--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/artifacts/src/main/java/org/dive4elements/river/collections/CollectionDescriptionHelper.java	Thu Apr 25 15:23:37 2013 +0200
@@ -0,0 +1,203 @@
+package org.dive4elements.river.collections;
+
+import java.util.ArrayList;
+import java.util.Date;
+import java.util.List;
+
+import javax.xml.xpath.XPathConstants;
+
+import org.apache.log4j.Logger;
+import org.w3c.dom.Document;
+import org.w3c.dom.Element;
+import org.w3c.dom.Node;
+import org.w3c.dom.NodeList;
+
+import org.dive4elements.artifacts.ArtifactDatabase;
+import org.dive4elements.artifacts.ArtifactDatabaseException;
+import org.dive4elements.artifacts.ArtifactNamespaceContext;
+import org.dive4elements.artifacts.CallContext;
+import org.dive4elements.artifacts.common.utils.XMLUtils;
+import org.dive4elements.artifacts.common.utils.XMLUtils.ElementCreator;
+
+
+public class CollectionDescriptionHelper {
+
+    private static final Logger logger =
+        Logger.getLogger(CollectionDescriptionHelper.class);
+
+
+    public static final String XPATH_ARTIFACT_STATE_DATA =
+        "/art:result/art:ui/art:static/art:state/art:data";
+
+    /** Constant XPath that points to the outputmodes of an artifact. */
+    public static final String XPATH_ARTIFACT_OUTPUTMODES =
+        "/art:result/art:outputmodes";
+
+
+    protected ElementCreator ec;
+
+    protected CallContext      context;
+    protected ArtifactDatabase database;
+
+    protected String name;
+    protected String uuid;
+    protected Date   creation;
+    protected long   ttl;
+
+    protected List<String>        artifacts;
+    protected CollectionAttribute attribute;
+
+
+    /**
+     * @param name The name of the collection.
+     * @param uuid The uuid of the collection.
+     * @param creation The creation time of the collection.
+     * @param ttl The time to live of the collection.
+     */
+    public CollectionDescriptionHelper(
+        String      name,
+        String      uuid,
+        Date        creation,
+        long        ttl,
+        CallContext callContext
+    ) {
+        this.name      = name;
+        this.uuid      = uuid;
+        this.creation  = creation;
+        this.ttl       = ttl;
+        this.context   = callContext;
+        this.database  = callContext.getDatabase();
+        this.artifacts = new ArrayList<String>();
+    }
+
+
+    public void addArtifact(String uuid) {
+        if (uuid != null && uuid.length() > 0) {
+            artifacts.add(uuid);
+        }
+    }
+
+
+    public void setAttribute(CollectionAttribute attribute) {
+        if (attribute != null) {
+            this.attribute = attribute;
+        }
+    }
+
+
+    public Document toXML() {
+        Document doc = XMLUtils.newDocument();
+
+        ec = new ElementCreator(
+            doc,
+            ArtifactNamespaceContext.NAMESPACE_URI,
+            ArtifactNamespaceContext.NAMESPACE_PREFIX);
+
+        Element root = ec.create("artifact-collection");
+        doc.appendChild(root);
+
+        String creationTime = creation != null
+            ? Long.toString(creation.getTime())
+            : "";
+
+        ec.addAttr(root, "name", name, true);
+        ec.addAttr(root, "uuid", uuid, true);
+        ec.addAttr(root, "creation", creationTime, true);
+        ec.addAttr(root, "ttl", String.valueOf(ttl), true);
+
+        appendArtifacts(root);
+        appendAttribute(root);
+
+        return doc;
+    }
+
+
+    /**
+     * Appends parts of the DESCRIBE document of each Artifact to <i>root</i>.
+     *
+     * @param root The root node.
+     */
+    protected void appendArtifacts(Element root) {
+        Element artifactsEl = ec.create("artifacts");
+
+        for (String uuid: artifacts) {
+            try {
+                Element e = buildArtifactNode(uuid);
+
+                if (e != null) {
+                    artifactsEl.appendChild(e);
+                }
+            }
+            catch (ArtifactDatabaseException dbe) {
+                logger.warn(dbe, dbe);
+            }
+        }
+
+        root.appendChild(artifactsEl);
+    }
+
+
+    /**
+     * Create the Artifacts Node that contains outputmode and statedata.
+     *
+     * @param uuid uuid of the artifact.
+     */
+    protected Element buildArtifactNode(String uuid)
+    throws    ArtifactDatabaseException
+    {
+        logger.debug("Append artifact '" + uuid + "' to collection description");
+
+        // TODO
+        String hash = "MYHASH";
+
+        Element ci = ec.create("artifact");
+        ec.addAttr(ci, "uuid", uuid, true);
+        ec.addAttr(ci, "hash", hash, true);
+
+        // XXX I am not sure if it works well every time with an empty document
+        // in the describe operation of an artifact.
+        Document description = database.describe(uuid, null, context.getMeta());
+
+        // Add outputmode element(s).
+        Node outputModes = (Node) XMLUtils.xpath(
+            description,
+            XPATH_ARTIFACT_OUTPUTMODES,
+            XPathConstants.NODE,
+            ArtifactNamespaceContext.INSTANCE);
+
+        if (outputModes != null) {
+            Document doc = ci.getOwnerDocument();
+            ci.appendChild(doc.importNode(outputModes, true));
+        }
+
+        // Add state-data element(s).
+        Node dataNode = ci.appendChild(
+            ci.getOwnerDocument().createElement("art:data-items"));
+
+        NodeList dataNodes = (NodeList) XMLUtils.xpath(
+            description,
+            XPATH_ARTIFACT_STATE_DATA,
+            XPathConstants.NODESET,
+            ArtifactNamespaceContext.INSTANCE);
+
+        if (dataNodes != null) {
+            Document doc = ci.getOwnerDocument();
+            for (int i = 0, D = dataNodes.getLength(); i < D; i++) {
+                dataNode.appendChild(doc.importNode(dataNodes.item(i), true));
+            }
+        }
+
+        return ci;
+    }
+
+
+    protected void appendAttribute(Element root) {
+        if (attribute != null) {
+            Document owner = root.getOwnerDocument();
+            Document attr  = attribute.toXML();
+
+            root.appendChild(owner.importNode(attr.getFirstChild(), true));
+        }
+    }
+}
+// vim:set ts=4 sw=4 si et sta sts=4 fenc=utf8 :