1 /*
   2  * Copyright (c) 1997, 2012, 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.xml.internal.bind.v2.runtime.reflect;
  27 
  28 import com.sun.xml.internal.bind.api.AccessorException;
  29 
  30 /**
  31  * {@link Accessor} wrapper that replaces a null with an empty collection.
  32  *
  33  * <p>
  34  * This is so that JAX-WS property accessor will work like an ordinary getter.
  35  *
  36  *
  37  * @author Kohsuke Kawaguchi
  38  */
  39 public class NullSafeAccessor<B,V,P> extends Accessor<B,V> {
  40     private final Accessor<B,V> core;
  41     private final Lister<B,V,?,P> lister;
  42 
  43     public NullSafeAccessor(Accessor<B,V> core, Lister<B,V,?,P> lister) {
  44         super(core.getValueType());
  45         this.core = core;
  46         this.lister = lister;
  47     }
  48 
  49     public V get(B bean) throws AccessorException {
  50         V v = core.get(bean);
  51         if(v==null) {
  52             // creates a new object
  53             P pack = lister.startPacking(bean,core);
  54             lister.endPacking(pack,bean,core);
  55             v = core.get(bean);
  56         }
  57         return v;
  58     }
  59 
  60     public void set(B bean, V value) throws AccessorException {
  61         core.set(bean,value);
  62     }
  63 }