Add gson adapters for special field types

Added type adapters for Instant, LocalDateTime, and ZonedDateTime.  UUID
seems to work already.
Added new Coder that offers an alternative encoding for Instant.

Issue-ID: POLICY-1625
Signed-off-by: Jim Hahn <jrh3@att.com>
Change-Id: I5230fa7fe955d78c5f2da1316cb1504b5875ea84

2 files changed, 126 insertions, 1 deletions

diff --git a/utils/src/main/java/org/onap/policy/common/utils/coder/StandardCoder.java b/utils/src/main/java/org/onap/policy/common/utils/coder/StandardCoder.java
index 9d444cae..2548dea4 100644
--- a/utils/src/main/java/org/onap/policy/common/utils/coder/StandardCoder.java
+++ b/utils/src/main/java/org/onap/policy/common/utils/coder/StandardCoder.java
@@ -363,7 +363,7 @@ public class StandardCoder implements Coder {
     /**
      * Adapter for standard objects.
      */
-    private static class StandardTypeAdapter extends TypeAdapter<StandardCoderObject> {
+    protected static class StandardTypeAdapter extends TypeAdapter<StandardCoderObject> {
 
         /**
          * Used to read/write a JsonElement.
diff --git a/utils/src/main/java/org/onap/policy/common/utils/coder/StandardCoderInstantAsMillis.java b/utils/src/main/java/org/onap/policy/common/utils/coder/StandardCoderInstantAsMillis.java
new file mode 100644
index 00000000..fbb53b91
--- /dev/null
+++ b/utils/src/main/java/org/onap/policy/common/utils/coder/StandardCoderInstantAsMillis.java
@@ -0,0 +1,125 @@
+/*-
+ * ============LICENSE_START=======================================================
+ * ONAP
+ * ================================================================================
+ * Copyright (C) 2020 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.utils.coder;
+
+import com.google.gson.Gson;
+import com.google.gson.GsonBuilder;
+import com.google.gson.JsonElement;
+import java.io.Reader;
+import java.io.Writer;
+import java.time.Instant;
+import lombok.AccessLevel;
+import lombok.Getter;
+import org.onap.policy.common.gson.GsonMessageBodyHandler;
+import org.onap.policy.common.gson.InstantAsMillisTypeAdapter;
+
+/**
+ * JSON encoder and decoder using the "standard" mechanism, but encodes Instant fields as
+ * Long milliseconds.
+ */
+public class StandardCoderInstantAsMillis extends StandardCoder {
+
+    /**
+     * Gson object used to encode and decode messages.
+     */
+    @Getter(AccessLevel.PROTECTED)
+    private static final Gson GSON;
+
+    /**
+     * Gson object used to encode messages in "pretty" format.
+     */
+    @Getter(AccessLevel.PROTECTED)
+    private static final Gson GSON_PRETTY;
+
+    static {
+        GsonBuilder builder = GsonMessageBodyHandler
+                        .configBuilder(new GsonBuilder().registerTypeAdapter(StandardCoderObject.class,
+                                        new StandardTypeAdapter()))
+                        .registerTypeAdapter(Instant.class, new InstantAsMillisTypeAdapter());
+
+        GSON = builder.create();
+        GSON_PRETTY = builder.setPrettyPrinting().create();
+    }
+
+    /**
+     * Constructs the object.
+     */
+    public StandardCoderInstantAsMillis() {
+        super();
+    }
+
+    @Override
+    protected String toPrettyJson(Object object) {
+        return GSON_PRETTY.toJson(object);
+    }
+
+    @Override
+    public StandardCoderObject toStandard(Object object) throws CoderException {
+        try {
+            return new StandardCoderObject(GSON.toJsonTree(object));
+
+        } catch (RuntimeException e) {
+            throw new CoderException(e);
+        }
+    }
+
+    @Override
+    public <T> T fromStandard(StandardCoderObject sco, Class<T> clazz) throws CoderException {
+        try {
+            return GSON.fromJson(sco.getData(), clazz);
+
+        } catch (RuntimeException e) {
+            throw new CoderException(e);
+        }
+    }
+
+    // the remaining methods are wrappers that can be overridden by junit tests
+
+    @Override
+    protected JsonElement toJsonTree(Object object) {
+        return GSON.toJsonTree(object);
+    }
+
+    @Override
+    protected String toJson(Object object) {
+        return GSON.toJson(object);
+    }
+
+    @Override
+    protected void toJson(Writer target, Object object) {
+        GSON.toJson(object, object.getClass(), target);
+    }
+
+    @Override
+    protected <T> T fromJson(JsonElement json, Class<T> clazz) {
+        return convertFromDouble(clazz, GSON.fromJson(json, clazz));
+    }
+
+    @Override
+    protected <T> T fromJson(String json, Class<T> clazz) {
+        return convertFromDouble(clazz, GSON.fromJson(json, clazz));
+    }
+
+    @Override
+    protected <T> T fromJson(Reader source, Class<T> clazz) {
+        return convertFromDouble(clazz, GSON.fromJson(source, clazz));
+    }
+}