/*
 * reserved comment block
 * DO NOT REMOVE OR ALTER!
 */
package com.sun.org.apache.bcel.internal.generic;

/* ====================================================================
 * The Apache Software License, Version 1.1
 *
 * Copyright (c) 2001 The Apache Software Foundation.  All rights
 * reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 *
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer.
 *
 * 2. Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in
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 *    distribution.
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 * 3. The end-user documentation included with the redistribution,
 *    if any, must include the following acknowledgment:
 *       "This product includes software developed by the
 *        Apache Software Foundation (http://www.apache.org/)."
 *    Alternately, this acknowledgment may appear in the software itself,
 *    if and wherever such third-party acknowledgments normally appear.
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 * 4. The names "Apache" and "Apache Software Foundation" and
 *    "Apache BCEL" must not be used to endorse or promote products
 *    derived from this software without prior written permission. For
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 * 5. Products derived from this software may not be called "Apache",
 *    "Apache BCEL", nor may "Apache" appear in their name, without
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 * ITS CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
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 * OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
 * SUCH DAMAGE.
 * ====================================================================
 *
 * This software consists of voluntary contributions made by many
 * individuals on behalf of the Apache Software Foundation.  For more
 * information on the Apache Software Foundation, please see
 * <http://www.apache.org/>.
 */
import com.sun.org.apache.bcel.internal.ExceptionConstants;
/**
 * CHECKCAST - Check whether object is of given type
 * <PRE>Stack: ..., objectref -&gt; ..., objectref</PRE>
 *
 * @author  <A HREF="mailto:markus.dahm@berlin.de">M. Dahm</A>
 */
public class CHECKCAST extends CPInstruction
  implements LoadClass, ExceptionThrower, StackProducer, StackConsumer {
  /**
   * Empty constructor needed for the Class.newInstance() statement in
   * Instruction.readInstruction(). Not to be used otherwise.
   */
  CHECKCAST() {}

  /** Check whether object is of given type
   * @param n index to class in constant pool
   */
  public CHECKCAST(int index) {
    super(com.sun.org.apache.bcel.internal.Constants.CHECKCAST, index);
  }

  /** @return exceptions this instruction may cause
   */
  public Class[] getExceptions() {
    Class[] cs = new Class[1 + ExceptionConstants.EXCS_CLASS_AND_INTERFACE_RESOLUTION.length];

    System.arraycopy(ExceptionConstants.EXCS_CLASS_AND_INTERFACE_RESOLUTION, 0,
                     cs, 0, ExceptionConstants.EXCS_CLASS_AND_INTERFACE_RESOLUTION.length);
    cs[ExceptionConstants.EXCS_CLASS_AND_INTERFACE_RESOLUTION.length] =
      ExceptionConstants.CLASS_CAST_EXCEPTION;
    return cs;
  }

  public ObjectType getLoadClassType(ConstantPoolGen cpg) {
    Type t = getType(cpg);

    if(t instanceof ArrayType)
      t = ((ArrayType) t).getBasicType();

    return (t instanceof ObjectType)? (ObjectType) t : null;
  }

  /**
   * 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
   */
  public void accept(Visitor v) {
    v.visitLoadClass(this);
    v.visitExceptionThrower(this);
    v.visitStackProducer(this);
    v.visitStackConsumer(this);
    v.visitTypedInstruction(this);
    v.visitCPInstruction(this);
    v.visitCHECKCAST(this);
  }
}