Add jackson behavior for methods

Added classes to make gson treat methods as jackson does.
Remove unneeded "forGetter" parameter from constructors.
Fixed sonar issue with too long "if" test.
Corrected comment about annotation names.
Adjusted error message.
Removed unused constant.
Removed trailing spaces.

Change-Id: I3a4fc92193737a0dc89f1218e70f093aedbdb152
Issue-ID: POLICY-1428
Signed-off-by: Jim Hahn <jrh3@att.com>

16 files changed, 1421 insertions, 8 deletions

diff --git a/gson/src/main/java/org/onap/policy/common/gson/JacksonMethodAdapterFactory.java b/gson/src/main/java/org/onap/policy/common/gson/JacksonMethodAdapterFactory.java
new file mode 100644
index 00000000..1c3039f7
--- /dev/null
+++ b/gson/src/main/java/org/onap/policy/common/gson/JacksonMethodAdapterFactory.java
@@ -0,0 +1,202 @@
+/*
+ * ============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 com.google.gson.JsonElement;
+import com.google.gson.JsonObject;
+import com.google.gson.TypeAdapter;
+import com.google.gson.TypeAdapterFactory;
+import com.google.gson.reflect.TypeToken;
+import com.google.gson.stream.JsonReader;
+import com.google.gson.stream.JsonWriter;
+import java.io.IOException;
+import java.lang.reflect.Method;
+import java.util.ArrayList;
+import java.util.HashSet;
+import java.util.List;
+import java.util.Set;
+import org.onap.policy.common.gson.internal.AnyGetterSerializer;
+import org.onap.policy.common.gson.internal.AnySetterDeserializer;
+import org.onap.policy.common.gson.internal.ClassWalker;
+import org.onap.policy.common.gson.internal.Deserializer;
+import org.onap.policy.common.gson.internal.MethodDeserializer;
+import org.onap.policy.common.gson.internal.MethodSerializer;
+import org.onap.policy.common.gson.internal.Serializer;
+
+/**
+ * Factory that serializes/deserializes class methods following the normal behavior of
+ * jackson. Supports the following annotations:
+ * <ul>
+ * <li>GsonJsonIgnore</li>
+ * <li>GsonJsonProperty</li>
+ * <li>GsonJsonAnyGetter</li>
+ * <li>GsonJsonAnySetter</li>
+ * </ul>
+ */
+public class JacksonMethodAdapterFactory implements TypeAdapterFactory {
+
+    @Override
+    public <T> TypeAdapter<T> create(Gson gson, TypeToken<T> type) {
+        Class<? super T> clazz = type.getRawType();
+
+        if (!JacksonExclusionStrategy.isManaged(clazz)) {
+            return null;
+        }
+
+        ClassWalker data = new ClassWalker();
+        data.walkClassHierarchy(clazz);
+
+        if (data.getInProps(Method.class).isEmpty() && data.getOutProps(Method.class).isEmpty()) {
+            if (data.getAnyGetter() == null && data.getAnySetter() == null) {
+                // no methods to serialize
+                return null;
+            }
+        }
+
+        return new JacksonMethodAdapter<>(gson, data, gson.getDelegateAdapter(this, type));
+    }
+
+    /**
+     * Adapter for a single class.
+     *
+     * @param <T> type of class on which the adapter works
+     */
+    private static class JacksonMethodAdapter<T> extends TypeAdapter<T> {
+
+        /**
+         * Used to create an object of the given class.
+         */
+        private final TypeAdapter<T> delegate;
+
+        /**
+         * Used to serialize/deserialize a JsonElement.
+         */
+        private final TypeAdapter<JsonElement> elementAdapter;
+
+        /**
+         * Serializers for each item within the object.
+         */
+        private final Serializer[] serializers;
+
+        /**
+         * Deserializers for each item within the object.
+         */
+        private final Deserializer[] deserializers;
+
+        /**
+         * Constructs the object.
+         *
+         * @param gson the associated gson object
+         * @param data data used to configure the adapter
+         * @param delegate default constructor for the type
+         */
+        public JacksonMethodAdapter(Gson gson, ClassWalker data, TypeAdapter<T> delegate) {
+            this.delegate = delegate;
+
+            this.elementAdapter = gson.getAdapter(JsonElement.class);
+
+            Set<String> unliftedProps = new HashSet<>();
+            unliftedProps.addAll(data.getInNotIgnored());
+            unliftedProps.addAll(data.getOutNotIgnored());
+
+            // create serializers
+            this.serializers = makeSerializers(gson, data, unliftedProps).toArray(new Serializer[0]);
+
+            // create deserializers
+            this.deserializers = makeDeserializers(gson, data, unliftedProps).toArray(new Deserializer[0]);
+        }
+
+        /**
+         * Creates a complete list of serializers.
