diff --git a/jps/model-api/src/org/jetbrains/jps/model/JpsElementType.java b/jps/model-api/src/org/jetbrains/jps/model/JpsElementType.java
index 1adee500560a..4f326b12f0cf 100644
--- a/jps/model-api/src/org/jetbrains/jps/model/JpsElementType.java
+++ b/jps/model-api/src/org/jetbrains/jps/model/JpsElementType.java
@@ -1,5 +1,5 @@
 /*
- * Copyright 2000-2012 JetBrains s.r.o.
+ * Copyright 2000-2013 JetBrains s.r.o.
  *
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
@@ -15,13 +15,12 @@
  */
 package org.jetbrains.jps.model;
 
+import org.jetbrains.annotations.NotNull;
+
 /**
  * @author nik
  */
-public abstract class JpsElementType<P extends JpsElement> {
-  private final JpsElementChildRole<P> myPropertiesRole = new JpsElementChildRole<P>();
-
-  public final JpsElementChildRole<P> getPropertiesRole() {
-    return myPropertiesRole;
-  }
+public interface JpsElementType<P extends JpsElement> {
+  @NotNull
+  JpsElementChildRole<P> getPropertiesRole();
 }
diff --git a/jps/model-api/src/org/jetbrains/jps/model/artifact/DirectoryArtifactType.java b/jps/model-api/src/org/jetbrains/jps/model/artifact/DirectoryArtifactType.java
index 3b66462f9d8a..79e970ee1bb3 100644
--- a/jps/model-api/src/org/jetbrains/jps/model/artifact/DirectoryArtifactType.java
+++ b/jps/model-api/src/org/jetbrains/jps/model/artifact/DirectoryArtifactType.java
@@ -16,10 +16,11 @@
 package org.jetbrains.jps.model.artifact;
 
 import org.jetbrains.jps.model.JpsDummyElement;
+import org.jetbrains.jps.model.ex.JpsElementTypeWithDummyProperties;
 
 /**
  * @author nik
  */
-public class DirectoryArtifactType extends JpsArtifactType<JpsDummyElement> {
+public class DirectoryArtifactType extends JpsElementTypeWithDummyProperties implements JpsArtifactType<JpsDummyElement> {
   public static final DirectoryArtifactType INSTANCE = new DirectoryArtifactType();
 }
diff --git a/jps/model-api/src/org/jetbrains/jps/model/artifact/JarArtifactType.java b/jps/model-api/src/org/jetbrains/jps/model/artifact/JarArtifactType.java
index c0306a9f447b..bd36fc4c34a7 100644
--- a/jps/model-api/src/org/jetbrains/jps/model/artifact/JarArtifactType.java
+++ b/jps/model-api/src/org/jetbrains/jps/model/artifact/JarArtifactType.java
@@ -16,10 +16,11 @@
 package org.jetbrains.jps.model.artifact;
 
 import org.jetbrains.jps.model.JpsDummyElement;
+import org.jetbrains.jps.model.ex.JpsElementTypeWithDummyProperties;
 
