Module org.eclipse.microprofile.openapi

Package org.eclipse.microprofile.openapi.annotations.media

Annotation Type Schema

@Target({FIELD,METHOD,PARAMETER,TYPE})
@Retention(RUNTIME)
@Inherited
public @interface Schema

The Schema Object allows the definition of input and output data types. These types can be objects, but also primitives and arrays. This object is an extended subset of the JSON Schema draft specification 2020-12.

Defining subschemas

Some of the parameters on this annotation correspond to parts of an OpenAPI document where a subschema is expected, for example allOf(), contains() and propertyNames(). Due to limitations in the Java language, we can't use a second @Schema annotation, so instead we allow a class to be provided. A schema will be generated from that class by introspecting its annotations, methods and fields.

In addition, several special values can be used:

• Schema.True to indicate a boolean true schema (accepts anything)
• Schema.False to indicate a boolean false schema (accepts nothing)
• Void to indicate that the schema should not be included at all (this is the default for most parameters)

See Also:

OpenAPI Specification Schema Object

Optional Element Summary

Optional Elements

Modifier and Type	Optional Element	Description
Class<?>	additionalProperties	Provides a Java class as implementation for additional properties that may be present in instances of this schema.
Class<?>[]	allOf	Provides an array of java class implementations which can be used to describe multiple acceptable schemas.
Class<?>[]	anyOf	Provides an array of java class implementations which can be used to describe multiple acceptable schemas.
String	comment	A comment to be included in the schema
String	constValue	Requires that the instance must be a specific value.
Class<?>	contains	A schema which at least one element of an array instance must validate against.
String	contentEncoding	The encoding used to allow binary data to be stored in a string.
String	contentMediaType	The media type of the data in a string.
Class<?>	contentSchema	The schema that data in a string must validate against.
String	defaultValue	Provides a default value.
DependentRequired[]	dependentRequired	Specifies that certain properties must be present if other properties are present.
DependentSchema[]	dependentSchemas	Schemas which an instance must validate against if the instance has certain properties.
boolean	deprecated	Specifies that a schema is deprecated and SHOULD be transitioned out of usage.
String	description	A description of the schema.
DiscriminatorMapping[]	discriminatorMapping	An array of discriminator mappings.
String	discriminatorProperty	Provides a discriminator property value.
Class<?>	elseSchema	A class used to create a schema that an instance must validate against if it does not validate against the if schema.
String[]	enumeration	Provides a list of enum values.
String	example	Deprecated. use examples()
String[]	examples	A free-form property to include examples of an instance for this schema.
boolean	exclusiveMaximum	If true, makes the maximum value exclusive, or a less-than criteria.
boolean	exclusiveMinimum	If true, makes the minimum value exclusive, or a greater-than criteria.
Extension[]	extensions	List of extensions to be added to the Schema model corresponding to the containing annotation.
ExternalDocumentation	externalDocs	Additional external documentation for this schema.
String	format	Provides an optional override for the format.
boolean	hidden	Allows schema to be marked as hidden.
Class<?>	ifSchema	A class used to create a schema used to control conditional evaluation.
Class<?>	implementation	Provides a java class as implementation for this schema.
int	maxContains	Specifies the maximum number of elements which may validate against the contains() schema.
String	maximum	Sets the maximum numeric value for a property.
int	maxItems	Only applicable if type=array.
int	maxLength	Sets the maximum length of a string value.
int	maxProperties	Constrains the number of arbitrary properties when additionalProperties is defined.
int	minContains	Specifies the minimum number of elements which must validate against the contains() schema.
String	minimum	Sets the minimum numeric value for a property.
int	minItems	Only applicable if type=array.
int	minLength	Sets the minimum length of a string value.
int	minProperties	Constrains the number of arbitrary properties when additionalProperties is defined.
double	multipleOf	Constrains a value such that when divided by the multipleOf, the result must be an integer.
String	name	The name of the schema or property.
Class<?>	not	Provides a java class to be used to disallow matching properties.
boolean	nullable	Allows sending a null value for the defined schema.
Class<?>[]	oneOf	Provides an array of java class implementations which can be used to describe multiple acceptable schemas.
String	pattern	A regular expression that the value must satisfy.
PatternProperty[]	patternProperties	Applies subschemas against properties matched by regular expressions.
Class<?>[]	prefixItems	Schemas which the leading elements of an array instance must validate against.
SchemaProperty[]	properties	Provides a list of properties present in this schema.
Class<?>	propertyNames	A schema which the names of properties of an object instance must validate against.
boolean	readOnly	Declares the property as "read only".
String	ref	Reference value to a Schema definition.
boolean	required	Specifies whether the annotated item is required or not.
String[]	requiredProperties	Allows multiple properties in an object to be marked as required.
Class<?>	thenSchema	A class used to create a schema that an instance must validate against if it validates against the if schema.
String	title	A title to explain the purpose of the schema.
SchemaType	type	Provides an override for the basic type of the schema.
boolean	uniqueItems	Only applicable if type=array.
boolean	writeOnly	Declares the property as "write only".

