diff --git a/lib/domain/atom_category.dart b/lib/domain/atom_category.dart
index 5364b60..22c6a97 100644
--- a/lib/domain/atom_category.dart
+++ b/lib/domain/atom_category.dart
@@ -1,9 +1,9 @@
 import 'package:xml/xml.dart';
 
 class AtomCategory {
-  String term;
-  String scheme;
-  String label;
+  final String term;
+  final String scheme;
+  final String label;
 
   AtomCategory(this.term, this.scheme, this.label);
 
@@ -11,15 +11,6 @@ class AtomCategory {
     var term = element.getAttribute("term");
     var scheme = element.getAttribute("scheme");
     var label = element.getAttribute("label");
-    return new AtomCategory(term, scheme, label);
-  }
-
-  @override
-  String toString() {
-    return '''
-      term: $term
-      scheme: $scheme
-      label: $label
-    ''';
+    return AtomCategory(term, scheme, label);
   }
 }
diff --git a/lib/domain/atom_feed.dart b/lib/domain/atom_feed.dart
index 2a0dffa..92f2cd6 100644
--- a/lib/domain/atom_feed.dart
+++ b/lib/domain/atom_feed.dart
@@ -7,20 +7,20 @@ import 'package:webfeed/util/helpers.dart';
 import 'package:xml/xml.dart';
 
 class AtomFeed {
-  String id;
-  String title;
-  String updated;
-  List<AtomItem> items;
+  final String id;
+  final String title;
+  final String updated;
+  final List<AtomItem> items;
 
-  List<AtomLink> links;
-  List<AtomPerson> authors;
-  List<AtomPerson> contributors;
-  List<AtomCategory> categories;
-  AtomGenerator generator;
-  String icon;
-  String logo;
-  String rights;
-  String subtitle;
+  final List<AtomLink> links;
+  final List<AtomPerson> authors;
+  final List<AtomPerson> contributors;
+  final List<AtomCategory> categories;
+  final AtomGenerator generator;
+  final String icon;
+  final String logo;
+  final String rights;
+  final String subtitle;
 
   AtomFeed({
     this.id,
@@ -46,73 +46,32 @@ class AtomFeed {
     } on StateError {
       throw new ArgumentError("feed not found");
     }
-    var id = xmlGetString(feedElement, "id", strict: false);
-    var title = xmlGetString(feedElement, "title", strict: false);
-    var updated = xmlGetString(feedElement, "updated", strict: false);
 
