HHH-16633 correct handling of null values in criteria-based @Find methods

tooling/metamodel-generator/src/main/java/org/hibernate/jpamodelgen/annotation/AnnotationMetaEntity.java

@@ -479,6 +479,9 @@ public class AnnotationMetaEntity extends AnnotationMeta {
 		}
 	}
 
+	/**
+	 * Create a finder method which returns multiple results.
+	 */
 	private void createCriteriaFinder(
 			ExecutableElement method, TypeMirror returnType, @Nullable TypeElement containerType, TypeElement entity) {
 		final String methodName = method.getSimpleName().toString();
@@ -496,6 +499,7 @@ public class AnnotationMetaEntity extends AnnotationMeta {
 						containerType == null ? null : containerType.toString(),
 						paramNames,
 						paramTypes,
+						false,
 						dao,
 						sessionType,
 						enabledFetchProfiles( method )
@@ -550,6 +554,7 @@ public class AnnotationMetaEntity extends AnnotationMeta {
 							null,
 							paramNames,
 							paramTypes,
+							false,
 							dao,
 							sessionType,
 							enabledFetchProfiles( method )
@@ -607,6 +612,7 @@ public class AnnotationMetaEntity extends AnnotationMeta {
 									null,
 									List.of( parameter.getSimpleName().toString() ),
 									List.of( parameter.asType().toString() ),
+									fieldType == FieldType.ID,
 									dao,
 									sessionType,
 									enabledFetchProfiles( method )

tooling/metamodel-generator/src/main/java/org/hibernate/jpamodelgen/annotation/CriteriaFinderMethod.java

@@ -11,6 +11,7 @@ import org.hibernate.jpamodelgen.model.Metamodel;
 import org.hibernate.jpamodelgen.util.Constants;
 
 import java.util.List;
+import java.util.Set;
 
 /**
  * @author Gavin King
@@ -18,18 +19,21 @@ import java.util.List;
 public class CriteriaFinderMethod extends AbstractFinderMethod {
 
 	private final @Nullable String containerType;
+	private final boolean isId;
 
 	public CriteriaFinderMethod(
 			Metamodel annotationMetaEntity,
 			String methodName, String entity,
 			@Nullable String containerType,
 			List<String> paramNames, List<String> paramTypes,
+			boolean isId,
 			boolean belongsToDao,
 			String sessionType,
 			List<String> fetchProfiles) {
 		super( annotationMetaEntity, methodName, entity, belongsToDao, sessionType, fetchProfiles,
 				paramNames, paramTypes );
 		this.containerType = containerType;
+		this.isId = isId;
 	}
 
 	@Override
@@ -43,7 +47,14 @@ public class CriteriaFinderMethod extends AbstractFinderMethod {
 				.append(methodName);
 		parameters( declaration );
 		declaration
-				.append(" {")
+				.append(" {");
+		if ( isId ) {
+			declaration
+					.append("\n\tif (")
+					.append(paramNames.get(0))
+					.append(" == null) throw new IllegalArgumentException(\"Null identifier\");");
+		}
+		declaration
 				.append("\n\tvar builder = entityManager")
 				.append(usingEntityManager
 						? ".getEntityManagerFactory()"
@@ -62,11 +73,24 @@ public class CriteriaFinderMethod extends AbstractFinderMethod {
 						.append(", ");
 			}
 			final String paramName = paramNames.get(i);
+			final String paramType = paramTypes.get(i);
+			declaration
+					.append("\n\t\t\t");
+			if ( !isId && !isPrimitive( paramType ) ) { //TODO: check the entity to see if it's @Basic(optional=false)
+				declaration
+						.append(paramName)
+						.append("==null")
+						.append("\n\t\t\t\t? ")
+						.append("entity.get(");
+				attributeRef( declaration, paramName );
+				declaration
+						.append(").isNull()")
+						.append("\n\t\t\t\t: ");
+			}
+			declaration
+					.append("builder.equal(entity.get(");
+			attributeRef( declaration, paramName );
 			declaration
-					.append("\n\t\t\tbuilder.equal(entity.get(")
-					.append(annotationMetaEntity.importType(entity + '_'))
-					.append('.')
-					.append(paramName)
 					.append("), ")
 					//TODO: only safe if we are binding literals as parameters!!!
 					.append(paramName)
@@ -106,6 +130,20 @@ public class CriteriaFinderMethod extends AbstractFinderMethod {
 		return declaration.toString();
 	}
 
+	private static boolean isPrimitive(String paramType) {
+		return PRIMITIVE_TYPES.contains( paramType );
+	}
+
+	private static final Set<String> PRIMITIVE_TYPES =
+			Set.of("boolean", "char", "long", "int", "short", "byte", "double", "float");
+
+	private void attributeRef(StringBuilder declaration, String paramName) {
+		declaration
+				.append(annotationMetaEntity.importType(entity + '_'))
+				.append('.')
+				.append(paramName);
+	}
+
 	private StringBuilder returnType() {
 		StringBuilder type = new StringBuilder();
 		if ( containerType != null ) {