diff --git a/pmd-java/src/main/java/net/sourceforge/pmd/lang/java/metrics/ClassMetric.java b/pmd-java/src/main/java/net/sourceforge/pmd/lang/java/oom/ClassMetric.java
similarity index 74%
rename from pmd-java/src/main/java/net/sourceforge/pmd/lang/java/metrics/ClassMetric.java
rename to pmd-java/src/main/java/net/sourceforge/pmd/lang/java/oom/ClassMetric.java
index e331513a46..8d0179044f 100644
--- a/pmd-java/src/main/java/net/sourceforge/pmd/lang/java/metrics/ClassMetric.java
+++ b/pmd-java/src/main/java/net/sourceforge/pmd/lang/java/oom/ClassMetric.java
@@ -1,9 +1,10 @@
 /**
  *
  */
-package net.sourceforge.pmd.lang.java.metrics;
+package net.sourceforge.pmd.lang.java.oom;
 
 import net.sourceforge.pmd.lang.java.ast.ASTClassOrInterfaceDeclaration;
+import net.sourceforge.pmd.lang.java.oom.visitor.PackageStats;
 
 /**
  * Metric that can be computed on a class node.
diff --git a/pmd-java/src/main/java/net/sourceforge/pmd/lang/java/metrics/Metric.java b/pmd-java/src/main/java/net/sourceforge/pmd/lang/java/oom/Metric.java
similarity index 70%
rename from pmd-java/src/main/java/net/sourceforge/pmd/lang/java/metrics/Metric.java
rename to pmd-java/src/main/java/net/sourceforge/pmd/lang/java/oom/Metric.java
index b4121f8a71..b58959f55d 100644
--- a/pmd-java/src/main/java/net/sourceforge/pmd/lang/java/metrics/Metric.java
+++ b/pmd-java/src/main/java/net/sourceforge/pmd/lang/java/oom/Metric.java
@@ -1,7 +1,7 @@
 /**
  *
  */
-package net.sourceforge.pmd.lang.java.metrics;
+package net.sourceforge.pmd.lang.java.oom;
 
 /**
  * Umbrella marker interface.
diff --git a/pmd-java/src/main/java/net/sourceforge/pmd/lang/java/metrics/Metrics.java b/pmd-java/src/main/java/net/sourceforge/pmd/lang/java/oom/Metrics.java
similarity index 88%
rename from pmd-java/src/main/java/net/sourceforge/pmd/lang/java/metrics/Metrics.java
rename to pmd-java/src/main/java/net/sourceforge/pmd/lang/java/oom/Metrics.java
index bfb1b444fb..61e77557f6 100644
--- a/pmd-java/src/main/java/net/sourceforge/pmd/lang/java/metrics/Metrics.java
+++ b/pmd-java/src/main/java/net/sourceforge/pmd/lang/java/oom/Metrics.java
@@ -1,10 +1,13 @@
 /**
  *
  */
-package net.sourceforge.pmd.lang.java.metrics;
+package net.sourceforge.pmd.lang.java.oom;
 
 import net.sourceforge.pmd.lang.java.ast.ASTClassOrInterfaceDeclaration;
 import net.sourceforge.pmd.lang.java.ast.ASTMethodOrConstructorDeclaration;
+import net.sourceforge.pmd.lang.java.oom.metrics.AtfdMetric;
+import net.sourceforge.pmd.lang.java.oom.metrics.WmcMetric;
+import net.sourceforge.pmd.lang.java.oom.visitor.PackageStats;
 
 /**
  * Façade of the Metrics Framework.
diff --git a/pmd-java/src/main/java/net/sourceforge/pmd/lang/java/metrics/OperationMetric.java b/pmd-java/src/main/java/net/sourceforge/pmd/lang/java/oom/OperationMetric.java
similarity index 74%
rename from pmd-java/src/main/java/net/sourceforge/pmd/lang/java/metrics/OperationMetric.java
rename to pmd-java/src/main/java/net/sourceforge/pmd/lang/java/oom/OperationMetric.java
index f716aaa57c..31630a68cc 100644
--- a/pmd-java/src/main/java/net/sourceforge/pmd/lang/java/metrics/OperationMetric.java
+++ b/pmd-java/src/main/java/net/sourceforge/pmd/lang/java/oom/OperationMetric.java
@@ -1,9 +1,10 @@
 /**
  *
  */
-package net.sourceforge.pmd.lang.java.metrics;
+package net.sourceforge.pmd.lang.java.oom;
 
 import net.sourceforge.pmd.lang.java.ast.ASTMethodOrConstructorDeclaration;
+import net.sourceforge.pmd.lang.java.oom.visitor.PackageStats;
 
