private Data transformIt()

in src/main/java/org/apache/jcp/xml/dsig/internal/dom/ApacheTransform.java [136:209]
70 lines of code
15 McCabe index (conditional complexity)

    private Data transformIt(Data data, XMLCryptoContext xc, OutputStream os)
        throws TransformException
    {
        if (ownerDoc == null) {
            throw new TransformException("transform must be marshalled");
        }

        if (transform == null) {
            try {
                transform =
                    new Transform(ownerDoc, getAlgorithm(), transformElem.getChildNodes());
                transform.setElement(transformElem, xc.getBaseURI());
                LOG.log(Level.DEBUG, "Created transform for algorithm: {0}", getAlgorithm());
            } catch (Exception ex) {
                throw new TransformException("Couldn't find Transform for: " +
                                             getAlgorithm(), ex);
            }
        }

        if (Utils.secureValidation(xc)) {
            String algorithm = getAlgorithm();
            if (Transforms.TRANSFORM_XSLT.equals(algorithm)) {
                throw new TransformException(
                    "Transform " + algorithm + " is forbidden when secure validation is enabled"
                );
            }
        }

        XMLSignatureInput in;
        if (data instanceof ApacheData) {
            LOG.log(Level.DEBUG, "ApacheData = true");
            in = ((ApacheData)data).getXMLSignatureInput();
        } else if (data instanceof NodeSetData) {
            LOG.log(Level.DEBUG, "isNodeSet() = true");
            if (data instanceof DOMSubTreeData) {
                LOG.log(Level.DEBUG, "DOMSubTreeData = true");
                DOMSubTreeData subTree = (DOMSubTreeData)data;
                in = new XMLSignatureNodeInput(subTree.getRoot());
                in.setExcludeComments(subTree.excludeComments());
            } else {
                @SuppressWarnings({"unchecked", "rawtypes"})
                Set<Node> nodeSet =
                    Utils.toNodeSet(((NodeSetData)data).iterator());
                in = new XMLSignatureNodeSetInput(nodeSet);
            }
        } else {
            LOG.log(Level.DEBUG, "isNodeSet() = false");
            try {
                in = new XMLSignatureStreamInput(((OctetStreamData) data).getOctetStream());
            } catch (Exception ex) {
                throw new TransformException(ex);
            }
        }
        boolean secVal = Utils.secureValidation(xc);
        in.setSecureValidation(secVal);

        try {
            if (os != null) {
                in = transform.performTransform(in, os, secVal);
                if (!in.isNodeSet() && !in.isElement()) {
                    return null;
                }
            } else {
                in = transform.performTransform(in, secVal);
            }
            if (in.hasUnprocessedInput()) {
                return new ApacheOctetStreamData(in);
            } else {
                return new ApacheNodeSetData(in);
            }
        } catch (Exception ex) {
            throw new TransformException(ex);
        }
    }