Add superclasses for gson-jackson migration

Added common classes needed by other gson-jackson code.
Modified some logic to make it more maintainable or perform better.
Updated comments and spacing.
Fix another comment.
Moved gson classes from utils to a separate gson project.
Added GsonXxx annotations to mirror jackson annotations.
Removed unneeded dependencies from gson pom.
Removed old GsonMessage class from policy-endpoints.
Removed trailing spaces.
Updated licenses.
Removed more trailing spaces.
Removed unneeded checkstyle suppression file from utils.

Change-Id: I1a285500faeb0a0b6a1467d09b92ecd3cded713e
Issue-ID: POLICY-1428
Signed-off-by: Jim Hahn <jrh3@att.com>

4 files changed, 7 insertions, 285 deletions

diff --git a/policy-endpoints/pom.xml b/policy-endpoints/pom.xml
index 41fa2f30..2c8b0d7f 100644
--- a/policy-endpoints/pom.xml
+++ b/policy-endpoints/pom.xml
@@ -53,6 +53,12 @@
 
         <dependency>
             <groupId>org.onap.policy.common</groupId>
+            <artifactId>gson</artifactId>
+            <version>${project.version}</version>
+        </dependency>
+
+        <dependency>
+            <groupId>org.onap.policy.common</groupId>
             <artifactId>utils</artifactId>
             <version>${project.version}</version>
         </dependency>
diff --git a/policy-endpoints/src/main/java/org/onap/policy/common/endpoints/http/server/internal/GsonMessageBodyHandler.java b/policy-endpoints/src/main/java/org/onap/policy/common/endpoints/http/server/internal/GsonMessageBodyHandler.java
deleted file mode 100644
index a29afef4..00000000
--- a/policy-endpoints/src/main/java/org/onap/policy/common/endpoints/http/server/internal/GsonMessageBodyHandler.java
+++ /dev/null
@@ -1,128 +0,0 @@
-/*
- * ============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.endpoints.http.server.internal;
-
-import com.google.gson.Gson;
-import java.io.IOException;
-import java.io.InputStream;
-import java.io.InputStreamReader;
-import java.io.OutputStream;
-import java.io.OutputStreamWriter;
-import java.lang.annotation.Annotation;
-import java.lang.reflect.Type;
-import java.nio.charset.StandardCharsets;
-import javax.ws.rs.Consumes;
-import javax.ws.rs.Produces;
-import javax.ws.rs.WebApplicationException;
-import javax.ws.rs.core.MediaType;
-import javax.ws.rs.core.MultivaluedMap;
-import javax.ws.rs.ext.MessageBodyReader;
-import javax.ws.rs.ext.MessageBodyWriter;
-import javax.ws.rs.ext.Provider;
-
-/**
- * Provider that serializes and de-serializes JSON via gson.
- * 
- * <p>Note: <i>jersey</i> will ignore this class if the maven artifact,
- * <i>jersey-media-json-jackson</i>, is included, regardless of whether it's included
- * directly or indirectly.
- */
-@Provider
-@Consumes(MediaType.WILDCARD)
-@Produces(MediaType.WILDCARD)
-public class GsonMessageBodyHandler implements MessageBodyReader<Object>, MessageBodyWriter<Object> {
-
-    /**
-     * Object to be used to serialize and de-serialize.
-     */
-    private Gson gson;
-
-    /**
-     * Constructs the object, using a plain Gson object.
-     */
-    public GsonMessageBodyHandler() {
-        this(new Gson());
-    }
-
-    /**
-     * Constructs the object.
-     * 
-     * @param gson the Gson object to be used to serialize and de-serialize
-     */
-    public GsonMessageBodyHandler(Gson gson) {
-        this.gson = gson;
-    }
-
-    @Override
-    public boolean isWriteable(Class<?> type, Type genericType, Annotation[] annotations, MediaType mediaType) {
-        return canHandle(mediaType);
-    }
-
-    @Override
-    public long getSize(Object object, Class<?> type, Type genericType, Annotation[] annotations, MediaType mediaType) {
-        return -1;
-    }
-
-    @Override
-    public void writeTo(Object object, Class<?> type, Type genericType, Annotation[] annotations, MediaType mediaType,
