| /* |
| * Copyright (C) 2019 The Dagger 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 dagger.example.atm; |
| |
| import java.util.List; |
| import java.util.Optional; |
| |
| /** A text-based command handler. */ |
| interface Command { |
| /** |
| * Processes and optionally acts upon the given {@code input}. |
| * |
| * @return a {@link Result} indicating how the input was handled |
| */ |
| Result handleInput(List<String> input); |
| |
| /** |
| * A command result, which has a {@link Status} and optionally a new {@link CommandRouter} that |
| * will handle subsequent commands. |
| */ |
| final class Result { |
| private final Status status; |
| private final Optional<CommandRouter> nestedCommandRouter; |
| |
| private Result(Status status, Optional<CommandRouter> nestedCommandRouter) { |
| this.status = status; |
| this.nestedCommandRouter = nestedCommandRouter; |
| } |
| |
| static Result invalid() { |
| return new Result(Status.INVALID, Optional.empty()); |
| } |
| |
| static Result handled() { |
| return new Result(Status.HANDLED, Optional.empty()); |
| } |
| |
| static Result inputCompleted() { |
| return new Result(Status.INPUT_COMPLETED, Optional.empty()); |
| } |
| |
| static Result enterNestedCommandSet(CommandRouter nestedCommandRouter) { |
| return new Result(Status.HANDLED, Optional.of(nestedCommandRouter)); |
| } |
| |
| Status status() { |
| return status; |
| } |
| |
| Optional<CommandRouter> nestedCommandRouter() { |
| return nestedCommandRouter; |
| } |
| } |
| |
| enum Status { |
| /** The command or its arguments were invalid. */ |
| INVALID, |
| |
| /** The command handled the input and no other commands should attempt to handle it. */ |
| HANDLED, |
| |
| // TODO(ronshapiro): maybe call this TERMINATED? If so, maybe this should be called |
| // ContinueStatus? |
| /** The command handled the input and no further inputs should be submitted. */ |
| INPUT_COMPLETED, |
| ; |
| } |
| } |