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 com.google.common.primitives.UnsignedInteger;
17 import java.lang.reflect.Array;
18 import java.util.Arrays;
19 import java.util.Collections;
20 import java.util.Comparator;
22 import javax.annotation.Nonnull;
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 static final OffsetMap EMPTY = new OffsetMap(Collections.emptySet());
35 private static final Logger LOG = LoggerFactory.getLogger(OffsetMap.class);
36 private static final String NEGATIVEOFFSET = "Invalid negative offset %s";
37 private static final String INVALIDOFFSET = "Invalid offset %s for %s router IDs";
38 private static final LoadingCache<Set<UnsignedInteger>, OffsetMap> OFFSETMAPS = CacheBuilder.newBuilder().weakValues().build(
39 new CacheLoader<Set<UnsignedInteger>, OffsetMap>() {
41 public OffsetMap load(@Nonnull final Set<UnsignedInteger> key) throws Exception {
42 return new OffsetMap(key);
45 private static final Comparator<UnsignedInteger> COMPARATOR = UnsignedInteger::compareTo;
46 private final UnsignedInteger[] routeKeys;
48 private OffsetMap(final Set<UnsignedInteger> routerIds) {
49 final UnsignedInteger[] array = routerIds.toArray(new UnsignedInteger[0]);
50 Arrays.sort(array, COMPARATOR);
51 this.routeKeys = array;
54 UnsignedInteger getRouterKey(final int offset) {
55 Preconditions.checkArgument(offset >= 0);
56 return this.routeKeys[offset];
59 public int offsetOf(final UnsignedInteger key) {
60 return Arrays.binarySearch(this.routeKeys, key, COMPARATOR);
64 return this.routeKeys.length;
67 public OffsetMap with(final UnsignedInteger key) {
68 // TODO: we could make this faster if we had an array-backed Set and requiring
69 // the caller to give us the result of offsetOf() -- as that indicates
70 // where to insert the new routerId while maintaining the sorted nature
72 final Builder<UnsignedInteger> builder = ImmutableSet.builder();
73 builder.add(this.routeKeys);
76 return OFFSETMAPS.getUnchecked(builder.build());
79 public OffsetMap without(final UnsignedInteger key) {
80 final Builder<UnsignedInteger> builder = ImmutableSet.builder();
81 final int index = indexOfRouterId(key);
83 LOG.trace("Router key not found", key);
85 builder.add(removeValue(this.routeKeys, index));
87 return OFFSETMAPS.getUnchecked(builder.build());
90 private int indexOfRouterId(final UnsignedInteger key) {
91 for (int i = 0; i < this.routeKeys.length; i++) {
92 if (key.equals(this.routeKeys[i])) {
99 public <T> T getValue(final T[] array, final int offset) {
100 Preconditions.checkArgument(offset >= 0, NEGATIVEOFFSET, offset);
101 Preconditions.checkArgument(offset < this.routeKeys.length, INVALIDOFFSET, offset, this.routeKeys.length);
102 return array[offset];
105 public <T> void setValue(final T[] array, final int offset, final T value) {
106 Preconditions.checkArgument(offset >= 0, NEGATIVEOFFSET, offset);
107 Preconditions.checkArgument(offset < this.routeKeys.length, INVALIDOFFSET, offset, this.routeKeys.length);
108 array[offset] = value;
111 <T> T[] expand(final OffsetMap oldOffsets, final T[] oldArray, final int offset) {
112 @SuppressWarnings("unchecked")
113 final T[] ret = (T[]) Array.newInstance(oldArray.getClass().getComponentType(), this.routeKeys.length);
114 final int oldSize = oldOffsets.routeKeys.length;
116 System.arraycopy(oldArray, 0, ret, 0, offset);
117 System.arraycopy(oldArray, offset, ret, offset + 1, oldSize - offset);
122 public <T> T[] removeValue(final T[] oldArray, final int offset) {
123 final int length = oldArray.length;
124 Preconditions.checkArgument(offset >= 0, NEGATIVEOFFSET, offset);
125 Preconditions.checkArgument(offset < this.routeKeys.length, INVALIDOFFSET, offset, length);
127 final T[] ret = (T[]) Array.newInstance(oldArray.getClass().getComponentType(), length - 1);
128 System.arraycopy(oldArray, 0, ret, 0, offset);
129 if (offset < length - 1) {
130 System.arraycopy(oldArray, offset + 1, ret, offset, length - offset - 1);
137 return this.size() == 0;