2 * Copyright (c) 2015 Cisco Systems, Inc. and others. 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.mode.impl.base;
10 import com.google.common.base.Preconditions;
11 import com.google.common.cache.CacheBuilder;
12 import com.google.common.cache.CacheLoader;
13 import com.google.common.cache.LoadingCache;
14 import com.google.common.collect.ImmutableSet;
15 import com.google.common.collect.ImmutableSet.Builder;
16 import java.lang.reflect.Array;
17 import java.util.Arrays;
18 import java.util.Collections;
19 import java.util.Comparator;
21 import javax.annotation.Nonnull;
22 import org.opendaylight.protocol.bgp.rib.spi.RouterId;
23 import org.slf4j.Logger;
24 import org.slf4j.LoggerFactory;
27 * A map of Router identifier to an offset. Used to maintain a simple
28 * offset-based lookup across multiple RouteEntry objects,
29 * which share either contributors or consumers.
30 * We also provide utility reformat methods, which provide access to
31 * array members and array management features.
33 final class OffsetMap {
34 private static final Logger LOG = LoggerFactory.getLogger(OffsetMap.class);
35 private static final String NEGATIVEOFFSET = "Invalid negative offset %s";
36 private static final String INVALIDOFFSET = "Invalid offset %s for %s router IDs";
37 private static final LoadingCache<Set<RouterId>, OffsetMap> OFFSETMAPS = CacheBuilder.newBuilder()
38 .weakValues().build(new CacheLoader<Set<RouterId>, OffsetMap>() {
40 public OffsetMap load(@Nonnull final Set<RouterId> key) {
41 return new OffsetMap(key);
44 private static final Comparator<RouterId> COMPARATOR = RouterId::compareTo;
45 private static final RouterId[] EMPTY_KEYS = new RouterId[0];
46 static final OffsetMap EMPTY = new OffsetMap(Collections.emptySet());
48 private final RouterId[] routerKeys;
50 private OffsetMap(final Set<RouterId> routerIds) {
51 final RouterId[] array = routerIds.toArray(EMPTY_KEYS);
52 Arrays.sort(array, COMPARATOR);
53 this.routerKeys = array;
56 RouterId getRouterKey(final int offset) {
57 Preconditions.checkArgument(offset >= 0);
58 return this.routerKeys[offset];
61 public int offsetOf(final RouterId key) {
62 return Arrays.binarySearch(this.routerKeys, key, COMPARATOR);
66 return this.routerKeys.length;
69 public OffsetMap with(final RouterId key) {
70 // TODO: we could make this faster if we had an array-backed Set and requiring
71 // the caller to give us the result of offsetOf() -- as that indicates
72 // where to insert the new routerId while maintaining the sorted nature
74 final Builder<RouterId> builder = ImmutableSet.builder();
75 builder.add(this.routerKeys);
78 return OFFSETMAPS.getUnchecked(builder.build());
81 public OffsetMap without(final RouterId key) {
82 final Builder<RouterId> builder = ImmutableSet.builder();
83 final int index = indexOfRouterId(key);
85 LOG.trace("Router key {} not found", key);
87 builder.add(removeValue(this.routerKeys, index, EMPTY_KEYS));
89 return OFFSETMAPS.getUnchecked(builder.build());
92 private int indexOfRouterId(final RouterId key) {
93 for (int i = 0; i < this.routerKeys.length; i++) {
94 if (key.equals(this.routerKeys[i])) {
101 public <T> T getValue(final T[] array, final int offset) {
102 Preconditions.checkArgument(offset >= 0, NEGATIVEOFFSET, offset);
103 Preconditions.checkArgument(offset < this.routerKeys.length, INVALIDOFFSET, offset, this.routerKeys.length);
104 return array[offset];
107 public <T> void setValue(final T[] array, final int offset, final T value) {
108 Preconditions.checkArgument(offset >= 0, NEGATIVEOFFSET, offset);
109 Preconditions.checkArgument(offset < this.routerKeys.length, INVALIDOFFSET, offset, this.routerKeys.length);
110 array[offset] = value;
113 <T> T[] expand(final OffsetMap oldOffsets, final T[] oldArray, final int offset) {
114 @SuppressWarnings("unchecked")
115 final T[] ret = (T[]) Array.newInstance(oldArray.getClass().getComponentType(), this.routerKeys.length);
116 final int oldSize = oldOffsets.routerKeys.length;
118 System.arraycopy(oldArray, 0, ret, 0, offset);
119 System.arraycopy(oldArray, offset, ret, offset + 1, oldSize - offset);
124 public <T> T[] removeValue(final T[] oldArray, final int offset, final T[] emptyArray) {
125 final int length = oldArray.length;
126 Preconditions.checkArgument(offset >= 0, NEGATIVEOFFSET, offset);
127 Preconditions.checkArgument(offset < this.routerKeys.length, INVALIDOFFSET, offset, length);
129 final int newLength = length - 1;
130 if (newLength == 0) {
131 Preconditions.checkArgument(emptyArray.length == 0);
135 final T[] ret = (T[]) Array.newInstance(oldArray.getClass().getComponentType(), newLength);
136 System.arraycopy(oldArray, 0, ret, 0, offset);
137 if (offset < newLength) {
138 System.arraycopy(oldArray, offset + 1, ret, offset, newLength - offset);
145 return this.size() == 0;