commons-bcel-master/src/main/java/org/apache/bcel/generic/LDC2_W.java
/*
 * Licensed to the Apache Software Foundation (ASF) under one or more
 * contributor license agreements.  See the NOTICE file distributed with
 * this work for additional information regarding copyright ownership.
 * The ASF licenses this file to You under the Apache License, Version 2.0
 * (the "License"); you may not use this file except in compliance with
 * the License.  You may obtain a copy of the License at
 *
 *      http://www.apache.org/licenses/LICENSE-2.0
 *
 *  Unless required by applicable law or agreed to in writing, software
 *  distributed under the License is distributed on an "AS IS" BASIS,
 *  WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 *  See the License for the specific language governing permissions and
 *  limitations under the License.
 */
package org.apache.bcel.generic;

/**
 * LDC2_W - Push long or double from constant pool
 *
 * <PRE>
 * Stack: ... -&gt; ..., item.word1, item.word2
 * </PRE>
 */
public class LDC2_W extends CPInstruction implements PushInstruction {

    /**
     * Empty constructor needed for Instruction.readInstruction. Not to be used otherwise.
     */
    LDC2_W() {
    }

    public LDC2_W(final int index) {
        super(org.apache.bcel.Const.LDC2_W, index);
    }

    /**
     * Call corresponding visitor method(s). The order is: Call visitor methods of implemented interfaces first, then call
     * methods according to the class hierarchy in descending order, i.e., the most specific visitXXX() call comes last.
     *
     * @param v Visitor object
     */
    @Override
    public void accept(final Visitor v) {
        v.visitStackProducer(this);
        v.visitPushInstruction(this);
        v.visitTypedInstruction(this);
        v.visitCPInstruction(this);
        v.visitLDC2_W(this);
    }

    @Override
    public Type getType(final ConstantPoolGen cpg) {
        switch (cpg.getConstantPool().getConstant(super.getIndex()).getTag()) {
        case org.apache.bcel.Const.CONSTANT_Long:
            return Type.LONG;
        case org.apache.bcel.Const.CONSTANT_Double:
            return Type.DOUBLE;
        default: // Never reached
            throw new IllegalArgumentException("Unknown constant type " + super.getOpcode());
        }
    }

    public Number getValue(final ConstantPoolGen cpg) {
        final org.apache.bcel.classfile.Constant c = cpg.getConstantPool().getConstant(super.getIndex());
        switch (c.getTag()) {
        case org.apache.bcel.Const.CONSTANT_Long:
            return Long.valueOf(((org.apache.bcel.classfile.ConstantLong) c).getBytes());
        case org.apache.bcel.Const.CONSTANT_Double:
            return Double.valueOf(((org.apache.bcel.classfile.ConstantDouble) c).getBytes());
        default: // Never reached
            throw new IllegalArgumentException("Unknown or invalid constant type at " + super.getIndex());
        }
    }
}