Element Detail

implementation

Class<?> implementation

Provides a java class as implementation for this schema. When provided, additional information in the Schema annotation (except for type information) will augment the java class after introspection.

Returns:

a class that implements this schema

Default:

java.lang.Void.class

not

Class<?> not

Provides a java class to be used to disallow matching properties. Inline or referenced schema MUST be of a Schema Object and not a standard JSON Schema.

Returns:

a class with disallowed properties

Default:

java.lang.Void.class

oneOf

Class<?>[] oneOf

Provides an array of java class implementations which can be used to describe multiple acceptable schemas. If more than one match the derived schemas, a validation error will occur.

Returns:

the list of possible classes for a single match

Default:

{}

anyOf

Class<?>[] anyOf

Provides an array of java class implementations which can be used to describe multiple acceptable schemas. If any match, the schema will be considered valid.

Returns:

the list of possible class matches

Default:

{}

allOf

Class<?>[] allOf

Provides an array of java class implementations which can be used to describe multiple acceptable schemas. If all match, the schema will be considered valid.

Returns:

the list of classes to match

Default:

{}

name

String name

The name of the schema or property.

The name is REQUIRED when the schema is defined within Components. The name will be used as the key to add this schema to the 'schemas' map for reuse.

Returns:

the name of the schema

Default:

""

title

String title

A title to explain the purpose of the schema.

Returns:

the title of the schema

Default:

""

multipleOf

double multipleOf

Constrains a value such that when divided by the multipleOf, the result must be an integer. Ignored if the value is 0.

Returns:

the multiplier constraint of the schema

Default:

0.0

maximum

String maximum

Sets the maximum numeric value for a property. Value must be a valid number. Ignored if the value is an empty string or not a number.

Returns:

the maximum value for this schema

Default:

""

exclusiveMaximum

boolean exclusiveMaximum

If true, makes the maximum value exclusive, or a less-than criteria.

Returns:

the exclusive maximum value for this schema

Default:

false

minimum

String minimum

Sets the minimum numeric value for a property. Value must be a valid number. Ignored if the value is an empty string or not a number.

Returns:

the minimum value for this schema

Default:

""

exclusiveMinimum

boolean exclusiveMinimum

If true, makes the minimum value exclusive, or a greater-than criteria.

Returns:

the exclusive minimum value for this schema

Default:

false

maxLength

int maxLength

Sets the maximum length of a string value. Ignored if the value is negative.

Returns:

the maximum length of this schema

Default:

2147483647

minLength

int minLength

Sets the minimum length of a string value. Ignored if the value is negative.

Returns:

the minimum length of this schema

Default:

0

pattern

String pattern

A regular expression that the value must satisfy. Ignored if the value is an empty string.

If the instance is a string, the regular expression must match the instance.

Returns:

the ECMA-262 regular expression to match against

Default:

""

maxProperties

int maxProperties

Constrains the number of arbitrary properties when additionalProperties is defined. Ignored if value is 0.

Returns:

the maximum number of properties for this schema

Default:

0

minProperties

int minProperties

Constrains the number of arbitrary properties when additionalProperties is defined. Ignored if value is 0.

Returns:

the minimum number of properties for this schema

Default:

0

requiredProperties

String[] requiredProperties

Allows multiple properties in an object to be marked as required.

Returns:

the list of required schema properties

Default:

{}

required

boolean required

Specifies whether the annotated item is required or not.

Returns:

whether or not this schema is required

Default:

false

description

String description

A description of the schema.

Returns:

this schema's description

Default:

""

format

String format

Provides an optional override for the format.

If a consumer is unaware of the meaning of the format, they shall fall back to using the basic type without format. For example, if \"type: integer, format: int128\" were used to designate a very large integer, most consumers will not understand how to handle it, and fall back to simply \"type: integer\"

Returns:

this schema's format

Default:

""

ref

String ref

Reference value to a Schema definition.

This property provides a reference to an object defined elsewhere.

Unlike ref on most MP OpenAPI annotations, this property is not mutually exclusive with other properties.

Returns:

a reference to a schema definition

Default:

""

nullable

boolean nullable

Allows sending a null value for the defined schema.

Returns:

whether or not this schema is nullable

Default:

false

readOnly

boolean readOnly

Declares the property as "read only". This means that it MAY be sent as part of a response but SHOULD NOT be sent as part of the request.

If the property is marked as readOnly being true and is in the required list, the required will take effect on the response only. A property MUST NOT be marked as both readOnly and writeOnly being true.