 /**
  * @author nik
  */
-public class JarArtifactType extends JpsArtifactType<JpsDummyElement> {
+public class JarArtifactType extends JpsElementTypeWithDummyProperties implements JpsArtifactType<JpsDummyElement> {
   public static final JarArtifactType INSTANCE = new JarArtifactType();
 }
diff --git a/jps/model-api/src/org/jetbrains/jps/model/artifact/JpsArtifactType.java b/jps/model-api/src/org/jetbrains/jps/model/artifact/JpsArtifactType.java
index a4a6c312438d..68bd879e298b 100644
--- a/jps/model-api/src/org/jetbrains/jps/model/artifact/JpsArtifactType.java
+++ b/jps/model-api/src/org/jetbrains/jps/model/artifact/JpsArtifactType.java
@@ -21,5 +21,5 @@ import org.jetbrains.jps.model.JpsElementType;
 /**
  * @author nik
  */
-public abstract class JpsArtifactType<P extends JpsElement> extends JpsElementType<P> {
+public interface JpsArtifactType<P extends JpsElement> extends JpsElementType<P> {
 }
diff --git a/jps/model-api/src/org/jetbrains/jps/model/ex/JpsElementTypeBase.java b/jps/model-api/src/org/jetbrains/jps/model/ex/JpsElementTypeBase.java
new file mode 100644
index 000000000000..70b82832dae6
--- /dev/null
+++ b/jps/model-api/src/org/jetbrains/jps/model/ex/JpsElementTypeBase.java
@@ -0,0 +1,34 @@
+/*
+ * Copyright 2000-2013 JetBrains s.r.o.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ * http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+package org.jetbrains.jps.model.ex;
+
+import org.jetbrains.annotations.NotNull;
+import org.jetbrains.jps.model.JpsElement;
+import org.jetbrains.jps.model.JpsElementChildRole;
+import org.jetbrains.jps.model.JpsElementType;
+
+/**
+ * @author nik
+ */
+public abstract class JpsElementTypeBase<P extends JpsElement>implements JpsElementType<P> {
+  private final JpsElementChildRole<P> myPropertiesRole = new JpsElementChildRole<P>();
+
+  @NotNull
+  @Override
+  public final JpsElementChildRole<P> getPropertiesRole() {
+    return myPropertiesRole;
+  }
+}
diff --git a/jps/model-api/src/org/jetbrains/jps/model/ex/JpsElementTypeWithDummyProperties.java b/jps/model-api/src/org/jetbrains/jps/model/ex/JpsElementTypeWithDummyProperties.java
new file mode 100644
index 000000000000..9fb039c05172
--- /dev/null
+++ b/jps/model-api/src/org/jetbrains/jps/model/ex/JpsElementTypeWithDummyProperties.java
@@ -0,0 +1,32 @@
+/*
+ * Copyright 2000-2013 JetBrains s.r.o.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ * http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+package org.jetbrains.jps.model.ex;
+
+import org.jetbrains.annotations.NotNull;
+import org.jetbrains.jps.model.JpsDummyElement;
+import org.jetbrains.jps.model.JpsElementFactory;
+import org.jetbrains.jps.model.JpsElementTypeWithDefaultProperties;
+
+/**
+ * @author nik
+ */
+public abstract class JpsElementTypeWithDummyProperties extends JpsElementTypeBase<JpsDummyElement> implements JpsElementTypeWithDefaultProperties<JpsDummyElement> {
+  @NotNull
+  @Override
+  public JpsDummyElement createDefaultProperties() {
+    return JpsElementFactory.getInstance().createDummyElement();
+  }
+}
diff --git a/jps/model-api/src/org/jetbrains/jps/model/java/JavaResourceRootType.java b/jps/model-api/src/org/jetbrains/jps/model/java/JavaResourceRootType.java
index 7baa1a9b8649..33adf96ebf1f 100644
--- a/jps/model-api/src/org/jetbrains/jps/model/java/JavaResourceRootType.java
+++ b/jps/model-api/src/org/jetbrains/jps/model/java/JavaResourceRootType.java
@@ -18,13 +18,13 @@ package org.jetbrains.jps.model.java;
 import org.jetbrains.annotations.NotNull;
 import org.jetbrains.jps.model.JpsDummyElement;
 import org.jetbrains.jps.model.JpsElementFactory;
-import org.jetbrains.jps.model.JpsElementTypeWithDefaultProperties;
+import org.jetbrains.jps.model.ex.JpsElementTypeWithDummyProperties;
 import org.jetbrains.jps.model.module.JpsModuleSourceRootType;
 
