Merge "Add jackson behavior for methods"

8 files changed, 844 insertions, 4 deletions

diff --git a/gson/src/test/java/org/onap/policy/common/gson/JacksonMethodAdapterFactoryTest.java b/gson/src/test/java/org/onap/policy/common/gson/JacksonMethodAdapterFactoryTest.java
new file mode 100644
index 00000000..47cf4b3b
--- /dev/null
+++ b/gson/src/test/java/org/onap/policy/common/gson/JacksonMethodAdapterFactoryTest.java
@@ -0,0 +1,311 @@
+/*
+ * ============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 static org.junit.Assert.assertEquals;
+import static org.junit.Assert.assertFalse;
+import static org.junit.Assert.assertNotNull;
+import static org.junit.Assert.assertNull;
+import static org.junit.Assert.assertTrue;
+
+import com.google.gson.Gson;
+import com.google.gson.GsonBuilder;
+import com.google.gson.JsonElement;
+import com.google.gson.reflect.TypeToken;
+import java.util.Map;
+import java.util.TreeMap;
+import org.junit.Test;
+import org.onap.policy.common.gson.JacksonExclusionStrategy;
+import org.onap.policy.common.gson.JacksonMethodAdapterFactory;
+import org.onap.policy.common.gson.annotation.GsonJsonAnyGetter;
+import org.onap.policy.common.gson.annotation.GsonJsonAnySetter;
+import org.onap.policy.common.gson.annotation.GsonJsonIgnore;
+import org.onap.policy.common.gson.annotation.GsonJsonProperty;
+
+public class JacksonMethodAdapterFactoryTest {
+
+    private static JacksonMethodAdapterFactory factory = new JacksonMethodAdapterFactory();
+
+    private static Gson gson = new GsonBuilder().setExclusionStrategies(new JacksonExclusionStrategy())
+                    .registerTypeAdapterFactory(factory).create();
+
+    @Test
+    public void testCreate() {
+        // unhandled types
+        assertNull(factory.create(gson, TypeToken.get(JsonElement.class)));
+        assertNull(factory.create(gson, TypeToken.get(NothingToSerialize.class)));
+
+        assertNotNull(factory.create(gson, TypeToken.get(Data.class)));
+        assertNotNull(factory.create(gson, TypeToken.get(Derived.class)));
+        assertNotNull(factory.create(gson, TypeToken.get(OnlyGetters.class)));
+        assertNotNull(factory.create(gson, TypeToken.get(OnlySetters.class)));
+        assertNotNull(factory.create(gson, TypeToken.get(OnlyAnyGetter.class)));
+        assertNotNull(factory.create(gson, TypeToken.get(OnlyAnySetter.class)));
+
+        // unhandled type
+
+        Data data = new Data();
+        data.id = 10;
+        data.text = "some text";
+
+        String result = gson.toJson(data);
+        Data data2 = gson.fromJson(result, Data.class);
+        assertEquals(data.toString(), data2.toString());
+
+        Derived der = new Derived();
+        der.setId(20);
+        der.setText("hello");
+        der.text = "world";
+        der.map = new TreeMap<>();
+        der.map.put("mapA", "valA");
+        der.map.put("mapB", "valB");
+
+        result = gson.toJson(der);
+
+        // should not contain the unserialized fields
+        assertFalse(result.contains("hello"));
+        assertFalse(result.contains("world"));
+
+        // null out unserialized fields
+        der.text = null;
+
+        // null out overridden field
+        der.setText(null);
+
+        Derived der2 = gson.fromJson(result, Derived.class);
+
+        assertEquals(der.toString(), der2.toString());
+
+        // override of AnyGetter
+        AnyGetterOverride dblget = new AnyGetterOverride();
+        dblget.setMap(der.map);
+        dblget.overMap = new TreeMap<>();
+        dblget.overMap.put("getA", 100);
+        dblget.overMap.put("getB", 110);
+
+        String result2 = gson.toJson(dblget);
+        dblget.overMap.keySet().forEach(key -> assertTrue("over contains " + key, result2.contains(key)));
