feat: Added ODP RestApi interface for sending Events to ODP (#485)

## Summary
This module provides an internal service for ODP event REST api access.

## Test plan
- Manually tested thoroughly.
- Added new unit tests.
- All Existing Unit tests pass.
- All existing Full stack compatibility tests pass.

## Jira
[OASIS-8387](https://optimizely.atlassian.net/browse/OASIS-8387)

core-api/src/main/java/com/optimizely/ab/odp/ODPApiManager.java

@@ -19,4 +19,6 @@
 
 public interface ODPApiManager {
     String fetchQualifiedSegments(String apiKey, String apiEndpoint, String userKey, String userValue, List<String> segmentsToCheck);
+
+    Integer sendEvents(String apiKey, String apiEndpoint, String eventPayload);
 }

core-api/src/main/java/com/optimizely/ab/odp/ODPEvent.java

@@ -0,0 +1,64 @@
+/**
+ *    Copyright 2022, Optimizely Inc. and contributors
+ *
+ *    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.
+ */
+package com.optimizely.ab.odp;
+
+import java.util.Map;
+
+public class ODPEvent {
+    private String type;
+    private String action;
+    private Map<String, String > identifiers;
+    private Map<String, Object> data;
+
+    public ODPEvent(String type, String action, Map<String, String> identifiers, Map<String, Object> data) {
+        this.type = type;
+        this.action = action;
+        this.identifiers = identifiers;
+        this.data = data;
+    }
+
+    public String getType() {
+        return type;
+    }
+
+    public void setType(String type) {
+        this.type = type;
+    }
+
+    public String getAction() {
+        return action;
+    }
+
+    public void setAction(String action) {
+        this.action = action;
+    }
+
+    public Map<String, String> getIdentifiers() {
+        return identifiers;
+    }
+
+    public void setIdentifiers(Map<String, String> identifiers) {
+        this.identifiers = identifiers;
+    }
+
+    public Map<String, Object> getData() {
+        return data;
+    }
+
+    public void setData(Map<String, Object> data) {
+        this.data = data;
+    }
+}

core-api/src/main/java/com/optimizely/ab/odp/serializer/ODPJsonSerializer.java

@@ -0,0 +1,24 @@
+/**
+ *    Copyright 2022, Optimizely Inc. and contributors
+ *
+ *    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.
+ */
+package com.optimizely.ab.odp.serializer;
+
+import com.optimizely.ab.odp.ODPEvent;
+
+import java.util.List;
+
+public interface ODPJsonSerializer {
+    public String serializeEvents(List<ODPEvent> events);
+}

core-api/src/main/java/com/optimizely/ab/odp/serializer/ODPJsonSerializerFactory.java

@@ -0,0 +1,49 @@
+/**
+ *    Copyright 2022, Optimizely Inc. and contributors
+ *
+ *    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.
+ */
+package com.optimizely.ab.odp.serializer;
+
+import com.optimizely.ab.internal.JsonParserProvider;
+import com.optimizely.ab.odp.serializer.impl.GsonSerializer;
+import com.optimizely.ab.odp.serializer.impl.JacksonSerializer;
+import com.optimizely.ab.odp.serializer.impl.JsonSerializer;
+import com.optimizely.ab.odp.serializer.impl.JsonSimpleSerializer;
+import org.slf4j.Logger;
+import org.slf4j.LoggerFactory;
+
+public class ODPJsonSerializerFactory {
+    private static final Logger logger = LoggerFactory.getLogger(ODPJsonSerializerFactory.class);
+
+    public static ODPJsonSerializer getSerializer() {
+        JsonParserProvider parserProvider = JsonParserProvider.getDefaultParser();
+        ODPJsonSerializer jsonSerializer = null;
+        switch (parserProvider) {
+            case GSON_CONFIG_PARSER:
+                jsonSerializer = new GsonSerializer();
+                break;
+            case JACKSON_CONFIG_PARSER:
+                jsonSerializer = new JacksonSerializer();
+                break;
+            case JSON_CONFIG_PARSER:
+                jsonSerializer = new JsonSerializer();
+                break;
+            case JSON_SIMPLE_CONFIG_PARSER:
+                jsonSerializer = new JsonSimpleSerializer();
+                break;
+        }
+        logger.info("Using " + parserProvider.toString() + " serializer");
+        return jsonSerializer;
+    }
+}

core-api/src/main/java/com/optimizely/ab/odp/serializer/impl/GsonSerializer.java

@@ -0,0 +1,31 @@
+/**
+ *    Copyright 2022, Optimizely Inc. and contributors
+ *
+ *    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.
+ */
+package com.optimizely.ab.odp.serializer.impl;
+
+import com.google.gson.Gson;
+import com.google.gson.GsonBuilder;
+import com.optimizely.ab.odp.ODPEvent;
+import com.optimizely.ab.odp.serializer.ODPJsonSerializer;
+
+import java.util.List;
+
+public class GsonSerializer implements ODPJsonSerializer {
+    @Override
+    public String serializeEvents(List<ODPEvent> events) {
+        Gson gson = new GsonBuilder().serializeNulls().create();
+        return gson.toJson(events);
+    }
+}

core-api/src/main/java/com/optimizely/ab/odp/serializer/impl/JacksonSerializer.java