-    var items = feedElement.findElements("entry").map((element) {
-      return new AtomItem.parse(element);
-    }).toList();
-
-    var links = feedElement.findElements("link").map((element) {
-      return new AtomLink.parse(element);
-    }).toList();
-
-    var authors = feedElement.findElements("author").map((element) {
-      return new AtomPerson.parse(element);
-    }).toList();
-
-    var contributors = feedElement.findElements("contributor").map((element) {
-      return new AtomPerson.parse(element);
-    }).toList();
-
-    var categories = feedElement.findElements("category").map((element) {
-      return new AtomCategory.parse(element);
-    }).toList();
-
-    AtomGenerator generator;
-    try {
-      generator =
-          new AtomGenerator.parse(feedElement.findElements("generator").first);
-    } on StateError {}
-
-    var icon = xmlGetString(feedElement, "icon", strict: false);
-    var logo = xmlGetString(feedElement, "logo", strict: false);
-    var rights = xmlGetString(feedElement, "rights", strict: false);
-    var subtitle = xmlGetString(feedElement, "subtitle", strict: false);
-
-    return new AtomFeed(
-        id: id,
-        title: title,
-        updated: updated,
-        items: items,
-        links: links,
-        authors: authors,
-        contributors: contributors,
-        categories: categories,
-        generator: generator,
-        icon: icon,
-        logo: logo,
-        rights: rights,
-        subtitle: subtitle);
-  }
-
-  @override
-  String toString() {
-    return '''
-      id: $id
-      title: $title
-      updated: $updated
-      items: $items
-      links: $links
-      authors: $authors
-      contributors: $contributors
-      categories: $categories
-      generator: $generator
-      icon: $icon
-      logo: $logo
-      rights: $rights
-      subtitle: $subtitle
-    ''';
+    return AtomFeed(
+      id: findElementOrNull(feedElement, "id")?.text,
+      title: findElementOrNull(feedElement, "title")?.text,
+      updated: findElementOrNull(feedElement, "updated")?.text,
+      items: feedElement.findElements("entry").map((element) {
+        return AtomItem.parse(element);
+      }).toList(),
+      links: feedElement.findElements("link").map((element) {
+        return AtomLink.parse(element);
+      }).toList(),
+      authors: feedElement.findElements("author").map((element) {
+        return AtomPerson.parse(element);
+      }).toList(),
+      contributors: feedElement.findElements("contributor").map((element) {
+        return AtomPerson.parse(element);
+      }).toList(),
+      categories: feedElement.findElements("category").map((element) {
+        return AtomCategory.parse(element);
+      }).toList(),
+      generator:
+          AtomGenerator.parse(findElementOrNull(feedElement, "generator")),
+      icon: findElementOrNull(feedElement, "icon")?.text,
+      logo: findElementOrNull(feedElement, "logo")?.text,
+      rights: findElementOrNull(feedElement, "rights")?.text,
+      subtitle: findElementOrNull(feedElement, "subtitle")?.text,
+    );
   }
 }
diff --git a/lib/domain/atom_generator.dart b/lib/domain/atom_generator.dart
index d5d1098..7fd8579 100644
--- a/lib/domain/atom_generator.dart
+++ b/lib/domain/atom_generator.dart
@@ -1,25 +1,19 @@
 import 'package:xml/xml.dart';
 
 class AtomGenerator {
-  String uri;
-  String version;
-  String value;
+  final String uri;
+  final String version;
+  final String value;
 
   AtomGenerator(this.uri, this.version, this.value);
 
   factory AtomGenerator.parse(XmlElement element) {
+    if (element == null) {
+      return null;
+    }
     var uri = element.getAttribute("uri");
     var version = element.getAttribute("version");
     var value = element.text;
     return new AtomGenerator(uri, version, value);
   }
-
-  @override
-  String toString() {
-    return '''
-      uri: $uri
-      version: $version
-      value: $value
-    ''';
-  }
 }
diff --git a/lib/domain/atom_item.dart b/lib/domain/atom_item.dart
index 11c74c5..618015b 100644
--- a/lib/domain/atom_item.dart
+++ b/lib/domain/atom_item.dart
@@ -39,68 +39,28 @@ class AtomItem {
   });
 
