Utilize Metadata.isView in more places

core/trino-main/src/main/java/io/trino/execution/CommentTask.java

@@ -32,6 +32,7 @@
 
 import java.util.List;
 import java.util.Map;
+import java.util.Optional;
 
 import static com.google.common.util.concurrent.Futures.immediateVoidFuture;
 import static io.trino.metadata.MetadataUtil.createQualifiedObjectName;
@@ -116,7 +117,7 @@ private void commentOnTable(Comment statement, Session session)
     private void commentOnView(Comment statement, Session session)
     {
         QualifiedObjectName viewName = createQualifiedObjectName(session, statement, statement.getName());
-        if (metadata.getView(session, viewName).isEmpty()) {
+        if (!metadata.isView(session, viewName)) {
             String additionalInformation;
             if (metadata.getMaterializedView(session, viewName).isPresent()) {
                 additionalInformation = ", but a materialized view with that name exists. Setting comments on materialized views is unsupported.";
@@ -140,8 +141,9 @@ private void commentOnColumn(Comment statement, Session session)
                 .orElseThrow(() -> semanticException(MISSING_TABLE, statement, "Table must be specified"));
 
         QualifiedObjectName originalObjectName = createQualifiedObjectName(session, statement, prefix);
-        if (metadata.isView(session, originalObjectName)) {
-            ViewDefinition viewDefinition = metadata.getView(session, originalObjectName).get();
+        Optional<ViewDefinition> view = metadata.getView(session, originalObjectName);
+        if (view.isPresent()) {
+            ViewDefinition viewDefinition = view.get();
             ViewColumn viewColumn = findAndCheckViewColumn(statement, session, viewDefinition, originalObjectName);
             metadata.setViewColumnComment(session, originalObjectName, viewColumn.getName(), statement.getComment());
         }

core/trino-main/src/main/java/io/trino/execution/DropNotNullConstraintTask.java

@@ -71,7 +71,7 @@ public ListenableFuture<Void> execute(
             if (metadata.getMaterializedView(session, tableName).isPresent()) {
                 exceptionMessage += ", but a materialized view with that name exists.";
             }
-            else if (metadata.getView(session, tableName).isPresent()) {
+            else if (metadata.isView(session, tableName)) {
                 exceptionMessage += ", but a view with that name exists.";
             }
             if (!statement.isTableExists()) {

core/trino-main/src/main/java/io/trino/execution/SetColumnTypeTask.java

@@ -89,7 +89,7 @@ public ListenableFuture<Void> execute(
             if (metadata.getMaterializedView(session, qualifiedObjectName).isPresent()) {
                 exceptionMessage += ", but a materialized view with that name exists.";
             }
-            else if (metadata.getView(session, qualifiedObjectName).isPresent()) {
+            else if (metadata.isView(session, qualifiedObjectName)) {
                 exceptionMessage += ", but a view with that name exists.";
             }
             if (!statement.isTableExists()) {

core/trino-main/src/main/java/io/trino/execution/SetPropertiesTask.java

@@ -131,7 +131,7 @@ private void setMaterializedViewProperties(
     {
         if (plannerContext.getMetadata().getMaterializedView(session, materializedViewName).isEmpty()) {
             String additionalInformation;
-            if (plannerContext.getMetadata().getView(session, materializedViewName).isPresent()) {
+            if (plannerContext.getMetadata().isView(session, materializedViewName)) {
                 additionalInformation = ", but a view with that name exists.";
             }
             else if (plannerContext.getMetadata().getTableHandle(session, materializedViewName).isPresent()) {

core/trino-main/src/main/java/io/trino/execution/SetViewAuthorizationTask.java

@@ -65,7 +65,7 @@ public ListenableFuture<Void> execute(
         Session session = stateMachine.getSession();
         QualifiedObjectName viewName = createQualifiedObjectName(session, statement, statement.getSource());
         getRequiredCatalogHandle(metadata, session, statement, viewName.getCatalogName());
-        if (metadata.getView(session, viewName).isEmpty()) {
+        if (!metadata.isView(session, viewName)) {
             throw semanticException(TABLE_NOT_FOUND, statement, "View '%s' does not exist", viewName);
         }
 

core/trino-main/src/main/java/io/trino/metadata/MetadataManager.java

@@ -1340,9 +1340,9 @@ public List<QualifiedObjectName> listViews(Session session, QualifiedTablePrefix
 
         Optional<QualifiedObjectName> objectName = prefix.asQualifiedObjectName();
         if (objectName.isPresent()) {
-            return getView(session, objectName.get())
-                    .map(handle -> ImmutableList.of(objectName.get()))
-                    .orElseGet(ImmutableList::of);
+            return isView(session, objectName.get())
+                    ? ImmutableList.of(objectName.get())
+                    : ImmutableList.of();
         }
 
         Optional<CatalogMetadata> catalog = getOptionalCatalogMetadata(session, prefix.getCatalogName());