#1002: Add Player Profile API

Slight changes may occur as this API is stabilized.

This PR is based on work previously done by DerFrZocker in #938.

By: blablubbabc <lukas@wirsindwir.de>

paper-server/src/main/java/org/bukkit/craftbukkit/util/JsonHelper.java

@@ -0,0 +1,49 @@
+package org.bukkit.craftbukkit.util;
+
+import com.google.gson.JsonElement;
+import com.google.gson.JsonObject;
+import com.google.gson.JsonPrimitive;
+import javax.annotation.Nonnull;
+import javax.annotation.Nullable;
+
+public final class JsonHelper {
+
+    @Nullable
+    public static JsonObject getObjectOrNull(@Nonnull JsonObject parent, @Nonnull String key) {
+        JsonElement element = parent.get(key);
+        return (element instanceof JsonObject) ? (JsonObject) element : null;
+    }
+
+    @Nonnull
+    public static JsonObject getOrCreateObject(@Nonnull JsonObject parent, @Nonnull String key) {
+        JsonObject jsonObject = getObjectOrNull(parent, key);
+        if (jsonObject == null) {
+            jsonObject = new JsonObject();
+            parent.add(key, jsonObject);
+        }
+        return jsonObject;
+    }
+
+    @Nullable
+    public static JsonPrimitive getPrimitiveOrNull(@Nonnull JsonObject parent, @Nonnull String key) {
+        JsonElement element = parent.get(key);
+        return (element instanceof JsonPrimitive) ? (JsonPrimitive) element : null;
+    }
+
+    @Nullable
+    public static String getStringOrNull(JsonObject parent, String key) {
+        JsonPrimitive primitive = getPrimitiveOrNull(parent, key);
+        return (primitive != null) ? primitive.getAsString() : null;
+    }
+
+    public static void setOrRemove(@Nonnull JsonObject parent, @Nonnull String key, @Nullable JsonElement value) {
+        if (value == null) {
+            parent.remove(key);
+        } else {
+            parent.add(key, value);
+        }
+    }
+
+    private JsonHelper() {
+    }
+}