 public interface LinkingService {
 
+    /**
+     * Links an existing {@link org.planqk.atlas.core.model.Algorithm} and an existing {@link
+     * org.planqk.atlas.core.model.Implementation}.
+     * <p>
+     * If either the {@link org.planqk.atlas.core.model.Algorithm} or the {@link org.planqk.atlas.core.model.Implementation}
+     * with given IDs could not be found a {@link java.util.NoSuchElementException} is thrown.
+     * <p>
+     * If both entities exist but they are already linked this method will throw an {@link
+     * org.planqk.atlas.core.exceptions.EntityReferenceConstraintViolationException}.
+     *
+     * @param implementationId The ID of the {@link org.planqk.atlas.core.model.Implementation} we want to link
+     * @param algorithmId   The ID of the {@link org.planqk.atlas.core.model.Algorithm} we want to link
+     */
+    @Transactional
+    void linkImplementationAndAlgorithm(UUID implementationId, UUID algorithmId);
+
+    /**
+     * Unlinks an existing {@link org.planqk.atlas.core.model.Algorithm} and an existing {@link
+     * org.planqk.atlas.core.model.Implementation}.
+     * If an {@link org.planqk.atlas.core.model.Implementation} has no reference to an other
+     * {@link org.planqk.atlas.core.model.Algorithm} after unlinking (orphaned), it will be completely deleted.
+     * <p>
+     * If either the {@link org.planqk.atlas.core.model.Algorithm} or the {@link org.planqk.atlas.core.model.Implementation}
+     * with given IDs could not be found a {@link java.util.NoSuchElementException} is thrown.
+     * <p>
+     * If both entities exist but they are already linked this method will throw an {@link
+     * org.planqk.atlas.core.exceptions.EntityReferenceConstraintViolationException}.
+     *
+     * @param implementationId The ID of the {@link org.planqk.atlas.core.model.Implementation} we want to link
+     * @param algorithmId   The ID of the {@link org.planqk.atlas.core.model.Algorithm} we want to link
+     */
+    @Transactional
+    void unlinkImplementationAndAlgorithm(UUID implementationId, UUID algorithmId);
+
     /**
      * Links an existing {@link org.planqk.atlas.core.model.Algorithm} and an existing {@link
      * org.planqk.atlas.core.model.Publication}.

org.planqk.atlas.core/src/main/java/org/planqk/atlas/core/services/LinkingServiceImpl.java

@@ -61,6 +61,38 @@ public class LinkingServiceImpl implements LinkingService {
 
     private final LearningMethodService learningMethodService;
 
+    @Override
+    @Transactional
+    public void linkImplementationAndAlgorithm(UUID implementationId, UUID algorithmId) {
+        final Algorithm algorithm = algorithmService.findById(algorithmId);
+        final Implementation implementation = implementationService.findById(implementationId);
+
+        if (algorithm.getImplementations().contains(implementation)) {
+            throw new EntityReferenceConstraintViolationException("Algorithm with ID \"" + algorithmId +
+                    "\" and Implementation with ID \"" + implementationId + "\" are already linked");
+        }
+
+        algorithm.addImplementation(implementation);
+    }
+
+    @Override
+    @Transactional
+    public void unlinkImplementationAndAlgorithm(UUID implementationId, UUID algorithmId) {
+        final Algorithm algorithm = algorithmService.findById(algorithmId);
+        final Implementation implementation = implementationService.findById(implementationId);
+
+        if (!algorithm.getImplementations().contains(implementation)) {
+            throw new EntityReferenceConstraintViolationException("Algorithm with ID \"" + algorithmId +
+                    "\" and Implementation with ID \"" + implementationId + "\" are not linked");
+        }
+
+        algorithm.removeImplementation(implementation);
+
+        if (implementation.getImplementedAlgorithms().size() == 0) {
+            implementationService.delete(implementationId);
+        }
+    }
+
     @Override
     @Transactional
     public void linkAlgorithmAndPublication(@NonNull UUID algorithmId, @NonNull UUID publicationId) {

org.planqk.atlas.core/src/test/java/org/planqk/atlas/core/services/AlgorithmServiceTest.java

@@ -289,7 +289,6 @@ void deleteAlgorithm_WithLinks() {
         // add Implementation
         Implementation implementation = new Implementation();
         implementation.setName("implementationName");
-        implementation.setImplementedAlgorithm(algorithm);
         implementationService.create(implementation, algorithm.getId());
 
         // add pattern Relation

org.planqk.atlas.core/src/test/java/org/planqk/atlas/core/services/ComputeResourcePropertyServiceTest.java

@@ -680,7 +680,6 @@ private QuantumImplementation getCreatedQuantumImplementation(String name) {
         QuantumImplementation implementation = new QuantumImplementation();
 
         implementation.setName(name);
-        implementation.setImplementedAlgorithm(algorithm);
 
         return (QuantumImplementation) implementationService.create(implementation, algorithm.getId());
     }