CARBON-161 add requestId to requestScope

elide-core/src/main/java/com/yahoo/elide/core/RequestScope.java

@@ -47,6 +47,7 @@
 import java.util.Map;
 import java.util.Optional;
 import java.util.Set;
+import java.util.UUID;
 import java.util.function.Function;
 
 import javax.ws.rs.core.MultivaluedHashMap;
@@ -77,6 +78,7 @@ public class RequestScope implements com.yahoo.elide.security.RequestScope {
     @Getter private final int updateStatusCode;
 
     @Getter private final MultipleFilterDialect filterDialect;
+    private String requestId;
     private final Map<String, FilterExpression> expressionsByType;
 
     private PublishSubject<CRUDEvent> lifecycleEvents;
@@ -126,6 +128,7 @@ public RequestScope(String path,
         this.newPersistentResources = new LinkedHashSet<>();
         this.dirtyResources = new LinkedHashSet<>();
         this.deletedResources = new LinkedHashSet<>();
+        this.requestId = UUID.randomUUID().toString();
 
         Function<RequestScope, PermissionExecutor> permissionExecutorGenerator = elideSettings.getPermissionExecutor();
         this.permissionExecutor = (permissionExecutorGenerator == null)
@@ -216,6 +219,7 @@ protected RequestScope(String path, JsonApiDocument jsonApiDocument, RequestScop
         this.lifecycleEvents = outerRequestScope.lifecycleEvents;
         this.distinctLifecycleEvents = outerRequestScope.distinctLifecycleEvents;
         this.queuedLifecycleEvents = outerRequestScope.queuedLifecycleEvents;
+        this.requestId = outerRequestScope.requestId;
     }
 
     @Override

elide-datastore/elide-datastore-hibernate/src/main/java/com/yahoo/elide/core/hibernate/hql/AbstractHQLQueryBuilder.java

@@ -52,6 +52,7 @@ public abstract class AbstractHQLQueryBuilder {
 
     protected static final boolean USE_ALIAS = true;
     protected static final boolean NO_ALIAS = false;
+    protected Set<String> alreadyJoined = new HashSet<>();
 
     /**
      * Represents a relationship between two entities.
@@ -118,14 +119,22 @@ protected void supplyFilterQueryParameters(Query query, Collection<FilterPredica
      * @return an HQL join clause
      */
     protected String getJoinClauseFromFilters(FilterExpression filterExpression) {
+        return getJoinClauseFromFilters(filterExpression, false);
+    }
+
+    /**
+     * Extracts all the HQL JOIN clauses from given filter expression.
+     * @param filterExpression the filter expression to extract a join clause from
+     * @param skipFetches JOIN but don't FETCH JOIN a relationship.
+     * @return an HQL join clause
+     */
+    protected String getJoinClauseFromFilters(FilterExpression filterExpression, boolean skipFetches) {
         PredicateExtractionVisitor visitor = new PredicateExtractionVisitor(new ArrayList<>());
         Collection<FilterPredicate> predicates = filterExpression.accept(visitor);
 
-        Set<String> alreadyJoined = new HashSet<>();
-
         return predicates.stream()
-            .map(predicate -> extractJoinClause(predicate, alreadyJoined))
-            .collect(Collectors.joining(SPACE));
+                .map(predicate -> extractJoinClause(predicate, skipFetches))
+                .collect(Collectors.joining(SPACE));
     }
 
     /**
@@ -143,10 +152,10 @@ protected void addPaginationToQuery(Query query) {
     /**
      * Extracts a join clause from a filter predicate (if it exists).
      * @param predicate The predicate to examine
-     * @param alreadyJoined A set of joins that have already been computed.
+     * @param skipFetches Don't fetch join
      * @return A HQL string representing the join
      */
-    private String extractJoinClause(FilterPredicate predicate, Set<String> alreadyJoined) {
+    private String extractJoinClause(FilterPredicate predicate, boolean skipFetches) {
         StringBuilder joinClause = new StringBuilder();
 
         String previousAlias = null;
@@ -163,18 +172,28 @@ private String extractJoinClause(FilterPredicate predicate, Set<String> alreadyJ
 
             String alias = typeAlias + UNDERSCORE + fieldName;
 
-            String joinFragment;
+            String joinKey;
 