   factory AtomItem.parse(XmlElement element) {
-    var id = xmlGetString(element, "id", strict: false);
-    var title = xmlGetString(element, "title", strict: false);
-    var updated = xmlGetString(element, "updated", strict: false);
-
-    var authors = element.findElements("author").map((element) {
-      return new AtomPerson.parse(element);
-    }).toList();
-
-    var links = element.findElements("link").map((element) {
-      return new AtomLink.parse(element);
-    }).toList();
-
-    var categories = element.findElements("category").map((element) {
-      return new AtomCategory.parse(element);
-    }).toList();
-
-    var contributors = element.findElements("contributor").map((element) {
-      return new AtomPerson.parse(element);
-    }).toList();
-
-    AtomSource source;
-    try {
-      source = new AtomSource.parse(element.findElements("source").first);
-    } on StateError {}
-
-    var published = xmlGetString(element, "published", strict: false);
-    var content = xmlGetString(element, "content", strict: false);
-    var summary = xmlGetString(element, "summary", strict: false);
-    var rights = xmlGetString(element, "rights", strict: false);
-
-    return new AtomItem(
-      id: id,
-      title: title,
-      updated: updated,
-      authors: authors,
-      links: links,
-      categories: categories,
-      contributors: contributors,
-      source: source,
-      published: published,
-      content: content,
-      summary: summary,
-      rights: rights,
-      media: new Media.parse(element),
+    return AtomItem(
+      id: findElementOrNull(element, "id")?.text,
+      title: findElementOrNull(element, "title")?.text,
+      updated: findElementOrNull(element, "updated")?.text,
+      authors: element.findElements("author").map((element) {
+        return AtomPerson.parse(element);
+      }).toList(),
+      links: element.findElements("link").map((element) {
+        return AtomLink.parse(element);
+      }).toList(),
+      categories: element.findElements("category").map((element) {
+        return AtomCategory.parse(element);
+      }).toList(),
+      contributors: element.findElements("contributor").map((element) {
+        return AtomPerson.parse(element);
+      }).toList(),
+      source: AtomSource.parse(findElementOrNull(element, "source")),
+      published: findElementOrNull(element, "published")?.text,
+      content: findElementOrNull(element, "content")?.text,
+      summary: findElementOrNull(element, "summary")?.text,
+      rights: findElementOrNull(element, "rights")?.text,
+      media: Media.parse(element),
     );
   }
-
-  @override
-  String toString() {
-    return '''
-      id: $id
-      title: $title
-      updated: $updated
-      authors: $authors
-      links: $links
-      categories: $categories
-      contributors: $contributors
-      source: $source
-      published: $published
-      content: $content
-      summary: $summary
-      rights: $rights
-    ''';
-  }
 }
diff --git a/lib/domain/atom_link.dart b/lib/domain/atom_link.dart
index a412298..3b570f2 100644
--- a/lib/domain/atom_link.dart
+++ b/lib/domain/atom_link.dart
@@ -1,12 +1,12 @@
 import 'package:xml/xml.dart';
 
 class AtomLink {
-  String href;
-  String rel;
-  String type;
-  String hreflang;
-  String title;
-  int length;
+  final String href;
+  final String rel;
+  final String type;
+  final String hreflang;
+  final String title;
+  final int length;
 
   AtomLink(
     this.href,
@@ -27,18 +27,6 @@ class AtomLink {
     if (element.getAttribute("length") != null) {
       length = int.parse(element.getAttribute("length"));
     }
-    return new AtomLink(href, rel, type, hreflang, title, length);
-  }
-
-  @override
-  String toString() {
-    return '''
-      href: $href
-      rel: $rel
-      type: $type
-      hreflang: $hreflang
-      title: $title
-      length: $length
-    ''';
+    return AtomLink(href, rel, type, hreflang, title, length);
   }
 }
diff --git a/lib/domain/atom_person.dart b/lib/domain/atom_person.dart
index ba24914..3eb1e4a 100644
--- a/lib/domain/atom_person.dart
+++ b/lib/domain/atom_person.dart
@@ -2,25 +2,16 @@ import 'package:webfeed/util/helpers.dart';
 import 'package:xml/xml.dart';
 
 class AtomPerson {
-  String name;
-  String uri;
-  String email;
+  final String name;
+  final String uri;
+  final String email;
 
   AtomPerson(this.name, this.uri, this.email);
 
   factory AtomPerson.parse(XmlElement element) {
-    var name = xmlGetString(element, "name");
-    var uri = xmlGetString(element, "uri", strict: false);
-    var email = xmlGetString(element, "email", strict: false);
-    return new AtomPerson(name, uri, email);
-  }
-
-  @override
-  String toString() {
-    return '''
-      name: $name
-      uri: $uri
-      email: $email
-    ''';
+    var name = findElementOrNull(element, "name")?.text;
+    var uri = findElementOrNull(element, "uri")?.text;
+    var email = findElementOrNull(element, "email")?.text;
+    return AtomPerson(name, uri, email);
   }
 }
diff --git a/lib/domain/atom_source.dart b/lib/domain/atom_source.dart
index 03d8a0b..37fb619 100644
--- a/lib/domain/atom_source.dart
+++ b/lib/domain/atom_source.dart
@@ -2,26 +2,20 @@ import 'package:webfeed/util/helpers.dart';
 import 'package:xml/xml.dart';
 
 class AtomSource {
-  String id;
-  String title;
-  String updated;
+  final String id;
+  final String title;
+  final String updated;
 
