add support for maxContains keyword

core/pom.xml

@@ -131,6 +131,9 @@
                     <!-- more than items keyword needed :(
                     <include>**/tests/draft2020-12/items.json</include>
                     -->
+                    <!-- needs minContains too :(
+                    <include>**/tests/draft2020-12/maxContains.json</include>
+                    -->
                     <include>**/tests/draft2020-12/maxItems.json</include>
                     <include>**/tests/draft2020-12/maxLength.json</include>
                     <include>**/tests/draft2020-12/maximum.json</include>

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

@@ -0,0 +1,116 @@
+/*
+ * The MIT License
+ *
+ * Copyright 2024 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 io.github.sebastiantoepfer.ddd.common.Media;
+import io.github.sebastiantoepfer.jsonschema.InstanceType;
+import io.github.sebastiantoepfer.jsonschema.JsonSchema;
+import io.github.sebastiantoepfer.jsonschema.core.keyword.type.IntegerKeywordType;
+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.JsonValue;
+import jakarta.json.spi.JsonProvider;
+import java.math.BigInteger;
+import java.util.Objects;
+
+/**
+ * <b>minProperties</b> : <i>Integer</i>
+ * An object instance is valid if its number of properties is less than, or equal to, the value of this keyword.<br/>
+ * keyword.<br/>
+ * <br/>
+ * <ul>
+ * <li>assertion</li>
+ * </ul>
+ *
+ * source: https://www.learnjsonschema.com/2020-12/validation/maxcontains/
+ * spec: https://json-schema.org/draft/2020-12/json-schema-validation.html#section-6.4.4
+ */
+final class MaxContainsKeywordType implements KeywordType {
+
+    private final JsonProvider jsonContext;
+
+    public MaxContainsKeywordType(final JsonProvider jsonContext) {
+        this.jsonContext = jsonContext;
+    }
+
+    @Override
+    public String name() {
+        return "maxContains";
+    }
+
+    @Override
+    public Keyword createKeyword(final JsonSchema schema) {
+        return new IntegerKeywordType(
+            jsonContext,
+            name(),
+            value -> new MaxContainsKeyword(schema, value)
+        ).createKeyword(schema);
+    }
+
+    private final class MaxContainsKeyword implements Assertion {
+
+        private final JsonSchema owner;
+        private final BigInteger maxContains;
+
+        public MaxContainsKeyword(final JsonSchema owner, final BigInteger maxContains) {
+            this.owner = Objects.requireNonNull(owner);
+            this.maxContains = Objects.requireNonNull(maxContains);
+        }
+
+        @Override
+        public boolean hasName(final String name) {
+            return Objects.equals(name(), name);
+        }
+
+        @Override
+        public <T extends Media<T>> T printOn(final T media) {
+            return media.withValue(name(), maxContains);
+        }
+
+        @Override
+        public boolean isValidFor(final JsonValue instance) {
+            return (
+                !InstanceType.ARRAY.isInstance(instance) ||
+                owner
+                    .keywordByName("contains")
+                    .map(Keyword::asAnnotation)
+                    .map(annotation -> annotation.valueFor(instance))
+                    .map(contains -> isValidFor(contains, instance.asJsonArray()))
+                    .orElse(true)
+            );
+        }
+
+        private boolean isValidFor(final JsonValue containing, final JsonArray values) {
+            final boolean result;
+            if (JsonValue.TRUE.equals(containing)) {
+                result = values.size() <= maxContains.intValue();
+            } else {
+                result = containing.asJsonArray().size() <= maxContains.intValue();
+            }
+            return result;
+        }
+    }
+}

