--- a/ChangeLog	Wed Mar 30 15:19:08 2011 +0000
+++ b/ChangeLog	Thu Mar 31 08:42:53 2011 +0000
@@ -1,3 +1,9 @@
+2011-03-31  Ingo Weinzierl <ingo@intevation.de>
+
+	* artifact-database/src/main/java/de/intevation/artifactdatabase/ArtifactDatabaseImpl.java:
+	  Added an implementation of DeferredOutput for ArtifactCollections and
+	  implemented the out() operation of an ArtifactCollection.
+
 2011-03-30  Ingo Weinzierl <ingo@intevation.de>
 
 	* artifact-database/src/main/java/de/intevation/artifactdatabase/ProtocolUtils.java:

--- a/artifact-database/src/main/java/de/intevation/artifactdatabase/ArtifactDatabaseImpl.java	Wed Mar 30 15:19:08 2011 +0000
+++ b/artifact-database/src/main/java/de/intevation/artifactdatabase/ArtifactDatabaseImpl.java	Thu Mar 31 08:42:53 2011 +0000
@@ -284,6 +284,69 @@
         }
     } // class DeferredOutputImpl
 
+
+    /**
+     * This inner class allows the deferral of writing the output
+     * of the artifact's out() call.
+     */
+    public class DeferredCollectionOutputImpl
+    implements   DeferredOutput
+    {
+        /**
+         * The persistence wrapper around a living collection.
+         */
+        protected ArtifactCollection collection;
+        /**
+         * The input document for the collection's out() call.
+         */
+        protected Document format;
+        /**
+         * The meta information of the collection's out() call.
+         */
+        protected CallMeta callMeta;
+
+        /**
+         * Default constructor.
+         */
+        public DeferredCollectionOutputImpl() {
+        }
+
+        /**
+         * Constructor to create a deferred execution unit for
+         * the collection's out() call given a collection, an input document
+         * an the meta information.
+         * @param collection The collection.
+         * @param format   The input document for the collection's out() call.
+         * @param callMeta The meta information of the collection's out() call.
+         */
+        public DeferredCollectionOutputImpl(
+            ArtifactCollection collection,
+            Document           format,
+            CallMeta           callMeta
+        ) {
+            this.collection = collection;
+            this.format     = format;
+            this.callMeta   = callMeta;
+        }
+
+        public void write(OutputStream output) throws IOException {
+
+            CollectionCallContext cc = new CollectionCallContext(
+                ArtifactDatabaseImpl.this,
+                CallContext.TOUCH,
+                callMeta,
+                context,
+                collection);
+
+            try {
+                collection.out(format, output, cc);
+            }
+            finally {
+                cc.postCall();
+            }
+        }
+    } // class DeferredCollectionOutputImpl
+
     /**
      * List of name/description pairs needed for
      * {@link #artifactFactoryNamesAndDescriptions() }.
@@ -1354,8 +1417,35 @@
 
     public DeferredOutput outCollection(String collectionId,
         Document format, CallMeta callMeta)
-        throws ArtifactDatabaseException{
-        throw new ArtifactDatabaseException("Not implemented, yet!");
+        throws ArtifactDatabaseException
+    {
+        ArtifactCollectionFactory acf = getArtifactCollectionFactory();
+
+        if (acf == null) {
+            throw new ArtifactDatabaseException(NO_SUCH_FACTORY);
+        }
+
+        UserFactory uf = getUserFactory();
+        if (uf == null) {
+            throw new ArtifactDatabaseException(NO_SUCH_FACTORY);
+        }
+
+        ArtifactCollection c = backend.getCollection(
+            collectionId, acf, uf, context);
+
+        if (c == null) {
+            logger.warn("No collection found with identifier: " + collectionId);
+            throw new ArtifactDatabaseException(NO_SUCH_COLLECTION);
+        }
+
+        CallContext cc = new CollectionCallContext(
+            ArtifactDatabaseImpl.this,
+            CallContext.NOTHING,
+            callMeta,
+            context,
+            c);
+
+        return new DeferredCollectionOutputImpl(c, format, callMeta);
     }
 }
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