 /**
  * Metric that can be computed on an operation.
diff --git a/pmd-java/src/main/java/net/sourceforge/pmd/lang/java/metrics/AbstractMetric.java b/pmd-java/src/main/java/net/sourceforge/pmd/lang/java/oom/metrics/AbstractMetric.java
similarity index 96%
rename from pmd-java/src/main/java/net/sourceforge/pmd/lang/java/metrics/AbstractMetric.java
rename to pmd-java/src/main/java/net/sourceforge/pmd/lang/java/oom/metrics/AbstractMetric.java
index b69ba02d3f..c5c0fcfeb6 100644
--- a/pmd-java/src/main/java/net/sourceforge/pmd/lang/java/metrics/AbstractMetric.java
+++ b/pmd-java/src/main/java/net/sourceforge/pmd/lang/java/oom/metrics/AbstractMetric.java
@@ -2,7 +2,7 @@
  * BSD-style license; for more info see http://pmd.sourceforge.net/license.html
  */
 
-package net.sourceforge.pmd.lang.java.metrics;
+package net.sourceforge.pmd.lang.java.oom.metrics;
 
 import net.sourceforge.pmd.lang.java.ast.ASTConstructorDeclaration;
 import net.sourceforge.pmd.lang.java.ast.ASTMethodDeclaration;
diff --git a/pmd-java/src/main/java/net/sourceforge/pmd/lang/java/metrics/AtfdMetric.java b/pmd-java/src/main/java/net/sourceforge/pmd/lang/java/oom/metrics/AtfdMetric.java
similarity index 75%
rename from pmd-java/src/main/java/net/sourceforge/pmd/lang/java/metrics/AtfdMetric.java
rename to pmd-java/src/main/java/net/sourceforge/pmd/lang/java/oom/metrics/AtfdMetric.java
index e24466f1e4..90751b7c61 100644
--- a/pmd-java/src/main/java/net/sourceforge/pmd/lang/java/metrics/AtfdMetric.java
+++ b/pmd-java/src/main/java/net/sourceforge/pmd/lang/java/oom/metrics/AtfdMetric.java
@@ -2,12 +2,16 @@
  * BSD-style license; for more info see http://pmd.sourceforge.net/license.html
  */
 
-package net.sourceforge.pmd.lang.java.metrics;
+package net.sourceforge.pmd.lang.java.oom.metrics;
 
 import net.sourceforge.pmd.lang.java.ast.ASTClassOrInterfaceDeclaration;
 import net.sourceforge.pmd.lang.java.ast.ASTMethodOrConstructorDeclaration;
-import net.sourceforge.pmd.lang.java.metrics.OperationSignature.Role;
-import net.sourceforge.pmd.lang.java.metrics.Signature.Visibility;
+import net.sourceforge.pmd.lang.java.oom.ClassMetric;
+import net.sourceforge.pmd.lang.java.oom.OperationMetric;
+import net.sourceforge.pmd.lang.java.oom.visitor.OperationSigMask;
+import net.sourceforge.pmd.lang.java.oom.visitor.OperationSignature.Role;
+import net.sourceforge.pmd.lang.java.oom.visitor.PackageStats;
+import net.sourceforge.pmd.lang.java.oom.visitor.Signature.Visibility;
 
 import java.util.List;
 
diff --git a/pmd-java/src/main/java/net/sourceforge/pmd/lang/java/metrics/WmcMetric.java b/pmd-java/src/main/java/net/sourceforge/pmd/lang/java/oom/metrics/WmcMetric.java
similarity index 72%
rename from pmd-java/src/main/java/net/sourceforge/pmd/lang/java/metrics/WmcMetric.java
rename to pmd-java/src/main/java/net/sourceforge/pmd/lang/java/oom/metrics/WmcMetric.java
index 7143ba455c..b9bf53dbec 100644
--- a/pmd-java/src/main/java/net/sourceforge/pmd/lang/java/metrics/WmcMetric.java
+++ b/pmd-java/src/main/java/net/sourceforge/pmd/lang/java/oom/metrics/WmcMetric.java
@@ -2,9 +2,11 @@
  * BSD-style license; for more info see http://pmd.sourceforge.net/license.html
  */
 
