1 files changed, 119 insertions, 0 deletions
diff --git a/utils/src/main/java/org/onap/policy/common/utils/coder/StandardValCoder.java b/utils/src/main/java/org/onap/policy/common/utils/coder/StandardValCoder.java
new file mode 100644
index 00000000..4deeba14
--- /dev/null
+++ b/utils/src/main/java/org/onap/policy/common/utils/coder/StandardValCoder.java
@@ -0,0 +1,119 @@
+/*--
+ * ============LICENSE_START=======================================================
+ *  Copyright (C) 2020-2021 AT&T Intellectual Property. All rights reserved.
+ * ================================================================================
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ *
+ * SPDX-License-Identifier: Apache-2.0
+ * ============LICENSE_END=========================================================
+ */
+
+package org.onap.policy.common.utils.coder;
+
+import com.worldturner.medeia.api.JsonSchemaVersion;
+import com.worldturner.medeia.api.SchemaSource;
+import com.worldturner.medeia.api.StringSchemaSource;
+import com.worldturner.medeia.api.ValidationFailedException;
+import com.worldturner.medeia.api.gson.MedeiaGsonApi;
+import com.worldturner.medeia.schema.validation.SchemaValidator;
+import java.io.Reader;
+import java.io.StringReader;
+import java.io.StringWriter;
+import java.io.Writer;
+import lombok.NonNull;
+import lombok.ToString;
+import org.slf4j.Logger;
+import org.slf4j.LoggerFactory;
+
+/**
+ * Extension to the StandardCoder to support streaming validation against a Draft-07 Json schema specification.
+ */
+
+@ToString
+public class StandardValCoder extends StandardCoder {
+
+    // The medeia-validator library integrates better than
+    // other libraries considered with GSON, and therefore
+    // the StandardCoder.
+
+    private static final Logger logger = LoggerFactory.getLogger(StandardValCoder.class);
+
+    private final MedeiaGsonApi validatorApi = new MedeiaGsonApi();
+    private final SchemaValidator validator;
+
+    /**
+     * StandardCoder with validation.
+     */
+    public StandardValCoder(@NonNull String jsonSchema, @NonNull String name) {
+        SchemaSource schemaSource = new StringSchemaSource(jsonSchema, JsonSchemaVersion.DRAFT07, null, name);
+        this.validator = validatorApi.loadSchema(schemaSource);
+    }
+
+    @Override
+    protected String toPrettyJson(Object object) {
+        /*
+         * The validator strips off the "pretty" stuff (i.e., spaces), thus we have to validate and generate the pretty
+         * JSON in separate steps.
+         */
+        gson.toJson(object, object.getClass(), validatorApi.createJsonWriter(validator, new StringWriter()));
+
+        return super.toPrettyJson(object);
+    }
+
+    @Override
+    protected String toJson(@NonNull Object object) {
+        var output = new StringWriter();
+        toJson(output, object);
+        return output.toString();
+    }
+
+    @Override
+    protected void toJson(@NonNull Writer target, @NonNull Object object) {
+        gson.toJson(object, object.getClass(), validatorApi.createJsonWriter(validator, target));
+    }
+
+    @Override
+    protected <T> T fromJson(@NonNull Reader source, @NonNull Class<T> clazz) {
+        return convertFromDouble(clazz, gson.fromJson(validatorApi.createJsonReader(validator, source), clazz));
+    }
+
+    @Override
+    protected <T> T fromJson(String json, Class<T> clazz) {
+        var reader = new StringReader(json);
+        return convertFromDouble(clazz, gson.fromJson(validatorApi.createJsonReader(validator, reader), clazz));
+    }
+
+    /**
+     * Is the json conformant?.
+     */
+    public boolean isConformant(@NonNull String json) {
+        try {
+            conformance(json);
+        } catch (CoderException e) {
+            logger.info("JSON is not conformant to schema", e);
+            return false;
+        }
+        return true;
+    }
+
+    /**
+     * Check a json string for conformance against its schema definition.
+     */
+    public void conformance(@NonNull String json) throws CoderException {
+        try {
+            validatorApi.parseAll(validatorApi.createJsonReader(validator, new StringReader(json)));
+        } catch (ValidationFailedException e) {
+            throw new CoderException(e);
+        }
+    }
+}