| /* |
| * 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 util |
| |
| import ( |
| "sort" |
| "sync" |
| ) |
| |
| // sorted set of strings. |
| // |
| // write-optimized and suitable only for fairly small values of N. |
| // Should this increase dramatically in size, a different implementation, |
| // such as a linked list, might be more appropriate. |
| type sortedSet struct { |
| members map[string]bool |
| sync.Mutex |
| } |
| |
| func NewSortedSet() *sortedSet { |
| return &sortedSet{ |
| members: make(map[string]bool), |
| } |
| } |
| |
| func (s *sortedSet) Add(value string) { |
| s.Lock() |
| s.members[value] = true |
| s.Unlock() |
| } |
| |
| func (s *sortedSet) Remove(value string) { |
| s.Lock() |
| delete(s.members, value) |
| s.Unlock() |
| } |
| |
| func (s *sortedSet) Items() []string { |
| s.Lock() |
| defer s.Unlock() |
| n := []string{} |
| for k := range s.members { |
| n = append(n, k) |
| } |
| sort.Strings(n) |
| return n |
| } |