Add JSON Schema support for patternProperties

docs/source/1.0/guides/converting-to-openapi.rst

@@ -514,6 +514,31 @@ unionStrategy (``string``)
             }
         }
 
+mapStrategy (``string``)
+    Configures how Smithy map shapes are converted to JSON Schema.
+
+    This property must be a string set to one of the following values:
+
+    * ``propertyNames``:  Converts to a schema that uses a combination of
+      "propertyNames" and "additionalProperties". This is the default setting
+      used if not configured.
+    * ``patternProperties``: Converts to a schema that uses
+      "patternProperties". If a map's key member or its target does not have a
+      "pattern" trait, a default indicating one or more of any character (".+")
+      is applied.
+
+    .. code-block:: json
+
+        {
+            "version": "1.0",
+            "plugins": {
+                "openapi": {
+                    "service": "smithy.example#Weather",
+                    "mapStrategy": "propertyNames"
+                }
+            }
+        }
+
 schemaDocumentExtensions (``Map<String, any>``)
     Adds custom top-level key-value pairs to the created OpenAPI specification.
     Any existing value is overwritten.

smithy-jsonschema/src/main/java/software/amazon/smithy/jsonschema/JsonSchemaConfig.java

@@ -62,10 +62,42 @@ public String toString() {
         }
     }
 
+    /**
+     * Configures how Smithy map shapes are converted to JSON Schema.
+     */
+    public enum MapStrategy {
+        /**
+         * Converts to a schema that uses a combination of "propertyNames"
+         * and "additionalProperties".
+         *
+         * <p>This is the default setting used if not configured.
+         */
+        PROPERTY_NAMES("propertyNames"),
+
+        /**
+         * Converts to a schema that uses "patternProperties". If a map's key
+         * member or its target does not have a {@code pattern} trait, a default
+         * indicating one or more of any character (".+") is applied.
+         */
+        PATTERN_PROPERTIES("patternProperties");
+
+        private String stringValue;
+
+        MapStrategy(String stringValue) {
+            this.stringValue = stringValue;
+        }
+
+        @Override
+        public String toString() {
+            return stringValue;
+        }
+    }
+
     private boolean alphanumericOnlyRefs;
     private boolean useJsonName;
     private TimestampFormatTrait.Format defaultTimestampFormat = TimestampFormatTrait.Format.DATE_TIME;
     private UnionStrategy unionStrategy = UnionStrategy.ONE_OF;
+    private MapStrategy mapStrategy = MapStrategy.PROPERTY_NAMES;
     private String definitionPointer = "#/definitions";
     private ObjectNode schemaDocumentExtensions = Node.objectNode();
     private ObjectNode extensions = Node.objectNode();
@@ -140,6 +172,19 @@ public void setUnionStrategy(UnionStrategy unionStrategy) {
         this.unionStrategy = unionStrategy;
     }
 
+    public MapStrategy getMapStrategy() {
+        return mapStrategy;
+    }
+
+    /**
+     * Configures how Smithy map shapes are converted to JSON Schema.
+     *
+     * @param mapStrategy The map strategy to use.
+     */
+    public void setMapStrategy(MapStrategy mapStrategy) {
+        this.mapStrategy = mapStrategy;
+    }
+
     public String getDefinitionPointer() {
         return definitionPointer;
     }

smithy-jsonschema/src/main/java/software/amazon/smithy/jsonschema/JsonSchemaShapeVisitor.java

@@ -109,9 +109,23 @@ private Schema createRef(MemberShape member) {
 
     @Override
     public Schema mapShape(MapShape shape) {
-        return buildSchema(shape, createBuilder(shape, "object")
-                .propertyNames(createRef(shape.getKey()))
-                .additionalProperties(createRef(shape.getValue())));
+        JsonSchemaConfig.MapStrategy mapStrategy = converter.getConfig().getMapStrategy();
+
+        switch (mapStrategy) {
+            case PROPERTY_NAMES:
+                return buildSchema(shape, createBuilder(shape, "object")
+                        .propertyNames(createRef(shape.getKey()))
+                        .additionalProperties(createRef(shape.getValue())));
+            case PATTERN_PROPERTIES:
+                String keyPattern = shape.getKey().getMemberTrait(model, PatternTrait.class)
+                        .map(PatternTrait::getPattern)
+                        .map(Pattern::pattern)
+                        .orElse(".+");
+                return buildSchema(shape, createBuilder(shape, "object")
+                        .putPatternProperty(keyPattern, createRef(shape.getValue())));
+            default:
+                throw new SmithyJsonSchemaException(String.format("Unsupported map strategy: %s", mapStrategy));
+        }
     }
 
     @Override

smithy-jsonschema/src/main/java/software/amazon/smithy/jsonschema/Schema.java

@@ -41,7 +41,6 @@
  * version of JSON Schema. The following properties are not supported:
  *
  * <ul>
- *     <li>patternProperties</li>
  *     <li>dependencies</li>
  *     <li>if</li>
  *     <li>then</li>
@@ -88,6 +87,7 @@ public final class Schema implements ToNode, ToSmithyBuilder<Schema> {
     private final Map<String, Schema> properties;
     private final Schema additionalProperties;
     private final Schema propertyNames;
+    private final Map<String, Schema> patternProperties;
 
     private final List<Schema> allOf;
     private final List<Schema> anyOf;
@@ -137,6 +137,7 @@ private Schema(Builder builder) {
         maxProperties = builder.maxProperties;
         minProperties = builder.minProperties;
         propertyNames = builder.propertyNames;
+        patternProperties = builder.patternProperties;
 
         allOf = ListUtils.copyOf(builder.allOf);
         oneOf = ListUtils.copyOf(builder.oneOf);
@@ -257,6 +258,10 @@ public Optional<Schema> getPropertyNames() {
         return Optional.ofNullable(propertyNames);
     }
 