-                    MultivaluedMap<String, Object> httpHeaders, OutputStream entityStream)
-                    throws IOException, WebApplicationException {
-
-        try (OutputStreamWriter writer = new OutputStreamWriter(entityStream, StandardCharsets.UTF_8)) {
-            Type jsonType = (type.equals(genericType) ? type : genericType);
-            gson.toJson(object, jsonType, writer);
-        }
-    }
-
-    @Override
-    public boolean isReadable(Class<?> type, Type genericType, Annotation[] annotations, MediaType mediaType) {
-        return canHandle(mediaType);
-    }
-
-    /**
-     * Determines if this provider can handle the given media type.
-     * 
-     * @param mediaType the media type of interest
-     * @return {@code true} if this provider handles the given media type, {@code false}
-     *         otherwise
-     */
-    private boolean canHandle(MediaType mediaType) {
-        if (mediaType == null) {
-            return true;
-        }
-
-        String subtype = mediaType.getSubtype();
-
-        return "json".equalsIgnoreCase(subtype) || subtype.endsWith("+json") || "javascript".equals(subtype)
-                        || "x-javascript".equals(subtype) || "x-json".equals(subtype);
-    }
-
-    @Override
-    public Object readFrom(Class<Object> type, Type genericType, Annotation[] annotations, MediaType mediaType,
-                    MultivaluedMap<String, String> httpHeaders, InputStream entityStream)
-                    throws IOException, WebApplicationException {
-
-        try (InputStreamReader streamReader = new InputStreamReader(entityStream, StandardCharsets.UTF_8)) {
-            Type jsonType = (type.equals(genericType) ? type : genericType);
-            return gson.fromJson(streamReader, jsonType);
-        }
-    }
-}
diff --git a/policy-endpoints/src/test/java/org/onap/policy/common/endpoints/http/server/test/GsonMessageBodyHandlerTest.java b/policy-endpoints/src/test/java/org/onap/policy/common/endpoints/http/server/test/GsonMessageBodyHandlerTest.java
deleted file mode 100644
index 9c6ec80d..00000000
--- a/policy-endpoints/src/test/java/org/onap/policy/common/endpoints/http/server/test/GsonMessageBodyHandlerTest.java
+++ /dev/null
@@ -1,156 +0,0 @@
-/*
- * ============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.endpoints.http.server.test;
-
-import static org.junit.Assert.assertEquals;
-import static org.junit.Assert.assertFalse;
-import static org.junit.Assert.assertTrue;
-
-import java.io.ByteArrayInputStream;
-import java.io.ByteArrayOutputStream;
-import javax.ws.rs.core.MediaType;
-import org.junit.Before;
-import org.junit.Test;
-import org.onap.policy.common.endpoints.http.server.internal.GsonMessageBodyHandler;
-
-public class GsonMessageBodyHandlerTest {
-    private static final String GEN_TYPE = "some-type";
-    private static final String[] subtypes = {"json", "jSoN", "hello+json", "javascript", "x-javascript", "x-json"};
-
-    @SuppressWarnings("rawtypes")
-    private static final Class GEN_CLASS = MyObject.class;
-
-    @SuppressWarnings("unchecked")
-    private static final Class<Object> CLASS_OBJ = GEN_CLASS;
-
-    private GsonMessageBodyHandler hdlr;
-
-    @Before
-    public void setUp() {
-        hdlr = new GsonMessageBodyHandler();
-    }
-
-    @Test
-    public void testIsWriteable() {
-        // null media type
-        assertTrue(hdlr.isWriteable(null, null, null, null));
-
-        for (String subtype : subtypes) {
-            assertTrue("writeable " + subtype, hdlr.isWriteable(null, null, null, new MediaType(GEN_TYPE, subtype)));
-
-        }
-
-        // the remaining should be FALSE
-
-        // null subtype
-        assertFalse(hdlr.isWriteable(null, null, null, new MediaType(GEN_TYPE, null)));
-
-        // text subtype
