Added the notion of a ContentContext to select the content store to write to.

Added AbstractRoutingContentStore as a start base implementation.
Added warnings to drive config away from disused setTransactionService towards setRetryingTransactionHelper.


git-svn-id: https://svn.alfresco.com/repos/alfresco-enterprise/alfresco/HEAD/root@5734 c4b6b30b-aa2e-2d43-bbcb-ca4b014f7261

source/java/org/alfresco/repo/content/EmptyContentReader.java

@@ -0,0 +1,76 @@
+/*
+ * Copyright (C) 2005-2007 Alfresco Software Limited.
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License
+ * as published by the Free Software Foundation; either version 2
+ * of the License, or (at your option) any later version.
+
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
+
+ * As a special exception to the terms and conditions of version 2.0 of 
+ * the GPL, you may redistribute this Program in connection with Free/Libre 
+ * and Open Source Software ("FLOSS") applications as described in Alfresco's 
+ * FLOSS exception.  You should have recieved a copy of the text describing 
+ * the FLOSS exception, and it is also available here: 
+ * http://www.alfresco.com/legal/licensing"
+ */
+package org.alfresco.repo.content;
+
+import java.nio.channels.ReadableByteChannel;
+
+import org.alfresco.service.cmr.repository.ContentIOException;
+import org.alfresco.service.cmr.repository.ContentReader;
+
+/**
+ * A blank reader for which <code>exists()</code> always returns false.
+ * 
+ * @author Derek Hulley
+ */
+public class EmptyContentReader extends AbstractContentReader
+{
+    /**
+     * @param contentUrl    the content URL
+     */
+    public EmptyContentReader(String contentUrl)
+    {
+        super(contentUrl);
+    }
+    
+    /**
+     * @return  Returns an instance of the this class
+     */
+    @Override
+    protected ContentReader createReader() throws ContentIOException
+    {
+        return new EmptyContentReader(this.getContentUrl());
+    }
+
+    @Override
+    protected ReadableByteChannel getDirectReadableChannel() throws ContentIOException
+    {
+        throw new UnsupportedOperationException("The content never exists");
+    }
+
+    public boolean exists()
+    {
+        return false;
+    }
+
+    public long getLastModified()
+    {
+        return 0L;
+    }
+
+    public long getSize()
+    {
+        return 0L;
+    }
+}