    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}