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>

1 files changed, 83 insertions, 0 deletions

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());
+            }
+        }
+    }
+}