| // Licensed to the Apache Software Foundation (ASF) under one |
| // or more contributor license agreements. See the NOTICE file |
| // distributed with this work for additional information |
| // regarding copyright ownership. The ASF licenses this file |
| // to you 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 statefun |
| |
| import ( |
| "errors" |
| "fmt" |
| ) |
| |
| // CancellationToken tags a delayed message send with statefun.SendAfterWithCancellationToken. |
| // It can then be used to cancel said message on a best effort basis with statefun.CancelDelayedMessage. |
| // The underlying string token can be retrieved by invoking Token(). |
| type CancellationToken interface { |
| fmt.Stringer |
| |
| // Token returns the underlying string |
| // used to create the CancellationToken. |
| Token() string |
| |
| // prevents external implementations |
| // of the interface. |
| internal() |
| } |
| |
| type token string |
| |
| func (t token) String() string { |
| return "CancellationToken(" + string(t) + ")" |
| } |
| |
| func (t token) Token() string { |
| return string(t) |
| } |
| |
| func (t token) internal() {} |
| |
| // NewCancellationToken creates a new cancellation token or |
| // returns an error if the token is invalid. |
| func NewCancellationToken(t string) (CancellationToken, error) { |
| if len(t) == 0 { |
| return nil, errors.New("cancellation token cannot be empty") |
| } |
| return token(t), nil |
| } |