1 /*
   2  * Copyright (c) 1997, 2011, Oracle and/or its affiliates. All rights reserved.
   3  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
   4  *
   5  * This code is free software; you can redistribute it and/or modify it
   6  * under the terms of the GNU General Public License version 2 only, as
   7  * published by the Free Software Foundation.  Oracle designates this
   8  * particular file as subject to the "Classpath" exception as provided
   9  * by Oracle in the LICENSE file that accompanied this code.
  10  *
  11  * This code is distributed in the hope that it will be useful, but WITHOUT
  12  * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
  13  * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
  14  * version 2 for more details (a copy is included in the LICENSE file that
  15  * accompanied this code).
  16  *
  17  * You should have received a copy of the GNU General Public License version
  18  * 2 along with this work; if not, write to the Free Software Foundation,
  19  * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
  20  *
  21  * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
  22  * or visit www.oracle.com if you need additional information or have any
  23  * questions.
  24  */
  25 
  26 package com.sun.tools.internal.xjc.generator.util;
  27 
  28 import com.sun.codemodel.internal.JBlock;
  29 
  30 /**
  31  * Lazy block reference.
  32  *
  33  * @author
  34  *     Kohsuke Kawaguchi (kohsuke.kawaguchi@sun.com)
  35  */
  36 public abstract class LazyBlockReference implements BlockReference {
  37 
  38     private JBlock block = null;
  39 
  40     /**
  41      * Called when a block needs to be created.
  42      * Only called once in the whole life time of this object.
  43      */
  44     protected abstract JBlock create();
  45 
  46     public JBlock get(boolean create) {
  47         if(!create)     return block;
  48         if(block==null)
  49             block = create();
  50         return block;
  51     }
  52 
  53 }