XmlDocumentBuilder.java

package at.ac.ait.archistar.engine.userinterface;

import java.io.StringWriter;
import java.io.Writer;
import java.security.MessageDigest;
import java.security.NoSuchAlgorithmException;
import java.util.Map;
import java.util.Map.Entry;
import java.util.Set;

import javax.xml.parsers.DocumentBuilder;
import javax.xml.parsers.DocumentBuilderFactory;
import javax.xml.parsers.ParserConfigurationException;

import org.jboss.resteasy.util.Hex;
import org.w3c.dom.DOMImplementation;
import org.w3c.dom.Document;
import org.w3c.dom.Element;
import org.w3c.dom.ls.DOMImplementationLS;
import org.w3c.dom.ls.LSOutput;
import org.w3c.dom.ls.LSSerializer;

import at.ac.ait.archistar.engine.dataobjects.SimpleFile;

public class XmlDocumentBuilder {

    private final DocumentBuilderFactory docFactory;
    private final DocumentBuilder docBuilder;

    public XmlDocumentBuilder() throws ParserConfigurationException {
        this.docFactory = DocumentBuilderFactory.newInstance();
        this.docBuilder = docFactory.newDocumentBuilder();
    }

    private Element createElement(Document doc, String name, String value) {
        Element xmlKey = doc.createElement(name);
        xmlKey.setTextContent(value);
        return xmlKey;
    }

    public Document listElements(String prefix, String bucketName, int maxKeys, Set<SimpleFile> results) {
        Document doc = this.docBuilder.newDocument();
        doc.setXmlVersion("1.0");

        Element rootElement = doc.createElement("ListBucketResult");
        rootElement.setAttribute("xmlns", "http://doc.s3.amazonaws.com/2006-03-01");
        doc.appendChild(rootElement);

        Element name = doc.createElement("Name");
        name.setTextContent(bucketName);

        rootElement.appendChild(name);
        rootElement.appendChild(doc.createElement("Prefix"));
        rootElement.appendChild(doc.createElement("Marker"));

        rootElement.appendChild(createElement(doc, "MaxKeys", "1000"));
        rootElement.appendChild(createElement(doc, "isTruncated", "false"));

        for (SimpleFile entry : results) {
            Element contents = doc.createElement("Contents");

            String eTag = "could not compute";

            try {
                MessageDigest md = MessageDigest.getInstance("MD5");
                byte[] thedigest = md.digest(entry.getData());
                eTag = Hex.encodeHex(thedigest);
            } catch (NoSuchAlgorithmException e) {
                assert(false);
            }

            contents.appendChild(createElement(doc, "Key", entry.getPath()));
            contents.appendChild(createElement(doc, "Size", "" + entry.getData().length));
            contents.appendChild(createElement(doc, "LastModified", "2006-02-03T16:41:58.000Z"));
            contents.appendChild(createElement(doc, "ETag", eTag));

            rootElement.appendChild(contents);
        }
        return doc;
    }

    public Document bucketNotFound(String bucket) {

        Document doc = this.docBuilder.newDocument();
        doc.setXmlVersion("1.0");

        Element rootElement = doc.createElement("Error");
        rootElement.setAttribute("xmlns", "http://doc.s3.amazonaws.com/2006-03-01");
        doc.appendChild(rootElement);

        rootElement.appendChild(createElement(doc, "Code", "NoSuchBucket"));
        rootElement.appendChild(createElement(doc, "Resource", bucket));
        rootElement.appendChild(createElement(doc, "Resource", bucket));

        return doc;
    }

    public Document listBuckets(Map<String, FakeBucket> bucketList) {
        Document doc = this.docBuilder.newDocument();
        doc.setXmlVersion("1.0");

        Element rootElement = doc.createElement("ListAllMyBucketsResult");
        rootElement.setAttribute("xmlns", "http://doc.s3.amazonaws.com/2006-03-01");
        doc.appendChild(rootElement);

        Element owner = doc.createElement("Owner");
        Element id = doc.createElement("ID");
        id.setTextContent("deadbeef");
        Element name = doc.createElement("DisplayName");
        name.setTextContent("Andreas Happe");

        owner.appendChild(id);
        owner.appendChild(name);
        rootElement.appendChild(owner);

        Element buckets = doc.createElement("Buckets");

        for (Entry<String, FakeBucket> e : bucketList.entrySet()) {

            Element bucket = doc.createElement("Bucket");

            bucket.appendChild(createElement(doc, "Name", e.getKey()));
            bucket.appendChild(createElement(doc, "CreationDate", "1982-07-07T16:41:58.000Z"));

            buckets.appendChild(bucket);
        }
        rootElement.appendChild(buckets);

        return doc;

    }

    public String stringFromDoc(Document doc) {
        DOMImplementation impl = doc.getImplementation();
        DOMImplementationLS implLS = (DOMImplementationLS) impl.getFeature("LS", "3.0");
        LSSerializer lsSerializer = implLS.createLSSerializer();
        lsSerializer.getDomConfig().setParameter("format-pretty-print", true);

        LSOutput lsOutput = implLS.createLSOutput();
        lsOutput.setEncoding("UTF-8");
        Writer stringWriter = new StringWriter();
        lsOutput.setCharacterStream(stringWriter);
        lsSerializer.write(doc, lsOutput);

        return stringWriter.toString();
    }

    Document noSuchKey(String id) {
        Document doc = this.docBuilder.newDocument();
        doc.setXmlVersion("1.0");

        Element rootElement = doc.createElement("Error");
        rootElement.setAttribute("xmlns", "http://doc.s3.amazonaws.com/2006-03-01");
        doc.appendChild(rootElement);

        rootElement.appendChild(createElement(doc, "Message", "The resource you requested does not exist"));
        rootElement.appendChild(createElement(doc, "Code", "NoSuchKey"));
        rootElement.appendChild(createElement(doc, "Resource", id));

        return doc;
    }
}