go.uber.org/cadence@v1.2.9/internal/common/cache/cache.go (about) 1 // Copyright (c) 2017 Uber Technologies, Inc. 2 // 3 // Permission is hereby granted, free of charge, to any person obtaining a copy 4 // of this software and associated documentation files (the "Software"), to deal 5 // in the Software without restriction, including without limitation the rights 6 // to use, copy, modify, merge, publish, distribute, sublicense, and/or sell 7 // copies of the Software, and to permit persons to whom the Software is 8 // furnished to do so, subject to the following conditions: 9 // 10 // The above copyright notice and this permission notice shall be included in 11 // all copies or substantial portions of the Software. 12 // 13 // THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR 14 // IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, 15 // FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE 16 // AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER 17 // LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, 18 // OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN 19 // THE SOFTWARE. 20 21 package cache 22 23 import ( 24 "time" 25 ) 26 27 // A Cache is a generalized interface to a cache. See cache.LRU for a specific 28 // implementation (bounded cache with LRU eviction) 29 type Cache interface { 30 // Exist checks if a given key exists in the cache 31 Exist(key string) bool 32 33 // Get retrieves an element based on a key, returning nil if the element 34 // does not exist 35 Get(key string) interface{} 36 37 // Put adds an element to the cache, returning the previous element 38 Put(key string, value interface{}) interface{} 39 40 // PutIfNotExist puts a value associated with a given key if it does not exist 41 PutIfNotExist(key string, value interface{}) (interface{}, error) 42 43 // Delete deletes an element in the cache 44 Delete(key string) 45 46 // Release decrements the ref count of a pinned element. If the ref count 47 // drops to 0, the element can be evicted from the cache. 48 Release(key string) 49 50 // Size returns the number of entries currently stored in the Cache 51 Size() int 52 } 53 54 // Options control the behavior of the cache 55 type Options struct { 56 // TTL controls the time-to-live for a given cache entry. Cache entries that 57 // are older than the TTL will not be returned 58 TTL time.Duration 59 60 // InitialCapacity controls the initial capacity of the cache 61 InitialCapacity int 62 63 // Pin prevents in-use objects from getting evicted 64 Pin bool 65 66 // RemovedFunc is an optional function called when an element 67 // is scheduled for deletion 68 RemovedFunc RemovedFunc 69 } 70 71 // RemovedFunc is a type for notifying applications when an item is 72 // scheduled for removal from the Cache. If f is a function with the 73 // appropriate signature and i is the interface{} scheduled for 74 // deletion, Cache calls go f(i) 75 type RemovedFunc func(interface{})