+/*
+ * Copyright (c) 2018 AT&T Intellectual Property. All rights reserved.
+ *
+ * This program and the accompanying materials are made available under the
+ * terms of the Eclipse Public License v1.0 which accompanies this distribution,
+ * and is available at http://www.eclipse.org/legal/epl-v10.html
+ */
+package org.opendaylight.protocol.bgp.rib.impl;
+
+import static java.util.Objects.requireNonNull;
+
+import java.util.AbstractList;
+import java.util.List;
+import org.opendaylight.protocol.bgp.parser.impl.message.update.CommunityUtil;
+import org.opendaylight.yang.gen.v1.urn.opendaylight.params.xml.ns.yang.bgp.message.rev180329.path.attributes.attributes.Communities;
+
+/**
+ * Utility class which prepends {@code LLGR_STALE} community in front of some other communities.
+ */
+class StaleCommunities extends AbstractList<Communities> {
+ private static final class RandomAccess extends StaleCommunities implements java.util.RandomAccess {
+ RandomAccess(final List<Communities> orig) {
+ super(orig);
+ }
+ }
+
+ static final Communities STALE_LLGR = (Communities) CommunityUtil.LLGR_STALE;
+
+ private final List<Communities> orig;
+
+ StaleCommunities(final List<Communities> orig) {
+ this.orig = requireNonNull(orig);
+ }
+
+ static StaleCommunities create(final List<Communities> orig) {
+ return orig instanceof java.util.RandomAccess ? new RandomAccess(orig) : new StaleCommunities(orig);
+ }
+
+ @Override
+ public final boolean contains(final Object obj) {
+ return STALE_LLGR.equals(obj) || orig.contains(obj);
+ }
+
+ @Override
+ public final Communities get(final int index) {
+ return index == 0 ? STALE_LLGR : orig.get(index - 1);
+ }
+
+ @Override
+ public final int size() {
+ return orig.size() + 1;
+ }
+}