001/*
002 * Licensed to the Apache Software Foundation (ASF) under one
003 * or more contributor license agreements.  See the NOTICE file
004 * distributed with this work for additional information
005 * regarding copyright ownership.  The ASF licenses this file
006 * to you under the Apache License, Version 2.0 (the
007 * "License"); you may not use this file except in compliance
008 * with the License.  You may obtain a copy of the License at
009 *
010 *   https://www.apache.org/licenses/LICENSE-2.0
011 *
012 * Unless required by applicable law or agreed to in writing,
013 * software distributed under the License is distributed on an
014 * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
015 * KIND, either express or implied.  See the License for the
016 * specific language governing permissions and limitations
017 * under the License.
018 */
019package org.apache.bcel.generic;
020
021/**
022 * DCONST - Push 0.0 or 1.0, other values cause an exception
023 *
024 * <PRE>
025 * Stack: ... -&gt; ...,
026 * </PRE>
027 */
028public class DCONST extends Instruction implements ConstantPushInstruction {
029
030    private final double value;
031
032    /**
033     * Empty constructor needed for Instruction.readInstruction. Not to be used otherwise.
034     */
035    DCONST() {
036        this(0);
037    }
038
039    /**
040     * Constructs a DCONST instruction.
041     *
042     * @param f the constant value (must be 0.0 or 1.0).
043     * @throws ClassGenException if f is not 0.0 or 1.0.
044     */
045    public DCONST(final double f) {
046        super(org.apache.bcel.Const.DCONST_0, (short) 1);
047        if (f == 0.0) {
048            super.setOpcode(org.apache.bcel.Const.DCONST_0);
049        } else if (f == 1.0) {
050            super.setOpcode(org.apache.bcel.Const.DCONST_1);
051        } else {
052            throw new ClassGenException("DCONST can be used only for 0.0 and 1.0: " + f);
053        }
054        value = f;
055    }
056
057    /**
058     * Call corresponding visitor method(s). The order is: Call visitor methods of implemented interfaces first, then call
059     * methods according to the class hierarchy in descending order, that is, the most specific visitXXX() call comes last.
060     *
061     * @param v Visitor object.
062     */
063    @Override
064    public void accept(final Visitor v) {
065        v.visitPushInstruction(this);
066        v.visitStackProducer(this);
067        v.visitTypedInstruction(this);
068        v.visitConstantPushInstruction(this);
069        v.visitDCONST(this);
070    }
071
072    /**
073     * @return Type.DOUBLE.
074     */
075    @Override
076    public Type getType(final ConstantPoolGen cp) {
077        return Type.DOUBLE;
078    }
079
080    @Override
081    public Number getValue() {
082        return Double.valueOf(value);
083    }
084}