+        der.map.keySet().forEach(key -> assertFalse("sub contains " + key, result2.contains(key)));
+
+        // override of AnySetter
+        Map<String, Integer> map = new TreeMap<>();
+        map.put("setA", 200);
+        map.put("setB", 210);
+        AnySetterOverride dblset = gson.fromJson(gson.toJson(map), AnySetterOverride.class);
+        assertEquals(map.toString(), dblset.overMap.toString());
+        assertNull(dblset.getTheMap());
+
+        // non-static nested class - can serialize, but not de-serialize
+        Container cont = new Container(500, "bye bye");
+        result = gson.toJson(cont);
+        assertEquals("{'id':500,'nested':{'value':'bye bye'}}".replace('\'', '"'), result);
+    }
+
+    protected static class Data {
+        private int id;
+        private String text;
+
+        public int getId() {
+            return id;
+        }
+
+        public void setId(int id) {
+            this.id = id;
+        }
+
+        // not public, but property provided
+        @GsonJsonProperty("text")
+        protected String getText() {
+            return text;
+        }
+
+        public void setText(String text) {
+            this.text = text;
+        }
+
+        public void unused(String text) {
+            // do nothing
+        }
+
+        @Override
+        public String toString() {
+            return "Data [id=" + id + ", text=" + text + "]";
+        }
+    }
+
+    protected static class Derived extends Data {
+
+        // overrides private field from Data
+        public String text;
+
+        private Map<String, String> map;
+
+        @GsonJsonAnyGetter
+        public Map<String, String> getTheMap() {
+            return map;
+        }
+
+        @GsonJsonIgnore
+        public void setMap(Map<String, String> map) {
+            this.map = map;
+        }
+
+        @GsonJsonAnySetter
+        public void setMapValue(String key, String value) {
+            if (map == null) {
+                map = new TreeMap<>();
+            }
+
+            map.put(key, value);
+        }
+
+        @Override
+        public String toString() {
+            return "Derived [text=" + text + ", map=" + map + ", toString()=" + super.toString() + "]";
+        }
+    }
+
+    /**
+     * Has {@link GsonJsonAnyGetter} method that overrides the super class' method.
+     */
+    private static class AnyGetterOverride extends Derived {
+        private Map<String, Integer> overMap;
+
+        @GsonJsonAnyGetter
+        private Map<String, Integer> getOverride() {
+            return overMap;
+        }
+    }
+
+    /**
+     * Has {@link GsonJsonAnySetter} method that overrides the super class' method.
+     */
+    private static class AnySetterOverride extends Derived {
+        private Map<String, Integer> overMap;
+
+        @GsonJsonAnySetter
+        private void setOverride(String key, int value) {
+            if (overMap == null) {
+                overMap = new TreeMap<>();
+            }
+
+            overMap.put(key, value);
+        }
+    }
+
+    /**
+     * Has nothing to serialize.
+     */
+    protected static class NothingToSerialize {
+        // not serialized
+        protected String unserialized;
+    }
+
+    /**
+     * Only has getters.
+     */
+    protected static class OnlyGetters {
+        public int getId() {
+            return 1010;
+        }
+    }
+
+    /**
+     * Only has setters.
+     */
+    protected static class OnlySetters {
+        public void setId(int id) {
+            // do nothing
+        }
+    }
+
+    /**
+     * Only has {@link GsonJsonAnyGetter}.
+     */
+    private static class OnlyAnyGetter {
+        @GsonJsonAnyGetter
+        public Map<String, Integer> getOverride() {
+            return null;
+        }
+    }
+
+    /**
+     * Only has {@link GsonJsonAnySetter}.
