private void mergeMapField(FieldDescriptor field, JsonElement json, Message.Builder builder)
throws InvalidProtocolBufferException {
if (!(json instanceof JsonObject)) {
throw new InvalidProtocolBufferException("Expect a map object but found: " + json);
}
Descriptor type = field.getMessageType();
FieldDescriptor keyField = type.findFieldByName("key");
FieldDescriptor valueField = type.findFieldByName("value");
if (keyField == null || valueField == null) {
throw new InvalidProtocolBufferException("Invalid map field: " + field.getFullName());
}
JsonObject object = (JsonObject) json;
for (Map.Entry<String, JsonElement> entry : object.entrySet()) {
Message.Builder entryBuilder = builder.newBuilderForField(field);
Object key = parseFieldValue(keyField, new JsonPrimitive(entry.getKey()), entryBuilder);
Object value = parseFieldValue(valueField, entry.getValue(), entryBuilder);
if (value == null) {
throw new InvalidProtocolBufferException("Map value cannot be null.");
}
entryBuilder.setField(keyField, key);
entryBuilder.setField(valueField, value);
builder.addRepeatedField(field, entryBuilder.build());
}
}