diff --git a/modules/setup/application/views/scripts/form/setup-requirements.phtml b/modules/setup/application/views/scripts/form/setup-requirements.phtml
index b3cf30101..09ca98d7f 100644
--- a/modules/setup/application/views/scripts/form/setup-requirements.phtml
+++ b/modules/setup/application/views/scripts/form/setup-requirements.phtml
@@ -1,7 +1,6 @@
 <?php
 
 use Icinga\Web\Wizard;
-use Icinga\Module\Setup\Requirements;
 
 $requirements = $form->getRequirements();
 
@@ -10,21 +9,22 @@ $requirements = $form->getRequirements();
   <tbody>
 <?php foreach ($requirements as $requirement): ?>
     <tr>
-      <td><h2><?= $requirement->title; ?></h2></td>
+      <td><h2><?= $requirement->getTitle(); ?></h2></td>
       <td style="width: 50%">
-      <?php if (is_array($requirement->description)): ?>
+      <?php $descriptions = $requirement->getDescriptions(); ?>
+      <?php if (count($descriptions) > 1): ?>
         <ul>
-        <?php foreach ($requirement->description as $desc): ?>
+        <?php foreach ($descriptions as $desc): ?>
           <li><?= $desc; ?></li>
         <?php endforeach ?>
         </ul>
-      <?php else: ?>
-        <?= $requirement->description; ?>
+      <?php elseif (! empty($descriptions)): ?>
+        <?= $descriptions[0]; ?>
       <?php endif ?>
       </td>
-      <td class="state <?= $requirement->state === Requirements::STATE_OK ? 'fulfilled' : (
-        $requirement->state === Requirements::STATE_OPTIONAL ? 'not-available' : 'missing'
-      ); ?>"><?= $requirement->message; ?></td>
+      <td class="state <?= $requirement->getState() ? 'fulfilled' : (
+        $requirement->isOptional() ? 'not-available' : 'missing'
+      ); ?>"><?= $requirement->getStateText(); ?></td>
     </tr>
 <?php endforeach ?>
     <tr>
diff --git a/modules/setup/library/Setup/Requirement.php b/modules/setup/library/Setup/Requirement.php
new file mode 100644
index 000000000..37bb5663e
--- /dev/null
+++ b/modules/setup/library/Setup/Requirement.php
@@ -0,0 +1,279 @@
+<?php
+/* Icinga Web 2 | (c) 2013-2015 Icinga Development Team | GPLv2+ */
+
+namespace Icinga\Module\Setup;
+
+use LogicException;
+
+abstract class Requirement
+{
+    /**
+     * The state of this requirement
+     *
+     * @var bool
+     */
+    protected $state;
+
+    /**
+     * A descriptive text representing the current state of this requirement
+     *
+     * @var string
+     */
+    protected $stateText;
+
+    /**
+     * The descriptions of this requirement
+     *
+     * @var array
+     */
+    protected $descriptions;
+
+    /**
+     * The title of this requirement
+     *
+     * @var string
+     */
+    protected $title;
+
+    /**
+     * The condition of this requirement
+     *
+     * @var mixed
+     */
+    protected $condition;
+
+    /**
+     * Whether this requirement is optional
+     *
+     * @var bool
+     */
+    protected $optional;
+
+    /**
+     * The alias to display the condition with in a human readable way
+     *
+     * @var string
+     */
+    protected $alias;
+
+    /**
+     * Create a new requirement
+     *
+     * @param   array   $options
+     *
+     * @throws  LogicException  In case there exists no setter for an option's key
+     */
+    public function __construct(array $options = array())
+    {
+        $this->optional = false;
+        $this->descriptions = array();
+
+        foreach ($options as $key => $value) {
+            $setMethod = 'set' . ucfirst($key);
+            $addMethod = 'add' . ucfirst($key);
+            if (method_exists($this, $setMethod)) {
+                $this->$setMethod($value);
+            } elseif (method_exists($this, $addMethod)) {
+                $this->$addMethod($value);
+            } else {
+                throw LogicException('No setter found for option key: ' . $key);
+            }
+        }
+    }
+
+    /**
+     * Set the state of this requirement
+     *
+     * @param   bool    $state
+     *
+     * @return  Requirement
+     */
+    public function setState($state)
+    {
+        $this->state = (bool) $state;
+        return $this;
+    }
+
+    /**
+     * Return the state of this requirement
+     *
+     * Evaluates the requirement in case there is no state set yet.
+     *
+     * @return  int
+     */
+    public function getState()
+    {
+        if ($this->state === null) {
+            $this->state = $this->evaluate();
+        }
+
+        return $this->state;
+    }
+
+    /**
+     * Set a descriptive text for this requirement's current state
+     *
+     * @param   string  $text
+     *
+     * @return  Requirement
+     */
+    public function setStateText($text)
+    {
+        $this->stateText = $text;
+        return $this;
+    }
+
+    /**
+     * Return a descriptive text for this requirement's current state
+     *
+     * @return  string
+     */
+    public function getStateText()
+    {
+        return $this->stateText;
+    }
+
+    /**
+     * Add a description for this requirement
+     *
+     * @param   string  $description
+     *
+     * @return  Requirement
+     */
+    public function addDescription($description)
+    {
+        $this->descriptions[] = $description;
+        return $this;
+    }
+
+    /**
+     * Return the descriptions of this wizard
+     *
+     * @return  array
+     */
+    public function getDescriptions()
+    {
+        return $this->descriptions;
+    }
+
+    /**
+     * Set the title for this requirement
+     *
+     * @param   string  $title
+     *
+     * @return  Requirement
+     */
+    public function setTitle($title)
+    {
+        $this->title = $title;
+        return $this;
+    }
+
+    /**
+     * Return the title of this requirement
+     *
+     * In case there is no title set the alias is returned instead.
+     *
+     * @return  string
+     */
+    public function getTitle()
+    {
+        if ($this->title === null) {
+            return $this->getAlias();
+        }
+
+        return $this->title;
+    }
+
+    /**
+     * Set the condition for this requirement
+     *
+     * @param   mixed   $condition
+     *
+     * @return  Requirement
+     */
+    public function setCondition($condition)
+    {
+        $this->condition = $condition;
+        return $this;
+    }
+
+    /**
+     * Return the condition of this requirement
+     *
+     * @return  mixed
+     */
+    public function getCondition()
+    {
+        return $this->condition;
+    }
+
+    /**
+     * Set whether this requirement is optional
+     *
+     * @param   bool    $state
+     *
+     * @return  Requirement
+     */
+    public function setOptional($state = true)
+    {
+        $this->optional = (bool) $state;
+        return $this;
+    }
+
+    /**
+     * Return whether this requirement is optional
+     *
+     * @return  bool
+     */
+    public function isOptional()
+    {
+        return $this->optional;
+    }
+
+    /**
+     * Set the alias to display the condition with in a human readable way
+     *
+     * @param   string  $alias
+     *
+     * @return  Requirement
+     */
+    public function setAlias($alias)
+    {
+        $this->alias = $alias;
+        return $this;
+    }
+
+    /**
+     * Return the alias to display the condition with in a human readable way
+     *
+     * @return  string
+     */
+    public function getAlias()
+    {
+        return $this->alias;
+    }
+
+    /**
+     * Evaluate this requirement and return whether it is fulfilled
+     *
+     * @return  bool
+     */
+    abstract protected function evaluate();
+
+    /**
+     * Return whether the given requirement equals this one
+     *
+     * @param   Requirement     $requirement
+     *
+     * @return  bool
+     */
+    public function equals(Requirement $requirement)
+    {
+        if ($requirement instanceof static) {
+            return $this->getCondition() === $requirement->getCondition();
+        }
+
+        return false;
+    }
+}
diff --git a/modules/setup/library/Setup/Requirements.php b/modules/setup/library/Setup/Requirements.php
index bede70aa0..e96a0f7ac 100644
--- a/modules/setup/library/Setup/Requirements.php
+++ b/modules/setup/library/Setup/Requirements.php
@@ -8,27 +8,9 @@ use IteratorAggregate;
 