+     */
+    private static class OnlyAnySetter {
+        @GsonJsonAnySetter
+        public void setOverride(String key, int value) {
+            // do nothing
+        }
+    }
+
+    /**
+     * Used to test serialization of non-static nested classes.
+     */
+    protected static class Container {
+        private int id;
+        private Nested nested;
+
+        public Container() {
+            super();
+        }
+
+        public Container(int id, String value) {
+            this.id = id;
+            this.nested = new Nested(value);
+        }
+
+        public int getId() {
+            return id;
+        }
+
+        public void setId(int id) {
+            this.id = id;
+        }
+
+        public Nested getNested() {
+            return nested;
+        }
+
+        @Override
+        public String toString() {
+            return "Container [id=" + id + ", nested=" + nested + "]";
+        }
+
+
+        protected class Nested {
+            private String value;
+
+            public Nested(String val) {
+                value = val;
+            }
+
+            public String getValue() {
+                return value;
+            }
+
+            @Override
+            public String toString() {
+                return "Nested [value=" + value + "]";
+            }
+        }
+    }
+}
diff --git a/gson/src/test/java/org/onap/policy/common/gson/internal/AdapterTest.java b/gson/src/test/java/org/onap/policy/common/gson/internal/AdapterTest.java
index fcb0d9ad..04f37164 100644
--- a/gson/src/test/java/org/onap/policy/common/gson/internal/AdapterTest.java
+++ b/gson/src/test/java/org/onap/policy/common/gson/internal/AdapterTest.java
@@ -140,7 +140,7 @@ public class AdapterTest {
 
         Method getter = mget("getMyList");
 
-        Adapter aget = new Adapter(gson, getter, true, getter.getReturnType());
+        Adapter aget = new Adapter(gson, getter, getter.getReturnType());
 
         dataAdapter.reset();
         JsonElement tree = aget.toJsonTree(listField);
@@ -148,7 +148,7 @@ public class AdapterTest {
         assertEquals(DataAdapterFactory.ENCODED_LIST, tree.toString());
 
         Method setter = AdapterTest.class.getDeclaredMethod("setMyList", List.class);
-        Adapter aset = new Adapter(gson, setter, true, setter.getGenericParameterTypes()[0]);
+        Adapter aset = new Adapter(gson, setter, setter.getGenericParameterTypes()[0]);
 
         dataAdapter.reset();
         @SuppressWarnings("unchecked")
@@ -168,7 +168,7 @@ public class AdapterTest {
 
 
         // test getter
-        adapter = new Adapter(gson, mget(GET_VALUE_NAME), true, String.class);
+        adapter = new Adapter(gson, mget(GET_VALUE_NAME), String.class);
 
         assertEquals(VALUE_NAME, adapter.getPropName());
         assertEquals(MY_NAME + ".getValue", adapter.getFullName());
@@ -177,7 +177,7 @@ public class AdapterTest {
 
 
         // test setter
-        adapter = new Adapter(gson, mset("setValue"), false, String.class);
+        adapter = new Adapter(gson, mset("setValue"), String.class);
 
         assertEquals(VALUE_NAME, adapter.getPropName());
         assertEquals(MY_NAME + ".setValue", adapter.getFullName());
diff --git a/gson/src/test/java/org/onap/policy/common/gson/internal/AnyGetterSerializerTest.java b/gson/src/test/java/org/onap/policy/common/gson/internal/AnyGetterSerializerTest.java
new file mode 100644
index 00000000..75128420
--- /dev/null
+++ b/gson/src/test/java/org/onap/policy/common/gson/internal/AnyGetterSerializerTest.java
@@ -0,0 +1,134 @@
+/*
+ * ============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.internal;
+
+import static org.assertj.core.api.Assertions.assertThatThrownBy;
+import static org.junit.Assert.assertEquals;
+import static org.junit.Assert.assertTrue;
+
+import com.google.gson.Gson;
+import com.google.gson.GsonBuilder;
+import com.google.gson.JsonObject;
+import com.google.gson.JsonParseException;
+import java.util.Arrays;
+import java.util.HashSet;
+import java.util.List;
+import java.util.Map;
+import java.util.Set;
+import org.junit.Before;
+import org.junit.Test;
+import org.onap.policy.common.gson.JacksonExclusionStrategy;
+import org.onap.policy.common.gson.internal.AnyGetterSerializer;
+import org.onap.policy.common.gson.internal.DataAdapterFactory.Data;
+
+public class AnyGetterSerializerTest {
+
+    private static DataAdapterFactory dataAdapter = new DataAdapterFactory();
+
+    private static Gson gson = new GsonBuilder().registerTypeAdapterFactory(dataAdapter)
+                    .setExclusionStrategies(new JacksonExclusionStrategy()).create();
+
+    private Set<String> set;
+    private AnyGetterSerializer ser;
+
+    /**
+     * Set up.