 /**
  * @author nik
  */
-public class JavaResourceRootType extends JpsModuleSourceRootType<JpsDummyElement> implements JpsElementTypeWithDefaultProperties<JpsDummyElement> {
+public class JavaResourceRootType extends JpsElementTypeWithDummyProperties implements JpsModuleSourceRootType<JpsDummyElement> {
   public static final JavaResourceRootType RESOURCE = new JavaResourceRootType();
   public static final JavaResourceRootType TEST_RESOURCE = new JavaResourceRootType();
 
diff --git a/jps/model-api/src/org/jetbrains/jps/model/java/JavaSourceRootType.java b/jps/model-api/src/org/jetbrains/jps/model/java/JavaSourceRootType.java
index 2a181f1cd485..97a03687a0fd 100644
--- a/jps/model-api/src/org/jetbrains/jps/model/java/JavaSourceRootType.java
+++ b/jps/model-api/src/org/jetbrains/jps/model/java/JavaSourceRootType.java
@@ -17,14 +17,14 @@ package org.jetbrains.jps.model.java;
 
 import org.jetbrains.annotations.NotNull;
 import org.jetbrains.jps.model.JpsElementFactory;
-import org.jetbrains.jps.model.JpsElementTypeWithDefaultProperties;
 import org.jetbrains.jps.model.JpsSimpleElement;
+import org.jetbrains.jps.model.ex.JpsElementTypeBase;
 import org.jetbrains.jps.model.module.JpsModuleSourceRootType;
 
 /**
  * @author nik
  */
-public class JavaSourceRootType extends JpsModuleSourceRootType<JpsSimpleElement<JavaSourceRootProperties>> implements JpsElementTypeWithDefaultProperties<JpsSimpleElement<JavaSourceRootProperties>> {
+public class JavaSourceRootType extends JpsElementTypeBase<JpsSimpleElement<JavaSourceRootProperties>> implements JpsModuleSourceRootType<JpsSimpleElement<JavaSourceRootProperties>> {
   public static final JavaSourceRootType SOURCE = new JavaSourceRootType();
   public static final JavaSourceRootType TEST_SOURCE = new JavaSourceRootType();
 
diff --git a/jps/model-api/src/org/jetbrains/jps/model/java/JpsJavaLibraryType.java b/jps/model-api/src/org/jetbrains/jps/model/java/JpsJavaLibraryType.java
index 533036071ee8..0fcc7ec395d3 100644
--- a/jps/model-api/src/org/jetbrains/jps/model/java/JpsJavaLibraryType.java
+++ b/jps/model-api/src/org/jetbrains/jps/model/java/JpsJavaLibraryType.java
@@ -16,13 +16,15 @@
 package org.jetbrains.jps.model.java;
 
 import org.jetbrains.annotations.NotNull;
-import org.jetbrains.jps.model.*;
+import org.jetbrains.jps.model.JpsDummyElement;
+import org.jetbrains.jps.model.JpsElementFactory;
+import org.jetbrains.jps.model.ex.JpsElementTypeWithDummyProperties;
 import org.jetbrains.jps.model.library.JpsLibraryType;
 
 /**
  * @author nik
  */
-public class JpsJavaLibraryType extends JpsLibraryType<JpsDummyElement> implements JpsElementTypeWithDefaultProperties<JpsDummyElement> {
+public class JpsJavaLibraryType extends JpsElementTypeWithDummyProperties implements JpsLibraryType<JpsDummyElement> {
   public static final JpsJavaLibraryType INSTANCE = new JpsJavaLibraryType();
 
