| /* |
| * Copyright 2020 The gRPC Authors |
| * |
| * Licensed under the Apache License, Version 2.0 (the "License"); |
| * you may not use this file except in compliance with the License. |
| * You may obtain a copy of the License at |
| * |
| * http://www.apache.org/licenses/LICENSE-2.0 |
| * |
| * Unless required by applicable law or agreed to in writing, software |
| * distributed under the License is distributed on an "AS IS" BASIS, |
| * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. |
| * See the License for the specific language governing permissions and |
| * limitations under the License. |
| */ |
| |
| package io.grpc.xds; |
| |
| import static com.google.common.base.Preconditions.checkNotNull; |
| |
| import io.grpc.Attributes; |
| import io.grpc.EquivalentAddressGroup; |
| import io.grpc.NameResolver.ResolutionResultAttr; |
| import java.util.ArrayList; |
| import java.util.Collections; |
| import java.util.List; |
| import javax.annotation.Nullable; |
| |
| final class AddressFilter { |
| @ResolutionResultAttr |
| private static final Attributes.Key<PathChain> PATH_CHAIN_KEY = |
| Attributes.Key.create("io.grpc.xds.AddressFilter.PATH_CHAIN_KEY"); |
| |
| // Prevent instantiation. |
| private AddressFilter() {} |
| |
| /** |
| * Returns a new EquivalentAddressGroup by setting a path filter to the given |
| * EquivalentAddressGroup. This method does not modify the input address. |
| */ |
| static EquivalentAddressGroup setPathFilter(EquivalentAddressGroup address, List<String> names) { |
| checkNotNull(address, "address"); |
| checkNotNull(names, "names"); |
| Attributes.Builder attrBuilder = address.getAttributes().toBuilder().discard(PATH_CHAIN_KEY); |
| PathChain pathChain = null; |
| for (String name : names) { |
| if (pathChain == null) { |
| pathChain = new PathChain(name); |
| attrBuilder.set(PATH_CHAIN_KEY, pathChain); |
| } else { |
| pathChain.next = new PathChain(name); |
| } |
| } |
| return new EquivalentAddressGroup(address.getAddresses(), attrBuilder.build()); |
| } |
| |
| /** |
| * Returns the next level hierarchical addresses derived from the given hierarchical addresses |
| * with the given filter name (any non-hierarchical addresses in the input will be ignored). |
| * This method does not modify the input addresses. |
| */ |
| static List<EquivalentAddressGroup> filter(List<EquivalentAddressGroup> addresses, String name) { |
| checkNotNull(addresses, "addresses"); |
| checkNotNull(name, "name"); |
| List<EquivalentAddressGroup> filteredAddresses = new ArrayList<>(); |
| for (EquivalentAddressGroup address : addresses) { |
| PathChain pathChain = address.getAttributes().get(PATH_CHAIN_KEY); |
| if (pathChain != null && pathChain.name.equals(name)) { |
| Attributes filteredAddressAttrs = |
| address.getAttributes().toBuilder().set(PATH_CHAIN_KEY, pathChain.next).build(); |
| filteredAddresses.add( |
| new EquivalentAddressGroup(address.getAddresses(), filteredAddressAttrs)); |
| } |
| } |
| return Collections.unmodifiableList(filteredAddresses); |
| } |
| |
| private static final class PathChain { |
| final String name; |
| @Nullable PathChain next; |
| |
| PathChain(String name) { |
| this.name = checkNotNull(name, "name"); |
| } |
| |
| @Override |
| public String toString() { |
| return name + (next == null ? "" : ", " + next); |
| } |
| } |
| } |