+     *
+     * @throws Exception if an error occurs
+     */
+    @Before
+    public void setUp() throws Exception {
+        set = new HashSet<>(Arrays.asList("id", "value"));
+        ser = new AnyGetterSerializer(gson, set, MapData.class.getDeclaredMethod("getTheMap"));
+    }
+
+    @Test
+    public void testAddToTree_testCopyLiftedItems() throws Exception {
+        JsonObject tree = new JsonObject();
+        tree.addProperty("hello", "world");
+
+        MapData data = new MapData();
+
+        data.map = DataAdapterFactory.makeMap();
+
+        // this should not be copied because it is in the "set"
+        data.map.put("value", Arrays.asList(new Data(1000)));
+
+        dataAdapter.reset();
+        JsonObject tree2 = tree.deepCopy();
+        ser.addToTree(data, tree2);
+
+        assertTrue(dataAdapter.isDataWritten());
+
+        DataAdapterFactory.addToObject(tree);
+
+        assertEquals(tree.toString(), tree2.toString());
+    }
+
+    @Test
+    public void testAddToTree_NullMap() throws Exception {
+        JsonObject tree = new JsonObject();
+        tree.addProperty("hello", "world");
+
+        MapData data = new MapData();
+
+        // leave "map" unset
+
+        JsonObject tree2 = tree.deepCopy();
+        ser.addToTree(data, tree2);
+
+        assertEquals(tree.toString(), tree2.toString());
+    }
+
+    @Test
+    public void testAddToTree_NotAnObject() throws Exception {
+        ser = new AnyGetterSerializer(gson, set, NotAnObject.class.getDeclaredMethod("getNonMap"));
+
+        JsonObject tree = new JsonObject();
+
+        NotAnObject data = new NotAnObject();
+        data.text = "bye bye";
+
+        assertThatThrownBy(() -> ser.addToTree(data, tree)).isInstanceOf(JsonParseException.class)
+                        .hasMessage(AnyGetterSerializer.NOT_AN_OBJECT_ERR + NotAnObject.class.getName() + ".getNonMap");
+    }
+
+    public static class MapData {
+        protected int id;
+        protected String value;
+        protected Map<String, List<Data>> map;
+
+        protected Map<String, List<Data>> getTheMap() {
+            return map;
+        }
+    }
+
+    /**
+     * The "lifted" property is not a JsonObject so it should throw an exception.