-package net.sourceforge.pmd.lang.java.metrics;
+package net.sourceforge.pmd.lang.java.oom.metrics;
 
 import net.sourceforge.pmd.lang.java.ast.ASTClassOrInterfaceDeclaration;
+import net.sourceforge.pmd.lang.java.oom.ClassMetric;
+import net.sourceforge.pmd.lang.java.oom.visitor.PackageStats;
 
 /**
  * @author Clément Fournier
diff --git a/pmd-java/src/main/java/net/sourceforge/pmd/lang/java/metrics/ClassStats.java b/pmd-java/src/main/java/net/sourceforge/pmd/lang/java/oom/visitor/ClassStats.java
similarity index 89%
rename from pmd-java/src/main/java/net/sourceforge/pmd/lang/java/metrics/ClassStats.java
rename to pmd-java/src/main/java/net/sourceforge/pmd/lang/java/oom/visitor/ClassStats.java
index 3b49d384c7..edf7bac9fc 100644
--- a/pmd-java/src/main/java/net/sourceforge/pmd/lang/java/metrics/ClassStats.java
+++ b/pmd-java/src/main/java/net/sourceforge/pmd/lang/java/oom/visitor/ClassStats.java
@@ -1,7 +1,7 @@
 /**
  * BSD-style license; for more info see http://pmd.sourceforge.net/license.html
  */
-package net.sourceforge.pmd.lang.java.metrics;
+package net.sourceforge.pmd.lang.java.oom.visitor;
 
 import java.util.HashMap;
 import java.util.List;
diff --git a/pmd-java/src/main/java/net/sourceforge/pmd/lang/java/metrics/FieldSigMask.java b/pmd-java/src/main/java/net/sourceforge/pmd/lang/java/oom/visitor/FieldSigMask.java
similarity index 81%
rename from pmd-java/src/main/java/net/sourceforge/pmd/lang/java/metrics/FieldSigMask.java
rename to pmd-java/src/main/java/net/sourceforge/pmd/lang/java/oom/visitor/FieldSigMask.java
index 5c38368fa2..c500c9918b 100644
--- a/pmd-java/src/main/java/net/sourceforge/pmd/lang/java/metrics/FieldSigMask.java
+++ b/pmd-java/src/main/java/net/sourceforge/pmd/lang/java/oom/visitor/FieldSigMask.java
@@ -1,7 +1,7 @@
 /**
  * BSD-style license; for more info see http://pmd.sourceforge.net/license.html
  */
-package net.sourceforge.pmd.lang.java.metrics;
+package net.sourceforge.pmd.lang.java.oom.visitor;
 
 /**
  * Signature mask for a field
diff --git a/pmd-java/src/main/java/net/sourceforge/pmd/lang/java/metrics/FieldSignature.java b/pmd-java/src/main/java/net/sourceforge/pmd/lang/java/oom/visitor/FieldSignature.java
similarity index 94%
rename from pmd-java/src/main/java/net/sourceforge/pmd/lang/java/metrics/FieldSignature.java
rename to pmd-java/src/main/java/net/sourceforge/pmd/lang/java/oom/visitor/FieldSignature.java
index e6db103ae8..abdaf26786 100644
--- a/pmd-java/src/main/java/net/sourceforge/pmd/lang/java/metrics/FieldSignature.java
+++ b/pmd-java/src/main/java/net/sourceforge/pmd/lang/java/oom/visitor/FieldSignature.java
@@ -1,7 +1,7 @@
 /**
  * BSD-style license; for more info see http://pmd.sourceforge.net/license.html
  */
-package net.sourceforge.pmd.lang.java.metrics;
+package net.sourceforge.pmd.lang.java.oom.visitor;
 
 import net.sourceforge.pmd.lang.java.ast.ASTFieldDeclaration;
 
diff --git a/pmd-java/src/main/java/net/sourceforge/pmd/lang/java/metrics/OperationSigMask.java b/pmd-java/src/main/java/net/sourceforge/pmd/lang/java/oom/visitor/OperationSigMask.java
similarity index 73%
rename from pmd-java/src/main/java/net/sourceforge/pmd/lang/java/metrics/OperationSigMask.java
rename to pmd-java/src/main/java/net/sourceforge/pmd/lang/java/oom/visitor/OperationSigMask.java
index d6fb4de1ba..92260024fc 100644
--- a/pmd-java/src/main/java/net/sourceforge/pmd/lang/java/metrics/OperationSigMask.java
+++ b/pmd-java/src/main/java/net/sourceforge/pmd/lang/java/oom/visitor/OperationSigMask.java
@@ -2,9 +2,7 @@
  * BSD-style license; for more info see http://pmd.sourceforge.net/license.html
  */
 
