Assim como quando declaramos parâmetros de consulta, quando um atributo do modelo possui um valor padrão, ele se torna opcional. Caso contrário, se torna obrigatório. Use `None` para torná-lo opcional.

Por exemplo, o modelo acima declara um JSON "`object`" (ou `dict` no Python) como esse:

```JSON
{
    "name": "Foo",
    "description": "An optional description",
    "price": 45.2,
    "tax": 3.5
}
```

import org.dbflute.cbean.ConditionBean;
import org.dbflute.cbean.result.ListResultBean;
import org.dbflute.cbean.result.PagingResultBean;
import org.dbflute.exception.IllegalBehaviorStateException;
import org.dbflute.optional.OptionalEntity;
import org.dbflute.util.DfTypeUtil;
import org.opensearch.action.bulk.BulkRequestBuilder;
import org.opensearch.action.delete.DeleteRequestBuilder;
import org.opensearch.action.index.IndexRequestBuilder;

import org.dbflute.cbean.ConditionBean;
import org.dbflute.cbean.result.ListResultBean;
import org.dbflute.cbean.result.PagingResultBean;
import org.dbflute.exception.IllegalBehaviorStateException;
import org.dbflute.optional.OptionalEntity;
import org.dbflute.util.DfTypeUtil;
import org.opensearch.action.bulk.BulkRequestBuilder;
import org.opensearch.action.delete.DeleteRequestBuilder;
import org.opensearch.action.index.IndexRequestBuilder;

import org.dbflute.cbean.ConditionBean;
import org.dbflute.cbean.result.ListResultBean;
import org.dbflute.cbean.result.PagingResultBean;
import org.dbflute.exception.IllegalBehaviorStateException;
import org.dbflute.optional.OptionalEntity;
import org.dbflute.util.DfTypeUtil;
import org.opensearch.action.bulk.BulkRequestBuilder;
import org.opensearch.action.delete.DeleteRequestBuilder;
import org.opensearch.action.index.IndexRequestBuilder;

import org.dbflute.cbean.ConditionBean;
import org.dbflute.cbean.result.ListResultBean;
import org.dbflute.cbean.result.PagingResultBean;
import org.dbflute.exception.IllegalBehaviorStateException;
import org.dbflute.optional.OptionalEntity;
import org.dbflute.util.DfTypeUtil;
import org.opensearch.action.bulk.BulkRequestBuilder;
import org.opensearch.action.delete.DeleteRequestBuilder;
import org.opensearch.action.index.IndexRequestBuilder;

import org.codelibs.curl.CurlResponse;
import org.codelibs.fess.Constants;
import org.codelibs.fess.util.ComponentUtil;
import org.codelibs.opensearch.runner.net.OpenSearchCurl;
import org.dbflute.optional.OptionalEntity;

import jakarta.annotation.PostConstruct;

/**
 * Manager class for handling dictionary files in the Fess search system.
 * This class provides functionality to retrieve, store, and manage various

	updated bool         `msg:"-"`
}

type deleteAllStorager interface {
	deleteAll(ctx context.Context, bucket, prefix string)
}

// newBucketMetacache creates a new bucketMetacache.
// Optionally remove all existing caches.
func newBucketMetacache(bucket string, cleanup bool) *bucketMetacache {
	if cleanup {
		// Recursively delete all caches.
		objAPI := newObjectLayerFn()
		if objAPI != nil {

import org.codelibs.fess.Constants;
import org.codelibs.fess.dict.DictionaryException;
import org.codelibs.fess.dict.DictionaryFile;
import org.codelibs.fess.util.ComponentUtil;
import org.dbflute.optional.OptionalEntity;

/**
 * Character mapping file handler for managing character mapping dictionaries.
 * This class provides functionality to load, parse, and manage character mapping

import static com.google.common.truth.Truth.assertThat;
import static org.junit.Assert.assertThrows;

import com.google.common.base.Functions;
import com.google.common.base.Optional;
import com.google.common.collect.ImmutableList;
import com.google.common.testing.ClassSanityTester.FactoryMethodReturnsNullException;
import com.google.common.testing.ClassSanityTester.ParameterHasNoDistinctValueException;

Например, модель выше описывает такой JSON "объект" (или Python `dict`):

```JSON
{
    "name": "Foo",
    "description": "An optional description",
    "price": 45.2,
    "tax": 3.5
}
```

...так как `description` и `tax` являются необязательными (со значением по умолчанию `None`), такой JSON "объект" тоже будет корректным:

```JSON
{