+         *
+         * @param gson the associated gson object
+         * @param data data used to configure the serializers
+         * @param unliftedProps properties that should not be lowered by "any-getters"
+         * @return a list of all serializers
+         */
+        private List<Serializer> makeSerializers(Gson gson, ClassWalker data, Set<String> unliftedProps) {
+            List<Serializer> ser = new ArrayList<Serializer>();
+
+            if (data.getAnyGetter() != null) {
+                ser.add(new AnyGetterSerializer(gson, unliftedProps, data.getAnyGetter()));
+            }
+
+            data.getOutProps(Method.class).forEach(method -> ser.add(new MethodSerializer(gson, method)));
+
+            return ser;
+        }
+
+        /**
+         * Creates a complete list of deserializers.
+         *
+         * @param gson the associated gson object
+         * @param data data used to configure the deserializers
+         * @param unliftedProps properties that should not be lifted by "any-setters"
+         * @return a list of all deserializers
+         */
+        private List<Deserializer> makeDeserializers(Gson gson, ClassWalker data, Set<String> unliftedProps) {
+            List<Deserializer> deser = new ArrayList<Deserializer>();
+
+            if (data.getAnySetter() != null) {
+                deser.add(new AnySetterDeserializer(gson, unliftedProps, data.getAnySetter()));
+            }
+
+            data.getInProps(Method.class).forEach(method -> deser.add(new MethodDeserializer(gson, method)));
+
+            return deser;
+        }
+
+        @Override
+        public void write(JsonWriter out, T value) throws IOException {
+            JsonElement tree = delegate.toJsonTree(value);
+
+            if (tree.isJsonObject()) {
+                JsonObject jsonObj = tree.getAsJsonObject();
+
+                // serialize each item from the value into the target tree
+                for (Serializer serializer : serializers) {
+                    serializer.addToTree(value, jsonObj);
+                }
+            }
+
+            elementAdapter.write(out, tree);
+        }
+
+        @Override
+        public T read(JsonReader in) throws IOException {
+            JsonElement tree = elementAdapter.read(in);
+
+            T object = delegate.fromJsonTree(tree);
+
+            if (tree.isJsonObject()) {
+                JsonObject jsonObj = tree.getAsJsonObject();
+
+                // deserialize each item from the tree into the target object
+                for (Deserializer dser : deserializers) {
+                    dser.getFromTree(jsonObj, object);
+                }
+            }
+
+            return object;
+        }
+    }
+}
diff --git a/gson/src/main/java/org/onap/policy/common/gson/internal/Adapter.java b/gson/src/main/java/org/onap/policy/common/gson/internal/Adapter.java
index b4ef53f7..bb8672bb 100644
--- a/gson/src/main/java/org/onap/policy/common/gson/internal/Adapter.java
+++ b/gson/src/main/java/org/onap/policy/common/gson/internal/Adapter.java
@@ -86,12 +86,11 @@ public class Adapter {
      *
      * @param gson Gson object providing type adapters
      * @param accessor method used to access the item from within an object
-     * @param forGetter {@code true} if the name is for a "getter" method, {@code false}
-     *        if for a "setter"
      * @param valueType the class of value on which this operates
      */
-    public Adapter(Gson gson, Method accessor, boolean forGetter, Type valueType) {
-        this.propName = (forGetter ? detmGetterPropName(accessor) : detmSetterPropName(accessor));
+    public Adapter(Gson gson, Method accessor, Type valueType) {
+        boolean forSetter = (accessor.getReturnType() == void.class);
+        this.propName = (forSetter ? detmSetterPropName(accessor) : detmGetterPropName(accessor));
         this.reader = new ConvInfo(TypeToken.get(valueType));
         this.gson = gson;
         this.fullName = getQualifiedName(accessor);
diff --git a/gson/src/main/java/org/onap/policy/common/gson/internal/AnyGetterSerializer.java b/gson/src/main/java/org/onap/policy/common/gson/internal/AnyGetterSerializer.java
new file mode 100644
index 00000000..da9ad173
--- /dev/null
+++ b/gson/src/main/java/org/onap/policy/common/gson/internal/AnyGetterSerializer.java
@@ -0,0 +1,83 @@
+/*
+ * ============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 com.google.gson.Gson;
+import com.google.gson.JsonElement;
+import com.google.gson.JsonObject;
+import com.google.gson.JsonParseException;
+import java.lang.reflect.Method;
+import java.util.Map.Entry;
+import java.util.Set;
+
+/**
+ * Serializer for methods having a JsonAnyGetter annotation.
