Don't map JSON values to Double

By default, gson treats all numbers as Double when placed into a
generic Map.  This is not backward compatible with existing policy
APIs.  Added a type adapter that walks Map objects and converts the
Double values to Integer or Long, where possible.
Made this the default behavior in the GsonMessageBodyHandler, the
JacksonHandler, and the StandardCoder.
Also fixed a couple of checkstyle errors in the gson project.

Change-Id: I9ac0c77e6592d1c039646f0662c077b77a1e9aaf
Issue-ID: POLICY-1542
Signed-off-by: Jim Hahn <jrh3@att.com>

5 files changed, 161 insertions, 12 deletions

diff --git a/gson/src/main/java/org/onap/policy/common/gson/GsonMessageBodyHandler.java b/gson/src/main/java/org/onap/policy/common/gson/GsonMessageBodyHandler.java
index 9dad6db8..a36f8a07 100644
--- a/gson/src/main/java/org/onap/policy/common/gson/GsonMessageBodyHandler.java
+++ b/gson/src/main/java/org/onap/policy/common/gson/GsonMessageBodyHandler.java
@@ -21,7 +21,7 @@
 package org.onap.policy.common.gson;
 
 import com.google.gson.Gson;
-
+import com.google.gson.GsonBuilder;
 import java.io.IOException;
 import java.io.InputStream;
 import java.io.InputStreamReader;
@@ -37,9 +37,7 @@ import javax.ws.rs.core.MultivaluedMap;
 import javax.ws.rs.ext.MessageBodyReader;
 import javax.ws.rs.ext.MessageBodyWriter;
 import javax.ws.rs.ext.Provider;
-
 import lombok.Getter;
-
 import org.slf4j.Logger;
 import org.slf4j.LoggerFactory;
 
@@ -60,10 +58,11 @@ public class GsonMessageBodyHandler implements MessageBodyReader<Object>, Messag
     private final Gson gson;
 
     /**
-     * Constructs the object, using a plain Gson object.
+     * Constructs the object, using a Gson object that translates Doubles inside of Maps
+     * into Integer/Long, where possible.
      */
     public GsonMessageBodyHandler() {
-        this(new Gson());
+        this(new GsonBuilder().registerTypeAdapterFactory(new MapDoubleAdapterFactory()).create());
 
         logger.info("Using GSON for REST calls");
     }
@@ -89,8 +88,7 @@ public class GsonMessageBodyHandler implements MessageBodyReader<Object>, Messag
 
     @Override
     public void writeTo(Object object, Class<?> type, Type genericType, Annotation[] annotations, MediaType mediaType,
-                    MultivaluedMap<String, Object> httpHeaders, OutputStream entityStream)
-                    throws IOException {
+                    MultivaluedMap<String, Object> httpHeaders, OutputStream entityStream) throws IOException {
 
         try (OutputStreamWriter writer = new OutputStreamWriter(entityStream, StandardCharsets.UTF_8)) {
             Type jsonType = (type.equals(genericType) ? type : genericType);
@@ -126,8 +124,7 @@ public class GsonMessageBodyHandler implements MessageBodyReader<Object>, Messag
 
     @Override
     public Object readFrom(Class<Object> type, Type genericType, Annotation[] annotations, MediaType mediaType,
-                    MultivaluedMap<String, String> httpHeaders, InputStream entityStream)
-                    throws IOException {
+                    MultivaluedMap<String, String> httpHeaders, InputStream entityStream) throws IOException {
 
         try (InputStreamReader streamReader = new InputStreamReader(entityStream, StandardCharsets.UTF_8)) {
             Type jsonType = (type.equals(genericType) ? type : genericType);
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
index b2648b0b..ad9692f4 100644
--- a/gson/src/main/java/org/onap/policy/common/gson/JacksonHandler.java
+++ b/gson/src/main/java/org/onap/policy/common/gson/JacksonHandler.java
@@ -37,7 +37,7 @@ public class JacksonHandler extends GsonMessageBodyHandler {
      */
     public JacksonHandler() {
         this(new GsonBuilder());
-        
+
         logger.info("Using GSON with Jackson behaviors for REST calls");
     }
 