 /**
  * Container to store and handle requirements
- *
- * TODO: Requirements should be registered as objects with a specific purpose (PhpModRequirement, PhpIniRequirement, ..)
- *       so that it's not necessary to define unique identifiers which may differ between different modules.
  */
 class Requirements implements IteratorAggregate
 {
-    /**
-     * Identifier representing the state OK
-     */
-    const STATE_OK = 2;
-
-    /**
-     * Identifier representing the state OPTIONAL
-     */
-    const STATE_OPTIONAL = 1;
-
-    /**
-     * Identifier representing the state MANDATORY
-     */
-    const STATE_MANDATORY = 0;
-
     /**
      * The registered requirements
      *
@@ -39,44 +21,35 @@ class Requirements implements IteratorAggregate
     /**
      * Register a requirement
      *
-     * @param   object  $requirement    The requirement to add
+     * @param   Requirement     $requirement    The requirement to add
      *
-     * @return  self
+     * @return  Requirements
      */
-    public function add($name, $requirement)
+    public function add(Requirement $requirement)
     {
-        $this->requirements[$name] = array_key_exists($name, $this->requirements)
-            ? $this->combine($this->requirements[$name], $requirement)
-            : $requirement;
+        $merged = false;
+        foreach ($this as $knownRequirement) {
+            if ($requirement->equals($knownRequirement)) {
+                if ($knownRequirement->isOptional() && !$requirement->isOptional()) {
+                    $knownRequirement->setOptional(false);
+                }
+
+                foreach ($requirement->getDescriptions() as $description) {
+                    $knownRequirement->addDescription($description);
+                }
+
+                $merged = true;
+                break;
+            }
+        }
+
+        if (! $merged) {
+            $this->requirements[] = $requirement;
+        }
+
         return $this;
     }
 