   @NotNull
diff --git a/jps/model-api/src/org/jetbrains/jps/model/java/JpsJavaModuleType.java b/jps/model-api/src/org/jetbrains/jps/model/java/JpsJavaModuleType.java
index 6a971cf7b8ef..c4f629999d63 100644
--- a/jps/model-api/src/org/jetbrains/jps/model/java/JpsJavaModuleType.java
+++ b/jps/model-api/src/org/jetbrains/jps/model/java/JpsJavaModuleType.java
@@ -18,13 +18,13 @@ package org.jetbrains.jps.model.java;
 import org.jetbrains.annotations.NotNull;
 import org.jetbrains.jps.model.JpsDummyElement;
 import org.jetbrains.jps.model.JpsElementFactory;
-import org.jetbrains.jps.model.JpsElementTypeWithDefaultProperties;
+import org.jetbrains.jps.model.ex.JpsElementTypeWithDummyProperties;
 import org.jetbrains.jps.model.module.JpsModuleType;
 
 /**
  * @author nik
  */
-public class JpsJavaModuleType extends JpsModuleType<JpsDummyElement> implements JpsElementTypeWithDefaultProperties<JpsDummyElement> {
+public class JpsJavaModuleType extends JpsElementTypeWithDummyProperties implements JpsModuleType<JpsDummyElement> {
   public static final JpsJavaModuleType INSTANCE = new JpsJavaModuleType();
 
   @NotNull
diff --git a/jps/model-api/src/org/jetbrains/jps/model/java/runConfiguration/JpsApplicationRunConfigurationType.java b/jps/model-api/src/org/jetbrains/jps/model/java/runConfiguration/JpsApplicationRunConfigurationType.java
index aa0a7a268d91..c5c880ca0958 100644
--- a/jps/model-api/src/org/jetbrains/jps/model/java/runConfiguration/JpsApplicationRunConfigurationType.java
+++ b/jps/model-api/src/org/jetbrains/jps/model/java/runConfiguration/JpsApplicationRunConfigurationType.java
@@ -15,12 +15,13 @@
  */
 package org.jetbrains.jps.model.java.runConfiguration;
 
+import org.jetbrains.jps.model.ex.JpsElementTypeBase;
 import org.jetbrains.jps.model.runConfiguration.JpsRunConfigurationType;
 
 /**
  * @author nik
  */
-public class JpsApplicationRunConfigurationType extends JpsRunConfigurationType<JpsApplicationRunConfigurationProperties> {
+public class JpsApplicationRunConfigurationType extends JpsElementTypeBase<JpsApplicationRunConfigurationProperties> implements JpsRunConfigurationType<JpsApplicationRunConfigurationProperties> {
   public static final JpsApplicationRunConfigurationType INSTANCE = new JpsApplicationRunConfigurationType();
 
   private JpsApplicationRunConfigurationType() {
diff --git a/jps/model-api/src/org/jetbrains/jps/model/library/JpsLibraryType.java b/jps/model-api/src/org/jetbrains/jps/model/library/JpsLibraryType.java
index 81a1de0fa604..bb973ecf713a 100644
--- a/jps/model-api/src/org/jetbrains/jps/model/library/JpsLibraryType.java
+++ b/jps/model-api/src/org/jetbrains/jps/model/library/JpsLibraryType.java
@@ -21,5 +21,5 @@ import org.jetbrains.jps.model.JpsElementType;
 /**
  * @author nik
  */
-public abstract class JpsLibraryType<P extends JpsElement> extends JpsElementType<P> {
+public interface JpsLibraryType<P extends JpsElement> extends JpsElementType<P> {
 }
diff --git a/jps/model-api/src/org/jetbrains/jps/model/library/sdk/JpsSdkType.java b/jps/model-api/src/org/jetbrains/jps/model/library/sdk/JpsSdkType.java
index 2699fdf8ec57..ecc62a718c38 100644
--- a/jps/model-api/src/org/jetbrains/jps/model/library/sdk/JpsSdkType.java
+++ b/jps/model-api/src/org/jetbrains/jps/model/library/sdk/JpsSdkType.java
@@ -17,13 +17,13 @@ package org.jetbrains.jps.model.library.sdk;
 
 import org.jetbrains.jps.model.JpsElement;
 import org.jetbrains.jps.model.JpsElementChildRole;
+import org.jetbrains.jps.model.ex.JpsElementTypeBase;
 import org.jetbrains.jps.model.library.JpsLibraryType;
-import org.jetbrains.jps.model.library.sdk.JpsSdk;
 
