encapsulate ObjectStubBase.id

java/java-impl/src/com/intellij/psi/stubsHierarchy/impl/JavaStubIndexer.java

@@ -139,7 +139,7 @@ public class JavaStubIndexer extends StubHierarchyIndexer {
     }
     String[] supers = superList.isEmpty() ? ArrayUtil.EMPTY_STRING_ARRAY : ArrayUtil.toStringArray(superList);
     Decl[] inners = innerList.isEmpty() ? Decl.EMPTY_ARRAY : innerList.toArray(Decl.EMPTY_ARRAY);
-    return new ClassDecl(classStub.id, flags, classStub.getName(), supers, inners);
+    return new ClassDecl(classStub.getStubId(), flags, classStub.getName(), supers, inners);
   }
 
   private static int translateFlags(PsiClassStubImpl<?> classStub) {

platform/core-api/src/com/intellij/psi/stubs/ObjectStubBase.java

@@ -27,7 +27,7 @@ public abstract class ObjectStubBase<T extends Stub> extends UserDataHolderBase
   private static final Key<Boolean> DANGLING_STUB = Key.create("DIRECT_PARENT_IS_STUBBED");
 
   protected final T myParent;
-  public int id;
+  int id;
 
   public ObjectStubBase(T parent) {
     myParent = parent;
@@ -52,4 +52,11 @@ public abstract class ObjectStubBase<T extends Stub> extends UserDataHolderBase
   public void markDangling() {
     putUserData(DANGLING_STUB, true);
   }
+
+  /**
+   * @return the index of this stub in {@code ObjectStubTree#getPlainList}.
+   */
+  public int getStubId() {
+    return id;
+  }
 }

platform/core-api/src/com/intellij/psi/stubs/StubBase.java

@@ -227,4 +227,14 @@ public abstract class StubBase<T extends PsiElement> extends ObjectStubBase<Stub
   public String toString() {
     return getClass().getSimpleName();
   }
+
+  /**
+   * @return comparison result (as in {@link Comparable}) of this stub with {@code another},
+   * where "a<b" means that "a" occurs before "b" in the deep-first traversal of the stub tree,
+   * and the same holds for their AST equivalents.
+   */
+  public int compareByOrderWith(ObjectStubBase<?> another) {
+    return Integer.compare(getStubId(), another.getStubId());
+  }
+
 }

platform/core-impl/src/com/intellij/psi/PsiAnchor.java

@@ -160,7 +160,7 @@ public abstract class PsiAnchor {
 
     StubElement liveStub = psi instanceof StubBasedPsiElementBase ? ((StubBasedPsiElementBase)psi).getGreenStub() : psi.getStub();
     if (liveStub != null) {
-      return ((StubBase)liveStub).id;
+      return ((StubBase)liveStub).getStubId();
     }
 
     return ((PsiFileImpl)psi.getContainingFile()).calcTreeElement().getStubbedSpine().getStubIndex(psi);

plugins/groovy/groovy-psi/src/org/jetbrains/plugins/groovy/lang/psi/stubs/hierarchy/GrStubIndexer.java

@@ -151,7 +151,7 @@ public class GrStubIndexer extends StubHierarchyIndexer {
     }
     String[] supers = superList.isEmpty() ? ArrayUtil.EMPTY_STRING_ARRAY : ArrayUtil.toStringArray(superList);
     Decl[] inners = innerList.isEmpty() ? Decl.EMPTY_ARRAY : innerList.toArray(Decl.EMPTY_ARRAY);
-    return new ClassDecl(classStub.id, flags, classStub.getName(), supers, inners);
+    return new ClassDecl(classStub.getStubId(), flags, classStub.getName(), supers, inners);
   }
 
   private static int translateFlags(GrTypeDefinitionStub classStub) {

xml/dom-impl/src/com/intellij/util/xml/impl/CollectionElementInvocationHandler.java

@@ -115,7 +115,7 @@ public class CollectionElementInvocationHandler extends DomInvocationHandler<Abs
   public int hashCode() {
     ElementStub stub = getStub();
     if (stub != null) {
-      return stub.getName().hashCode() + stub.id;
+      return stub.getName().hashCode() + stub.getStubId();
     }
     final XmlElement element = getXmlElement();
     return element == null ? super.hashCode() : element.hashCode();