-    /**
-     * Combine the two given requirements
-     *
-     * Returns the most important requirement with the description from the other one being added.
-     *
-     * @param   object  $oldRequirement
-     * @param   object  $newRequirement
-     *
-     * @return  object
-     */
-    protected function combine($oldRequirement, $newRequirement)
-    {
-        if ($newRequirement->state === static::STATE_MANDATORY && $oldRequirement->state === static::STATE_OPTIONAL) {
-            $tempRequirement = $oldRequirement;
-            $oldRequirement = $newRequirement;
-            $newRequirement = $tempRequirement;
-        }
-
-        if (! is_array($oldRequirement->description)) {
-            $oldRequirement->description = array($oldRequirement->description);
-        }
-
-        $oldRequirement->description[] = $newRequirement->description;
-        return $oldRequirement;
-    }
-
     /**
      * Return all registered requirements
      *
@@ -97,83 +70,17 @@ class Requirements implements IteratorAggregate
         return new ArrayIterator($this->getAll());
     }
 
-    /**
-     * Register an optional requirement
-     *
-     * @param   string      $name
-     * @param   string      $title
-     * @param   string      $description
-     * @param   bool        $state
-     * @param   string      $message
-     *
-     * @return  self
-     */
-    public function addOptional($name, $title, $description, $state, $message)
-    {
-        $this->add(
-            $name,
-            (object) array(
-                'title'         => $title,
-                'message'       => $message,
-                'description'   => $description,
-                'state'         => (bool) $state ? static::STATE_OK : static::STATE_OPTIONAL
-            )
-        );
-        return $this;
-    }
-
-    /**
-     * Register a mandatory requirement
-     *
-     * @param   string      $name
-     * @param   string      $title
-     * @param   string      $description
-     * @param   bool        $state
-     * @param   string      $message
-     *
-     * @return  self
-     */
-    public function addMandatory($name, $title, $description, $state, $message)
-    {
-        $this->add(
-            $name,
-            (object) array(
-                'title'         => $title,
-                'message'       => $message,
-                'description'   => $description,
-                'state'         => (bool) $state ? static::STATE_OK : static::STATE_MANDATORY
-            )
-        );
-        return $this;
-    }
-
     /**
      * Register the given requirements
      *
      * @param   Requirements    $requirements   The requirements to register
      *
-     * @return  self
+     * @return  Requirements
      */
     public function merge(Requirements $requirements)
     {
-        foreach ($requirements->getAll() as $name => $requirement) {
-            $this->add($name, $requirement);
-        }
-
-        return $this;
-    }
-
-    /**
-     * Make all registered requirements being optional
-     *
-     * @return  self
-     */
-    public function allOptional()
-    {
-        foreach ($this->getAll() as $requirement) {
-            if ($requirement->state === static::STATE_MANDATORY) {
-                $requirement->state = static::STATE_OPTIONAL;
-            }
+        foreach ($requirements as $requirement) {
+            $this->add($requirement);
         }
 
         return $this;
@@ -186,8 +93,8 @@ class Requirements implements IteratorAggregate
      */
     public function fulfilled()
     {
-        foreach ($this->getAll() as $requirement) {
-            if ($requirement->state === static::STATE_MANDATORY) {
+        foreach ($this as $requirement) {
+            if (! $requirement->getState() && !$requirement->isOptional()) {
                 return false;
             }
         }