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

@@ -0,0 +1,189 @@
+/*
+ * The MIT License
+ *
+ * Copyright 2024 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.hasEntry;
+import static org.hamcrest.Matchers.is;
+
+import io.github.sebastiantoepfer.ddd.media.core.HashMapMedia;
+import io.github.sebastiantoepfer.jsonschema.core.DefaultJsonSchemaFactory;
+import io.github.sebastiantoepfer.jsonschema.keyword.Keyword;
+import jakarta.json.Json;
+import jakarta.json.JsonObject;
+import jakarta.json.JsonValue;
+import jakarta.json.spi.JsonProvider;
+import java.math.BigInteger;
+import org.hamcrest.Matcher;
+import org.junit.jupiter.api.Test;
+
+class MaxContainsKeywordTypeTest {
+
+    @Test
+    void should_know_his_name() {
+        final Keyword enumKeyword = createKeywordFrom(Json.createObjectBuilder().add("maxContains", 2).build());
+
+        assertThat(enumKeyword.hasName("maxContains"), is(true));
+        assertThat(enumKeyword.hasName("test"), is(false));
+    }
+
+    @Test
+    void should_be_printable() {
+        assertThat(
+            createKeywordFrom(Json.createObjectBuilder().add("maxContains", 2).build()).printOn(new HashMapMedia()),
+            (Matcher) hasEntry(is("maxContains"), is(BigInteger.valueOf(2)))
+        );
+    }
+
+    @Test
+    void should_be_valid_for_non_arrays() {
+        assertThat(
+            createKeywordFrom(Json.createObjectBuilder().add("maxContains", 2).build())
+                .asAssertion()
+                .isValidFor(JsonValue.EMPTY_JSON_OBJECT),
+            is(true)
+        );
+    }
+
+    @Test
+    void should_be_valid_if_no_contains_is_present() {
+        assertThat(
+            createKeywordFrom(Json.createObjectBuilder().add("maxContains", 2).build())
+                .asAssertion()
+                .isValidFor(Json.createArrayBuilder().add("foo").build()),
+            is(true)
+        );
+    }
+
+    @Test
+    void should_be_valid_if_contains_applies_to_exact_count() {
+        assertThat(
+            createKeywordFrom(
+                Json.createObjectBuilder()
+                    .add("contains", Json.createObjectBuilder().add("type", "string"))
+                    .add("maxContains", 2)
+                    .build()
+            )
+                .asAssertion()
+                .isValidFor(Json.createArrayBuilder().add("foo").add("bar").add(1).build()),
+            is(true)
+        );
+    }
+
+    @Test
+    void should_be_valid_if_contains_applies_to_less_items() {
+        assertThat(
+            createKeywordFrom(
+                Json.createObjectBuilder()
+                    .add("contains", Json.createObjectBuilder().add("type", "string"))
+                    .add("maxContains", 2)
+                    .build()
+            )
+                .asAssertion()
+                .isValidFor(Json.createArrayBuilder().add("foo").add(2).add(3).build()),
+            is(true)
+        );
+    }
+
+    @Test
+    void should_be_valid_for_empty_arrays() {
+        assertThat(
+            createKeywordFrom(
+                Json.createObjectBuilder()
+                    .add("contains", Json.createObjectBuilder().add("type", "string"))
+                    .add("maxContains", 2)
+                    .build()
+            )
+                .asAssertion()
+                .isValidFor(JsonValue.EMPTY_JSON_ARRAY),
+            is(true)
+        );
+    }
+
+    @Test
+    void should_be_invalid_if_contains_applies_to_more_items() {
+        assertThat(
+            createKeywordFrom(
+                Json.createObjectBuilder()
+                    .add("contains", Json.createObjectBuilder().add("type", "string"))
+                    .add("maxContains", 2)
+                    .build()
+            )
+                .asAssertion()
+                .isValidFor(Json.createArrayBuilder().add("foo").add("bar").add(1).add("baz").build()),
+            is(false)
+        );
+    }
+
+    @Test
+    void should_be_valid_if_contains_applies_to_all_and_less_items_in_array() {
+        assertThat(
+            createKeywordFrom(
+                Json.createObjectBuilder()
+                    .add("contains", Json.createObjectBuilder().add("type", "string"))
+                    .add("maxContains", 2)
+                    .build()
+            )
+                .asAssertion()
+                .isValidFor(Json.createArrayBuilder().add("foo").build()),
+            is(true)
+        );
+    }
+
+    @Test
+    void should_be_valid_if_contains_applies_to_all_and_exact_items_count_in_array() {
+        assertThat(
+            createKeywordFrom(
+                Json.createObjectBuilder()
+                    .add("contains", Json.createObjectBuilder().add("type", "string"))
+                    .add("maxContains", 2)
+                    .build()
+            )
+                .asAssertion()
+                .isValidFor(Json.createArrayBuilder().add("foo").add("bar").build()),
+            is(true)
+        );
+    }
+
+    @Test
+    void should_be_invalid_if_contains_applies_to_all_and_more_items_in_array() {
+        assertThat(
+            createKeywordFrom(
+                Json.createObjectBuilder()
+                    .add("contains", Json.createObjectBuilder().add("type", "string"))
+                    .add("maxContains", 2)
+                    .build()
+            )
+                .asAssertion()
+                .isValidFor(Json.createArrayBuilder().add("foo").add("bar").add("baz").build()),
+            is(false)
+        );
+    }
+
+    private static Keyword createKeywordFrom(final JsonObject json) {
+        return new MaxContainsKeywordType(JsonProvider.provider()).createKeyword(
+            new DefaultJsonSchemaFactory().create(json)
+        );
+    }
+}