Schema validation extension to StandardCoder

Issue-ID: POLICY-2331
Signed-off-by: jhh <jorge.hernandez-herrero@att.com>
Change-Id: Ic3e8d21715d17a61ea5d07740dd9f4dd0dbb8641
Signed-off-by: jhh <jorge.hernandez-herrero@att.com>

2 files changed, 115 insertions, 6 deletions

diff --git a/utils/src/main/java/org/onap/policy/common/utils/coder/StandardCoder.java b/utils/src/main/java/org/onap/policy/common/utils/coder/StandardCoder.java
index e84a92f2..26746b79 100644
--- a/utils/src/main/java/org/onap/policy/common/utils/coder/StandardCoder.java
+++ b/utils/src/main/java/org/onap/policy/common/utils/coder/StandardCoder.java
@@ -1,8 +1,8 @@
 /*
  * ============LICENSE_START=======================================================
- * ONAP PAP
+ * ONAP
  * ================================================================================
- * Copyright (C) 2019 AT&T Intellectual Property. All rights reserved.
+ * Copyright (C) 2019-2020 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.
@@ -78,7 +78,7 @@ public class StandardCoder implements Coder {
         try {
             toJson(target, object);
 
-        } catch (RuntimeException | IOException e) {
+        } catch (RuntimeException e) {
             throw new CoderException(e);
         }
     }
@@ -238,9 +238,8 @@ public class StandardCoder implements Coder {
      *
      * @param target target to which to write the encoded json
      * @param object object to be encoded
-     * @throws IOException if an I/O error occurs
      */
-    protected void toJson(Writer target, Object object) throws IOException {
+    protected void toJson(Writer target, Object object) {
         GSON.toJson(object, object.getClass(), target);
     }
 
@@ -286,7 +285,7 @@ public class StandardCoder implements Coder {
      * @param value value to be converted
      * @return the converted value
      */
-    private <T> T convertFromDouble(Class<T> clazz, T value) {
+    protected <T> T convertFromDouble(Class<T> clazz, T value) {
         if (clazz != Object.class) {
             return value;
         }
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..378254b8
--- /dev/null
+++ b/utils/src/main/java/org/onap/policy/common/utils/coder/StandardValCoder.java
@@ -0,0 +1,110 @@
+/*
+ * ============LICENSE_START=======================================================
+ *  Copyright (C) 2020 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 toJson(@NonNull Object object) {
+        StringWriter output = new StringWriter();
+        toJson(output, object);
+        return String.valueOf(output);
+    }
+
+    @Override
+    protected void toJson(@NonNull Writer target, @NonNull Object object) {
+        getGSON().toJson(object, object.getClass(), validatorApi.createJsonWriter(validator, target));
+    }
+
+    @Override
+    protected <T> T fromJson(@NonNull Reader source, @NonNull Class<T> clazz) {
+        return convertFromDouble(clazz, getGSON().fromJson(validatorApi.createJsonReader(validator, source), clazz));
+    }
+
+    @Override
+    protected <T> T fromJson(String json, Class<T> clazz) {
+        StringReader reader = new StringReader(json);
+        return convertFromDouble(clazz, getGSON().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);
+        }
+    }
+}