case-study/jdt-before/core extension/org/eclipse/jdt/internal/corext/dom/LocalVariableIndex.java

   1 /*******************************************************************************
   2  * Copyright (c) 2000, 2011 IBM Corporation and others.
   3  * All rights reserved. This program and the accompanying materials
   4  * are made available under the terms of the Eclipse Public License v1.0
   5  * which accompanies this distribution, and is available at
   6  * http://www.eclipse.org/legal/epl-v10.html
   7  *
   8  * Contributors:
   9  *     IBM Corporation - initial API and implementation
  10  *******************************************************************************/
  11 package org.eclipse.jdt.internal.corext.dom;
  12
  13 import org.eclipse.core.runtime.Assert;
  14
  15 import org.eclipse.jdt.core.dom.ASTNode;
  16 import org.eclipse.jdt.core.dom.ASTVisitor;
  17 import org.eclipse.jdt.core.dom.BodyDeclaration;
  18 import org.eclipse.jdt.core.dom.FieldDeclaration;
  19 import org.eclipse.jdt.core.dom.IVariableBinding;
  20 import org.eclipse.jdt.core.dom.Initializer;
  21 import org.eclipse.jdt.core.dom.MethodDeclaration;
  22 import org.eclipse.jdt.core.dom.SingleVariableDeclaration;
  23 import org.eclipse.jdt.core.dom.VariableDeclarationFragment;
  24
  25
  26 public class LocalVariableIndex extends ASTVisitor {
  27
  28         private int fTopIndex;
  29
  30         /**
  31          * Computes the maximum number of local variable declarations in the
  32          * given body declaration.
  33          *
  34          * @param declaration the body declaration. Must either be a method
  35          *  declaration, or an initializer, or a field declaration.
  36          * @return the maximum number of local variables
  37          */
  38         public static int perform(BodyDeclaration declaration) {
  39                 Assert.isTrue(declaration != null);
  40                 switch (declaration.getNodeType()) {
  41                         case ASTNode.METHOD_DECLARATION:
  42                         case ASTNode.FIELD_DECLARATION:
  43                         case ASTNode.INITIALIZER:
  44                                 return internalPerform(declaration);
  45                         default:
  46                                 throw new IllegalArgumentException(declaration.toString());
  47                 }
  48         }
  49
  50         private static int internalPerform(BodyDeclaration methodOrInitializer) {
  51                 // we have to find the outermost method/initializer/field declaration since a local or anonymous
  52                 // type can reference final variables from the outer scope.
  53                 BodyDeclaration target= methodOrInitializer;
  54                 ASTNode parent= target.getParent();
  55                 while (parent != null) {
  56                         if (parent instanceof MethodDeclaration || parent instanceof Initializer || parent instanceof FieldDeclaration) {
  57                                 target= (BodyDeclaration)parent;
  58                         }
  59                         parent= parent.getParent();
  60                 }
  61
  62                 return doPerform(target);
  63         }
  64
  65         private static int doPerform(BodyDeclaration node) {
  66                 LocalVariableIndex counter= new LocalVariableIndex();
  67                 node.accept(counter);
  68                 return counter.fTopIndex;
  69         }
  70
  71         @Override
  72         public boolean visit(SingleVariableDeclaration node) {
  73                 handleVariableBinding(node.resolveBinding());
  74                 return true;
  75         }
  76
  77         @Override
  78         public boolean visit(VariableDeclarationFragment node) {
  79                 handleVariableBinding(node.resolveBinding());
  80                 return true;
  81         }
  82
  83         private void handleVariableBinding(IVariableBinding binding) {
  84                 if (binding == null)
  85                         return;
  86                 fTopIndex= Math.max(fTopIndex, binding.getVariableId());
  87         }
  88 }