2 * Copyright (c) 2018 AT&T Intellectual Property. All rights reserved.
4 * This program and the accompanying materials are made available under the
5 * terms of the Eclipse Public License v1.0 which accompanies this distribution,
6 * and is available at http://www.eclipse.org/legal/epl-v10.html
8 package org.opendaylight.protocol.bgp.openconfig.routing.policy.statement.actions;
10 import com.google.common.collect.ImmutableList;
11 import java.util.ArrayList;
12 import java.util.Iterator;
13 import java.util.List;
14 import org.opendaylight.protocol.util.Values;
15 import org.opendaylight.yang.gen.v1.urn.ietf.params.xml.ns.yang.ietf.inet.types.rev130715.AsNumber;
16 import org.opendaylight.yang.gen.v1.urn.opendaylight.params.xml.ns.yang.bgp.message.rev180329.path.attributes.Attributes;
17 import org.opendaylight.yang.gen.v1.urn.opendaylight.params.xml.ns.yang.bgp.message.rev180329.path.attributes.AttributesBuilder;
18 import org.opendaylight.yang.gen.v1.urn.opendaylight.params.xml.ns.yang.bgp.message.rev180329.path.attributes.attributes.AsPathBuilder;
19 import org.opendaylight.yang.gen.v1.urn.opendaylight.params.xml.ns.yang.bgp.message.rev180329.path.attributes.attributes.as.path.Segments;
20 import org.opendaylight.yang.gen.v1.urn.opendaylight.params.xml.ns.yang.bgp.message.rev180329.path.attributes.attributes.as.path.SegmentsBuilder;
22 abstract class AbstractPrependAsPath {
24 static final Attributes prependAS(final Attributes attributes, final AsNumber as) {
25 return new AttributesBuilder(attributes)
26 .setAsPath(new AsPathBuilder()
27 .setSegments(prependAS(attributes.getAsPath().getSegments(), as))
32 private static List<Segments> prependAS(final List<Segments> oldSegments, final AsNumber as) {
33 if (oldSegments == null || oldSegments.isEmpty()) {
34 return ImmutableList.of(singleSequence(as));
38 * We need to check the first segment.
39 * If it has as-set then new as-sequence with local AS is prepended.
40 * If it has as-sequence, we may add local AS when it has less than 255 elements.
41 * Otherwise we need to create new as-sequence for local AS.
43 final Iterator<Segments> it = oldSegments.iterator();
44 final Segments firstSegment = it.next();
45 final List<AsNumber> firstAsSequence = firstSegment.getAsSequence();
47 final List<Segments> newSegments;
48 if (firstAsSequence != null && firstAsSequence.size() < Values.UNSIGNED_BYTE_MAX_VALUE) {
49 final ArrayList<AsNumber> newAsSequence = new ArrayList<>(firstAsSequence.size() + 1);
50 newAsSequence.add(as);
51 newAsSequence.addAll(firstAsSequence);
53 newSegments = new ArrayList<>(oldSegments.size());
54 newSegments.add(new SegmentsBuilder().setAsSequence(newAsSequence).build());
56 newSegments = new ArrayList<>(oldSegments.size() + 1);
57 newSegments.add(singleSequence(as));
58 newSegments.add(firstSegment);
61 it.forEachRemaining(newSegments::add);
65 private static Segments singleSequence(final AsNumber as) {
66 return new SegmentsBuilder().setAsSequence(ImmutableList.of(as)).build();