Extract YamlJsonTranslator from StandardYamlCoder

Refactored StandardYamlCoder, extracting a new class, YamlJsonTranslator,
from it.  This facilitates performing yaml translation when not using a
standard "gson" coder.
Added YamlJacksonHandler which supports YAML translation layered on
top of a JacksonHandler instead of a GsonMessageBodyHandler.
Also added junit tests to complete coverage of StandardCoder.
Also added public APPLICATION_YAML to YamlMessageBodyHandler.

Change-Id: Ia470fa194661fbf1aebeaf0f18b57f2a984cb64b
Issue-ID: POLICY-2081
Signed-off-by: Jim Hahn <jrh3@att.com>

3 files changed, 81 insertions, 26 deletions

diff --git a/policy-endpoints/src/main/java/org/onap/policy/common/endpoints/http/server/YamlExceptionMapper.java b/policy-endpoints/src/main/java/org/onap/policy/common/endpoints/http/server/YamlExceptionMapper.java
index ac96cab0..7eac932a 100644
--- a/policy-endpoints/src/main/java/org/onap/policy/common/endpoints/http/server/YamlExceptionMapper.java
+++ b/policy-endpoints/src/main/java/org/onap/policy/common/endpoints/http/server/YamlExceptionMapper.java
@@ -34,7 +34,7 @@ import org.yaml.snakeyaml.error.YAMLException;
  * error code to an HTTP 400 error code.
  */
 @Provider
-@Produces("application/yaml")
+@Produces(YamlMessageBodyHandler.APPLICATION_YAML)
 public class YamlExceptionMapper implements ExceptionMapper<YAMLException> {
     private static Logger logger = LoggerFactory.getLogger(YamlExceptionMapper.class);
 
diff --git a/policy-endpoints/src/main/java/org/onap/policy/common/endpoints/http/server/YamlJacksonHandler.java b/policy-endpoints/src/main/java/org/onap/policy/common/endpoints/http/server/YamlJacksonHandler.java
new file mode 100644
index 00000000..0cab374f
--- /dev/null
+++ b/policy-endpoints/src/main/java/org/onap/policy/common/endpoints/http/server/YamlJacksonHandler.java
@@ -0,0 +1,51 @@
+/*
+ * ============LICENSE_START=======================================================
+ * ONAP
+ * ================================================================================
+ * Copyright (C) 2019 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.
+ * ============LICENSE_END=========================================================
+ */
+
+package org.onap.policy.common.endpoints.http.server;
+
+import javax.ws.rs.Consumes;
+import javax.ws.rs.Produces;
+import javax.ws.rs.core.MediaType;
+import javax.ws.rs.ext.Provider;
+import org.onap.policy.common.gson.JacksonHandler;
+import org.onap.policy.common.utils.coder.YamlJsonTranslator;
+
+/**
+ * Provider that serializes and de-serializes YAML via snakeyaml and gson using jackson
+ * default behaviors and annotations.
+ */
+@Provider
+@Consumes(MediaType.WILDCARD)
+@Produces(MediaType.WILDCARD)
+public class YamlJacksonHandler extends YamlMessageBodyHandler {
+
+    /**
+     * Translator to be used. We want a GSON object that's configured the same way as it
+     * is in {@link JacksonHandler}, so just get it from there.
+     */
+    private static final YamlJsonTranslator TRANS = new YamlJsonTranslator(new JacksonHandler().getGson());
+
+    /**
+     * Constructs the object.
+     */
+    public YamlJacksonHandler() {
+        super(TRANS);
+    }
+}
diff --git a/policy-endpoints/src/main/java/org/onap/policy/common/endpoints/http/server/YamlMessageBodyHandler.java b/policy-endpoints/src/main/java/org/onap/policy/common/endpoints/http/server/YamlMessageBodyHandler.java
index 36418e4a..89aa8ff6 100644
--- a/policy-endpoints/src/main/java/org/onap/policy/common/endpoints/http/server/YamlMessageBodyHandler.java
+++ b/policy-endpoints/src/main/java/org/onap/policy/common/endpoints/http/server/YamlMessageBodyHandler.java
@@ -26,7 +26,6 @@ import java.io.InputStream;
 import java.io.InputStreamReader;
 import java.io.OutputStream;
 import java.io.OutputStreamWriter;
-import java.io.Reader;
 import java.lang.annotation.Annotation;
 import java.lang.reflect.Type;
 import java.nio.charset.StandardCharsets;
@@ -37,14 +36,14 @@ import javax.ws.rs.core.MultivaluedMap;
 import javax.ws.rs.ext.MessageBodyReader;
 import javax.ws.rs.ext.MessageBodyWriter;
 import javax.ws.rs.ext.Provider;
-import org.onap.policy.common.utils.coder.CoderException;
-import org.onap.policy.common.utils.coder.StandardYamlCoder;
+import org.onap.policy.common.gson.GsonMessageBodyHandler;
+import org.onap.policy.common.utils.coder.YamlJsonTranslator;
 import org.slf4j.Logger;
 import org.slf4j.LoggerFactory;
 import org.yaml.snakeyaml.error.YAMLException;
 