+     */
+    public static class NotAnObject {
+        protected String text;
+
+        public String getNonMap() {
+            return text;
+        }
+    }
+}
diff --git a/gson/src/test/java/org/onap/policy/common/gson/internal/AnySetterDeserializerTest.java b/gson/src/test/java/org/onap/policy/common/gson/internal/AnySetterDeserializerTest.java
new file mode 100644
index 00000000..b180605e
--- /dev/null
+++ b/gson/src/test/java/org/onap/policy/common/gson/internal/AnySetterDeserializerTest.java
@@ -0,0 +1,94 @@
+/*
+ * ============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.internal;
+
+import static org.junit.Assert.assertEquals;
+import static org.junit.Assert.assertNotNull;
+import static org.junit.Assert.assertTrue;
+
+import com.google.gson.Gson;
+import com.google.gson.GsonBuilder;
+import com.google.gson.JsonObject;
+import java.util.Arrays;
+import java.util.HashSet;
+import java.util.List;
+import java.util.Map;
+import java.util.Set;
+import java.util.TreeMap;
+import org.junit.Before;
+import org.junit.Test;
+import org.onap.policy.common.gson.JacksonExclusionStrategy;
+import org.onap.policy.common.gson.internal.AnySetterDeserializer;
+import org.onap.policy.common.gson.internal.DataAdapterFactory.Data;
+
+public class AnySetterDeserializerTest {
+
+    private static DataAdapterFactory dataAdapter = new DataAdapterFactory();
+
+    private static Gson gson = new GsonBuilder().registerTypeAdapterFactory(dataAdapter)
+                    .setExclusionStrategies(new JacksonExclusionStrategy()).create();
+
+    private Set<String> set;
+    private AnySetterDeserializer deser;
+
+    /**
+     * Set up.
+     *
+     * @throws Exception if an error occurs
+     */
+    @Before
+    public void setUp() throws Exception {
+        set = new HashSet<>(Arrays.asList("id", "value"));
+        deser = new AnySetterDeserializer(gson, set,
+                        MapData.class.getDeclaredMethod("setItem", String.class, List.class));
+    }
+
+    @Test
+    public void testAnySetterDeserializer() {
+        JsonObject json = new JsonObject();
+
+        // these should not be copied
+        json.addProperty("id", 10);
+        json.addProperty("value", "the-value");
+
+        // these should be copied
+        DataAdapterFactory.addToObject(json);
+
+        MapData data = new MapData();
+        data.map = new TreeMap<>();
+
+        dataAdapter.reset();
+        deser.getFromTree(json, data);
+
+        assertTrue(dataAdapter.isDataRead());
+        assertNotNull(data.map);
+        assertEquals(DataAdapterFactory.makeMap().toString(), data.map.toString());
+    }
+
+    public static class MapData {
+        protected Map<String, List<Data>> map;
+
+        protected void setItem(String key, List<Data> value) {
+            map.put(key, value);
+        }
+    }
+
+}
diff --git a/gson/src/test/java/org/onap/policy/common/gson/internal/LifterTest.java b/gson/src/test/java/org/onap/policy/common/gson/internal/LifterTest.java
new file mode 100644
index 00000000..55a3b674
--- /dev/null
+++ b/gson/src/test/java/org/onap/policy/common/gson/internal/LifterTest.java
@@ -0,0 +1,55 @@
+/*
+ * ============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.internal;
+
+import static org.junit.Assert.assertFalse;
+import static org.junit.Assert.assertTrue;
+
+import com.google.gson.Gson;
+import java.util.Arrays;
+import java.util.HashSet;
+import java.util.Set;
+import org.junit.Test;
+import org.onap.policy.common.gson.internal.Lifter;
+
+public class LifterTest {
+
+    private static Gson gson = new Gson();
+
+    @Test
+    public void testLifter_testShouldLift() throws Exception {
+        Set<String> set = new HashSet<>(Arrays.asList("abc", "def"));
+        Lifter lifter = new Lifter(gson, set, LifterTest.class.getDeclaredMethod("getValue"), String.class);
+
