switch (form.crudMode) {
        case CrudMode.CREATE:
            return OptionalEntity.of(new User()).map(entity -> {
                entity.setId(Base64.getUrlEncoder().encodeToString(form.name.getBytes(Constants.CHARSET_UTF_8)));
                return entity;
            });
        case CrudMode.EDIT:
            if (form instanceof EditForm) {

 * methods of the delegate. For example, overriding {@link #add} alone <b>will not</b> change the
 * behavior of {@link #offer} which can lead to unexpected behavior. In this case, you should
 * override {@code offer} as well.
 *
 * <p><b>{@code default} method warning:</b> This class does <i>not</i> forward calls to {@code

	if err == nil {
		t.Fatalf("should returns error but got nil")
	}
}

func TestReturningWithNullToZeroValues(t *testing.T) {
	dialect := DB.Dialector.Name()
	switch dialect {
	case "mysql", "sqlserver":
		// these dialects do not support the "returning" clause
		return
	default:
		// This user struct will leverage the existing users table, but override
		// the Name field to default to null.

   * those sublists might implement a private {@code MySubList} type but serialize as a plain {@code
   * MyList} to save space. So long as {@code MyList} has all the public supertypes of {@code
   * MySubList}, this is safe. For these cases, for which {@code reserializeAndAssert} is too
   * strict, use {@link #reserialize}.
   *
   * @return the re-serialized object
   * @throws RuntimeException if the specified object was not successfully serialized or

 *
 * <p>{@code UncheckedExecutionException} is intended as an alternative to {@code
 * ExecutionException} when the exception thrown by a task is an unchecked exception. However, it
 * may also wrap a checked exception in some cases.
 *
 * <p>When wrapping an {@code Error} from another thread, prefer {@link ExecutionError}. When
 * wrapping a checked exception, prefer {@code ExecutionException}.
 *
 * @author Charles Fry
 * @since 10.0
 */

```

`app.add_middleware()` receives a middleware class as the first argument and any additional arguments to be passed to the middleware.

## Integrated middlewares

**FastAPI** includes several middlewares for common use cases, we'll see next how to use them.

/// note | "Technical Details"

For the next examples, you could also use `from starlette.middleware.something import SomethingMiddleware`.

        switch (form.crudMode) {
        case CrudMode.CREATE:
            return OptionalEntity.of(new FileAuthentication()).map(entity -> {
                entity.setCreatedBy(username);
                entity.setCreatedTime(currentTime);
                return entity;
            });
        case CrudMode.EDIT:
            if (form instanceof EditForm) {

        switch (form.crudMode) {
        case CrudMode.CREATE:
            return OptionalEntity.of(new RequestHeader()).map(entity -> {
                entity.setCreatedBy(username);
                entity.setCreatedTime(currentTime);
                return entity;
            });
        case CrudMode.EDIT:
            if (form instanceof EditForm) {

   * Adds a number of occurrences of an element to this multiset. Note that if {@code occurrences ==
   * 1}, this method has the identical effect to {@link #add(Object)}. This method is functionally
   * equivalent (except in the case of overflow) to the call {@code
   * addAll(Collections.nCopies(element, occurrences))}, which would presumably perform much more
   * poorly.
   *

import com.google.common.annotations.GwtCompatible;
import java.util.Map;
import org.checkerframework.checker.nullness.qual.NonNull;
import org.checkerframework.checker.nullness.qual.Nullable;

/**
 * Test cases for a {@link Table} implementation supporting reads and writes.
 *
 * @author Jared Levy
 * @author Louis Wasserman
 */
@GwtCompatible
@ElementTypesAreNonnullByDefault