   AtomSource(this.id, this.title, this.updated);
 
   factory AtomSource.parse(XmlElement element) {
-    var id = xmlGetString(element, "id", strict: false);
-    var title = xmlGetString(element, "title", strict: false);
-    var updated = xmlGetString(element, "updated", strict: false);
+    if (element == null) {
+      return null;
+    }
+    var id = findElementOrNull(element, "id")?.text;
+    var title = findElementOrNull(element, "title")?.text;
+    var updated = findElementOrNull(element, "updated")?.text;
 
-    return new AtomSource(id, title, updated);
-  }
-
-  @override
-  String toString() {
-    return '''
-      id: $id
-      title: $title
-      updated: $updated
-    ''';
+    return AtomSource(id, title, updated);
   }
 }
diff --git a/lib/domain/rss_category.dart b/lib/domain/rss_category.dart
index bb611b5..845a837 100644
--- a/lib/domain/rss_category.dart
+++ b/lib/domain/rss_category.dart
@@ -13,6 +13,6 @@ class RssCategory {
     var domain = element.getAttribute("domain");
     var value = element.text;
 
-    return new RssCategory(domain, value);
+    return RssCategory(domain, value);
   }
 }
diff --git a/lib/domain/rss_cloud.dart b/lib/domain/rss_cloud.dart
index 729d632..74d8b6a 100644
--- a/lib/domain/rss_cloud.dart
+++ b/lib/domain/rss_cloud.dart
@@ -24,17 +24,6 @@ class RssCloud {
     var path = node.getAttribute("path");
     var registerProcedure = node.getAttribute("registerProcedure");
     var protocol = node.getAttribute("protocol");
-    return new RssCloud(domain, port, path, registerProcedure, protocol);
-  }
-
-  @override
-  String toString() {
-    return '''
-      domain: $domain
-      port: $port
-      path: $path
-      registerProcedure: $registerProcedure
-      protocol: $protocol
-    ''';
+    return RssCloud(domain, port, path, registerProcedure, protocol);
   }
 }
diff --git a/lib/domain/rss_content.dart b/lib/domain/rss_content.dart
index 93cc97a..ae68d21 100644
--- a/lib/domain/rss_content.dart
+++ b/lib/domain/rss_content.dart
@@ -25,14 +25,6 @@ class RssContent {
     _imagesRegExp.allMatches(content).forEach((match) {
       images.add(match.group(1));
     });
-    return new RssContent(content, images);
-  }
-
-  @override
-  String toString() {
-    return '''
-      content: $value
-      images: $images
-    ''';
+    return RssContent(content, images);
   }
 }
diff --git a/lib/domain/rss_enclosure.dart b/lib/domain/rss_enclosure.dart
index fa9ebf2..4b125e2 100644
--- a/lib/domain/rss_enclosure.dart
+++ b/lib/domain/rss_enclosure.dart
@@ -14,6 +14,6 @@ class RssEnclosure {
     var url = element.getAttribute("url");
     var type = element.getAttribute("type");
     var length = int.tryParse(element.getAttribute("length") ?? "0");
-    return new RssEnclosure(url, type, length);
+    return RssEnclosure(url, type, length);
   }
 }
diff --git a/lib/domain/rss_feed.dart b/lib/domain/rss_feed.dart
index 85d4249..aca0250 100644
--- a/lib/domain/rss_feed.dart
+++ b/lib/domain/rss_feed.dart
@@ -77,12 +77,12 @@ class RssFeed {
           ?.findAllElements("day")
           ?.map((element) {
         return element.text;
-      })?.toList(),
+      })?.toList() ?? [],
       skipHours: findElementOrNull(channelElement, "skipHours")
           ?.findAllElements("hour")
           ?.map((element) {
         return int.tryParse(element.text ?? "0");
-      })?.toList(),
+      })?.toList() ?? [],
       lastBuildDate: findElementOrNull(channelElement, "lastBuildDate")?.text,
       language: findElementOrNull(channelElement, "language")?.text,
       generator: findElementOrNull(channelElement, "generator")?.text,
diff --git a/lib/domain/rss_image.dart b/lib/domain/rss_image.dart
index 48dadce..cfc9479 100644
--- a/lib/domain/rss_image.dart
+++ b/lib/domain/rss_image.dart
@@ -12,19 +12,10 @@ class RssImage {
     if (element == null) {
       return null;
     }
-    var title = xmlGetString(element, "title", strict: false);
-    var url = xmlGetString(element, "url", strict: false);
-    var link = xmlGetString(element, "link", strict: false);
+    var title = findElementOrNull(element, "title")?.text;
+    var url = findElementOrNull(element, "url")?.text;
+    var link = findElementOrNull(element, "link")?.text;
 