@@ -0,0 +1,36 @@
+/**
+ *    Copyright 2022, Optimizely Inc. and contributors
+ *
+ *    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.
+ */
+package com.optimizely.ab.odp.serializer.impl;
+
+import com.fasterxml.jackson.core.JsonProcessingException;
+import com.fasterxml.jackson.databind.ObjectMapper;
+import com.optimizely.ab.odp.ODPEvent;
+import com.optimizely.ab.odp.serializer.ODPJsonSerializer;
+
+import java.util.List;
+
+public class JacksonSerializer implements ODPJsonSerializer {
+    @Override
+    public String serializeEvents(List<ODPEvent> events) {
+        ObjectMapper objectMapper = new ObjectMapper();
+        try {
+            return objectMapper.writeValueAsString(events);
+        } catch (JsonProcessingException e) {
+            // log error here
+        }
+        return null;
+    }
+}

core-api/src/main/java/com/optimizely/ab/odp/serializer/impl/JsonSerializer.java

@@ -0,0 +1,59 @@
+/**
+ *    Copyright 2022, Optimizely Inc. and contributors
+ *
+ *    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.
+ */
+package com.optimizely.ab.odp.serializer.impl;
+
+import com.optimizely.ab.odp.ODPEvent;
+import com.optimizely.ab.odp.serializer.ODPJsonSerializer;
+import org.json.JSONArray;
+import org.json.JSONObject;
+
+import java.util.List;
+import java.util.Map;
+
+public class JsonSerializer implements ODPJsonSerializer {
+    @Override
+    public String serializeEvents(List<ODPEvent> events) {
+        JSONArray jsonArray = new JSONArray();
+        for (ODPEvent event: events) {
+            JSONObject eventObject = new JSONObject();
+            eventObject.put("type", event.getType());
+            eventObject.put("action", event.getAction());
+
+            if (event.getIdentifiers() != null) {
+                JSONObject identifiers = new JSONObject();
+                for (Map.Entry<String, String> identifier : event.getIdentifiers().entrySet()) {
+                    identifiers.put(identifier.getKey(), identifier.getValue());
+                }
+                eventObject.put("identifiers", identifiers);
+            }
+
+            if (event.getData() != null) {
+                JSONObject data = new JSONObject();
+                for (Map.Entry<String, Object> dataEntry : event.getData().entrySet()) {
+                    data.put(dataEntry.getKey(), getJSONObjectValue(dataEntry.getValue()));
+                }
+                eventObject.put("data", data);
+            }
+
+            jsonArray.put(eventObject);
+        }
+        return jsonArray.toString();
+    }
+
+    private static Object getJSONObjectValue(Object value)  {
+        return value == null ? JSONObject.NULL : value;
+    }
+}

core-api/src/main/java/com/optimizely/ab/odp/serializer/impl/JsonSimpleSerializer.java

@@ -0,0 +1,55 @@
+/**
+ *    Copyright 2022, Optimizely Inc. and contributors
+ *
+ *    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.
+ */
+package com.optimizely.ab.odp.serializer.impl;
+
+import com.optimizely.ab.odp.ODPEvent;
+import com.optimizely.ab.odp.serializer.ODPJsonSerializer;
+import org.json.simple.JSONArray;
+import org.json.simple.JSONObject;
+
+import java.util.List;
+import java.util.Map;
+
+public class JsonSimpleSerializer implements ODPJsonSerializer {
+    @Override
+    public String serializeEvents(List<ODPEvent> events) {
+        JSONArray jsonArray = new JSONArray();
+        for (ODPEvent event: events) {
+            JSONObject eventObject = new JSONObject();
+            eventObject.put("type", event.getType());
+            eventObject.put("action", event.getAction());
+
+            if (event.getIdentifiers() != null) {
+                JSONObject identifiers = new JSONObject();
+                for (Map.Entry<String, String> identifier : event.getIdentifiers().entrySet()) {
+                    identifiers.put(identifier.getKey(), identifier.getValue());
+                }
+                eventObject.put("identifiers", identifiers);
+            }
+
+            if (event.getData() != null) {
+                JSONObject data = new JSONObject();
+                for (Map.Entry<String, Object> dataEntry : event.getData().entrySet()) {
+                    data.put(dataEntry.getKey(), dataEntry.getValue());
+                }
+                eventObject.put("data", data);
+            }
+
+            jsonArray.add(eventObject);
+        }
+        return jsonArray.toJSONString();
+    }
+}

core-api/src/test/java/com/optimizely/ab/odp/parser/ResponseJsonParserFactoryTest.java

@@ -15,7 +15,6 @@
  */
 package com.optimizely.ab.odp.parser;
 
-import com.optimizely.ab.internal.JsonParserProvider;
 import com.optimizely.ab.internal.PropertyUtils;
 import com.optimizely.ab.odp.parser.impl.GsonParser;
 import com.optimizely.ab.odp.parser.impl.JsonParser;