Check if system can be created or deleted

src/main/java/cz/cvut/kbss/analysis/controller/SystemController.java

@@ -60,8 +60,7 @@ public Set<FailureMode> getFailureModes(@PathVariable(name = "systemFragment") S
     @PostMapping(consumes = {MediaType.APPLICATION_JSON_VALUE, JsonLd.MEDIA_TYPE})
     public System create(@RequestBody System system) {
         log.info("> create - {}", system);
-        repositoryService.persist(system);
-        return system;
+        return repositoryService.create(system);
     }
 
     @PutMapping(consumes = {MediaType.APPLICATION_JSON_VALUE, JsonLd.MEDIA_TYPE})

src/main/java/cz/cvut/kbss/analysis/dao/NamedEntityDao.java

@@ -39,4 +39,22 @@ public List<T> findAllSummaries(){
         }
     }
 
+    public List<URI> findUriByName(String name){
+        try {
+            return em.createNativeQuery("""
+                                    SELECT ?x WHERE {
+                                        ?x a ?type ; ?hasName ?val .
+                                        FILTER(str(?val) = ?name)
+                                    }
+                                    """,
+                            URI.class)
+                    .setParameter("type", typeUri)
+                    .setParameter("hasName", URI.create(Vocabulary.s_p_name))
+                    .setParameter("name", name)
+                    .getResultList();
+        } catch (RuntimeException e) {
+            throw new PersistenceException(e);
+        }
+    }
+
 }

src/main/java/cz/cvut/kbss/analysis/dao/SystemDao.java

@@ -1,6 +1,7 @@
 package cz.cvut.kbss.analysis.dao;
 
 import cz.cvut.kbss.analysis.config.conf.PersistenceConf;
+import cz.cvut.kbss.analysis.exception.PersistenceException;
 import cz.cvut.kbss.analysis.model.Component;
 import cz.cvut.kbss.analysis.model.System;
 import cz.cvut.kbss.analysis.service.IdentifierService;
@@ -48,4 +49,28 @@ public List<Component> findComponents(URI systemURI){
                 .setParameter("hasComponentPartProp", HAS_COMPONENT_PART)
                 .getResultList();
     }
+
+    public List<URI> findSystemsFaultTrees(URI uri){
+        try {
+            return em.createNativeQuery("""
+                                    PREFIX fta: <http://onto.fel.cvut.cz/ontologies/fta-fmea-application/>
+
+                                    SELECT DISTINCT ?ftUri WHERE {
+                                        ?uri a ?type.
+                                        ?_subsystemUri fta:is-part-of* ?uri.
+                                        ?behavior fta:has-component ?_subsystemUri.
+                                        ?rootEventType fta:is-manifestation-of ?behavior .
+                                        ?rootEvent fta:is-derived-from ?rootEventType.
+                                        ?ftUri fta:is-manifested-by ?rootEvent .
+                                        ?ftUri a fta:fault-tree.
+                                    }
+                                    """,
+                            URI.class)
+                    .setParameter("uri", uri)
+                    .setParameter("type", typeUri)
+                    .getResultList();
+        } catch (RuntimeException e) {
+            throw new PersistenceException(e);
+        }
+    }
 }

src/main/java/cz/cvut/kbss/analysis/service/SystemRepositoryService.java

@@ -4,13 +4,15 @@
 import cz.cvut.kbss.analysis.dao.GenericDao;
 import cz.cvut.kbss.analysis.dao.SystemDao;
 import cz.cvut.kbss.analysis.dao.UserDao;
+import cz.cvut.kbss.analysis.exception.LogicViolationException;
 import cz.cvut.kbss.analysis.model.Component;
 import cz.cvut.kbss.analysis.model.FailureMode;
 import cz.cvut.kbss.analysis.model.Item;
 import cz.cvut.kbss.analysis.model.System;
 import cz.cvut.kbss.analysis.model.opdata.OperationalDataFilter;
 import cz.cvut.kbss.analysis.service.security.SecurityUtils;
 import cz.cvut.kbss.analysis.util.Vocabulary;
+import lombok.NonNull;
 import lombok.extern.slf4j.Slf4j;
 import org.springframework.beans.factory.annotation.Autowired;
 import org.springframework.beans.factory.annotation.Qualifier;
@@ -65,6 +67,32 @@ public System findRequired(URI id) {
         return system;
     }
 
+    @Transactional
+    public System create(System system){
+        List<URI> existingSystems = systemDao.findUriByName(system.getName());
+        if(!existingSystems.isEmpty())
+            throw new LogicViolationException((
+                    "Cannot create system with name \"%s\", " +
+                            "the name is already assigned by other system.")
+                    .formatted(system.getName()));
+        this.persist(system);
+        return system;
+    }
+
+    @Override
+    public void remove(@NonNull URI instanceUri) {
+        System system = findAllSummary(instanceUri);
+        List<URI> faultTrees = systemDao.findSystemsFaultTrees(instanceUri);
+        if(!faultTrees.isEmpty()) {
+
+            throw new LogicViolationException((
+                    "Cannot delete system \"%s\" (<%s>), " +
+                            "the system has fault %d trees.")
+                    .formatted(system.getName(), instanceUri, faultTrees.size()));
+        }
+        super.remove(instanceUri);
+    }
+
     @Transactional
     public System rename(System systemRename) {
         log.info("> rename - {}", systemRename);