             //This is the first path element
             if (previousAlias == null) {
-                joinFragment = LEFT + JOIN + typeAlias + PERIOD + fieldName + SPACE + alias + SPACE;
+                joinKey = typeAlias + PERIOD + fieldName;
             } else {
-                joinFragment = LEFT + JOIN + previousAlias + PERIOD + fieldName + SPACE + alias + SPACE;
+                joinKey = previousAlias + PERIOD + fieldName;
             }
 
-            if (!alreadyJoined.contains(joinFragment)) {
+            String fetch = "";
+            RelationshipType type = dictionary.getRelationshipType(pathElement.getType(), fieldName);
+
+            //This is a to-One relationship belonging to the collection being retrieved.
+            if (!skipFetches && type.isToOne() && !type.isComputed() && previousAlias == null) {
+                fetch = "FETCH ";
+
+            }
+            String joinFragment = LEFT + JOIN + fetch + joinKey + SPACE + alias + SPACE;
+
+            if (!alreadyJoined.contains(joinKey)) {
                 joinClause.append(joinFragment);
-                alreadyJoined.add(joinFragment);
+                alreadyJoined.add(joinKey);
             }
 
             previousAlias = alias;
@@ -203,10 +222,14 @@ protected String extractToOneMergeJoins(Class<?> entityClass, String alias,
                 if (skipRelation.apply(relationshipName)) {
                     continue;
                 }
+                String joinKey = alias + PERIOD + relationshipName;
+
+                if (alreadyJoined.contains(joinKey)) {
+                    continue;
+                }
+
                 joinString.append(" LEFT JOIN FETCH ");
-                joinString.append(alias);
-                joinString.append(PERIOD);
-                joinString.append(relationshipName);
+                joinString.append(joinKey);
                 joinString.append(SPACE);
             }
         }

elide-datastore/elide-datastore-hibernate/src/main/java/com/yahoo/elide/core/hibernate/hql/RootCollectionPageTotalsQueryBuilder.java

@@ -70,7 +70,7 @@ public Query build() {
             filterClause = new FilterTranslator().apply(filterExpression.get(), USE_ALIAS);
 
             //Build the JOIN clause
-            joinClause =  getJoinClauseFromFilters(filterExpression.get());
+            joinClause =  getJoinClauseFromFilters(filterExpression.get(), true);
 
         } else {
             predicates = new HashSet<>();

elide-datastore/elide-datastore-hibernate/src/main/java/com/yahoo/elide/core/hibernate/hql/SubCollectionPageTotalsQueryBuilder.java

@@ -102,7 +102,7 @@ public Query build() {
             FilterExpression joinedExpression = new AndFilterExpression(scoped, idExpression);
 
             //Build the JOIN clause from the filter predicate
-            joinClause = getJoinClauseFromFilters(joinedExpression);
+            joinClause = getJoinClauseFromFilters(joinedExpression, true);
 
             //Build the WHERE clause
             filterClause = new FilterTranslator().apply(joinedExpression, USE_ALIAS);

elide-datastore/elide-datastore-hibernate/src/test/java/com/yahoo/elide/datastores/hibernate/hql/SubCollectionFetchQueryBuilderTest.java

@@ -142,7 +142,7 @@ public void testSubCollectionFetchWithJoinFilter() {
 
         String expected = "SELECT example_Book FROM example.Author example_Author__fetch "
                 + "JOIN example_Author__fetch.books example_Book "
-                + "LEFT JOIN example_Book.publisher example_Book_publisher  LEFT JOIN FETCH example_Book.publisher  "
+                + "LEFT JOIN FETCH example_Book.publisher example_Book_publisher  "
                 + "WHERE example_Book_publisher.name IN (:books_publisher_name_XXX) AND example_Author__fetch=:example_Author__fetch ";
         String actual = query.getQueryText();
         actual = actual.replaceFirst(":publisher_name_\\w+_\\w+", ":books_publisher_name_XXX");
@@ -188,7 +188,7 @@ public void testSubCollectionFetchWithSortingAndFilters() {
 
         String expected = "SELECT example_Book FROM example.Author example_Author__fetch "
                 + "JOIN example_Author__fetch.books example_Book "
-                + "LEFT JOIN example_Book.publisher example_Book_publisher  LEFT JOIN FETCH example_Book.publisher  "
+                + "LEFT JOIN FETCH example_Book.publisher example_Book_publisher  "
                 + "WHERE example_Book_publisher.name IN (:publisher_name_XXX) AND example_Author__fetch=:example_Author__fetch  order by example_Book.title asc";
 
         String actual = query.getQueryText();