org.wikimedia.eventutilities.core.event.types

Class JsonSchemaConverter<T>

java.lang.Object

org.wikimedia.eventutilities.core.event.types.JsonSchemaConverter<T>

Type Parameters:

T - SchemaConversions implementation

@ParametersAreNonnullByDefault
public class JsonSchemaConverter<T>
extends Object

JsonSchemaConverter iterates through the JSONSchema properties and uses the provided SchemaConversions implementation to convert from JSONSchema types. This was implemented expecting to support JSONSchema Draft 7, but will likely work with many JSONSchema versions. Support for JSONSchema Draft 3 has been added; notably support for Draft 3's method of marking a field as required.

Constructor Summary

Constructors

Constructor and Description
JsonSchemaConverter(SchemaConversions<T> schemaConversions)

Method Summary

Modifier and Type	Method and Description
static void	checkJsonSchemaIsObject(com.fasterxml.jackson.databind.node.ObjectNode jsonSchema) DRY helper function that asserts that the jsonSchema has "type": "object".
T	convert(com.fasterxml.jackson.databind.node.ObjectNode jsonSchema) Converts this JSONSchema using the provided SchemaConversions.
protected T	convert(com.fasterxml.jackson.databind.node.ObjectNode jsonSchema, String nodePath) Iterates through jsonSchema and calls appropriate TypeConverter methods on each jsonSchema property type in order to convert it into type T.
protected T	convertArrayType(com.fasterxml.jackson.databind.node.ObjectNode jsonSchema, String nodePath)
protected T	convertMapType(com.fasterxml.jackson.databind.node.ObjectNode jsonSchema, String nodePath)
protected T	convertRowType(com.fasterxml.jackson.databind.node.ObjectNode jsonSchema, String nodePath)
static com.fasterxml.jackson.databind.JsonNode	getJsonNode(com.fasterxml.jackson.databind.node.ObjectNode objectNode, String key, String errorMessage) DRY helper function to get a JsonNode out of an ObjectNode by key, throwing IllegalArgumentException if the key does not exist, or is set to "null".
static String	getJsonSchemaType(com.fasterxml.jackson.databind.node.ObjectNode jsonSchema) DRY helper function to extract the JSONSchema "type".

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Constructor Detail

JsonSchemaConverter

public JsonSchemaConverter(SchemaConversions<T> schemaConversions)

Method Detail

convert

@Nonnull
public T convert(com.fasterxml.jackson.databind.node.ObjectNode jsonSchema)

Converts this JSONSchema using the provided SchemaConversions. Note: A special case of converting object with an additionalProperties schema to a Map is included. In JSONSchema, additionalProperties can either be a boolean or an object. If it is an object, it expected to specify the schema of the unknown properties. This is what we need for a Map type. We want to still allow object schemas to indicate that they have specific property keys in a Map type though, so an object with additionalProperties with a schema can still include a defined properties. In this case, we will use a Map type here and the defined properties will be ignored in final map type. It is up to the schema author to ensure that the types of the defined properties match the additionalProperties schema; that is, all defined properties must have the same type as the additionalProperties, as this is what will be used for the value type in the Map. See: https://wikitech.wikimedia.org/wiki/Event_Platform/Schemas/Guidelines#map_types

Parameters:

jsonSchema - The JSONSchema Object. This should have at minimum type.

Returns:

jsonSchema converted to T using the provided SchemaConversions.

convert

@Nonnull
protected T convert(com.fasterxml.jackson.databind.node.ObjectNode jsonSchema,
                             String nodePath)

Iterates through jsonSchema and calls appropriate TypeConverter methods on each jsonSchema property type in order to convert it into type T.

Parameters:

jsonSchema - The JSONSchema Object. This should have at minimum type.

nodePath - Fully qualified dotted json path to the current node in the JSONSchema. Used only for informational error and log messages.

convertArrayType

@Nonnull
protected T convertArrayType(com.fasterxml.jackson.databind.node.ObjectNode jsonSchema,
                                      String nodePath)

convertMapType

@Nonnull
protected T convertMapType(com.fasterxml.jackson.databind.node.ObjectNode jsonSchema,
                                    String nodePath)

convertRowType

@Nonnull
protected T convertRowType(com.fasterxml.jackson.databind.node.ObjectNode jsonSchema,
                                    String nodePath)

getJsonNode

@Nonnull
public static com.fasterxml.jackson.databind.JsonNode getJsonNode(com.fasterxml.jackson.databind.node.ObjectNode objectNode,
                                                                           String key,
                                                                           String errorMessage)

DRY helper function to get a JsonNode out of an ObjectNode by key, throwing IllegalArgumentException if the key does not exist, or is set to "null".

Parameters:

objectNode - ObjectNode from which to get JsonNode by key

key - Field name key to get out of the ObjectNode.

errorMessage - Error message for IllegalArgumentException if key is not set or is "null".

Returns:

JsonNode in objectNode at key

getJsonSchemaType

@Nonnull
public static String getJsonSchemaType(com.fasterxml.jackson.databind.node.ObjectNode jsonSchema)

DRY helper function to extract the JSONSchema "type".

checkJsonSchemaIsObject

@Nonnull
public static void checkJsonSchemaIsObject(com.fasterxml.jackson.databind.node.ObjectNode jsonSchema)

DRY helper function that asserts that the jsonSchema has "type": "object".

Throws:

IllegalArgumentException - if jsonSchema "type" != "object"