 /**
  * @author nik
  */
-public abstract class JpsSdkType<P extends JpsElement> extends JpsLibraryType<JpsSdk<P>> {
+public abstract class JpsSdkType<P extends JpsElement> extends JpsElementTypeBase<JpsSdk<P>> implements JpsLibraryType<JpsSdk<P>> {
   private final JpsElementChildRole<P> mySdkPropertiesRole = new JpsElementChildRole<P>();
 
   public final JpsElementChildRole<P> getSdkPropertiesRole() {
diff --git a/jps/model-api/src/org/jetbrains/jps/model/module/JpsModuleSourceRootType.java b/jps/model-api/src/org/jetbrains/jps/model/module/JpsModuleSourceRootType.java
index 5a2dbb34d9ad..adc98d447fe6 100644
--- a/jps/model-api/src/org/jetbrains/jps/model/module/JpsModuleSourceRootType.java
+++ b/jps/model-api/src/org/jetbrains/jps/model/module/JpsModuleSourceRootType.java
@@ -17,9 +17,10 @@ package org.jetbrains.jps.model.module;
 
 import org.jetbrains.jps.model.JpsElement;
 import org.jetbrains.jps.model.JpsElementType;
+import org.jetbrains.jps.model.JpsElementTypeWithDefaultProperties;
 
 /**
  * @author nik
  */
-public abstract class JpsModuleSourceRootType<P extends JpsElement> extends JpsElementType<P> {
+public interface JpsModuleSourceRootType<P extends JpsElement> extends JpsElementType<P>, JpsElementTypeWithDefaultProperties<P> {
 }
diff --git a/jps/model-api/src/org/jetbrains/jps/model/module/JpsModuleType.java b/jps/model-api/src/org/jetbrains/jps/model/module/JpsModuleType.java
index 9062744badea..d3af4b661b4f 100644
--- a/jps/model-api/src/org/jetbrains/jps/model/module/JpsModuleType.java
+++ b/jps/model-api/src/org/jetbrains/jps/model/module/JpsModuleType.java
@@ -21,5 +21,5 @@ import org.jetbrains.jps.model.JpsElementType;
 /**
  * @author nik
  */
-public abstract class JpsModuleType<P extends JpsElement> extends JpsElementType<P> {
+public interface JpsModuleType<P extends JpsElement> extends JpsElementType<P> {
 }
diff --git a/jps/model-api/src/org/jetbrains/jps/model/runConfiguration/JpsRunConfigurationType.java b/jps/model-api/src/org/jetbrains/jps/model/runConfiguration/JpsRunConfigurationType.java
index 558bf0548396..588453ff9b8c 100644
--- a/jps/model-api/src/org/jetbrains/jps/model/runConfiguration/JpsRunConfigurationType.java
+++ b/jps/model-api/src/org/jetbrains/jps/model/runConfiguration/JpsRunConfigurationType.java
@@ -21,5 +21,5 @@ import org.jetbrains.jps.model.JpsElementType;
 /**
  * @author nik
  */
-public abstract class JpsRunConfigurationType<P extends JpsElement> extends JpsElementType<P> {
+public interface JpsRunConfigurationType<P extends JpsElement> extends JpsElementType<P> {
 }
diff --git a/plugins/devkit/jps-plugin/src/org/jetbrains/jps/devkit/model/JpsPluginModuleType.java b/plugins/devkit/jps-plugin/src/org/jetbrains/jps/devkit/model/JpsPluginModuleType.java
index 2cc4166fbe10..296fd243178d 100644
--- a/plugins/devkit/jps-plugin/src/org/jetbrains/jps/devkit/model/JpsPluginModuleType.java
+++ b/plugins/devkit/jps-plugin/src/org/jetbrains/jps/devkit/model/JpsPluginModuleType.java
@@ -16,12 +16,13 @@
 package org.jetbrains.jps.devkit.model;
 
 import org.jetbrains.jps.model.JpsSimpleElement;
+import org.jetbrains.jps.model.ex.JpsElementTypeBase;
 import org.jetbrains.jps.model.module.JpsModuleType;
 
