diff --git a/include/plasp/pddl/Domain.h b/include/plasp/pddl/Domain.h
index b7bf001..a882cce 100644
--- a/include/plasp/pddl/Domain.h
+++ b/include/plasp/pddl/Domain.h
@@ -26,7 +26,7 @@ class Domain
 
 	public:
 		const std::string &name() const;
-		const Requirement::Types &requirements() const;
+		const Requirements &requirements() const;
 		const TypeHashMap &types() const;
 
 	private:
@@ -35,7 +35,7 @@ class Domain
 		void parseSection(utils::Parser &parser);
 
 		void parseRequirementsSection(utils::Parser &parser);
-		bool hasRequirement(Requirement::Type requirement) const;
+		bool hasRequirement(Requirement::Type requirementType) const;
 		void computeDerivedRequirements();
 
 		void parseTypingSection(utils::Parser &parser);
@@ -45,7 +45,7 @@ class Domain
 		Context &m_context;
 
 		std::string m_name;
-		Requirement::Types m_requirements;
+		Requirements m_requirements;
 };
 
 ////////////////////////////////////////////////////////////////////////////////////////////////////
diff --git a/include/plasp/pddl/Requirement.h b/include/plasp/pddl/Requirement.h
index 730e211..99ca03e 100644
--- a/include/plasp/pddl/Requirement.h
+++ b/include/plasp/pddl/Requirement.h
@@ -1,9 +1,10 @@
 #ifndef __PLASP__PDDL__REQUIREMENT_H
 #define __PLASP__PDDL__REQUIREMENT_H
 
-#include <plasp/utils/Parser.h>
 #include <vector>
 
+#include <plasp/utils/Parser.h>
+
 namespace plasp
 {
 namespace pddl
@@ -15,39 +16,51 @@ namespace pddl
 //
 ////////////////////////////////////////////////////////////////////////////////////////////////////
 
-struct Requirement
+class Requirement;
+using Requirements = std::vector<Requirement>;
+
+////////////////////////////////////////////////////////////////////////////////////////////////////
+
+class Requirement
 {
-	enum class Type
-	{
-		STRIPS,
-		Typing,
-		NegativePreconditions,
-		DisjunctivePreconditions,
-		Equality,
-		ExistentialPreconditions,
-		UniversalPreconditions,
-		QuantifiedPreconditions,
-		ConditionalEffects,
-		Fluents,
-		NumericFluents,
-		ObjectFluents,
-		ADL,
-		DurativeActions,
-		DurationInequalities,
-		ContinuousEffects,
-		DerivedPredicates,
-		TimedInitialLiterals,
-		Preferences,
-		Constraints,
-		ActionCosts
-	};
+	public:
+		enum class Type
+		{
+			STRIPS,
+			Typing,
+			NegativePreconditions,
+			DisjunctivePreconditions,
+			Equality,
+			ExistentialPreconditions,
+			UniversalPreconditions,
+			QuantifiedPreconditions,
+			ConditionalEffects,
+			Fluents,
+			NumericFluents,
+			ObjectFluents,
+			ADL,
+			DurativeActions,
+			DurationInequalities,
+			ContinuousEffects,
+			DerivedPredicates,
+			TimedInitialLiterals,
+			Preferences,
+			Constraints,
+			ActionCosts
+		};
 
-	using Types = std::vector<Type>;
+		static Requirement parse(utils::Parser &parser);
 
-	static Requirement::Type fromPDDL(utils::Parser &parser);
+	public:
+		Requirement(Type type);
 
-	static void toPDDL(std::ostream &ostream, Requirement::Type requirementType);
-	static void toASP(std::ostream &ostream, Requirement::Type requirementType);
+		Type type() const;
+
+		void printAsPDDL(std::ostream &ostream) const;
+		void printAsASP(std::ostream &ostream) const;
+
+	private:
+		Type m_type;
 };
 
 ////////////////////////////////////////////////////////////////////////////////////////////////////
diff --git a/src/plasp/pddl/Domain.cpp b/src/plasp/pddl/Domain.cpp
index 09fb06c..69f889d 100644
--- a/src/plasp/pddl/Domain.cpp
+++ b/src/plasp/pddl/Domain.cpp
@@ -60,7 +60,7 @@ const std::string &Domain::name() const
 
 ////////////////////////////////////////////////////////////////////////////////////////////////////
 
-const Requirement::Types &Domain::requirements() const
+const Requirements &Domain::requirements() const
 {
 	return m_requirements;
 }
@@ -134,7 +134,7 @@ void Domain::parseRequirementsSection(utils::Parser &parser)
 		if (parser.currentCharacter() == ':')
 			parser.advance();
 
-		m_requirements.emplace_back(Requirement::fromPDDL(parser));
+		m_requirements.emplace_back(Requirement::parse(parser));
 	}
 
 	if (m_requirements.empty())
@@ -145,9 +145,13 @@ void Domain::parseRequirementsSection(utils::Parser &parser)
 
 ////////////////////////////////////////////////////////////////////////////////////////////////////
 