+ */
+public class AnyGetterSerializer extends Lifter implements Serializer {
+
+    public static final String NOT_AN_OBJECT_ERR = "expecting a JsonObject for ";
+
+    /**
+     * Constructs the object.
+     *
+     * @param gson Gson object providing type adapters
+     * @param propName property name associated with the lifted field
+     * @param unliftedProps property names that should not be lifted
+     * @param getter method used to get the item from within an object
+     */
+    public AnyGetterSerializer(Gson gson, Set<String> unliftedProps, Method getter) {
+        super(gson, unliftedProps, getter, getter.getGenericReturnType());
+    }
+
+    @Override
+    public void addToTree(Object source, JsonObject target) {
+        // get the value from the object
+        Object value = invoke(source);
+        if (value == null) {
+            // nothing to lift
+            return;
+        }
+
+        JsonElement inner = toJsonTree(value);
+        if (!inner.isJsonObject()) {
+            throw new JsonParseException(makeError(NOT_AN_OBJECT_ERR));
+        }
+
+        // lift items from inner into the target
+        copyLiftedItems(inner.getAsJsonObject(), target);
+    }
+
+    /**
+     * Copies lifted items from one tree into another, without removing them from the
+     * source tree.
+     *
+     * @param source tree from which items are to be copied
+     * @param target tree into which items are to be copied
+     */
+    private void copyLiftedItems(JsonObject source, JsonObject target) {
+        for (Entry<String, JsonElement> ent : source.entrySet()) {
+            String name = ent.getKey();
+            if (shouldLift(name)) {
+                target.add(name, ent.getValue());
+            }
+        }
+    }
+}
diff --git a/gson/src/main/java/org/onap/policy/common/gson/internal/AnySetterDeserializer.java b/gson/src/main/java/org/onap/policy/common/gson/internal/AnySetterDeserializer.java
new file mode 100644
index 00000000..85d42dfa
--- /dev/null
+++ b/gson/src/main/java/org/onap/policy/common/gson/internal/AnySetterDeserializer.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 com.google.gson.Gson;
+import com.google.gson.JsonElement;
+import com.google.gson.JsonObject;
+import java.lang.reflect.Method;
+import java.util.Map.Entry;
+import java.util.Set;
+
+/**
+ * De-serializer for methods having a JsonAnySetter annotation.
+ */
+public class AnySetterDeserializer extends Lifter implements Deserializer {
+
+    /**
+     * Constructs the object.
+     *
+     * @param gson Gson object providing type adapters
+     * @param unliftedProps property names that should not be lifted
+     * @param getter method used to get the item from within an object
+     */
+    public AnySetterDeserializer(Gson gson, Set<String> unliftedProps, Method setter) {
+        super(gson, unliftedProps, setter, setter.getGenericParameterTypes()[1]);
+    }
+
+    @Override
+    public void getFromTree(JsonObject source, Object target) {
+        for (Entry<String, JsonElement> ent : source.entrySet()) {
+            String name = ent.getKey();
+
+            if (shouldLift(name)) {
+                Object value = fromJsonTree(ent.getValue());
+                invoke(target, name, value);
+            }
+        }
+    }
+
+}
diff --git a/gson/src/main/java/org/onap/policy/common/gson/internal/Lifter.java b/gson/src/main/java/org/onap/policy/common/gson/internal/Lifter.java
new file mode 100644
index 00000000..bb8ec321
--- /dev/null
+++ b/gson/src/main/java/org/onap/policy/common/gson/internal/Lifter.java
@@ -0,0 +1,62 @@
+/*
+ * ============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 com.google.gson.Gson;
+import java.lang.reflect.Method;
+import java.lang.reflect.Type;
+import java.util.Set;
+
+/**
+ * Super class of serializers and de-serializers that deal with "lifted" data, that is,
+ * data that is lifted from a nested json object into the containing object.
+ */
+public class Lifter extends MethodAdapter {
+
+    /**
+     * Names of the properties that are <i>not</i> to be lifted.
+     */
+    private final Set<String> unliftedProps;
+
+    /**
+     * Constructs the object.
+     *
+     * @param gson Gson object providing type adapters
+     * @param unliftedProps property names that should not be lifted
+     * @param accessor method used to access the item from within an object
+     * @param type the class of value on which this operates
+     */
+    public Lifter(Gson gson, Set<String> unliftedProps, Method accessor, Type type) {
+        super(gson, accessor, type);
+
+        this.unliftedProps = unliftedProps;
+    }
+
+    /**
+     * Determines if a property should be lifted.
