Tuesday, March 10, 2015

TargetLostException

com.sun.org.apache.bcel.internal.generic.TargetLostException

TargetLostException is described in the javadoc comments as:

Thrown by InstructionList.remove() when one or multiple disposed instruction are still being referenced by a InstructionTargeter object. I.e. the InstructionTargeter has to be notified that (one of) the InstructionHandle it is referencing is being removed from the InstructionList and thus not valid anymore. Making this an exception instead of a return value forces the user to handle these case explicitely in a try { ... } catch. The following code illustrates how this may be done:
   ...   try { il.delete(start_ih, end_ih);   } catch(TargetLostException e) {    InstructionHandle[] targets = e.getTargets();  for(int i=0; i < targets.length; i++) {   InstructionTargeter[] targeters = targets[i].getTargeters();      for(int j=0; j < targeters.length; j++)    targeters[j].updateTarget(targets[i], new_target);    }   } 

see: InstructionHandle see: InstructionList see: InstructionTargeter version: $Id: TargetLostException.java,v 1.1.1.1 2001/10/29 20:00:27 jvanzyl Exp $ author: M. Dahm

Where is this exception thrown?

Following, is a list of exception messages cross-referenced to the source code responsible for throwing them. Click on the method link to view the code and see how the exception is thrown.

How is this exception thrown?

The following sub-sections identify where this exception is thrown, and how (or why) the code is throwing the exception.

Any source code quoted in this section is subject to the Java Research License unless stated otherwise.

com.sun.org.apache.bcel.internal.generic.InstructionList.remove(InstructionHandle, InstructionHandle)

/**
   * Remove from instruction `prev' to instruction `next' both contained
   * in this list. Throws TargetLostException when one of the removed instruction handles
   * is still being targeted.
   * @param prev where to start deleting (predecessor, exclusive)
   * @param next where to end deleting (successor, exclusive)
   */
private void remove(InstructionHandle prev, InstructionHandle next) throws TargetLostException {
    InstructionHandle first, last;
    if ((prev == null) && (next == null)) {
        first = last = start;
        start = end = null;
    } else {
        if (prev == null) {
            first = start;
            start = next;
        } else {
            first = prev.next;
            prev.next = next;
        }
        if (next == null) {
            last = end;
            end = prev;
        } else {
            last = next.prev;
            next.prev = prev;
        }
    }
    first.prev = null;
    last.next = null;
    ArrayList target_vec = new ArrayList();
    for (InstructionHandle ih = first; ih != null; ih = ih.next) ih.getInstruction().dispose();
    StringBuffer buf = new StringBuffer('{ ');
    for (InstructionHandle ih = first; ih != null; ih = next) {
        next = ih.next;
        length--;
        if (ih.hasTargeters()) {
            target_vec.add(ih);
            buf.append(ih.toString(true) + ' ');
            ih.next = ih.prev = null;
        } else ih.dispose();
    }
    buf.append('}');
    if (!target_vec.isEmpty()) {
        InstructionHandle[] targeted = new InstructionHandle[target_vec.size()];
        target_vec.toArray(targeted);
        throw new TargetLostException(targeted, buf.toString());
    }
}

Source: "Java SE Downloads: Java SE 6 JDK Source Code", at: http://www.oracle.com/technetwork/java/javase/downloads/index.html

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