-bool Domain::hasRequirement(Requirement::Type requirement) const
+bool Domain::hasRequirement(Requirement::Type requirementType) const
 {
-	const auto match = std::find(m_requirements.cbegin(), m_requirements.cend(), requirement);
+	const auto match = std::find_if(m_requirements.cbegin(), m_requirements.cend(),
+		[&](const auto &requirement)
+		{
+			return requirement.type() == requirementType;
+		});
 
 	return match != m_requirements.cend();
 }
@@ -162,7 +166,7 @@ void Domain::computeDerivedRequirements()
 			if (hasRequirement(requirement))
 				return;
 
-			m_requirements.push_back(requirement);
+			m_requirements.push_back(Requirement(requirement));
 		};
 
 	// If no requirements are specified, assume STRIPS
@@ -220,7 +224,7 @@ void Domain::checkConsistency()
 	{
 		throw ConsistencyException("Domain contains typing information but does not declare typing requirement");
 
-		m_requirements.push_back(Requirement::Type::Typing);
+		m_requirements.push_back(Requirement(Requirement::Type::Typing));
 	}
 
 	// Verify that all used types have been declared
diff --git a/src/plasp/pddl/Requirement.cpp b/src/plasp/pddl/Requirement.cpp
index c7b2ad3..95e4616 100644
--- a/src/plasp/pddl/Requirement.cpp
+++ b/src/plasp/pddl/Requirement.cpp
@@ -72,7 +72,14 @@ const RequirementTypeNames requirementTypesToASP = boost::assign::list_of<Requir
 
 ////////////////////////////////////////////////////////////////////////////////////////////////////
 
-Requirement::Type Requirement::fromPDDL(utils::Parser &parser)
+Requirement::Requirement(Requirement::Type type)
+:	m_type{type}
+{
+}
+
+////////////////////////////////////////////////////////////////////////////////////////////////////
+
+Requirement Requirement::parse(utils::Parser &parser)
 {
 	const auto requirementName = parser.parseIdentifier(isIdentifier);
 
@@ -81,14 +88,21 @@ Requirement::Type Requirement::fromPDDL(utils::Parser &parser)
 	if (match == requirementTypesToPDDL.right.end())
 		throw utils::ParserException(parser.row(), parser.column(), "Unknown PDDL requirement \"" + requirementName + "\"");
 
-	return match->second;
+	return Requirement(match->second);
 }
 
 ////////////////////////////////////////////////////////////////////////////////////////////////////
 
-void Requirement::toPDDL(std::ostream &ostream, Requirement::Type requirementType)
+Requirement::Type Requirement::type() const
 {
-	const auto match = requirementTypesToPDDL.left.find(requirementType);
+	return m_type;
+}
+
+////////////////////////////////////////////////////////////////////////////////////////////////////
+
+void Requirement::printAsPDDL(std::ostream &ostream) const
+{
+	const auto match = requirementTypesToPDDL.left.find(m_type);
 
 	BOOST_ASSERT(match != requirementTypesToPDDL.left.end());
 
@@ -97,9 +111,9 @@ void Requirement::toPDDL(std::ostream &ostream, Requirement::Type requirementTyp
 
 ////////////////////////////////////////////////////////////////////////////////////////////////////
 
-void Requirement::toASP(std::ostream &ostream, Requirement::Type requirementType)
+void Requirement::printAsASP(std::ostream &ostream) const
 {
-	const auto match = requirementTypesToASP.left.find(requirementType);
+	const auto match = requirementTypesToASP.left.find(m_type);
 
 	BOOST_ASSERT(match != requirementTypesToASP.left.end());
 
diff --git a/tests/TestPDDLParser.cpp b/tests/TestPDDLParser.cpp
index 6e0a87d..419e1eb 100644
--- a/tests/TestPDDLParser.cpp
+++ b/tests/TestPDDLParser.cpp
@@ -51,8 +51,8 @@ TEST_F(PDDLParserTests, ParseBlocksWorldDomain)
 		ASSERT_EQ(domain.name(), "BLOCKS");
 
 		ASSERT_EQ(domain.requirements().size(), 2u);
-		ASSERT_EQ(domain.requirements()[0], plasp::pddl::Requirement::Type::STRIPS);
-		ASSERT_EQ(domain.requirements()[1], plasp::pddl::Requirement::Type::Typing);
+		ASSERT_EQ(domain.requirements()[0].type(), plasp::pddl::Requirement::Type::STRIPS);
+		ASSERT_EQ(domain.requirements()[1].type(), plasp::pddl::Requirement::Type::Typing);
 
 		ASSERT_EQ(domain.types().size(), 1u);
 
@@ -83,7 +83,7 @@ TEST_F(PDDLParserTests, ParseStorageDomain)
 		ASSERT_EQ(domain.name(), "Storage-Propositional");
 
 		ASSERT_EQ(domain.requirements().size(), 1u);
-		ASSERT_EQ(domain.requirements()[0], plasp::pddl::Requirement::Type::Typing);
+		ASSERT_EQ(domain.requirements()[0].type(), plasp::pddl::Requirement::Type::Typing);
 
 		const auto area = domain.types().find("area");
 		ASSERT_NE(area, domain.types().cend());