jdk/src/java.base/share/classes/sun/misc/CompoundEnumeration.java
changeset 25859 3317bb8137f4
parent 14342 8435a30053c1
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/jdk/src/java.base/share/classes/sun/misc/CompoundEnumeration.java	Sun Aug 17 15:54:13 2014 +0100
@@ -0,0 +1,63 @@
+/*
+ * Copyright (c) 1998, 2011, Oracle and/or its affiliates. All rights reserved.
+ * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
+ *
+ * This code is free software; you can redistribute it and/or modify it
+ * under the terms of the GNU General Public License version 2 only, as
+ * published by the Free Software Foundation.  Oracle designates this
+ * particular file as subject to the "Classpath" exception as provided
+ * by Oracle in the LICENSE file that accompanied this code.
+ *
+ * This code 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
+ * version 2 for more details (a copy is included in the LICENSE file that
+ * accompanied this code).
+ *
+ * You should have received a copy of the GNU General Public License version
+ * 2 along with this work; if not, write to the Free Software Foundation,
+ * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
+ *
+ * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
+ * or visit www.oracle.com if you need additional information or have any
+ * questions.
+ */
+
+package sun.misc;
+
+import java.util.Enumeration;
+import java.util.NoSuchElementException;
+
+/*
+ * A useful utility class that will enumerate over an array of
+ * enumerations.
+ */
+public class CompoundEnumeration<E> implements Enumeration<E> {
+    private Enumeration<E>[] enums;
+    private int index = 0;
+
+    public CompoundEnumeration(Enumeration<E>[] enums) {
+        this.enums = enums;
+    }
+
+    private boolean next() {
+        while (index < enums.length) {
+            if (enums[index] != null && enums[index].hasMoreElements()) {
+                return true;
+            }
+            index++;
+        }
+        return false;
+    }
+
+    public boolean hasMoreElements() {
+        return next();
+    }
+
+    public E nextElement() {
+        if (!next()) {
+            throw new NoSuchElementException();
+        }
+        return enums[index].nextElement();
+    }
+}