diff --git a/ChangeLog b/ChangeLog
index 4be44e2d79..673fc91ae1 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,3 +1,8 @@
+Thu Nov 13 21:59:58 2014  CHIKANAGA Tomoyuki  <nagachika@ruby-lang.org>
+
+	* lib/rexml/document.rb: add REXML::Document#document.
+	  reported by Tomas Hoger <thoger@redhat.com> and patched by nahi.
+
 Thu Nov 13 21:51:56 2014  Tanaka Akira  <akr@fsij.org>
 
 	* test/monitor/test_monitor.rb: Use assert_join_threads.
diff --git a/lib/rexml/document.rb b/lib/rexml/document.rb
index 8342b96e6a..d7d24f4732 100644
--- a/lib/rexml/document.rb
+++ b/lib/rexml/document.rb
@@ -278,6 +278,10 @@ module REXML
       end
     end
 
+    def document
+      self
+    end
+
     private
     def build( source )
       Parsers::TreeParser.new( source, self ).parse
diff --git a/lib/rexml/entity.rb b/lib/rexml/entity.rb
index f447202394..3a35ec6b94 100644
--- a/lib/rexml/entity.rb
+++ b/lib/rexml/entity.rb
@@ -157,6 +157,7 @@ module REXML
 
   # This is a set of entity constants -- the ones defined in the XML
   # specification.  These are +gt+, +lt+, +amp+, +quot+ and +apos+.
+  # CAUTION: these entities does not have parent and document
   module EntityConst
     # +>+
     GT = Entity.new( 'gt', '>' )
diff --git a/test/rexml/test_document.rb b/test/rexml/test_document.rb
index 171d480557..43efbca38c 100644
--- a/test/rexml/test_document.rb
+++ b/test/rexml/test_document.rb
@@ -46,6 +46,22 @@ EOF
 <member>
 &a;
 </member>
+EOF
+
+    XML_WITH_NESTED_EMPTY_ENTITY = <<EOF
+<?xml version="1.0" encoding="UTF-8"?>
+<!DOCTYPE member [
+  <!ENTITY a "&b;&b;&b;&b;&b;&b;&b;&b;&b;&b;">
+  <!ENTITY b "&c;&c;&c;&c;&c;&c;&c;&c;&c;&c;">
+  <!ENTITY c "&d;&d;&d;&d;&d;&d;&d;&d;&d;&d;">
+  <!ENTITY d "&e;&e;&e;&e;&e;&e;&e;&e;&e;&e;">
+  <!ENTITY e "&f;&f;&f;&f;&f;&f;&f;&f;&f;&f;">
+  <!ENTITY f "&g;&g;&g;&g;&g;&g;&g;&g;&g;&g;">
+  <!ENTITY g "">
+]>
+<member>
+&a;
+</member>
 EOF
 
     XML_WITH_NESTED_PARAMETER_ENTITY = <<EOF
@@ -60,6 +76,20 @@ EOF
   <!ENTITY test "test %g;">
 ]>
 <cd></cd>
+EOF
+
+    XML_WITH_NESTED_EMPTY_PARAMETER_ENTITY = <<EOF
+<!DOCTYPE root [
+  <!ENTITY % a "">
+  <!ENTITY % b "%a;%a;%a;%a;%a;%a;%a;%a;%a;%a;%a;%a;%a;%a;%a;">
+  <!ENTITY % c "%b;%b;%b;%b;%b;%b;%b;%b;%b;%b;%b;%b;%b;%b;%b;">
+  <!ENTITY % d "%c;%c;%c;%c;%c;%c;%c;%c;%c;%c;%c;%c;%c;%c;%c;">
+  <!ENTITY % e "%d;%d;%d;%d;%d;%d;%d;%d;%d;%d;%d;%d;%d;%d;%d;">
+  <!ENTITY % f "%e;%e;%e;%e;%e;%e;%e;%e;%e;%e;%e;%e;%e;%e;%e;">
+  <!ENTITY % g "%f;%f;%f;%f;%f;%f;%f;%f;%f;%f;%f;%f;%f;%f;%f;">
+  <!ENTITY test "test %g;">
+]>
+<cd></cd>
 EOF
 
     XML_WITH_4_ENTITY_EXPANSION = <<EOF
@@ -88,6 +118,18 @@ EOF
       end
       assert_equal(101, doc.entity_expansion_count)
 
+      doc = REXML::Document.new(XML_WITH_NESTED_EMPTY_ENTITY)
+      assert_raise(RuntimeError) do
+        doc.root.children.first.value
+      end
+      REXML::Security.entity_expansion_limit = 100
+      assert_equal(100, REXML::Security.entity_expansion_limit)
+      doc = REXML::Document.new(XML_WITH_NESTED_EMPTY_ENTITY)
+      assert_raise(RuntimeError) do
+        doc.root.children.first.value
+      end
+      assert_equal(101, doc.entity_expansion_count)
+
       REXML::Security.entity_expansion_limit = 4
       doc = REXML::Document.new(XML_WITH_4_ENTITY_EXPANSION)
       assert_equal("\na\na a\n<\n", doc.root.children.first.value)
@@ -109,6 +151,15 @@ EOF
       assert_raise(REXML::ParseException) do
         REXML::Document.new(XML_WITH_NESTED_PARAMETER_ENTITY)
       end
+
+      assert_raise(REXML::ParseException) do
+        REXML::Document.new(XML_WITH_NESTED_EMPTY_PARAMETER_ENTITY)
+      end
+      REXML::Security.entity_expansion_limit = 100
+      assert_equal(100, REXML::Security.entity_expansion_limit)
+      assert_raise(REXML::ParseException) do
+        REXML::Document.new(XML_WITH_NESTED_EMPTY_PARAMETER_ENTITY)
+      end
     ensure
       REXML::Security.entity_expansion_limit = 10000
     end