public void merge()

in src/main/java/org/apache/bcel/verifier/structurals/OperandStack.java [132:166]
27 lines of code
15 McCabe index (conditional complexity)

    public void merge(final OperandStack s) {
        try {
            if (slotsUsed() != s.slotsUsed() || size() != s.size()) {
                throw new StructuralCodeConstraintException("Cannot merge stacks of different size:\nOperandStack A:\n" + this + "\nOperandStack B:\n" + s);
            }

            for (int i = 0; i < size(); i++) {
                // If the object _was_ initialized and we're supposed to merge
                // in some uninitialized object, we reject the code (see vmspec2, 4.9.4, last paragraph).
                if (!(stack.get(i) instanceof UninitializedObjectType) && s.stack.get(i) instanceof UninitializedObjectType) {
                    throw new StructuralCodeConstraintException("Backwards branch with an uninitialized object on the stack detected.");
                }
                // Even harder, we're not initialized but are supposed to broaden
                // the known object type
                if (!stack.get(i).equals(s.stack.get(i)) && stack.get(i) instanceof UninitializedObjectType
                    && !(s.stack.get(i) instanceof UninitializedObjectType)) {
                    throw new StructuralCodeConstraintException("Backwards branch with an uninitialized object on the stack detected.");
                }
                // on the other hand...
                if (stack.get(i) instanceof UninitializedObjectType && !(s.stack.get(i) instanceof UninitializedObjectType)) { // that has been initialized by
                                                                                                                               // now
                    stack.set(i, ((UninitializedObjectType) stack.get(i)).getInitialized()); // note that.
                }
                if (!stack.get(i).equals(s.stack.get(i))) {
                    if (!(stack.get(i) instanceof ReferenceType) || !(s.stack.get(i) instanceof ReferenceType)) {
                        throw new StructuralCodeConstraintException("Cannot merge stacks of different types:\nStack A:\n" + this + "\nStack B:\n" + s);
                    }
                    stack.set(i, ((ReferenceType) stack.get(i)).getFirstCommonSuperclass((ReferenceType) s.stack.get(i)));
                }
            }
        } catch (final ClassNotFoundException e) {
            // FIXME: maybe not the best way to handle this
            throw new AssertionViolatedException("Missing class: " + e, e);
        }
    }