 /**
  * @author nik
  */
-public class JpsPluginModuleType extends JpsModuleType<JpsSimpleElement<JpsPluginModuleProperties>> {
+public class JpsPluginModuleType extends JpsElementTypeBase<JpsSimpleElement<JpsPluginModuleProperties>> implements JpsModuleType<JpsSimpleElement<JpsPluginModuleProperties>> {
   public static final JpsPluginModuleType INSTANCE = new JpsPluginModuleType();
 
 }
diff --git a/plugins/javaFX/javaFX-jps-plugin/src/org/jetbrains/plugins/javaFX/JpsJavaFxApplicationArtifactType.java b/plugins/javaFX/javaFX-jps-plugin/src/org/jetbrains/plugins/javaFX/JpsJavaFxApplicationArtifactType.java
index 3d1df6e092f2..fbad37aff6ca 100644
--- a/plugins/javaFX/javaFX-jps-plugin/src/org/jetbrains/plugins/javaFX/JpsJavaFxApplicationArtifactType.java
+++ b/plugins/javaFX/javaFX-jps-plugin/src/org/jetbrains/plugins/javaFX/JpsJavaFxApplicationArtifactType.java
@@ -1,11 +1,12 @@
 package org.jetbrains.plugins.javaFX;
 
 import org.jetbrains.jps.model.artifact.JpsArtifactType;
+import org.jetbrains.jps.model.ex.JpsElementTypeBase;
 
 /**
  * User: anna
  * Date: 3/13/13
  */
-public class JpsJavaFxApplicationArtifactType extends JpsArtifactType<JpsJavaFxArtifactProperties> {
+public class JpsJavaFxApplicationArtifactType extends JpsElementTypeBase<JpsJavaFxArtifactProperties> implements JpsArtifactType<JpsJavaFxArtifactProperties> {
   public static final JpsJavaFxApplicationArtifactType INSTANCE = new JpsJavaFxApplicationArtifactType();
 }
diff --git a/plugins/javaFX/javaFX-jps-plugin/src/org/jetbrains/plugins/javaFX/preloader/JpsJavaFxPreloaderArtifactType.java b/plugins/javaFX/javaFX-jps-plugin/src/org/jetbrains/plugins/javaFX/preloader/JpsJavaFxPreloaderArtifactType.java
index ab0440dc9195..d05fed5d5f54 100644
--- a/plugins/javaFX/javaFX-jps-plugin/src/org/jetbrains/plugins/javaFX/preloader/JpsJavaFxPreloaderArtifactType.java
+++ b/plugins/javaFX/javaFX-jps-plugin/src/org/jetbrains/plugins/javaFX/preloader/JpsJavaFxPreloaderArtifactType.java
@@ -16,11 +16,12 @@
 package org.jetbrains.plugins.javaFX.preloader;
 
 import org.jetbrains.jps.model.artifact.JpsArtifactType;
+import org.jetbrains.jps.model.ex.JpsElementTypeBase;
 
 /**
  * User: anna
  * Date: 3/13/13
  */
-public class JpsJavaFxPreloaderArtifactType extends JpsArtifactType<JpsJavaFxPreloaderArtifactProperties> {
+public class JpsJavaFxPreloaderArtifactType extends JpsElementTypeBase<JpsJavaFxPreloaderArtifactProperties> implements JpsArtifactType<JpsJavaFxPreloaderArtifactProperties> {
   public static final JpsJavaFxPreloaderArtifactType INSTANCE = new JpsJavaFxPreloaderArtifactType();
 }