| /* |
| * Copyright 2015, gRPC Authors All rights reserved. |
| * |
| * 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.internal; |
| |
| import com.google.common.base.Preconditions; |
| import io.grpc.Attributes; |
| import io.grpc.NameResolverProvider; |
| import java.net.URI; |
| |
| /** |
| * A provider for {@link DnsNameResolver}. |
| * |
| * <p>It resolves a target URI whose scheme is {@code "dns"}. The (optional) authority of the target |
| * URI is reserved for the address of alternative DNS server (not implemented yet). The path of the |
| * target URI, excluding the leading slash {@code '/'}, is treated as the host name and the optional |
| * port to be resolved by DNS. Example target URIs: |
| * |
| * <ul> |
| * <li>{@code "dns:///foo.googleapis.com:8080"} (using default DNS)</li> |
| * <li>{@code "dns://8.8.8.8/foo.googleapis.com:8080"} (using alternative DNS (not implemented |
| * yet))</li> |
| * <li>{@code "dns:///foo.googleapis.com"} (without port)</li> |
| * </ul> |
| */ |
| public final class DnsNameResolverProvider extends NameResolverProvider { |
| |
| private static final String SCHEME = "dns"; |
| |
| @Override |
| public DnsNameResolver newNameResolver(URI targetUri, Attributes params) { |
| if (SCHEME.equals(targetUri.getScheme())) { |
| String targetPath = Preconditions.checkNotNull(targetUri.getPath(), "targetPath"); |
| Preconditions.checkArgument(targetPath.startsWith("/"), |
| "the path component (%s) of the target (%s) must start with '/'", targetPath, targetUri); |
| String name = targetPath.substring(1); |
| return new DnsNameResolver(targetUri.getAuthority(), name, params, GrpcUtil.TIMER_SERVICE, |
| GrpcUtil.SHARED_CHANNEL_EXECUTOR); |
| } else { |
| return null; |
| } |
| } |
| |
| @Override |
| public String getDefaultScheme() { |
| return SCHEME; |
| } |
| |
| @Override |
| protected boolean isAvailable() { |
| return true; |
| } |
| |
| @Override |
| protected int priority() { |
| return 5; |
| } |
| } |