+        // should not lift these
+        assertFalse(lifter.shouldLift("abc"));
+        assertFalse(lifter.shouldLift("def"));
+
+        // should lift anything else
+        assertTrue(lifter.shouldLift("hello"));
+        assertTrue(lifter.shouldLift("world"));
+    }
+
+    public String getValue() {
+        return "";
+    }
+
+}
diff --git a/gson/src/test/java/org/onap/policy/common/gson/internal/MethodAdapterTest.java b/gson/src/test/java/org/onap/policy/common/gson/internal/MethodAdapterTest.java
new file mode 100644
index 00000000..9f39e3ce
--- /dev/null
+++ b/gson/src/test/java/org/onap/policy/common/gson/internal/MethodAdapterTest.java
@@ -0,0 +1,58 @@
+/*
+ * ============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.internal;
+
+import static org.assertj.core.api.Assertions.assertThatThrownBy;
+import static org.junit.Assert.assertEquals;
+
+import com.google.gson.Gson;
+import com.google.gson.JsonParseException;
+import org.junit.Test;
+import org.onap.policy.common.gson.internal.MethodAdapter;
+
+public class MethodAdapterTest {
+    private static final Gson gson = new Gson();
+
+    private String saved;
+
+    @Test
+    public void testMethodAdapter_testInvoke() throws Exception {
+        MethodAdapter adapter =
+                        new MethodAdapter(gson, MethodAdapterTest.class.getDeclaredMethod("getValue"), String.class);
+        assertEquals("hello", adapter.invoke(this));
+
+        MethodAdapter adapter2 = new MethodAdapter(gson,
+                        MethodAdapterTest.class.getDeclaredMethod("setValue", String.class), String.class);
+        adapter2.invoke(this, "world");
+        assertEquals("world", saved);
+
+        assertThatThrownBy(() -> adapter2.invoke(this, 100)).isInstanceOf(JsonParseException.class)
+                        .hasMessage(MethodAdapter.INVOKE_ERR + MethodAdapterTest.class.getName() + ".setValue");
+    }
+
+    public String getValue() {
+        return "hello";
+    }
+
+    public void setValue(String val) {
+        saved = val;
+    }
+}
diff --git a/gson/src/test/java/org/onap/policy/common/gson/internal/MethodDeserializerTest.java b/gson/src/test/java/org/onap/policy/common/gson/internal/MethodDeserializerTest.java
new file mode 100644
index 00000000..338644ae
--- /dev/null
+++ b/gson/src/test/java/org/onap/policy/common/gson/internal/MethodDeserializerTest.java
@@ -0,0 +1,100 @@
+/*
+ * ============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.internal;
+
+import static org.junit.Assert.assertEquals;
+import static org.junit.Assert.assertNotNull;
+import static org.junit.Assert.assertTrue;
+
+import com.google.gson.Gson;
+import com.google.gson.GsonBuilder;
+import com.google.gson.JsonNull;
+import com.google.gson.JsonObject;
+import java.util.List;
+import org.junit.Test;
+import org.onap.policy.common.gson.JacksonExclusionStrategy;
+import org.onap.policy.common.gson.internal.DataAdapterFactory.Data;
+import org.onap.policy.common.gson.internal.MethodDeserializer;
+
+public class MethodDeserializerTest {
+    private static final String PROP_NAME = "text";
+    private static final String METHOD_NAME = "setText";
+    private static final String INITIAL_VALUE = "initial value";
+    private static final String NEW_VALUE = "new value";
+
+    private static DataAdapterFactory dataAdapter = new DataAdapterFactory();
+
+    private static Gson gson = new GsonBuilder().registerTypeAdapterFactory(dataAdapter)
+                    .setExclusionStrategies(new JacksonExclusionStrategy()).create();
+
+    private MethodDeserializer deser;
+
+    private String text;
+
+    private List<Data> listField;
+
+    @Test
+    public void testGetFromTree() throws Exception {
+        deser = new MethodDeserializer(gson, MethodDeserializerTest.class.getDeclaredMethod(METHOD_NAME, String.class));
+
