{8.1.0-updated} @FormData

The {@link oaj.http.annotation.FormData @FormData} annotation is used to retrieve request form post entries.

- {@link oaj.http.annotation.FormData}
  - {@link oaj.http.annotation.FormData#_default() _default} - Default value if not present.
  - {@link oaj.http.annotation.FormData#_enum() _enum} - Input validation. Must match one of the values.
  - {@link oaj.http.annotation.FormData#allowEmptyValue() allowEmptyValue} - Input validation. Allow empty value.
  - {@link oaj.http.annotation.FormData#api() api()} - Free-form Swagger JSON.
  - {@link oaj.http.annotation.FormData#collectionFormat() collectionFormat} - How collections of items are formatted.
  - {@link oaj.http.annotation.FormData#description() description} - Description.
  - {@link oaj.http.annotation.FormData#example() example()} - Serialized example.
  - {@link oaj.http.annotation.FormData#exclusiveMaximum() exclusiveMaximum} - Input validation. Whether maximum is exclusive.
  - {@link oaj.http.annotation.FormData#exclusiveMinimum() exclusiveMinimum} - Input validation. Whether minimum is exclusive.
  - {@link oaj.http.annotation.FormData#format() format} - The schema type format.
  - {@link oaj.http.annotation.FormData#items() items} - The schema of items in a collection.
  - {@link oaj.http.annotation.FormData#maximum() maximum} - Input validation. Maximum numeric value.
  - {@link oaj.http.annotation.FormData#maxItems() maxItems} - Input validation. Maximum number of items in a collection.
  - {@link oaj.http.annotation.FormData#maxLength() maxLength} - Input validation. Maximum length of a string.
  - {@link oaj.http.annotation.FormData#minimum() minimum} - Input validation. Minimum numeric value.
  - {@link oaj.http.annotation.FormData#minItems() minItems} - Input validation. Minimum number of items in a collection.
  - {@link oaj.http.annotation.FormData#minLength() minLength} - Input validation. Minimum length of a string.
  - {@link oaj.http.annotation.FormData#multipleOf() multipleOf} - Input validation. Number must be a multiple of.
  - {@link oaj.http.annotation.FormData#name() name} - Form data entry name.
  - {@link oaj.http.annotation.FormData#parser() parser} - Override the part parser.
  - {@link oaj.http.annotation.FormData#pattern() pattern} - Input validation. Must match regular expression.
  - {@link oaj.http.annotation.FormData#required() required} - Input validation. Form data entry must be present.
  - {@link oaj.http.annotation.FormData#type() type} - The schema type.
  - {@link oaj.http.annotation.FormData#uniqueItems() uniqueItems} - Input validation. Collections must contain unique items only.
  - {@link oaj.http.annotation.FormData#value() value} - Free-form Swagger JSON.

The most typical scenario is to simply use the value field to define form data parameter names:

##### Example:

@RestMethod(name=POST) public void doPost( @FormData("p1") int p1, @FormData("p2") String p2, @FormData("p3") UUID p3) {...}

This is functionally equivalent to the following code:

@RestMethod(name=POST) public void doPost(RestRequest req) { RequestFormData fd = req.getFormData(); int p1 = fd.get("p1", 0, int.class); String p2 = fd.get("p2", String.class); UUID p3 = fd.get("p3", UUID.class); }

The special name "*" (or blank) can be used to represent all values. When used, the data type must be a Map or bean.

##### Examples:

// Multiple values passed as a map. @RestMethod(name=POST) public void doPost(@FormData("*") Map<String,Object> map) {...}

// Same, but name "*" is inferred. @RestMethod(name=POST) public void doPost(@FormData Map<String,Object> map) {...}

// Multiple values passed as a bean. @RestMethod(name=POST) public void doPost(@FormData MyBean bean) {...}

The registered {@link oajr.RestContext#REST_partParser REST_partParser} is used to convert strings to POJOs and controls what POJO types are supported. By default, this is the {@link oaj.oapi.OpenApiParser} which supports the standard Swagger-based rules for parsing.

For example, the following shows how a pipe-delimited list of comma-delimited numbers (e.g. "1,2,3|4,5,6|7,8,9") can be converted to a 2-dimensional array of Longs:

@RestMethod(method="POST", path="/testFormData") public void testFormData( @FormData( name="formDataParamName", collectionFormat="pipes", items=@SubItems( collectionFormat="csv", type="integer", format="int64", minimum="0", maximum="100" minLength=1, maxLength=10 ), minLength=1, maxLength=10 ) Long[][] formDataParameter ) {...}

Input will be converted based on the types and formats defined in the schema definition. Input validations such as minLength/maxLength that don't match the input will result in automatic 400 Bad Request responses.

For more information about valid parameter types, see {@doc juneau-marshall.OpenApiDetails.Parsers OpenAPI Parsers}

The @FormData annotation is also used for supplying swagger information about the HTTP part. This information is used to populate the auto-generated Swagger documentation and UI.

##### Examples:

// Normal @FormData( name="name", description="Pet name", required=true, example="Doggie" )

// Free-form // Note the extra field @FormData( name="name", api={ "description: 'Pet name',", "required: true,", "example: 'Doggie'," "x-extra: 'extra field'" } )

{@doc DefaultRestSvlVariables} (e.g. "$L{my.localized.variable}") are supported on annotation fields.

##### Example:

@FormData( description="$L{PetNameDescription}" )

This annotation should not be combined with the {@link oaj.http.annotation.Body @Body} annotation or {@link oajr.RestRequest#getBody()} method for application/x-www-form-urlencoded POST posts, since it will trigger the underlying servlet API to parse the body content as key-value pairs resulting in empty content.
The {@link oaj.http.annotation.Query @Query} annotation can be used to retrieve a URL parameter in the URL string without triggering the servlet to drain the body content.
If using this annotation on a Spring bean, note that you are likely to encounter issues when using on parameterized types such as `List<MyBean>`. This is due to the fact that Spring uses CGLIB to recompile classes at runtime, and CGLIB was written before generics were introduced into Java and is a virtually-unsupported library. Therefore, parameterized types will often be stripped from class definitions and replaced with unparameterized types (e.g. `List`). Under these circumstances, you are likely to get `ClassCastExceptions` when trying to access generalized `ObjectMaps` as beans. The best solution to this issue is to either specify the parameter as a bean array (e.g. `MyBean[]`) or declare the method as final so that CGLIB will not try to recompile it.

- {@link oajr.RequestFormData}
- {@doc juneau-rest-server.OpenApiSchemaPartParsing}