-    return new RssImage(title, url, link);
-  }
-
-  @override
-  String toString() {
-    return '''
-      title: $title
-      url: $url
-      link: $link
-    ''';
+    return RssImage(title, url, link);
   }
 }
diff --git a/lib/domain/rss_item.dart b/lib/domain/rss_item.dart
index f290a96..4f64d67 100644
--- a/lib/domain/rss_item.dart
+++ b/lib/domain/rss_item.dart
@@ -6,7 +6,6 @@ import 'package:webfeed/domain/rss_enclosure.dart';
 import 'package:webfeed/domain/rss_source.dart';
 import 'package:webfeed/util/helpers.dart';
 import 'package:xml/xml.dart';
-import 'package:webfeed/util/helpers.dart';
 
 class RssItem {
   final String title;
diff --git a/lib/domain/rss_source.dart b/lib/domain/rss_source.dart
index a08877d..42882f0 100644
--- a/lib/domain/rss_source.dart
+++ b/lib/domain/rss_source.dart
@@ -1,8 +1,8 @@
 import 'package:xml/xml/nodes/element.dart';
 
 class RssSource {
-  String url;
-  String value;
+  final String url;
+  final String value;
 
   RssSource(this.url, this.value);
 
@@ -13,6 +13,6 @@ class RssSource {
     var url = element.getAttribute("url");
     var value = element.text;
 