+        // non-existent value - should not overwrite
+        text = INITIAL_VALUE;
+        JsonObject json = new JsonObject();
+        deser.getFromTree(json, this);
+        assertEquals(INITIAL_VALUE, text);
+
+        // null value - should not overwrite
+        text = INITIAL_VALUE;
+        json.add(PROP_NAME, JsonNull.INSTANCE);
+        deser.getFromTree(json, this);
+        assertEquals(INITIAL_VALUE, text);
+
+        // has a value - should store it
+        text = INITIAL_VALUE;
+        json.addProperty(PROP_NAME, NEW_VALUE);
+        deser.getFromTree(json, this);
+        assertEquals(NEW_VALUE, text);
+
+        /*
+         * check list field
+         */
+        deser = new MethodDeserializer(gson, MethodDeserializerTest.class.getDeclaredMethod("setTheList", List.class));
+
+        json = new JsonObject();
+        json.add("theList", DataAdapterFactory.makeArray());
+
+        dataAdapter.reset();
+        listField = null;
+        deser.getFromTree(json, this);
+
+        assertTrue(dataAdapter.isDataRead());
+        assertNotNull(listField);
+        assertEquals(DataAdapterFactory.makeList().toString(), listField.toString());
+    }
+
+    protected void setText(String text) {
+        this.text = text;
+    }
+
+    protected void setTheList(List<Data> lst) {
+        listField = lst;
+    }
+}
diff --git a/gson/src/test/java/org/onap/policy/common/gson/internal/MethodSerializerTest.java b/gson/src/test/java/org/onap/policy/common/gson/internal/MethodSerializerTest.java
new file mode 100644
index 00000000..586bf54d
--- /dev/null
+++ b/gson/src/test/java/org/onap/policy/common/gson/internal/MethodSerializerTest.java
@@ -0,0 +1,88 @@
+/*
+ * ============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.internal;
+
+import static org.junit.Assert.assertEquals;
+import static org.junit.Assert.assertTrue;
+
+import com.google.gson.Gson;
+import com.google.gson.GsonBuilder;
+import com.google.gson.JsonElement;
+import com.google.gson.JsonObject;
+import java.util.List;
+import org.junit.Test;
+import org.onap.policy.common.gson.JacksonExclusionStrategy;
+import org.onap.policy.common.gson.internal.DataAdapterFactory.Data;
+import org.onap.policy.common.gson.internal.MethodSerializer;
+
+public class MethodSerializerTest {
+    private static final String PROP_NAME = "text";
+    private static final String METHOD_NAME = "getText";
+
+    private static DataAdapterFactory dataAdapter = new DataAdapterFactory();
+
+    private static Gson gson = new GsonBuilder().registerTypeAdapterFactory(dataAdapter)
+                    .setExclusionStrategies(new JacksonExclusionStrategy()).create();
+
+    private MethodSerializer ser;
+
+    private String text;
+
+    private List<Data> listField;
+
+    @Test
+    public void testAddToTree() throws Exception {
+        ser = new MethodSerializer(gson, MethodSerializerTest.class.getDeclaredMethod(METHOD_NAME));
+
+        // serialize null value first
+        text = null;
+
+        JsonObject json = new JsonObject();
+        ser.addToTree(this, json);
+        assertTrue(json.get(PROP_NAME).isJsonNull());
+
+        // serialize an actual value
+        text = "hello";
+        ser.addToTree(this, json);
+        assertEquals("hello", json.get(PROP_NAME).getAsString());
+
+        /*
+         * check list field
+         */
+        listField = DataAdapterFactory.makeList();
+
+        ser = new MethodSerializer(gson, MethodSerializerTest.class.getDeclaredMethod("getTheList"));
+
+        dataAdapter.reset();
+        JsonElement tree = ser.toJsonTree(listField);
+
+        assertTrue(dataAdapter.isDataWritten());
+        assertEquals(DataAdapterFactory.ENCODED_LIST, tree.toString());
+    }
+
+    protected String getText() {
+        return text;
+    }
+
+    protected List<Data> getTheList() {
+        return listField;
+    }
+}