@@ -49,6 +49,7 @@ public class JacksonHandler extends GsonMessageBodyHandler {
         super(builder
                         .registerTypeAdapterFactory(new JacksonFieldAdapterFactory())
                         .registerTypeAdapterFactory(new JacksonMethodAdapterFactory())
+                        .registerTypeAdapterFactory(new MapDoubleAdapterFactory())
                         .setExclusionStrategies(new JacksonExclusionStrategy())
                         .create());
     }
diff --git a/gson/src/main/java/org/onap/policy/common/gson/MapDoubleAdapterFactory.java b/gson/src/main/java/org/onap/policy/common/gson/MapDoubleAdapterFactory.java
new file mode 100644
index 00000000..3892a07f
--- /dev/null
+++ b/gson/src/main/java/org/onap/policy/common/gson/MapDoubleAdapterFactory.java
@@ -0,0 +1,152 @@
+/*
+ * ============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.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.ParameterizedType;
+import java.lang.reflect.Type;
+import java.util.Map;
+import java.util.Map.Entry;
+import java.util.Set;
+
+/**
+ * Adapter factory for Map&lt;String,Object&gt;. By default, GSON treats all Objects, that
+ * are numbers, as Double. This walks the map and converts Doubles to Integer or Long, if
+ * possible.
+ */
+public class MapDoubleAdapterFactory implements TypeAdapterFactory {
+
+    @Override
+    public <T> TypeAdapter<T> create(Gson gson, TypeToken<T> type) {
+        if (type.getRawType() != Map.class) {
+            return null;
+        }
+
+        Type[] actualParams = ((ParameterizedType) type.getType()).getActualTypeArguments();
+
+        // only supports Map<String,Object>
+        if (actualParams[0] != String.class || actualParams[1] != Object.class) {
+            return null;
+        }
+
+        TypeAdapter<T> delegate = gson.getDelegateAdapter(this, type);
+
+        return new MapAdapter<T>(delegate);
+    }
+
+    /**
+     * Type adapter that performs conversion from Double to Integer/Long.
+     *
+     * @param <T> type of object on which this works (always Map.class)
+     */
+    private static class MapAdapter<T> extends TypeAdapter<T> {
+
+        /**
+         * Used to perform conversion between JSON and Map&lt;String,Object&gt;.
+         */
+        private final TypeAdapter<T> delegate;
+
+        /**
+         * Constructs the object.
+         *
+         * @param delegate JSON/Map converter
+         */
+        public MapAdapter(TypeAdapter<T> delegate) {
+            this.delegate = delegate;
+        }
+
+        @Override
+        public void write(JsonWriter out, T value) throws IOException {
+            delegate.write(out, value);
+        }
+
+        @Override
+        public T read(JsonReader in) throws IOException {
+            T value = delegate.read(in);
+
+            @SuppressWarnings("rawtypes")
+            Map map = (Map) value;
+
+            convertFromDouble(map);
+
+            return value;
+        }
+
+        /**
+         * Performs conversion of all values in a map.
+         *
+         * @param map the map whose values are to be converted
+         */
+        @SuppressWarnings("rawtypes")
+        private void convertFromDouble(Map map) {
+
+            @SuppressWarnings("unchecked")
+            Set<Entry> set = map.entrySet();
+
+            for (Entry entry : set) {
+                convertFromDouble(entry);
+            }
+        }
+
+        /**
+         * Converts an entry's value. If the value is a Map, then it recursively converts
+         * the entries of the map.
+         *
+         * @param entry entry whose value is to be converted
+         */
+        @SuppressWarnings({"unchecked", "rawtypes"})
+        private void convertFromDouble(Entry entry) {
+            Object obj = entry.getValue();
+
+            if (obj instanceof Map) {
+                convertFromDouble((Map) obj);
+                return;
+            }
+
+            if (!(obj instanceof Double)) {
+                return;
+            }
+
+            Double num = (Double) obj;
+            long longval = num.longValue();
+
+            if (num.doubleValue() == longval) {
+                // it's integral - determine if it's an integer or a long
+                int intval = (int) longval;
+
+                if (intval == longval) {
+                    // it fits in an integer
+                    entry.setValue(intval);
+
+                } else {
+                    // doesn't fit in an integer - must be a long
+                    entry.setValue(longval);
+                }
+            }
+        }
+    }
+}
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
index da9ad173..4ad924af 100644
--- 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
@@ -39,7 +39,6 @@ public class AnyGetterSerializer extends Lifter implements Serializer {
      * 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
      */
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
index 85d42dfa..411d30cd 100644
--- 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
@@ -37,7 +37,7 @@ public class AnySetterDeserializer extends Lifter implements Deserializer {
      *
      * @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
+     * @param setter method used to set the item within an object
      */
     public AnySetterDeserializer(Gson gson, Set<String> unliftedProps, Method setter) {
         super(gson, unliftedProps, setter, setter.getGenericParameterTypes()[1]);