Merge pull request #643 from altrisi/json-reading

Reading/Writing JSON in Scarpet

src/main/java/carpet/script/utils/ScarpetJsonDeserializer.java

@@ -0,0 +1,78 @@
+package carpet.script.utils;
+
+import java.lang.reflect.Type;
+import java.util.ArrayList;
+import java.util.HashMap;
+import java.util.List;
+import java.util.Map;
+
+import com.google.gson.JsonArray;
+import com.google.gson.JsonDeserializationContext;
+import com.google.gson.JsonDeserializer;
+import com.google.gson.JsonElement;
+import com.google.gson.JsonObject;
+import com.google.gson.JsonParseException;
+import com.google.gson.JsonPrimitive;
+
+import carpet.script.value.ListValue;
+import carpet.script.value.MapValue;
+import carpet.script.value.NumericValue;
+import carpet.script.value.StringValue;
+import carpet.script.value.Value;
+
+public class ScarpetJsonDeserializer implements JsonDeserializer<Value>{
+
+    @Override
+    public Value deserialize(JsonElement json, Type typeOfT, JsonDeserializationContext context)
+            throws JsonParseException {
+        return parseElement(json);
+    }
+    
+    private Value parseElement(JsonElement element) throws JsonParseException {
+        if (element.isJsonObject())
+        {
+            return parseMap(element.getAsJsonObject());
+        }
+        else if (element.isJsonArray())
+        {
+            return parseList(element.getAsJsonArray());
+        }
+        else if (element.isJsonPrimitive())
+        {
+            return parsePrimitive(element.getAsJsonPrimitive());
+        }
+        return Value.NULL;
+    }
+
+    private Value parseMap(JsonObject jsonMap) throws JsonParseException {
+        Map<Value, Value> map = new HashMap<Value, Value>();
+        jsonMap.entrySet().forEach(entry -> {
+            map.put(new StringValue(entry.getKey()), parseElement(entry.getValue()));
+        });
+        return MapValue.wrap(map);
+    }
+
+    private Value parseList(JsonArray jsonList) throws JsonParseException {
+        List<Value> list = new ArrayList<Value>();
+        jsonList.forEach(elem -> {
+            list.add(parseElement(elem));
+        });
+        return new ListValue(list);
+    }
+    
+    private Value parsePrimitive(JsonPrimitive primitive) throws JsonParseException {
+        if (primitive.isString())
+        {
+            return new StringValue(primitive.getAsString());
+        }
+        else if (primitive.isBoolean())
+        {
+            return primitive.getAsBoolean() ? Value.TRUE : Value.FALSE;
+        }
+        else if (primitive.isNumber())
+        {
+            return NumericValue.of(primitive.getAsNumber());
+        }
+        return Value.NULL;
+    }
+}