/*
* Copyright 2000-2004 The Apache Software Foundation
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*
*/
package org.apache.bcel.generic;
import org.apache.bcel.classfile.CodeException;
/**
* 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 1.4 2004/12/15 08:28:34 conor Exp $
* @author <A HREF="mailto:m.dahm@gmx.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.
*
* @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.<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(ConstantPoolGen 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) {
BranchInstruction.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) {
BranchInstruction.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) {
BranchInstruction.notifyTarget(this.handler_pc, handler_pc, this);
this.handler_pc = handler_pc;
}
/**
* @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 + "}");
}
/**
* @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. */
public void setCatchType(ObjectType catch_type) { this.catch_type = catch_type; }
/** Gets the type of the Exception to catch, 'null' for ANY. */
public ObjectType getCatchType() { return catch_type; }
/** @return start of handled region (inclusive)
*/
public InstructionHandle getStartPC() { return start_pc; }
/** @return end of handled region (inclusive)
*/
public InstructionHandle getEndPC() { return end_pc; }
/** @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;
}
}
}