Rework Gson in Camel

Create new Camel DataFormat class to handle the Clamp JSon model
specific type

Issue-ID: CLAMP-303
Change-Id: I2abd173c7d2a96a03d333a8def4307bc3cf082d7
Signed-off-by: sebdet <sebastien.determe@intl.att.com>

3 files changed, 178 insertions, 64 deletions

diff --git a/src/main/java/org/onap/clamp/clds/config/CamelConfiguration.java b/src/main/java/org/onap/clamp/clds/config/CamelConfiguration.java
index c3b24bc81..f178ce039 100644
--- a/src/main/java/org/onap/clamp/clds/config/CamelConfiguration.java
+++ b/src/main/java/org/onap/clamp/clds/config/CamelConfiguration.java
@@ -36,7 +36,7 @@ public class CamelConfiguration extends RouteBuilder {
 
     @Override
     public void configure() {
-        restConfiguration().component("servlet").bindingMode(RestBindingMode.json).jsonDataFormat("json-gson")
+        restConfiguration().component("servlet").bindingMode(RestBindingMode.json).jsonDataFormat("clamp-gson")
             .dataFormatProperty("prettyPrint", "true")// .enableCORS(true)
             // turn on swagger api-doc
             .apiContextPath("api-doc").apiVendorExtension(true).apiProperty("api.title", "Clamp Rest API")
diff --git a/src/main/java/org/onap/clamp/configuration/CamelGsonConfiguration.java b/src/main/java/org/onap/clamp/configuration/CamelGsonConfiguration.java
deleted file mode 100644
index f71d2f091..000000000
--- a/src/main/java/org/onap/clamp/configuration/CamelGsonConfiguration.java
+++ /dev/null
@@ -1,63 +0,0 @@
-/*-
- * ============LICENSE_START=======================================================
- * ONAP CLAMP
- * ================================================================================
- * Copyright (C) 2019 Nokia 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.clamp.configuration;
-
-import com.google.gson.ExclusionStrategy;
-import com.google.gson.FieldAttributes;
-import com.google.gson.annotations.Expose;
-import java.util.Collections;
-import java.util.List;
-import java.util.Optional;
-import org.apache.camel.component.gson.GsonDataFormat;
-import org.apache.camel.spi.DataFormatCustomizer;
-import org.springframework.context.annotation.Bean;
-import org.springframework.context.annotation.Configuration;
-
-@Configuration
-public class CamelGsonConfiguration {
-
-    @Bean
-    public List<DataFormatCustomizer<GsonDataFormat>> provideGsonCustomizers() {
-        DataFormatCustomizer<GsonDataFormat> dataFormatCustomizer = dataformat ->
-            dataformat.setExclusionStrategies(
-                Collections.singletonList(new ExcludeFieldsWithoutExposedAnnotation())
-            );
-        return Collections.singletonList(dataFormatCustomizer);
-    }
-
-    private static class ExcludeFieldsWithoutExposedAnnotation implements ExclusionStrategy {
-
-        @Override
-        public boolean shouldSkipField(FieldAttributes f) {
-            return Optional.ofNullable(f.getAnnotation(Expose.class))
-                .map(expose -> !expose.serialize())
-                .orElse(true);
-        }
-
-        @Override
-        public boolean shouldSkipClass(Class<?> clazz) {
-            return false;
-        }
-    }
-}
diff --git a/src/main/java/org/onap/clamp/configuration/ClampGsonDataFormat.java b/src/main/java/org/onap/clamp/configuration/ClampGsonDataFormat.java
new file mode 100644
index 000000000..aad1ab4c7
--- /dev/null
+++ b/src/main/java/org/onap/clamp/configuration/ClampGsonDataFormat.java
@@ -0,0 +1,177 @@
+/*-
+ * ============LICENSE_START=======================================================
+ * ONAP CLAMP
+ * ================================================================================
+ * 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.clamp.configuration;
+
+import com.google.gson.Gson;
+
+import java.io.BufferedReader;
+import java.io.BufferedWriter;
+import java.io.InputStream;
+import java.io.InputStreamReader;
+import java.io.OutputStream;
+import java.io.OutputStreamWriter;
+import java.lang.reflect.Type;
+import java.nio.charset.StandardCharsets;
+
+import org.apache.camel.Exchange;
+import org.apache.camel.spi.DataFormat;
+import org.apache.camel.spi.DataFormatName;
+import org.apache.camel.support.ServiceSupport;