 /**
- * Provider that serializes and de-serializes JSON via gson.
+ * Provider that serializes and de-serializes YAML via snakeyaml and gson.
  */
 @Provider
 @Consumes(MediaType.WILDCARD)
@@ -53,11 +52,33 @@ public class YamlMessageBodyHandler implements MessageBodyReader<Object>, Messag
 
     public static final Logger logger = LoggerFactory.getLogger(YamlMessageBodyHandler.class);
 
+    public static final String APPLICATION_YAML = "application/yaml";
+
+    /**
+     * Translator that's used when none is specified. We want a GSON object that's
+     * configured the same way as it is in {@link GsonMessageBodyHandler}, so just get it
+     * from there.
+     */
+    private static final YamlJsonTranslator DEFAULT_TRANSLATOR =
+                    new YamlJsonTranslator(new GsonMessageBodyHandler().getGson());
+
+    private final YamlJsonTranslator translator;
+
     /**
      * Constructs the object.
      */
     public YamlMessageBodyHandler() {
+        this(DEFAULT_TRANSLATOR);
+    }
+
+    /**
+     * Constructs the object.
+     *
+     * @param translator translator to use to translate to/from YAML
+     */
+    public YamlMessageBodyHandler(YamlJsonTranslator translator) {
         logger.info("Accepting YAML for REST calls");
+        this.translator = translator;
     }
 
     @Override
@@ -75,10 +96,7 @@ public class YamlMessageBodyHandler implements MessageBodyReader<Object>, Messag
                     MultivaluedMap<String, Object> httpHeaders, OutputStream entityStream) throws IOException {
 
         try (OutputStreamWriter writer = new OutputStreamWriter(entityStream, StandardCharsets.UTF_8)) {
-            new MyYamlCoder().encode(writer, object);
-
-        } catch (CoderException e) {
-            throw new IOException(e);
+            translator.toYaml(writer, object);
         }
     }
 
@@ -104,24 +122,10 @@ public class YamlMessageBodyHandler implements MessageBodyReader<Object>, Messag
 
         try (InputStreamReader streamReader = new InputStreamReader(entityStream, StandardCharsets.UTF_8)) {
             Class<?> clazz = (Class<?>) genericType;
-            return new MyYamlCoder().decode(streamReader, clazz);
-        }
-    }
+            return translator.fromYaml(streamReader, clazz);
 
-    /**
-     * Yaml coder that yields YAMLException on input so that the http servlet can identify
-     * it and generate a bad-request status code. Only the {@link #decode(Reader, Class)}
-     * method must be overridden.
-     */
-    private static class MyYamlCoder extends StandardYamlCoder {
-        @Override
-        public <T> T decode(Reader source, Class<T> clazz) {
-            try {
-                return fromJson(source, clazz);
-
-            } catch (JsonSyntaxException e) {
-                throw new YAMLException(e);
-            }
+        } catch (JsonSyntaxException e) {
+            throw new YAMLException(e);
         }
     }
 }