1 /*
2  * Licensed to the Apache Software Foundation (ASF) under one or more
3  * contributor license agreements.  See the NOTICE file distributed with
4  * this work for additional information regarding copyright ownership.
5  * The ASF licenses this file to You under the Apache License, Version 2.0
6  * (the "License"); you may not use this file except in compliance with
7  * the License.  You may obtain a copy of the License at
8  *
9  *      http://www.apache.org/licenses/LICENSE-2.0
10  *
11  *  Unless required by applicable law or agreed to in writing, software
12  *  distributed under the License is distributed on an "AS IS" BASIS,
13  *  WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
14  *  See the License for the specific language governing permissions and
15  *  limitations under the License.
16  *
17  */
18 package org.apache.bcel.generic;
19 
20 /**
21  * IFNULL - Branch if reference is not null
22  *
23  * <PRE>Stack: ..., reference -&gt; ...</PRE>
24  *
25  * @version $Id$
26  */
27 public class IFNULL extends IfInstruction {
28 
29     /**
30      * Empty constructor needed for Instruction.readInstruction.
31      * Not to be used otherwise.
32      */
IFNULL()33     IFNULL() {
34     }
35 
36 
IFNULL(final InstructionHandle target)37     public IFNULL(final InstructionHandle target) {
38         super(org.apache.bcel.Const.IFNULL, target);
39     }
40 
41 
42     /**
43      * @return negation of instruction
44      */
45     @Override
negate()46     public IfInstruction negate() {
47         return new IFNONNULL(super.getTarget());
48     }
49 
50 
51     /**
52      * Call corresponding visitor method(s). The order is:
53      * Call visitor methods of implemented interfaces first, then
54      * call methods according to the class hierarchy in descending order,
55      * i.e., the most specific visitXXX() call comes last.
56      *
57      * @param v Visitor object
58      */
59     @Override
accept( final Visitor v )60     public void accept( final Visitor v ) {
61         v.visitStackConsumer(this);
62         v.visitBranchInstruction(this);
63         v.visitIfInstruction(this);
64         v.visitIFNULL(this);
65     }
66 }
67