package org.aspectj.apache.bcel.generic;

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import org.aspectj.apache.bcel.classfile.CodeException;
import org.aspectj.apache.bcel.classfile.ConstantPool;

This class represents an exception handler, i.e., specifies the  region where
a handler is active and an instruction where the actual handling is done.
pool as parameters. Opposed to the JVM specification the end of the handled
region is set to be inclusive, i.e. all instructions between start and end
are protected including the start and end instructions (handles) themselves.
The end of the region is automatically mapped to be exclusive when calling
getCodeException(), i.e., there is no difference semantically.
Author:
 M. Dahm
See Also:
MethodGen
CodeException
InstructionHandle
Version:
$Id: CodeExceptionGen.java,v 1.5 2008/05/28 23:52:56 aclement Exp $/** 
 * This class represents an exception handler, i.e., specifies the  region where
 * a handler is active and an instruction where the actual handling is done.
 * pool as parameters. Opposed to the JVM specification the end of the handled
 * region is set to be inclusive, i.e. all instructions between start and end
 * are protected including the start and end instructions (handles) themselves.
 * The end of the region is automatically mapped to be exclusive when calling
 * getCodeException(), i.e., there is no difference semantically.
 *
 * @version $Id: CodeExceptionGen.java,v 1.5 2008/05/28 23:52:56 aclement Exp $
 * @author  <A HREF="mailto:markus.dahm@berlin.de">M. Dahm</A>
 * @see     MethodGen
 * @see     CodeException
 * @see     InstructionHandle
 */
public final class CodeExceptionGen
  implements InstructionTargeter, Cloneable, java.io.Serializable {
  private InstructionHandle start_pc;
  private InstructionHandle end_pc;
  private InstructionHandle handler_pc;
  private ObjectType        catch_type;
  
  
Add an exception handler, i.e., specify region where a handler is active and an
instruction where the actual handling is done.
Params:
start_pc – Start of handled region (inclusive)
end_pc – End of handled region (inclusive)
handler_pc – Where handling is done
catch_type – which exception is handled, null for ANY/**
   * Add an exception handler, i.e., specify region where a handler is active and an
   * instruction where the actual handling is done.
   *
   * @param start_pc Start of handled region (inclusive)
   * @param end_pc End of handled region (inclusive)
   * @param handler_pc Where handling is done
   * @param catch_type which exception is handled, null for ANY
   */
  public CodeExceptionGen(InstructionHandle start_pc, InstructionHandle end_pc,
			  InstructionHandle handler_pc, ObjectType catch_type) {
    setStartPC(start_pc);
    setEndPC(end_pc);
    setHandlerPC(handler_pc);
    this.catch_type = catch_type;
  }

  
Get CodeException object.

This relies on that the instruction list has already been dumped
to byte code or or that the `setPositions' methods has been
called for the instruction list.
Params:
cp – constant pool/**
   * Get CodeException object.<BR>
   *
   * This relies on that the instruction list has already been dumped
   * to byte code or or that the `setPositions' methods has been
   * called for the instruction list.
   *
   * @param cp constant pool
   */
  public CodeException getCodeException(ConstantPool cp) {
    return new CodeException(start_pc.getPosition(),
			     end_pc.getPosition() + end_pc.getInstruction().getLength(),
			     handler_pc.getPosition(),
			     (catch_type == null)? 0 : cp.addClass(catch_type));
  }

  /* Set start of handler 
   * @param start_pc Start of handled region (inclusive)
   */
  public void setStartPC(InstructionHandle start_pc) {
	  InstructionBranch.notifyTarget(this.start_pc, start_pc, this);
    this.start_pc = start_pc; 
  }

  /* Set end of handler 
   * @param end_pc End of handled region (inclusive)
   */
  public void setEndPC(InstructionHandle end_pc) {
	  InstructionBranch.notifyTarget(this.end_pc, end_pc, this);
    this.end_pc = end_pc;
  }

  /* Set handler code
   * @param handler_pc Start of handler
   */
  public void setHandlerPC(InstructionHandle handler_pc) {
	  InstructionBranch.notifyTarget(this.handler_pc, handler_pc, this);
    this.handler_pc = handler_pc;
  }

  
Params:
old_ih – old target, either start or end
new_ih – new target/**
   * @param old_ih old target, either start or end
   * @param new_ih new target
   */
  public void updateTarget(InstructionHandle old_ih, InstructionHandle new_ih) {
    boolean targeted = false;

    if(start_pc == old_ih) {
      targeted = true;
      setStartPC(new_ih);
    }

    if(end_pc == old_ih) {
      targeted = true;
      setEndPC(new_ih);
    }

    if(handler_pc == old_ih) {
      targeted = true;
      setHandlerPC(new_ih);
    }

    if(!targeted)
      throw new ClassGenException("Not targeting " + old_ih + ", but {" + start_pc + ", " +
				  end_pc + ", " + handler_pc + "}");
  }

  
Returns:
true, if ih is target of this handler/**
   * @return true, if ih is target of this handler
   */
  public boolean containsTarget(InstructionHandle ih) {
    return (start_pc == ih) || (end_pc == ih) || (handler_pc == ih);
  }

  
Sets the type of the Exception to catch. Set 'null' for ANY. /** Sets the type of the Exception to catch. Set 'null' for ANY. */
  public void              setCatchType(ObjectType catch_type)        { this.catch_type = catch_type; }
  
Gets the type of the Exception to catch, 'null' for ANY. /** Gets the type of the Exception to catch, 'null' for ANY. */
  public ObjectType        getCatchType()                             { return catch_type; }

  
Returns:
start of handled region (inclusive)/** @return start of handled region (inclusive)
   */
  public InstructionHandle getStartPC()                               { return start_pc; }

  
Returns:
end of handled region (inclusive)/** @return end of handled region (inclusive)
   */
  public InstructionHandle getEndPC()                                 { return end_pc; }

  
Returns:
start of handler/** @return start of handler
   */
  public InstructionHandle getHandlerPC()                             { return handler_pc; }

  public String toString() {
    return "CodeExceptionGen(" + start_pc + ", " + end_pc + ", " + handler_pc + ")";
  }

  public Object clone() {
    try {
      return super.clone();
    } catch(CloneNotSupportedException e) {
      System.err.println(e);
      return null;
    }
  }
}