-        assertFalse(hdlr.isWriteable(null, null, null, MediaType.TEXT_HTML_TYPE));
-    }
-
-    @Test
-    public void testGetSize() {
-        assertEquals(-1, hdlr.getSize(null, null, null, null, null));
-    }
-
-    @Test
-    public void testWriteTo_testReadFrom() throws Exception {
-        ByteArrayOutputStream outstr = new ByteArrayOutputStream();
-        MyObject obj1 = new MyObject(10);
-        hdlr.writeTo(obj1, obj1.getClass(), CLASS_OBJ, null, null, null, outstr);
-
-        Object obj2 = hdlr.readFrom(CLASS_OBJ, CLASS_OBJ, null, null, null,
-                        new ByteArrayInputStream(outstr.toByteArray()));
-        assertEquals(obj1.toString(), obj2.toString());
-    }
-
-    @Test
-    public void testWriteTo_DifferentTypes() throws Exception {
-        ByteArrayOutputStream outstr = new ByteArrayOutputStream();
-
-        // use a derived type, but specify the base type when writing
-        MyObject obj1 = new MyObject(10) {};
-        hdlr.writeTo(obj1, obj1.getClass(), CLASS_OBJ, null, null, null, outstr);
-
-        Object obj2 = hdlr.readFrom(CLASS_OBJ, CLASS_OBJ, null, null, null,
-                        new ByteArrayInputStream(outstr.toByteArray()));
-        assertEquals(obj1.toString(), obj2.toString());
-    }
-
-    @Test
-    public void testIsReadable() {
-        // null media type
-        assertTrue(hdlr.isReadable(null, null, null, null));
-
-        // null subtype
-        assertFalse(hdlr.isReadable(null, null, null, new MediaType(GEN_TYPE, null)));
-
-        for (String subtype : subtypes) {
-            assertTrue("readable " + subtype, hdlr.isReadable(null, null, null, new MediaType(GEN_TYPE, subtype)));
-
-        }
-
-        // the remaining should be FALSE
-
-        // null subtype
-        assertFalse(hdlr.isReadable(null, null, null, new MediaType(GEN_TYPE, null)));
-
-        // text subtype
-        assertFalse(hdlr.isReadable(null, null, null, MediaType.TEXT_HTML_TYPE));
-    }
-
-    @Test
-    public void testReadFrom_DifferentTypes() throws Exception {
-        ByteArrayOutputStream outstr = new ByteArrayOutputStream();
-        MyObject obj1 = new MyObject(10);
-        hdlr.writeTo(obj1, obj1.getClass(), CLASS_OBJ, null, null, null, outstr);
-
-        // use a derived type, but specify the base type when reading
-        @SuppressWarnings("rawtypes")
-        Class clazz = new MyObject() {}.getClass();
-
-        @SuppressWarnings("unchecked")
-        Class<Object> objclazz = clazz;
-
-        Object obj2 = hdlr.readFrom(objclazz, CLASS_OBJ, null, null, null,
-                        new ByteArrayInputStream(outstr.toByteArray()));
-        assertEquals(obj1.toString(), obj2.toString());
-    }
-
-    public static class MyObject {
-        private int id;
-
-        public MyObject() {
-            super();
-        }
-
-        public MyObject(int id) {
-            this.id = id;
-        }
-
-        @Override
-        public String toString() {
-            return "MyObject [id=" + id + "]";
-        }
-    }
-
-}
diff --git a/policy-endpoints/src/test/java/org/onap/policy/common/endpoints/http/server/test/MyGsonProvider.java b/policy-endpoints/src/test/java/org/onap/policy/common/endpoints/http/server/test/MyGsonProvider.java
index 037f6c6f..286d73dc 100644
--- a/policy-endpoints/src/test/java/org/onap/policy/common/endpoints/http/server/test/MyGsonProvider.java
+++ b/policy-endpoints/src/test/java/org/onap/policy/common/endpoints/http/server/test/MyGsonProvider.java
@@ -27,7 +27,7 @@ import java.lang.annotation.Annotation;
 import java.lang.reflect.Type;
 import javax.ws.rs.core.MediaType;
 import javax.ws.rs.core.MultivaluedMap;
-import org.onap.policy.common.endpoints.http.server.internal.GsonMessageBodyHandler;
+import org.onap.policy.common.gson.GsonMessageBodyHandler;
 
 /**
  * GsonMessageBodyHandler that tracks activities.