1 /*
2 * Licensed to the Apache Software Foundation (ASF) under one or more
3 * contributor license agreements. See the NOTICE file distributed with
4 * this work for additional information regarding copyright ownership.
5 * The ASF licenses this file to You under the Apache License, Version 2.0
6 * (the "License"); you may not use this file except in compliance with
7 * the License. You may obtain a copy of the License at
8 *
9 * http://www.apache.org/licenses/LICENSE-2.0
10 *
11 * Unless required by applicable law or agreed to in writing, software
12 * distributed under the License is distributed on an "AS IS" BASIS,
13 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
14 * See the License for the specific language governing permissions and
15 * limitations under the License.
16 */
17 package org.apache.bcel.generic;
18
19 import org.apache.bcel.ExceptionConst;
20
21 /**
22 * CHECKCAST - Check whether object is of given type
23 *
24 * <PRE>
25 * Stack: ..., objectref -> ..., objectref
26 * </PRE>
27 */
28 public class CHECKCAST extends CPInstruction implements LoadClass, ExceptionThrower, StackProducer, StackConsumer {
29
30 /**
31 * Empty constructor needed for Instruction.readInstruction. Not to be used otherwise.
32 */
33 CHECKCAST() {
34 }
35
36 /**
37 * Check whether object is of given type
38 *
39 * @param index index to class in constant pool
40 */
41 public CHECKCAST(final int index) {
42 super(org.apache.bcel.Const.CHECKCAST, index);
43 }
44
45 /**
46 * Call corresponding visitor method(s). The order is: Call visitor methods of implemented interfaces first, then call
47 * methods according to the class hierarchy in descending order, i.e., the most specific visitXXX() call comes last.
48 *
49 * @param v Visitor object
50 */
51 @Override
52 public void accept(final Visitor v) {
53 v.visitLoadClass(this);
54 v.visitExceptionThrower(this);
55 v.visitStackProducer(this);
56 v.visitStackConsumer(this);
57 v.visitTypedInstruction(this);
58 v.visitCPInstruction(this);
59 v.visitCHECKCAST(this);
60 }
61
62 /**
63 * @return exceptions this instruction may cause
64 */
65 @Override
66 public Class<?>[] getExceptions() {
67 return ExceptionConst.createExceptions(ExceptionConst.EXCS.EXCS_CLASS_AND_INTERFACE_RESOLUTION, ExceptionConst.CLASS_CAST_EXCEPTION);
68 }
69
70 @Override
71 public ObjectType getLoadClassType(final ConstantPoolGen cpg) {
72 Type t = getType(cpg);
73 if (t instanceof ArrayType) {
74 t = ((ArrayType) t).getBasicType();
75 }
76 return t instanceof ObjectType ? (ObjectType) t : null;
77 }
78 }