add avro data wrapper and hides serde classes from public

Signed-off-by: Ning Sun <sunng@protonmail.com>

Author: sunng87

formats/avro/src/main/java/io/cloudevents/avro/AvroCloudEventDataWrapper.java

@@ -0,0 +1,54 @@
+/*
+ * Copyright 2018-Present The CloudEvents Authors
+ * <p>
+ * 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
+ * <p>
+ * http://www.apache.org/licenses/LICENSE-2.0
+ * <p>
+ * 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.
+ *
+ */
+package io.cloudevents.avro;
+
+import java.io.ByteArrayOutputStream;
+import java.io.IOException;
+import java.util.List;
+import java.util.Map;
+
+import io.cloudevents.AvroCloudEventData;
+import io.cloudevents.CloudEventData;
+
+/**
+ * Encode JSON style cloudevent data into Avro format.
+ *
+ */
+public class AvroCloudEventDataWrapper implements CloudEventData {
+
+    private AvroCloudEventData avroCloudEventData;
+
+    /**
+     * Wraps a JSON object-like data structure.
+     */
+    public AvroCloudEventDataWrapper(Map<CharSequence, Object> data) {
+        avroCloudEventData = new AvroCloudEventData();
+        avroCloudEventData.setValue(data);
+    }
+
+    @Override
+    public byte[] toBytes() {
+        ByteArrayOutputStream bytes = new ByteArrayOutputStream();
+        try {
+            AvroCloudEventData.getEncoder().encode(this.avroCloudEventData, bytes);
+        } catch (IOException ignore) {
+            // ignored
+        }
+
+        return bytes.toByteArray();
+    }
+}

formats/avro/src/main/java/io/cloudevents/avro/AvroDeserializer.java

@@ -32,7 +32,7 @@
 import io.cloudevents.rw.CloudEventWriter;
 import io.cloudevents.rw.CloudEventWriterFactory;
 
-public class AvroDeserializer implements CloudEventReader {
+class AvroDeserializer implements CloudEventReader {
 
     private final AvroCloudEvent avroCloudEvent;
 

formats/avro/src/main/java/io/cloudevents/avro/AvroSerializer.java

@@ -24,9 +24,8 @@
 import io.cloudevents.CloudEventData;
 import io.cloudevents.core.v1.CloudEventV1;
 import io.cloudevents.AvroCloudEvent;
-import io.cloudevents.AvroCloudEventData;
 
-public class AvroSerializer {
+class AvroSerializer {
 
     public static final AvroCloudEvent toAvro(CloudEvent e) {
         AvroCloudEvent avroCloudEvent = new AvroCloudEvent();