Returns:

whether or not this schema is read only

Default:

false

writeOnly

boolean writeOnly

Declares the property as "write only". This means that it MAY be sent as part of a request but SHOULD NOT be sent as part of the response.

If the property is marked as writeOnly being true and is in the required list, the required will take effect on the request only. A property MUST NOT be marked as both readOnly and writeOnly being true.

Returns:

whether or not this schema is write only

Default:

false

example

@Deprecated(since="4.0")
String example

Deprecated.

use examples()

A free-form property to include an example of an instance for this schema.

Returns:

an example of this schema

Default:

""

examples

String[] examples

A free-form property to include examples of an instance for this schema.

Each example SHOULD validate against this schema.

If the schema type() is STRING, the value will be interpreted as a literal string, otherwise it will be parsed as JSON.

Returns:

an array of examples of this schema

Since:

4.0

Default:

{}

externalDocs

ExternalDocumentation externalDocs

Additional external documentation for this schema.

Returns:

additional schema documentation

Default:

@org.eclipse.microprofile.openapi.annotations.ExternalDocumentation

deprecated

boolean deprecated

Specifies that a schema is deprecated and SHOULD be transitioned out of usage.

Returns:

whether or not this schema is deprecated

Default:

false

type

SchemaType type

Provides an override for the basic type of the schema.

Value MUST be a string. Multiple types via an array are not supported.

MUST be a valid type per the OpenAPI Specification.

Returns:

the type of this schema

Default:

org.eclipse.microprofile.openapi.annotations.enums.SchemaType.DEFAULT

enumeration

String[] enumeration

Provides a list of enum values. Corresponds to the enum property in the OAS schema and the enumeration property in the schema model.

Returns:

a list of allowed schema values

Default:

{}

defaultValue

String defaultValue

Provides a default value. The default value represents what would be assumed by the consumer of the input as the value of the schema if one is not provided.

Unlike JSON Schema, the value MUST conform to the defined type for the Schema Object defined at the same level.

For example, if type is string, then default can be "foo" but cannot be 1.

Returns:

the default value of this schema

Default:

""

discriminatorProperty

String discriminatorProperty

Provides a discriminator property value. Adds support for polymorphism.

The discriminator is an object name that is used to differentiate between other schemas which may satisfy the payload description.

Returns:

the discriminator property

Default:

""

discriminatorMapping

DiscriminatorMapping[] discriminatorMapping

An array of discriminator mappings.

Returns:

the discriminator mappings for this schema

Default:

{}

hidden

boolean hidden

Allows schema to be marked as hidden.

Returns:

whether or not this schema is hidden

Default:

false

maxItems

int maxItems

Only applicable if type=array. Sets the maximum number of items in an array. This integer MUST be greater than, or equal to, 0.

An array instance is valid against "maxItems" if its size is less than, or equal to, the value of this keyword.

Ignored if value is Integer.MIN_VALUE.

Returns:

the maximum number of items in this array

Default:

-2147483648

minItems

int minItems

Only applicable if type=array. Sets the minimum number of items in an array. This integer MUST be greater than, or equal to, 0.

An array instance is valid against "minItems" if its size is greater than, or equal to, the value of this keyword.

Ignored if value is Integer.MAX_VALUE.

Returns:

the minimum number of items in this array

Default:

2147483647

uniqueItems

boolean uniqueItems

Only applicable if type=array. Determines if the items in the array SHOULD be unique.

If false, the instance validates successfully. If true, the instance validates successfully if all of its elements are unique.

Returns:

whether the items in this array are unique

Default:

false

properties

SchemaProperty[] properties

Provides a list of properties present in this schema. Use of the properties list does not preclude the annotation scanning runtime from also including other properties found in the scan process. For example, if an implementation is also specified, the final set of properties used by the annotation scanner will include properties from both this list and those found from introspection of the implementation class, if any.

In the case where properties are specified here in addition to an implementation, the attributes given for a property using a SchemaProperty will override the same attributes scanned (or derived) from the implementation class.

Example:

 @Schema(properties = {
   @SchemaProperty(name = "creditCard", example = "4567100043210001"),
   @SchemaProperty(name = "departureFlight", description = "The departure flight information."),
   @SchemaProperty(name = "returningFlight")
})
 

Returns:

a list of defined properties

Since:

2.0

Default:

{}

additionalProperties

Class<?> additionalProperties

Provides a Java class as implementation for additional properties that may be present in instances of this schema.

If no additional properties are allowed, the value of this property should be set to False.class which will be rendered as boolean false in the resulting OpenAPI document.

The default value Void.class will result in no additionalProperties attribute being generated in the resulting OpenAPI document. The effective value in that case is true per the OpenAPI specification.

Implementations MAY ignore this property if this schema's type is not OBJECT, either explicitly or as derived by the placement of the annotation.

