1 files changed, 56 insertions, 0 deletions
diff --git a/src/com/vaadin/event/dd/acceptcriteria/ServerSideCriterion.java b/src/com/vaadin/event/dd/acceptcriteria/ServerSideCriterion.java
new file mode 100644
index 0000000000..69405db8ed
--- /dev/null
+++ b/src/com/vaadin/event/dd/acceptcriteria/ServerSideCriterion.java
@@ -0,0 +1,56 @@
+/*
+@ITMillApache2LicenseForJavaFiles@
+ */
+package com.vaadin.event.dd.acceptCriteria;
+
+import java.io.Serializable;
+
+import com.vaadin.event.Transferable;
+import com.vaadin.terminal.PaintException;
+import com.vaadin.terminal.PaintTarget;
+import com.vaadin.terminal.gwt.client.ui.dd.VServerAccept;
+
+/**
+ * Parent class for criteria which are verified on the server side during a drag
+ * operation to accept/discard dragged content (presented by
+ * {@link Transferable}).
+ * <p>
+ * Subclasses should implement the
+ * {@link AcceptCriterion#accept(com.vaadin.event.dd.DragAndDropEvent)} method.
+ * <p>
+ * As all server side state can be used to make a decision, this is more
+ * flexible than {@link ClientSideCriterion}. However, this does require
+ * additional requests from the browser to the server during a drag operation.
+ * 
+ * @see AcceptCriterion
+ * @see ClientSideCriterion
+ * 
+ * @since 6.3
+ */
+@ClientCriterion(VServerAccept.class)
+public abstract class ServerSideCriterion implements Serializable,
+        AcceptCriterion {
+
+    private static final long serialVersionUID = 2128510128911628902L;
+
+    public final boolean isClientSideVerifiable() {
+        return false;
+    }
+
+    public void paint(PaintTarget target) throws PaintException {
+        target.startTag("-ac");
+        target.addAttribute("name", getIdentifier());
+        paintContent(target);
+        target.endTag("-ac");
+    }
+
+    public void paintContent(PaintTarget target) {
+    }
+
+    public void paintResponse(PaintTarget target) throws PaintException {
+    }
+
+    protected String getIdentifier() {
+        return ServerSideCriterion.class.getCanonicalName();
+    }
+}