-package net.sourceforge.pmd.lang.java.metrics;
-
-import net.sourceforge.pmd.lang.java.metrics.OperationSignature.Role;
+package net.sourceforge.pmd.lang.java.oom.visitor;
 
 import java.util.Arrays;
 import java.util.HashSet;
@@ -17,10 +15,10 @@ import java.util.Set;
  */
 public class OperationSigMask extends SigMask<OperationSignature> {
 
-    private Set<Role> roleMask = new HashSet<>();
+    private Set<OperationSignature.Role> roleMask = new HashSet<>();
     private boolean isAbstractIncluded = false;
 
-    public void setRoleMask(Role... roles) {
+    public void setRoleMask(OperationSignature.Role... roles) {
         roleMask.clear();
         roleMask.addAll(Arrays.asList(roles));
     }
@@ -30,10 +28,10 @@ public class OperationSigMask extends SigMask<OperationSignature> {
     }
 
     public void setAllRoles() {
-        roleMask.addAll(Arrays.asList(Role.ALL));
+        roleMask.addAll(Arrays.asList(OperationSignature.Role.ALL));
     }
 
-    public void remove(Role... roles) {
+    public void remove(OperationSignature.Role... roles) {
         roleMask.removeAll(Arrays.asList(roles));
     }
 
diff --git a/pmd-java/src/main/java/net/sourceforge/pmd/lang/java/metrics/OperationSignature.java b/pmd-java/src/main/java/net/sourceforge/pmd/lang/java/oom/visitor/OperationSignature.java
similarity index 97%
rename from pmd-java/src/main/java/net/sourceforge/pmd/lang/java/metrics/OperationSignature.java
rename to pmd-java/src/main/java/net/sourceforge/pmd/lang/java/oom/visitor/OperationSignature.java
index 6359458d3d..c3633f824c 100644
--- a/pmd-java/src/main/java/net/sourceforge/pmd/lang/java/metrics/OperationSignature.java
+++ b/pmd-java/src/main/java/net/sourceforge/pmd/lang/java/oom/visitor/OperationSignature.java
@@ -2,7 +2,7 @@
  * BSD-style license; for more info see http://pmd.sourceforge.net/license.html
  */
 
-package net.sourceforge.pmd.lang.java.metrics;
+package net.sourceforge.pmd.lang.java.oom.visitor;
 
 import net.sourceforge.pmd.lang.java.ast.ASTConstructorDeclaration;
 import net.sourceforge.pmd.lang.java.ast.ASTMethodDeclaration;
diff --git a/pmd-java/src/main/java/net/sourceforge/pmd/lang/java/metrics/PackageStats.java b/pmd-java/src/main/java/net/sourceforge/pmd/lang/java/oom/visitor/PackageStats.java
similarity index 95%
rename from pmd-java/src/main/java/net/sourceforge/pmd/lang/java/metrics/PackageStats.java
rename to pmd-java/src/main/java/net/sourceforge/pmd/lang/java/oom/visitor/PackageStats.java
index c1757117e7..7a9246c558 100644
--- a/pmd-java/src/main/java/net/sourceforge/pmd/lang/java/metrics/PackageStats.java
+++ b/pmd-java/src/main/java/net/sourceforge/pmd/lang/java/oom/visitor/PackageStats.java
@@ -2,7 +2,7 @@
  * BSD-style license; for more info see http://pmd.sourceforge.net/license.html
  */
 
-package net.sourceforge.pmd.lang.java.metrics;
+package net.sourceforge.pmd.lang.java.oom.visitor;
 
 import java.util.HashMap;
 import java.util.Map;
diff --git a/pmd-java/src/main/java/net/sourceforge/pmd/lang/java/metrics/SigMask.java b/pmd-java/src/main/java/net/sourceforge/pmd/lang/java/oom/visitor/SigMask.java
similarity index 76%
rename from pmd-java/src/main/java/net/sourceforge/pmd/lang/java/metrics/SigMask.java
rename to pmd-java/src/main/java/net/sourceforge/pmd/lang/java/oom/visitor/SigMask.java
index 72442865fd..de321b1b4b 100644
--- a/pmd-java/src/main/java/net/sourceforge/pmd/lang/java/metrics/SigMask.java
+++ b/pmd-java/src/main/java/net/sourceforge/pmd/lang/java/oom/visitor/SigMask.java
@@ -2,14 +2,12 @@
  * BSD-style license; for more info see http://pmd.sourceforge.net/license.html
  */
 
