1 /*
2 * Licensed to the Apache Software Foundation (ASF) under one
3 * or more contributor license agreements. See the NOTICE file
4 * distributed with this work for additional information
5 * regarding copyright ownership. The ASF licenses this file
6 * to you under the Apache License, Version 2.0 (the
7 * "License"); you may not use this file except in compliance
8 * with the License. You may obtain a copy of the License at
9 *
10 * https://www.apache.org/licenses/LICENSE-2.0
11 *
12 * Unless required by applicable law or agreed to in writing,
13 * software distributed under the License is distributed on an
14 * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
15 * KIND, either express or implied. See the License for the
16 * specific language governing permissions and limitations
17 * under the License.
18 */
19 package org.apache.bcel.generic;
20
21 /**
22 * DCONST - Push 0.0 or 1.0, other values cause an exception
23 *
24 * <PRE>
25 * Stack: ... -> ...,
26 * </PRE>
27 */
28 public class DCONST extends Instruction implements ConstantPushInstruction {
29
30 private final double value;
31
32 /**
33 * Empty constructor needed for Instruction.readInstruction. Not to be used otherwise.
34 */
35 DCONST() {
36 this(0);
37 }
38
39 /**
40 * Constructs a DCONST instruction.
41 *
42 * @param f the constant value (must be 0.0 or 1.0).
43 * @throws ClassGenException if f is not 0.0 or 1.0.
44 */
45 public DCONST(final double f) {
46 super(org.apache.bcel.Const.DCONST_0, (short) 1);
47 if (f == 0.0) {
48 super.setOpcode(org.apache.bcel.Const.DCONST_0);
49 } else if (f == 1.0) {
50 super.setOpcode(org.apache.bcel.Const.DCONST_1);
51 } else {
52 throw new ClassGenException("DCONST can be used only for 0.0 and 1.0: " + f);
53 }
54 value = f;
55 }
56
57 /**
58 * Call corresponding visitor method(s). The order is: Call visitor methods of implemented interfaces first, then call
59 * methods according to the class hierarchy in descending order, that is, the most specific visitXXX() call comes last.
60 *
61 * @param v Visitor object.
62 */
63 @Override
64 public void accept(final Visitor v) {
65 v.visitPushInstruction(this);
66 v.visitStackProducer(this);
67 v.visitTypedInstruction(this);
68 v.visitConstantPushInstruction(this);
69 v.visitDCONST(this);
70 }
71
72 /**
73 * @return Type.DOUBLE.
74 */
75 @Override
76 public Type getType(final ConstantPoolGen cp) {
77 return Type.DOUBLE;
78 }
79
80 @Override
81 public Number getValue() {
82 return Double.valueOf(value);
83 }
84 }