-    return new RssSource(url, value);
+    return RssSource(url, value);
   }
 }
diff --git a/lib/util/helpers.dart b/lib/util/helpers.dart
index 37c7710..fdce64c 100644
--- a/lib/util/helpers.dart
+++ b/lib/util/helpers.dart
@@ -9,28 +9,3 @@ XmlElement findElementOrNull(XmlElement element, String name) {
     return null;
   }
 }
-
-String xmlGetString(XmlElement element, String name, {strict: true}) {
-  try {
-    return element.findElements(name).first.text;
-  } on StateError {
-    if (strict) {
-      throw new ArgumentError("$name not found");
-    }
-  }
-  return null;
-}
-
-int xmlGetInt(XmlElement element, String name, {strict: true}) {
-  var value = xmlGetString(element, name, strict: strict);
-  if (value != null) {
-    try {
-      return int.parse(value);
-    } on FormatException {
-      if (strict) {
-        throw new ArgumentError("$name has invalid format");
-      }
-    }
-  }
-  return null;
-}
diff --git a/test/atom_test.dart b/test/atom_test.dart
index d397a9a..e7ba377 100644
--- a/test/atom_test.dart
+++ b/test/atom_test.dart
@@ -219,4 +219,38 @@ void main() {
     expect(item.media.scenes.first.startTime, "00:15");
     expect(item.media.scenes.first.endTime, "00:45");
   });
+
+  test("parse Atom-Empty.xml", () {
+    var xmlString = File("test/xml/Atom-Empty.xml").readAsStringSync();
+
+    var feed = AtomFeed.parse(xmlString);
+
+    expect(feed.id, null);
+    expect(feed.title, null);
+    expect(feed.updated, null);
+    expect(feed.links.length, 0);
+    expect(feed.authors.length, 0);
+    expect(feed.contributors.length, 0);
+    expect(feed.categories.length, 0);
+    expect(feed.generator, null);
+    expect(feed.icon, null);
+    expect(feed.logo, null);
+    expect(feed.subtitle, null);
+
+    expect(feed.items.length, 1);
+    var item = feed.items.first;
+
+    expect(item.authors.length, 0);
+
+    expect(item.links.length, 0);
+
+    expect(item.categories.length, 0);
+
+    expect(item.contributors.length, 0);
+
+    expect(item.published, null);
+    expect(item.summary, null);
+    expect(item.content, null);
+    expect(item.rights, null);
+  });
 }
diff --git a/test/rss_test.dart b/test/rss_test.dart
index d42752e..4fd76c2 100644
--- a/test/rss_test.dart
+++ b/test/rss_test.dart
@@ -250,4 +250,48 @@ void main() {
     expect(feed.items.first.dc.coverage, "coverage");
     expect(feed.items.first.dc.rights, "rights");
   });
+
+  test("parse RSS-Empty.xml", () {
+    var xmlString = File("test/xml/RSS-Empty.xml").readAsStringSync();
+
+    var feed = RssFeed.parse(xmlString);
+    
+    expect(feed.title, null);
+    expect(feed.description, null);
+    expect(feed.link, null);
+    expect(feed.language, null);
+    expect(feed.lastBuildDate, null);
+    expect(feed.generator, null);
+    expect(feed.copyright, null);
+    expect(feed.docs, null);
+    expect(feed.managingEditor, null);
+    expect(feed.rating, null);
+    expect(feed.webMaster, null);
+    expect(feed.ttl, 0);
+
+    expect(feed.image, null);
+
+    expect(feed.cloud, null);
+
+    expect(feed.categories.length, 0);
+
+    expect(feed.skipDays.length, 0);
+
+    expect(feed.skipHours.length, 0);
+
+    expect(feed.items.length, 1);
+
+    expect(feed.items.first.title, null);
+    expect(feed.items.first.description, null);
+    expect(feed.items.first.link, null);
+    expect(feed.items.first.guid, null);
+    expect(feed.items.first.pubDate, null);
+    expect(feed.items.first.categories.length, 0);
+    expect(feed.items.first.author, null);
+    expect(feed.items.first.source, null);
+    expect(feed.items.first.comments, null);
+    expect(feed.items.first.enclosure, null);
+
+    expect(feed.items.first.content, null);
+  });
 }
diff --git a/test/xml/Atom-Empty.xml b/test/xml/Atom-Empty.xml
new file mode 100644
index 0000000..638fb04
--- /dev/null
+++ b/test/xml/Atom-Empty.xml
@@ -0,0 +1,5 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<feed xmlns="http://www.w3.org/2005/Atom">
+    <entry>
+    </entry>
+</feed>
\ No newline at end of file
diff --git a/test/xml/RSS-Empty.xml b/test/xml/RSS-Empty.xml
new file mode 100644
index 0000000..4a74627
--- /dev/null
+++ b/test/xml/RSS-Empty.xml
@@ -0,0 +1,8 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<rss version="2.0" 
+    xmlns:content="http://purl.org/rss/1.0/modules/content/">
+    <channel>
+        <item>
+        </item>
+    </channel>
+</rss>
\ No newline at end of file