--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/tango/tango/util/collection/model/BagView.d	Fri Jan 11 17:57:40 2008 +0100
@@ -0,0 +1,66 @@
+/*
+ File: BagView.d
+
+ Originally written by Doug Lea and released into the public domain. 
+ Thanks for the assistance and support of Sun Microsystems Labs, Agorics 
+ Inc, Loral, and everyone contributing, testing, and using this code.
+
+ History:
+ Date     Who                What
+ 24Sep95  dl@cs.oswego.edu   Create from collections.d  working file
+
+*/
+
+
+module tango.util.collection.model.BagView;
+
+private import tango.util.collection.model.View;
+
+
+/**
+ *
+ * Bags are collections supporting multiple occurrences of elements.
+ * 
+        author: Doug Lea
+ * @version 0.93
+ *
+ * <P> For an introduction to this package see <A HREF="index.html"> Overview </A>.
+ *
+**/
+
+public interface BagView(V) : View!(V)
+{
+version (VERBOSE)
+{
+        public alias adding opCat;
+
+        /**
+         * Construct a new Bag that is a clone of self except
+         * that it includes indicated element. This can be used
+         * to create a series of Bag, each differing from the
+         * other only in that they contain additional elements.
+         *
+         * @param the element to add to the new Bag
+         * Returns: the new Bag c, with the matches as this except that
+         * c.occurrencesOf(element) == occurrencesOf(element)+1 
+         * Throws: IllegalElementException if !canInclude(element)
+        **/
+
+        public Bag adding(V element);
+
+        /**
+         * Construct a new Collection that is a clone of self except
+         * that it adds the indicated element if not already present. This can be used
+         * to create a series of collections, each differing from the
+         * other only in that they contain additional elements.
+         *
+         * @param element the element to include in the new collection
+         * Returns: a new collection c, with the matches as this, except that
+         * c.occurrencesOf(element) = min(1, occurrencesOfElement)
+         * Throws: IllegalElementException if !canInclude(element)
+        **/
+
+        public Bag addingIfAbsent(V element);
+} // version
+
+}