/*

 * reserved comment block

 * DO NOT REMOVE OR ALTER!

 */

package com.sun.org.apache.bcel.internal.generic;

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);

  }

}