1 files changed, 124 insertions, 0 deletions
diff --git a/gson/src/main/java/org/onap/policy/common/gson/GsonMessageBodyHandler.java b/gson/src/main/java/org/onap/policy/common/gson/GsonMessageBodyHandler.java
new file mode 100644
index 00000000..2112c97c
--- /dev/null
+++ b/gson/src/main/java/org/onap/policy/common/gson/GsonMessageBodyHandler.java
@@ -0,0 +1,124 @@
+/*
+ * ============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.gson;
+
+import com.google.gson.Gson;
+import java.io.IOException;
+import java.io.InputStream;
+import java.io.InputStreamReader;
+import java.io.OutputStream;
+import java.io.OutputStreamWriter;
+import java.lang.annotation.Annotation;
+import java.lang.reflect.Type;
+import java.nio.charset.StandardCharsets;
+import javax.ws.rs.Consumes;
+import javax.ws.rs.Produces;
+import javax.ws.rs.WebApplicationException;
+import javax.ws.rs.core.MediaType;
+import javax.ws.rs.core.MultivaluedMap;
+import javax.ws.rs.ext.MessageBodyReader;
+import javax.ws.rs.ext.MessageBodyWriter;
+import javax.ws.rs.ext.Provider;
+
+/**
+ * Provider that serializes and de-serializes JSON via gson.
+ */
+@Provider
+@Consumes(MediaType.WILDCARD)
+@Produces(MediaType.WILDCARD)
+public class GsonMessageBodyHandler implements MessageBodyReader<Object>, MessageBodyWriter<Object> {
+
+    /**
+     * Object to be used to serialize and de-serialize.
+     */
+    private Gson gson;
+
+    /**
+     * Constructs the object, using a plain Gson object.
+     */
+    public GsonMessageBodyHandler() {
+        this(new Gson());
+    }
+
+    /**
+     * Constructs the object.
+     *
+     * @param gson the Gson object to be used to serialize and de-serialize
+     */
+    public GsonMessageBodyHandler(Gson gson) {
+        this.gson = gson;
+    }
+
+    @Override
+    public boolean isWriteable(Class<?> type, Type genericType, Annotation[] annotations, MediaType mediaType) {
+        return canHandle(mediaType);
+    }
+
+    @Override
+    public long getSize(Object object, Class<?> type, Type genericType, Annotation[] annotations, MediaType mediaType) {
+        return -1;
+    }
+
+    @Override
+    public void writeTo(Object object, Class<?> type, Type genericType, Annotation[] annotations, MediaType mediaType,
+                    MultivaluedMap<String, Object> httpHeaders, OutputStream entityStream)
+                    throws IOException, WebApplicationException {
+
+        try (OutputStreamWriter writer = new OutputStreamWriter(entityStream, StandardCharsets.UTF_8)) {
+            Type jsonType = (type.equals(genericType) ? type : genericType);
+            gson.toJson(object, jsonType, writer);
+        }
+    }
+
+    @Override
+    public boolean isReadable(Class<?> type, Type genericType, Annotation[] annotations, MediaType mediaType) {
+        return canHandle(mediaType);
+    }
+
+    /**
+     * Determines if this provider can handle the given media type.
+     *
+     * @param mediaType the media type of interest
+     * @return {@code true} if this provider handles the given media type, {@code false}
+     *         otherwise
+     */
+    private boolean canHandle(MediaType mediaType) {
+        if (mediaType == null) {
+            return true;
+        }
+
+        String subtype = mediaType.getSubtype();
+
+        return "json".equalsIgnoreCase(subtype) || subtype.endsWith("+json") || "javascript".equals(subtype)
+                        || "x-javascript".equals(subtype) || "x-json".equals(subtype);
+    }
+
+    @Override
+    public Object readFrom(Class<Object> type, Type genericType, Annotation[] annotations, MediaType mediaType,
+                    MultivaluedMap<String, String> httpHeaders, InputStream entityStream)
+                    throws IOException, WebApplicationException {
+
+        try (InputStreamReader streamReader = new InputStreamReader(entityStream, StandardCharsets.UTF_8)) {
+            Type jsonType = (type.equals(genericType) ? type : genericType);
+            return gson.fromJson(streamReader, jsonType);
+        }
+    }
+}