add support for enum keyword

core/pom.xml

@@ -106,9 +106,7 @@
                                         -->
                                         <inculde>**/tests/draft2020-12/additionalProperties.json</inculde>
                                         <inculde>**/tests/draft2020-12/boolean_schema.json</inculde>
-                                        <!-- needs required
                                         <inculde>**/tests/draft2020-12/enum.json</inculde>
-                                        -->
                                         <inculde>**/tests/draft2020-12/exclusiveMaximum.json</inculde>
                                         <inculde>**/tests/draft2020-12/exclusiveMinimum.json</inculde>
                                         <!-- more than items keyword needed :(

core/src/main/java/io/github/sebastiantoepfer/jsonschema/core/vocab/validation/EnumKeywordType.java

@@ -0,0 +1,82 @@
+/*
+ * The MIT License
+ *
+ * Copyright 2023 sebastian.
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a copy
+ * of this software and associated documentation files (the "Software"), to deal
+ * in the Software without restriction, including without limitation the rights
+ * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+ * copies of the Software, and to permit persons to whom the Software is
+ * furnished to do so, subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be included in
+ * all copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+ * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+ * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+ * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
+ * THE SOFTWARE.
+ */
+package io.github.sebastiantoepfer.jsonschema.core.vocab.validation;
+
+import static java.util.function.Predicate.isEqual;
+
+import io.github.sebastiantoepfer.jsonschema.InstanceType;
+import io.github.sebastiantoepfer.jsonschema.JsonSchema;
+import io.github.sebastiantoepfer.jsonschema.keyword.Assertion;
+import io.github.sebastiantoepfer.jsonschema.keyword.Keyword;
+import io.github.sebastiantoepfer.jsonschema.keyword.KeywordType;
+import jakarta.json.JsonArray;
+import jakarta.json.JsonNumber;
+import jakarta.json.JsonValue;
+import java.math.BigDecimal;
+import java.util.Objects;
+
+final class EnumKeywordType implements KeywordType {
+
+    @Override
+    public String name() {
+        return "enum";
+    }
+
+    @Override
+    public Keyword createKeyword(final JsonSchema schema, final JsonValue value) {
+        return new EnumKeyword(value.asJsonArray());
+    }
+
+    private class EnumKeyword implements Assertion {
+
+        private final JsonArray allowedValues;
+
+        public EnumKeyword(final JsonArray allowedValues) {
+            this.allowedValues = allowedValues;
+        }
+
+        @Override
+        public boolean isValidFor(final JsonValue instance) {
+            final boolean result;
+            if (InstanceType.NUMBER.isInstance(instance)) {
+                result =
+                    allowedValues
+                        .stream()
+                        .filter(InstanceType.NUMBER::isInstance)
+                        .map(JsonNumber.class::cast)
+                        .map(JsonNumber::bigDecimalValue)
+                        .map(BigDecimal::stripTrailingZeros)
+                        .anyMatch(isEqual(((JsonNumber) instance).bigDecimalValue().stripTrailingZeros()));
+            } else {
+                result = allowedValues.stream().anyMatch(isEqual(instance));
+            }
+            return result;
+        }
+
+        @Override
+        public boolean hasName(final String name) {
+            return Objects.equals(name(), name);
+        }
+    }
+}

core/src/main/java/io/github/sebastiantoepfer/jsonschema/core/vocab/validation/ValidationVocabulary.java

@@ -39,6 +39,7 @@ public ValidationVocabulary() {
                 URI.create("https://json-schema.org/draft/2020-12/vocab/validation"),
                 new RequiredKeywordType(),
                 new TypeKeywordType(),
+                new EnumKeywordType(),
                 new MinLengthKeywordType(),
                 new MaxLengthKeywordType(),
                 new PatternKeywordType(),

core/src/test/java/io/github/sebastiantoepfer/jsonschema/core/vocab/validation/EnumKeywordTypeTest.java

@@ -0,0 +1,87 @@
+/*
+ * The MIT License
+ *
+ * Copyright 2023 sebastian.
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a copy
+ * of this software and associated documentation files (the "Software"), to deal
+ * in the Software without restriction, including without limitation the rights
+ * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+ * copies of the Software, and to permit persons to whom the Software is
+ * furnished to do so, subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be included in
+ * all copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+ * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+ * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+ * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
+ * THE SOFTWARE.
+ */
+package io.github.sebastiantoepfer.jsonschema.core.vocab.validation;
+
+import static org.hamcrest.MatcherAssert.assertThat;
+import static org.hamcrest.Matchers.is;
+
+import io.github.sebastiantoepfer.jsonschema.core.DefaultJsonSchemaFactory;
+import io.github.sebastiantoepfer.jsonschema.keyword.Keyword;
+import jakarta.json.Json;
+import jakarta.json.JsonValue;
+import org.junit.jupiter.api.Test;
+
+class EnumKeywordTypeTest {
+
+    @Test
+    void should_know_his_name() {
+        final Keyword enumKeyword = new EnumKeywordType()
+            .createKeyword(new DefaultJsonSchemaFactory().create(JsonValue.TRUE), JsonValue.EMPTY_JSON_ARRAY);
+
+        assertThat(enumKeyword.hasName("enum"), is(true));
+        assertThat(enumKeyword.hasName("test"), is(false));
+    }
+
+    @Test
+    void should_valid_for_string_value_which_is_in_array() {
+        assertThat(
+            new EnumKeywordType()
+                .createKeyword(
+                    new DefaultJsonSchemaFactory().create(JsonValue.TRUE),
+                    Json.createArrayBuilder().add("TEST").add("VALID").build()
+                )
+                .asAssertion()
+                .isValidFor(Json.createValue("TEST")),
+            is(true)
+        );
+    }
+
+    @Test
+    void should_be_invalid_for_number_which_is_not_in_array() {
+        assertThat(
+            new EnumKeywordType()
+                .createKeyword(
+                    new DefaultJsonSchemaFactory().create(JsonValue.TRUE),
+                    Json.createArrayBuilder().add("TEST").add("VALID").build()
+                )
+                .asAssertion()
+                .isValidFor(Json.createValue(2)),
+            is(false)
+        );
+    }
+
+    @Test
+    void should_be_valid_for_decimal_without_scale_if_number_is_valid() {
+        assertThat(
+            new EnumKeywordType()
+                .createKeyword(
+                    new DefaultJsonSchemaFactory().create(JsonValue.TRUE),
+                    Json.createArrayBuilder().add(1).build()
+                )
+                .asAssertion()
+                .isValidFor(Json.createValue(1.0)),
+            is(true)
+        );
+    }
+}