001/*
002 * Licensed to the Apache Software Foundation (ASF) under one or more
003 * contributor license agreements.  See the NOTICE file distributed with
004 * this work for additional information regarding copyright ownership.
005 * The ASF licenses this file to You under the Apache License, Version 2.0
006 * (the "License"); you may not use this file except in compliance with
007 * the License.  You may obtain a copy of the License at
008 *
009 *      http://www.apache.org/licenses/LICENSE-2.0
010 *
011 *  Unless required by applicable law or agreed to in writing, software
012 *  distributed under the License is distributed on an "AS IS" BASIS,
013 *  WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
014 *  See the License for the specific language governing permissions and
015 *  limitations under the License.
016 */
017package org.apache.bcel.generic;
018
019/**
020 * IFNULL - Branch if reference is not null
021 *
022 * <PRE>
023 * Stack: ..., reference -&gt; ...
024 * </PRE>
025 */
026public class IFNULL extends IfInstruction {
027
028    /**
029     * Empty constructor needed for Instruction.readInstruction. Not to be used otherwise.
030     */
031    IFNULL() {
032    }
033
034    public IFNULL(final InstructionHandle target) {
035        super(org.apache.bcel.Const.IFNULL, target);
036    }
037
038    /**
039     * Call corresponding visitor method(s). The order is: Call visitor methods of implemented interfaces first, then call
040     * methods according to the class hierarchy in descending order, i.e., the most specific visitXXX() call comes last.
041     *
042     * @param v Visitor object
043     */
044    @Override
045    public void accept(final Visitor v) {
046        v.visitStackConsumer(this);
047        v.visitBranchInstruction(this);
048        v.visitIfInstruction(this);
049        v.visitIFNULL(this);
050    }
051
052    /**
053     * @return negation of instruction
054     */
055    @Override
056    public IfInstruction negate() {
057        return new IFNONNULL(super.getTarget());
058    }
059}