+    public Map<String, Schema> getPatternProperties() {
+        return patternProperties;
+    }
+
     public List<Schema> getAllOf() {
         return allOf;
     }
@@ -365,6 +370,11 @@ public Node toNode() {
                     .collect(ObjectNode.collectStringKeys(Map.Entry::getKey, e -> e.getValue().toNode())));
         }
 
+        if (!patternProperties.isEmpty()) {
+            result.withMember("patternProperties", patternProperties.entrySet().stream()
+                    .collect(ObjectNode.collectStringKeys(Map.Entry::getKey, e -> e.getValue().toNode())));
+        }
+
         if (!required.isEmpty()) {
             result.withMember("required", required.stream().sorted().map(Node::from).collect(ArrayNode.collect()));
         }
@@ -516,6 +526,7 @@ public Builder toBuilder() {
                 .contentEncoding(contentEncoding)
                 .contentMediaType(contentMediaType);
         properties.forEach(builder::putProperty);
+        patternProperties.forEach(builder::putPatternProperty);
         extensions.forEach(builder::putExtension);
         return builder;
     }
@@ -567,6 +578,7 @@ public static final class Builder implements SmithyBuilder<Schema> {
         private Map<String, Schema> properties = new HashMap<>();
         private Schema additionalProperties;
         private Schema propertyNames;
+        private Map<String, Schema> patternProperties = new HashMap<>();
 
         private List<Schema> allOf = ListUtils.of();
         private List<Schema> anyOf = ListUtils.of();
@@ -728,6 +740,26 @@ public Builder propertyNames(Schema propertyNames) {
             return this;
         }
 
+        public Builder patternProperties(Map<String, Schema> patternProperties) {
+            this.patternProperties.clear();
+
+            if (patternProperties != null) {
+                patternProperties.forEach(this::putPatternProperty);
+            }
+
+            return this;
+        }
+
+        public Builder putPatternProperty(String key, Schema value) {
+            this.patternProperties.put(key, value);
+            return this;
+        }
+
+        public Builder removePatternProperty(String key) {
+            patternProperties.remove(key);
+            return this;
+        }
+
         public Builder allOf(List<Schema> allOf) {
             this.allOf = allOf == null ? ListUtils.of() : allOf;
             return this;

smithy-jsonschema/src/test/java/software/amazon/smithy/jsonschema/JsonSchemaConverterTest.java

@@ -458,6 +458,64 @@ public void supportsUnionStructure() {
         assertThat(schema.getProperties().keySet(), contains("foo"));
     }
 
+    @Test
+    public void supportsMapPropertyNames() {
+        ShapeId shapeId = ShapeId.from("smithy.api#String");
+        StringShape string = StringShape.builder().id(shapeId).build();
+        MapShape map = MapShape.builder().id("a.b#Map").key(shapeId).value(shapeId).build();
+        Model model = Model.builder().addShapes(map, string).build();
+        SchemaDocument document = JsonSchemaConverter.builder().model(model).build().convertShape(map);
+        Schema schema = document.getRootSchema();
+
+        assertTrue(schema.getPropertyNames().isPresent());
+        assertThat(schema.getPropertyNames().get().getType().get(), equalTo("string"));
+        assertTrue(schema.getAdditionalProperties().isPresent());
+        assertThat(schema.getAdditionalProperties().get().getType().get(), equalTo("string"));
+    }
+
+    @Test
+    public void supportsMapPatternProperties() {
+        ShapeId shapeId = ShapeId.from("smithy.api#String");
+        StringShape string = StringShape.builder().id(shapeId).build();
+        String pattern = "[a-z]{1,16}";
+        StringShape key = StringShape.builder().id("a.b#Key")
+                .addTrait(new PatternTrait(pattern)).build();
+        MapShape map = MapShape.builder().id("a.b#Map").key(key.getId()).value(shapeId).build();
+        Model model = Model.builder().addShapes(map, key, string).build();
+        JsonSchemaConfig config = new JsonSchemaConfig();
+        config.setMapStrategy(JsonSchemaConfig.MapStrategy.PATTERN_PROPERTIES);
+        SchemaDocument document = JsonSchemaConverter.builder()
+                .config(config)
+                .model(model)
+                .build()
+                .convertShape(map);
+        Schema schema = document.getRootSchema();
+
+        assertThat(schema.getPatternProperties().size(), equalTo(1));
+        assertTrue(schema.getPatternProperties().containsKey(pattern));
+        assertThat(schema.getPatternProperties().get(pattern).getType().get(), equalTo("string"));
+    }
+
+    @Test
+    public void supportsMapPatternPropertiesWithDefaultPattern() {
+        ShapeId shapeId = ShapeId.from("smithy.api#String");
+        StringShape string = StringShape.builder().id(shapeId).build();
+        MapShape map = MapShape.builder().id("a.b#Map").key(shapeId).value(shapeId).build();
+        Model model = Model.builder().addShapes(map, string).build();
+        JsonSchemaConfig config = new JsonSchemaConfig();
+        config.setMapStrategy(JsonSchemaConfig.MapStrategy.PATTERN_PROPERTIES);
+        SchemaDocument document = JsonSchemaConverter.builder()
+                .config(config)
+                .model(model)
+                .build()
+                .convertShape(map);
+        Schema schema = document.getRootSchema();
+
+        assertThat(schema.getPatternProperties().size(), equalTo(1));
+        assertTrue(schema.getPatternProperties().containsKey(".+"));
+        assertThat(schema.getPatternProperties().get(".+").getType().get(), equalTo("string"));
+    }
+
     @Test
     public void convertingToBuilderGivesSameResult() {
         Model model = Model.assembler()