+import org.apache.camel.util.IOHelper;
+import org.onap.clamp.clds.util.JsonUtils;
+
+public class ClampGsonDataFormat extends ServiceSupport implements DataFormat, DataFormatName {
+    private Gson gson;
+    private Class<?> unmarshalType;
+    private Type unmarshalGenericType;
+    private boolean contentTypeHeader = true;
+
+    public ClampGsonDataFormat() {
+        this(Object.class);
+    }
+
+    /**
+     * Use the default Gson {@link Gson} and with a custom unmarshal type
+     *
+     * @param unmarshalType
+     *        the custom unmarshal type
+     */
+    public ClampGsonDataFormat(Class<?> unmarshalType) {
+        this(null, unmarshalType);
+    }
+
+    /**
+     * Use a custom Gson mapper and and unmarshal type
+     *
+     * @param gson
+     *        the custom mapper
+     * @param unmarshalType
+     *        the custom unmarshal type
+     */
+    public ClampGsonDataFormat(Gson gson, Class<?> unmarshalType) {
+        this.gson = gson;
+        this.unmarshalType = unmarshalType;
+    }
+
+    /**
+     * Use the default Gson {@link Gson} and with a custom unmarshal generic type
+     *
+     * @param unmarshalGenericType
+     *        the custom unmarshal generic type
+     */
+    public ClampGsonDataFormat(Type unmarshalGenericType) {
+        this(null, unmarshalGenericType);
+    }
+
+    /**
+     * Use a custom Gson mapper and and unmarshal token type
+     *
+     * @param gson
+     *        the custom mapper
+     * @param unmarshalGenericType
+     *        the custom unmarshal generic type
+     */
+    public ClampGsonDataFormat(Gson gson, Type unmarshalGenericType) {
+        this.gson = gson;
+        this.unmarshalGenericType = unmarshalGenericType;
+    }
+
+    @Override
+    public String getDataFormatName() {
+        return "clamp-gson";
+    }
+
+    @Override
+    public void marshal(final Exchange exchange, final Object graph, final OutputStream stream) throws Exception {
+        try (final OutputStreamWriter osw = new OutputStreamWriter(stream, StandardCharsets.UTF_8);
+            final BufferedWriter writer = IOHelper.buffered(osw)) {
+            gson.toJson(graph, writer);
+        }
+
+        if (contentTypeHeader) {
+            if (exchange.hasOut()) {
+                exchange.getOut().setHeader(Exchange.CONTENT_TYPE, "application/json");
+            } else {
+                exchange.getIn().setHeader(Exchange.CONTENT_TYPE, "application/json");
+            }
+        }
+    }
+
+    @Override
+    public Object unmarshal(final Exchange exchange, final InputStream stream) throws Exception {
+        try (final InputStreamReader isr = new InputStreamReader(stream, StandardCharsets.UTF_8);
+            final BufferedReader reader = IOHelper.buffered(isr)) {
+            if (unmarshalGenericType == null) {
+                return gson.fromJson(reader, unmarshalType);
+            } else {
+                return gson.fromJson(reader, unmarshalGenericType);
+            }
+        }
+    }
+
+    @Override
+    protected void doStart() throws Exception {
+        if (gson == null) {
+            gson = JsonUtils.GSON_JPA_MODEL;
+        }
+    }
+
+    @Override
+    protected void doStop() throws Exception {
+        // noop
+    }
+
+    // Properties
+    // -------------------------------------------------------------------------
+
+    public Class<?> getUnmarshalType() {
+        return this.unmarshalType;
+    }
+
+    public void setUnmarshalType(Class<?> unmarshalType) {
+        this.unmarshalType = unmarshalType;
+    }
+
+    public Type getUnmarshalGenericType() {
+        return this.unmarshalType;
+    }
+
+    public void setUnmarshalGenericType(Type unmarshalGenericType) {
+        this.unmarshalGenericType = unmarshalGenericType;
+    }
+
+    public boolean isContentTypeHeader() {
+        return contentTypeHeader;
+    }
+
+    /**
+     * If enabled then Gson will set the Content-Type header to
+     * <tt>application/json</tt> when marshalling.
+     */
+    public void setContentTypeHeader(boolean contentTypeHeader) {
+        this.contentTypeHeader = contentTypeHeader;
+    }
+
+    public Gson getGson() {
+        return this.gson;
+    }
+}