src/org/eclipse/jdt/internal/compiler/ast/NullLiteral.java

   1 /*******************************************************************************
   2  * Copyright (c) 2000, 2004 IBM Corporation and others.
   3  * All rights reserved. This program and the accompanying materials
   4  * are made available under the terms of the Common Public License v1.0
   5  * which accompanies this distribution, and is available at
   6  * http://www.eclipse.org/legal/cpl-v10.html
   7  *
   8  * Contributors:
   9  *     IBM Corporation - initial API and implementation
  10  *******************************************************************************/
  11 package org.eclipse.jdt.internal.compiler.ast;
  12
  13 import org.eclipse.jdt.internal.compiler.ASTVisitor;
  14 import org.eclipse.jdt.internal.compiler.codegen.*;
  15 import org.eclipse.jdt.internal.compiler.lookup.*;
  16
  17 public class NullLiteral extends MagicLiteral {
  18
  19         static final char[] source = {'n' , 'u' , 'l' , 'l'};
  20
  21         public NullLiteral(int s , int e) {
  22
  23                 super(s,e);
  24         }
  25
  26         public void computeConstant() {
  27
  28                 constant = NotAConstant;
  29         }
  30
  31         /**
  32          * Code generation for the null literal
  33          *
  34          * @param currentScope org.eclipse.jdt.internal.compiler.lookup.BlockScope
  35          * @param codeStream org.eclipse.jdt.internal.compiler.codegen.CodeStream
  36          * @param valueRequired boolean
  37          */
  38         public void generateCode(BlockScope currentScope, CodeStream codeStream, boolean valueRequired) {
  39                 int pc = codeStream.position;
  40                 if (valueRequired)
  41                         codeStream.aconst_null();
  42                 codeStream.recordPositionsFrom(pc, this.sourceStart);
  43         }
  44         public TypeBinding literalType(BlockScope scope) {
  45                 return NullBinding;
  46         }
  47
  48         /**
  49          *
  50          */
  51         public char[] source() {
  52                 return source;
  53         }
  54
  55         public void traverse(ASTVisitor visitor, BlockScope scope) {
  56                 visitor.visit(this, scope);
  57                 visitor.endVisit(this, scope);
  58         }
  59 }