Returns:

a class that describes the allowable schema for additional properties not explicitly defined

Since:

3.1

See Also:

Schema.True, Schema.False

Default:

java.lang.Void.class

extensions

Extension[] extensions

List of extensions to be added to the Schema model corresponding to the containing annotation.

Returns:

array of extensions

Since:

3.1

Default:

{}

comment

String comment

A comment to be included in the schema

This value is set in the $comment property of the schema object

Returns:

the comment

Since:

4.0

Default:

""

constValue

String constValue

Requires that the instance must be a specific value. No other values are permitted.

The value is parsed as JSON if the schema type is anything other than STRING.

Returns:

the value which the instance must be equal to, expressed according to the type of the schema

Since:

4.0

Default:

""

ifSchema

Class<?> ifSchema

A class used to create a schema used to control conditional evaluation. If an instance validates against the if schema then it must also validate against the then schema. Otherwise it must validate against the else schema.

Returns:

a class used to create the if schema

Since:

4.0

See Also:

thenSchema(), elseSchema()

Default:

java.lang.Void.class

thenSchema

Class<?> thenSchema

A class used to create a schema that an instance must validate against if it validates against the if schema.

Returns:

a class used to create the then schema

Since:

4.0

See Also:

ifSchema(), elseSchema()

Default:

java.lang.Void.class

elseSchema

Class<?> elseSchema

A class used to create a schema that an instance must validate against if it does not validate against the if schema.

Returns:

a class used to create the else schema

Since:

4.0

See Also:

ifSchema(), thenSchema()

Default:

java.lang.Void.class

dependentSchemas

DependentSchema[] dependentSchemas

Schemas which an instance must validate against if the instance has certain properties.

For each DependentSchema listed, if the instance is an object which has a property named name() then the instance must validate against the schema created from schema().

Returns:

an array of DependentSchema entries

Since:

4.0

Default:

{}

contains

Class<?> contains

A schema which at least one element of an array instance must validate against.

The class is used to create a schema. If the instance is an array, then at least one element of the array must validate against the schema.

Returns:

a class used to create a schema which at least one element of an array instance must validate against

Since:

4.0

Default:

java.lang.Void.class

maxContains

int maxContains

Specifies the maximum number of elements which may validate against the contains() schema.

If more than this number of elements of an array instance match the contains schema, the instance does not validate against this schema.

Returns:

the maximum number of elements which may validate against the contains() schema

Since:

4.0

Default:

2147483647

minContains

int minContains

Specifies the minimum number of elements which must validate against the contains() schema.

If fewer than this number of elements of an array instance match the contains schema, the instance does not validate against this schema.

Returns:

the minimum number of elements which must validate against the contains() schema

Since:

4.0

Default:

0

prefixItems

Class<?>[] prefixItems

Schemas which the leading elements of an array instance must validate against.

The array of classes is used to create an array of schemas. If an instance is an array, the first element of the array must validate against the first schema, the second element must validate against the second schema and so on.

Returns:

an array of classes used to create an array of schemas used to validate the leading elements of an array instance

Since:

4.0

Default:

{}

patternProperties

PatternProperty[] patternProperties

Applies subschemas against properties matched by regular expressions.

For each PatternProperty listed, for each property whose name matches | regex(), its value must validate against the schema created from schema().

Returns:

a mapping from regular expressions to schemas

Since:

4.0

Default:

{}

dependentRequired

DependentRequired[] dependentRequired

Specifies that certain properties must be present if other properties are present.

For each DependentRequired entry in the list, if the instance is an object and has a property named DependentRequired.name() then it must also have property named for each entry of DependentRequired.requires() to validate against this schema.

Returns:

the properties required if certain other properties are present

Since:

4.0

Default:

{}

propertyNames

Class<?> propertyNames

A schema which the names of properties of an object instance must validate against.

The class is used to create a schema. If the instance is an object, then the name of each property in the instance must validate against the schema.

Returns:

a schema that property names must validate against

Since:

4.0

Default:

java.lang.Void.class

contentEncoding

String contentEncoding

The encoding used to allow binary data to be stored in a string.

If the instance is a string, this property specifies that it contains binary data encoded as text using the specified encoding (e.g. base64).

Returns:

the encoding

Since:

4.0

Default:

""

contentMediaType

String contentMediaType

The media type of the data in a string.

If the instance is a string, this property specifies the media type of the data it contains. If contentEncoding() is also set, it specifies the media type of the decoded string.

Returns:

the media type of the data in a string

Since:

4.0

Default:

""

contentSchema

Class<?> contentSchema

The schema that data in a string must validate against.

The class is used to create a schema. If the instance is a string and contentMediaType() is set, the data must validate against the schema when interpreted as the given media type.

Returns:

a class used to create a schema used to validate the data in a string

Since:

4.0

Default:

java.lang.Void.class