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+/* EmptyEnumeration.java -- a constant empty enumeration
+ Copyright (C) 2001, 2002 Free Software Foundation, Inc.
+
+This file is part of GNU Classpath.
+
+GNU Classpath 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, or (at your option)
+any later version.
+
+GNU Classpath 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 GNU Classpath; see the file COPYING. If not, write to the
+Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA
+02110-1301 USA.
+
+Linking this library statically or dynamically with other modules is
+making a combined work based on this library. Thus, the terms and
+conditions of the GNU General Public License cover the whole
+combination.
+
+As a special exception, the copyright holders of this library give you
+permission to link this library with independent modules to produce an
+executable, regardless of the license terms of these independent
+modules, and to copy and distribute the resulting executable under
+terms of your choice, provided that you also meet, for each linked
+independent module, the terms and conditions of the license of that
+module. An independent module is a module which is not derived from
+or based on this library. If you modify this library, you may extend
+this exception to your version of the library, but you are not
+obligated to do so. If you do not wish to do so, delete this
+exception statement from your version. */
+
+package gnu.java.util;
+
+import java.io.Serializable;
+import java.util.Enumeration;
+import java.util.NoSuchElementException;
+
+/**
+ * This is a helper class that produces an empty Enumerations. There is only
+ * one instance of this class that can be used whenever one needs a
+ * non-null but empty enumeration. Using this class prevents multiple
+ * small objects and inner classes. <code>getInstance()</code> returns
+ * the only instance of this class. It can be shared by multiple objects and
+ * threads.
+ *
+ * @author Mark Wielaard (mark@klomp.org)
+ */
+public final class EmptyEnumeration<T> implements Enumeration<T>, Serializable
+{
+ /** The only instance of this class */
+ private static final EmptyEnumeration<Object> instance =
+ new EmptyEnumeration<Object>();
+
+ /**
+ * Returns an instance of this class for Object.
+ * It can be shared by multiple objects and threads.
+ *
+ * @return the common empty enumeration
+ */
+ public static EmptyEnumeration<Object> getInstance()
+ {
+ return instance;
+ }
+
+ /**
+ * Returns false, since there are no elements.
+ *
+ * @return false
+ */
+ public boolean hasMoreElements()
+ {
+ return false;
+ }
+
+ /**
+ * Always throws <code>NoSuchElementException</code>, since it is empty.
+ *
+ * @throws NoSuchElementException this is empty
+ */
+ public T nextElement()
+ {
+ throw new NoSuchElementException();
+ }
+}