Write interface added to ASTNode. Implementations delegate to ChangeUtil.

openapi/src/com/intellij/lang/ASTNode.java

@@ -30,5 +30,11 @@ public interface ASTNode extends UserDataHolder {
 
   ASTNode[] getChildren(TokenSet filter);
 
+  void addChild(ASTNode child, ASTNode anchorBefore);
+  void removeChild(ASTNode child);
+  void replaceChild(ASTNode oldChild, ASTNode newChild);
+  void replaceAllChildrenToChildrenOf(ASTNode anotherParent);
+  void addChildren(ASTNode firstChild, ASTNode lastChild, ASTNode anchorBefore);
+
   Object clone();
 }

source/com/intellij/psi/impl/source/tree/ChangeUtil.java

@@ -1,18 +1,17 @@
 package com.intellij.psi.impl.source.tree;
 
+import com.intellij.lang.ASTNode;
 import com.intellij.lexer.JavaLexer;
 import com.intellij.lexer.Lexer;
 import com.intellij.openapi.diagnostic.Logger;
+import com.intellij.openapi.editor.Document;
 import com.intellij.openapi.util.Key;
 import com.intellij.openapi.vfs.VirtualFile;
-import com.intellij.openapi.editor.Document;
 import com.intellij.pom.java.LanguageLevel;
 import com.intellij.psi.*;
-import com.intellij.psi.impl.DebugUtil;
+import com.intellij.psi.impl.PsiDocumentManagerImpl;
 import com.intellij.psi.impl.PsiManagerImpl;
 import com.intellij.psi.impl.PsiTreeChangeEventImpl;
-import com.intellij.psi.impl.PsiDocumentManagerImpl;
-import com.intellij.psi.impl.compiled.ClsFileImpl;
 import com.intellij.psi.impl.cache.RepositoryManager;
 import com.intellij.psi.impl.light.LightClassReference;
 import com.intellij.psi.impl.light.LightTypeElement;
@@ -22,11 +21,12 @@ import com.intellij.psi.impl.source.codeStyle.CodeStyleManagerEx;
 import com.intellij.psi.impl.source.parsing.*;
 import com.intellij.util.CharTable;
 import com.intellij.util.IncorrectOperationException;
-import com.intellij.lang.ASTNode;
 
 public class ChangeUtil implements Constants {
   private static final Logger LOG = Logger.getInstance("#com.intellij.psi.impl.source.tree.ChangeUtil");
 
+  private ChangeUtil() {}
+
   public static void addChild(final CompositeElement parent, final TreeElement child, TreeElement anchorBefore) {
     LOG.assertTrue(anchorBefore == null || anchorBefore.getTreeParent() == parent);
 
@@ -93,7 +93,7 @@ public class ChangeUtil implements Constants {
     }
   }
 
-  public static void registerLeafsInCharTab(CharTable newCharTab, ASTNode child, CharTable oldCharTab) {
+  private static void registerLeafsInCharTab(CharTable newCharTab, ASTNode child, CharTable oldCharTab) {
     if(newCharTab == oldCharTab) return;
     while(child != null){
       CharTable charTable = child.getUserData(CharTable.CHAR_TABLE_KEY);

source/com/intellij/psi/impl/source/tree/CompositeElement.java

@@ -306,4 +306,24 @@ public class CompositeElement extends TreeElement implements Cloneable{
   public ASTNode getLastChildNode() {
     return lastChild;
   }
+
+  public void addChild(ASTNode child, ASTNode anchorBefore) {
+    ChangeUtil.addChild(this, (TreeElement)child, (TreeElement)anchorBefore);
+  }
+
+  public void removeChild(ASTNode child) {
+    ChangeUtil.removeChild(this, (TreeElement)child);
+  }
+
+  public void replaceChild(ASTNode oldChild, ASTNode newChild) {
+    ChangeUtil.replaceChild(this, (TreeElement)oldChild, (TreeElement)newChild);
+  }
+
+  public void replaceAllChildrenToChildrenOf(ASTNode anotherParent) {
+    ChangeUtil.replaceAllChildren(this, (CompositeElement)anotherParent);
+  }
+
+  public void addChildren(ASTNode firstChild, ASTNode lastChild, ASTNode anchorBefore) {
+    ChangeUtil.addChildren(this, (TreeElement)firstChild, lastChild, (TreeElement)anchorBefore);
+  }
 }

source/com/intellij/psi/impl/source/tree/LeafElement.java

@@ -3,8 +3,10 @@ package com.intellij.psi.impl.source.tree;
 import com.intellij.psi.tree.IElementType;
 import com.intellij.psi.tree.TokenSet;
 import com.intellij.util.CharTable;
+import com.intellij.util.IncorrectOperationException;
 import com.intellij.util.text.StringSearcher;
 import com.intellij.lang.ASTNode;
+import sun.plugin.dom.exception.InvalidStateException;
 
 public abstract class LeafElement extends TreeElement {
   private volatile int myState = 0; // 16 bit for type, 15 bit for state and 1 bit for parentFlag
@@ -127,5 +129,25 @@ public abstract class LeafElement extends TreeElement {
 
   public ASTNode[] getChildren(TokenSet filter) {
     return TreeElement.EMPTY_ARRAY;
-  }  
+  }
+
+  public void addChild(ASTNode child, ASTNode anchorBefore) {
+    throw new InvalidStateException("Leaf elements cannot have children.");
+  }
+
+  public void removeChild(ASTNode child) {
+    throw new InvalidStateException("Leaf elements cannot have children.");
+  }
+
+  public void replaceChild(ASTNode oldChild, ASTNode newChild) {
+    throw new InvalidStateException("Leaf elements cannot have children.");
+  }
+
+  public void replaceAllChildrenToChildrenOf(ASTNode anotherParent) {
+    throw new InvalidStateException("Leaf elements cannot have children.");
+  }
+
+  public void addChildren(ASTNode firstChild, ASTNode lastChild, ASTNode anchorBefore) {
+    throw new InvalidStateException("Leaf elements cannot have children.");
+  }
 }