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    1   /*
    2    * Copyright  2000-2004 The Apache Software Foundation
    3    *
    4    *  Licensed under the Apache License, Version 2.0 (the "License");
    5    *  you may not use this file except in compliance with the License.
    6    *  You may obtain a copy of the License at
    7    *
    8    *      http://www.apache.org/licenses/LICENSE-2.0
    9    *
    10   *  Unless required by applicable law or agreed to in writing, software
    11   *  distributed under the License is distributed on an "AS IS" BASIS,
    12   *  WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
    13   *  See the License for the specific language governing permissions and
    14   *  limitations under the License.
    15   *
    16   */
    17  package org.apache.bcel.generic;
    18
    19  /***
    20   * INSTANCEOF - Determine if object is of given type
    21   * <PRE>Stack: ..., objectref -&gt; ..., result</PRE>
    22   *
    23   * @version $Id: INSTANCEOF.java 386056 2006-03-15 11:31:56Z tcurdt $
    24   * @author  <A HREF="mailto:m.dahm@gmx.de">M. Dahm</A>
    25   */
    26  public class INSTANCEOF extends CPInstruction implements LoadClass, ExceptionThrower,
    27          StackProducer, StackConsumer {
    28
    29      /***
    30       * Empty constructor needed for the Class.newInstance() statement in
    31       * Instruction.readInstruction(). Not to be used otherwise.
    32       */
    33      INSTANCEOF() {
    34      }
    35
    36
    37      public INSTANCEOF(int index) {
    38          super(org.apache.bcel.Constants.INSTANCEOF, index);
    39      }
    40
    41
    42      public Class[] getExceptions() {
    43          return org.apache.bcel.ExceptionConstants.EXCS_CLASS_AND_INTERFACE_RESOLUTION;
    44      }
    45
    46
    47      public ObjectType getLoadClassType( ConstantPoolGen cpg ) {
    48          Type t = getType(cpg);
    49          if (t instanceof ArrayType) {
    50              t = ((ArrayType) t).getBasicType();
    51          }
    52          return (t instanceof ObjectType) ? (ObjectType) t : null;
    53      }
    54
    55
    56      /***
    57       * Call corresponding visitor method(s). The order is:
    58       * Call visitor methods of implemented interfaces first, then
    59       * call methods according to the class hierarchy in descending order,
    60       * i.e., the most specific visitXXX() call comes last.
    61       *
    62       * @param v Visitor object
    63       */
    64      public void accept( Visitor v ) {
    65          v.visitLoadClass(this);
    66          v.visitExceptionThrower(this);
    67          v.visitStackProducer(this);
    68          v.visitStackConsumer(this);
    69          v.visitTypedInstruction(this);
    70          v.visitCPInstruction(this);
    71          v.visitINSTANCEOF(this);
    72      }
    73  }