+     *
+     * @param propName the name of the property
+     * @return {@code true} if the property should be lifted, {@code false} otherwise
+     */
+    public boolean shouldLift(String propName) {
+        return !unliftedProps.contains(propName);
+    }
+}
diff --git a/gson/src/main/java/org/onap/policy/common/gson/internal/MethodAdapter.java b/gson/src/main/java/org/onap/policy/common/gson/internal/MethodAdapter.java
new file mode 100644
index 00000000..579864da
--- /dev/null
+++ b/gson/src/main/java/org/onap/policy/common/gson/internal/MethodAdapter.java
@@ -0,0 +1,69 @@
+/*
+ * ============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 com.google.gson.Gson;
+import com.google.gson.JsonParseException;
+import java.lang.reflect.InvocationTargetException;
+import java.lang.reflect.Method;
+import java.lang.reflect.Type;
+
+/**
+ * Super class of adapters used to serialize and de-serialize a method.
+ */
+public class MethodAdapter extends Adapter {
+
+    public static final String INVOKE_ERR = "cannot invoke method to serialize/deserialize: ";
+
+    /**
+     * Method used to access the item within an object.
+     */
+    private final Method accessor;
+
+    /**
+     * Constructs the object.
+     *
+     * @param gson Gson object providing type adapters
+     * @param accessor method used to access the item from within an object
+     * @param type the class of value on which this operates
+     */
+    public MethodAdapter(Gson gson, Method accessor, Type type) {
+        super(gson, accessor, type);
+
+        this.accessor = accessor;
+    }
+
+    /**
+     * Invokes the accessor method.
+     *
+     * @param self object on which to invoke the method
+     * @param args arguments to be passed to the method
+     * @return the method's result
+     */
+    public Object invoke(Object self, Object... args) {
+        try {
+            return accessor.invoke(self, args);
+
+        } catch (IllegalAccessException | IllegalArgumentException | InvocationTargetException e) {
+            throw new JsonParseException(makeError(INVOKE_ERR), e);
+        }
+    }
+}
diff --git a/gson/src/main/java/org/onap/policy/common/gson/internal/MethodDeserializer.java b/gson/src/main/java/org/onap/policy/common/gson/internal/MethodDeserializer.java
new file mode 100644
index 00000000..bb0724eb
--- /dev/null
+++ b/gson/src/main/java/org/onap/policy/common/gson/internal/MethodDeserializer.java
@@ -0,0 +1,53 @@
+/*
+ * ============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 com.google.gson.Gson;
+import com.google.gson.JsonElement;
+import com.google.gson.JsonObject;
+import java.lang.reflect.Method;
+
+/**
+ * De-serializer for methods that are exposed.
+ */
+public class MethodDeserializer extends MethodAdapter implements Deserializer {
+
+    /**
+     * Constructs the object.
+     *
+     * @param gson Gson object providing type adapters
+     * @param setter method used to set the item within an object
+     */
+    public MethodDeserializer(Gson gson, Method setter) {
+        super(gson, setter, setter.getGenericParameterTypes()[0]);
+    }
+
+    @Override
+    public void getFromTree(JsonObject source, Object target) {
+        JsonElement jsonEl = source.get(getPropName());
+        if (jsonEl == null || jsonEl.isJsonNull()) {
+            return;
+        }
+
+        invoke(target, fromJsonTree(jsonEl));
+    }
+
+}
diff --git a/gson/src/main/java/org/onap/policy/common/gson/internal/MethodSerializer.java b/gson/src/main/java/org/onap/policy/common/gson/internal/MethodSerializer.java
new file mode 100644
index 00000000..ab544614
--- /dev/null
+++ b/gson/src/main/java/org/onap/policy/common/gson/internal/MethodSerializer.java
@@ -0,0 +1,47 @@
+/*
+ * ============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 com.google.gson.Gson;
+import com.google.gson.JsonObject;
+import java.lang.reflect.Method;
+
+/**
+ * Serializer for methods that are exposed.
+ */
+public class MethodSerializer extends MethodAdapter implements Serializer {
+
+    /**
+     * Constructs the object.
+     *
+     * @param gson Gson object providing type adapters
+     * @param getter method used to get the item from within an object
+     */
+    public MethodSerializer(Gson gson, Method getter) {
+        super(gson, getter, getter.getGenericReturnType());
+    }
+
+    @Override
+    public void addToTree(Object source, JsonObject target) {
+        Object value = invoke(source);
+        target.add(getPropName(), (value == null ? null : toJsonTree(value)));
+    }
+}
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;
+    }
+}