jps: toString() for root types (debuggability)

jps/model-api/src/org/jetbrains/jps/model/java/JpsAnnotationRootType.java

@@ -1,5 +1,5 @@
 /*
- * Copyright 2000-2012 JetBrains s.r.o.
+ * Copyright 2000-2015 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.
@@ -23,6 +23,10 @@ import org.jetbrains.jps.model.library.JpsOrderRootType;
 public class JpsAnnotationRootType extends JpsOrderRootType {
   public static final JpsAnnotationRootType INSTANCE = new JpsAnnotationRootType();
 
-  private JpsAnnotationRootType() {
+  private JpsAnnotationRootType() { }
+
+  @Override
+  public String toString() {
+    return "annotation root";
   }
 }

jps/model-api/src/org/jetbrains/jps/model/java/JpsNativeLibraryRootType.java

@@ -1,5 +1,5 @@
 /*
- * Copyright 2000-2014 JetBrains s.r.o.
+ * Copyright 2000-2015 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.
@@ -23,6 +23,10 @@ import org.jetbrains.jps.model.library.JpsOrderRootType;
 public class JpsNativeLibraryRootType extends JpsOrderRootType {
   public static final JpsNativeLibraryRootType INSTANCE = new JpsNativeLibraryRootType();
 
-  private JpsNativeLibraryRootType() {
+  private JpsNativeLibraryRootType() { }
+
+  @Override
+  public String toString() {
+    return "native lib root";
   }
 }

jps/model-api/src/org/jetbrains/jps/model/library/JpsOrderRootType.java

@@ -1,5 +1,5 @@
 /*
- * Copyright 2000-2012 JetBrains s.r.o.
+ * Copyright 2000-2015 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.
@@ -20,9 +20,21 @@ package org.jetbrains.jps.model.library;
  */
 public abstract class JpsOrderRootType {
   public static final JpsOrderRootType COMPILED = new JpsOrderRootType() {
+    @Override
+    public String toString() {
+      return "compiled root";
+    }
   };
   public static final JpsOrderRootType SOURCES = new JpsOrderRootType() {
+    @Override
+    public String toString() {
+      return "sources root";
+    }
   };
   public static final JpsOrderRootType DOCUMENTATION = new JpsOrderRootType() {
+    @Override
+    public String toString() {
+      return "documentation root";
+    }
   };
 }