-package net.sourceforge.pmd.lang.java.metrics;
+package net.sourceforge.pmd.lang.java.oom.visitor;
 
 import java.util.Arrays;
 import java.util.HashSet;
 import java.util.Set;
 
-import net.sourceforge.pmd.lang.java.metrics.Signature.Visibility;
-
 /**
  * Generic signature mask.
  *
@@ -19,14 +17,14 @@ public abstract class SigMask<T extends Signature> {
     /**
      * Visibility mask
      */
-    protected Set<Visibility> visMask = new HashSet<>();
+    protected Set<Signature.Visibility> visMask = new HashSet<>();
 
     /**
      * Clears the visibility mask and adds all parameters.
      *
      * @param visibilities The visibilities to add
      */
-    public void setVisibilityMask(Visibility... visibilities) {
+    public void setVisibilityMask(Signature.Visibility... visibilities) {
         visMask.clear();
         visMask.addAll(Arrays.asList(visibilities));
     }
@@ -35,7 +33,7 @@ public abstract class SigMask<T extends Signature> {
      * Sets the mask to cover all visibilities.
      */
     public void setAllVisibility() {
-        visMask.addAll(Arrays.asList(Visibility.ALL));
+        visMask.addAll(Arrays.asList(Signature.Visibility.ALL));
     }
 
     /**
@@ -43,7 +41,7 @@ public abstract class SigMask<T extends Signature> {
      *
      * @param visibilities The visibilities to remove
      */
-    public void remove(Visibility... visibilities) {
+    public void remove(Signature.Visibility... visibilities) {
         visMask.removeAll(Arrays.asList(visibilities));
     }
 
diff --git a/pmd-java/src/main/java/net/sourceforge/pmd/lang/java/metrics/Signature.java b/pmd-java/src/main/java/net/sourceforge/pmd/lang/java/oom/visitor/Signature.java
similarity index 95%
rename from pmd-java/src/main/java/net/sourceforge/pmd/lang/java/metrics/Signature.java
rename to pmd-java/src/main/java/net/sourceforge/pmd/lang/java/oom/visitor/Signature.java
index d6a70a6208..615f765214 100644
--- a/pmd-java/src/main/java/net/sourceforge/pmd/lang/java/metrics/Signature.java
+++ b/pmd-java/src/main/java/net/sourceforge/pmd/lang/java/oom/visitor/Signature.java
@@ -2,7 +2,7 @@
  * BSD-style license; for more info see http://pmd.sourceforge.net/license.html
  */
 
-package net.sourceforge.pmd.lang.java.metrics;
+package net.sourceforge.pmd.lang.java.oom.visitor;
 
 import net.sourceforge.pmd.lang.java.ast.AbstractJavaAccessNode;
 
diff --git a/pmd-java/src/main/java/net/sourceforge/pmd/lang/java/rule/metrics/AtfdRule.java b/pmd-java/src/main/java/net/sourceforge/pmd/lang/java/rule/metrics/AtfdRule.java
index a55da43325..bbda2b0c65 100644
--- a/pmd-java/src/main/java/net/sourceforge/pmd/lang/java/rule/metrics/AtfdRule.java
+++ b/pmd-java/src/main/java/net/sourceforge/pmd/lang/java/rule/metrics/AtfdRule.java
@@ -4,8 +4,8 @@
 package net.sourceforge.pmd.lang.java.rule.metrics;
 
 import net.sourceforge.pmd.lang.java.ast.ASTClassOrInterfaceDeclaration;
-import net.sourceforge.pmd.lang.java.metrics.Metrics;
-import net.sourceforge.pmd.lang.java.metrics.Metrics.ClassMetricKey;
+import net.sourceforge.pmd.lang.java.oom.Metrics;
+import net.sourceforge.pmd.lang.java.oom.Metrics.ClassMetricKey;
 import net.sourceforge.pmd.lang.java.rule.AbstractJavaRule;
 
 /**