Add gson handler and tests

Added JacksonHandler which provides jackson behavior in gson.
Also added classes to facilitate testing of gson serializations.
Added compareGson(xxx, Class).
Removed trailing spaces from some files.
Updated license dates.
Replaced incorrect constant with ${xxx} in json test file.
Fixed typo in test method name.

Change-Id: If05b654d76a4ffc88646f03334be82b32506f28f
Issue-ID: POLICY-1428
Signed-off-by: Jim Hahn <jrh3@att.com>

2 files changed, 182 insertions, 0 deletions

diff --git a/gson/src/main/java/org/onap/policy/common/gson/JacksonHandler.java b/gson/src/main/java/org/onap/policy/common/gson/JacksonHandler.java
new file mode 100644
index 00000000..d48649ea
--- /dev/null
+++ b/gson/src/main/java/org/onap/policy/common/gson/JacksonHandler.java
@@ -0,0 +1,50 @@
+/*
+ * ============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.GsonBuilder;
+
+/**
+ * Provider used to serialize and deserialize policy objects via gson using jackson
+ * default behaviors and annotations.
+ */
+public class JacksonHandler extends GsonMessageBodyHandler {
+
+    /**
+     * Constructs the object.
+     */
+    public JacksonHandler() {
+        this(new GsonBuilder());
+    }
+
+    /**
+     * Constructs the object.
+     * @param builder builder to use to create the gson object
+     */
+    public JacksonHandler(GsonBuilder builder) {
+        super(builder
+                        .registerTypeAdapterFactory(new JacksonFieldAdapterFactory())
+                        .registerTypeAdapterFactory(new JacksonMethodAdapterFactory())
+                        .setExclusionStrategies(new JacksonExclusionStrategy())
+                        .create());
+    }
+
+}
diff --git a/gson/src/test/java/org/onap/policy/common/gson/JacksonHandlerTest.java b/gson/src/test/java/org/onap/policy/common/gson/JacksonHandlerTest.java
new file mode 100644
index 00000000..5a49a403
--- /dev/null
+++ b/gson/src/test/java/org/onap/policy/common/gson/JacksonHandlerTest.java
@@ -0,0 +1,132 @@
+/*
+ * ============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.assertTrue;
+
+import com.google.gson.Gson;
+import com.google.gson.JsonObject;
+import java.io.ByteArrayInputStream;
+import java.io.ByteArrayOutputStream;
+import java.io.StringReader;
+import java.util.HashMap;
+import java.util.Map;
+import java.util.TreeMap;
+import javax.ws.rs.core.MediaType;
+import org.junit.Test;
+import org.onap.policy.common.gson.JacksonHandler;
+import org.onap.policy.common.gson.annotation.GsonJsonAnyGetter;
+import org.onap.policy.common.gson.annotation.GsonJsonAnySetter;
+
+public class JacksonHandlerTest {
+
+    @Test
+    public void test() throws Exception {
+        JacksonHandler hdlr = new JacksonHandler();
+
+        assertTrue(hdlr.isReadable(null, null, null, MediaType.APPLICATION_JSON_TYPE));
+        assertFalse(hdlr.isReadable(null, null, null, MediaType.TEXT_PLAIN_TYPE));
+
+        JsonObject expected = new JsonObject();
+        expected.addProperty("myId", 100);
+        expected.addProperty("value", "a value");
+        expected.addProperty("abc", "def");
+        expected.addProperty("hello", "world");
+
+        Data data = new Data();
+        data.id = 10;
+        data.value = "a value";
+        data.props = new HashMap<>();
+        data.props.put("abc", "def");
+        data.props.put("hello", "world");
+
+        /*
+         * Ensure everything serializes as expected.
+         */
+        ByteArrayOutputStream outstr = new ByteArrayOutputStream();
+        hdlr.writeTo(data, Data.class, Data.class, null, null, null, outstr);
+
+        StringReader rdr = new StringReader(outstr.toString("UTF-8"));
+        JsonObject json = new Gson().fromJson(rdr, JsonObject.class);
+
+        assertEquals(expected, json);
+
+        /*
+         * Ensure everything deserializes as expected.
+         */
+        Data data2 = (Data) hdlr.readFrom(Object.class, Data.class, null, null, null,
+                        new ByteArrayInputStream(outstr.toByteArray()));
+
+        // id is not serialized, so we must copy it manually before comparing
+        data2.id = data.id;
+
+        assertEquals(data.toString(), data2.toString());
+    }
+
+    /**
+     * This class includes all policy-specific gson annotations.
+     */
+    public static class Data {
+        protected int id;
+
+        protected String value;
+
+        protected Map<String, String> props;
+
+        public int getMyId() {
+            return 100;
+        }
+
+        public String getValue() {
+            return value;
+        }
+
+        public void setValue(String value) {
+            this.value = value;
+        }
+
+        @GsonJsonAnyGetter
+        public Map<String, String> getProps() {
+            return props;
+        }
+
+        /**
+         * Sets a property.
+         * @param name property name
+         * @param value new value
+         */
+        @GsonJsonAnySetter
+        public void setProperty(String name, String value) {
+            if (props == null) {
+                props = new TreeMap<>();
+            }
+
+            props.put(name, value);
+        }
+
+        @Override
+        public String toString() {
+            return "Data [id=" + id + ", value=" + value + ", props=" + props + "]";
+        }
+    }
+}