缓存适配

v1.14.0新版本特性。

gcache模块采用了适配器设计模式，提供了Adapter适配器接口，任何实现了Adapter接口的对象均可注册到缓存管理对象中，使得开发者可以对缓存管理对象进行灵活的扩展。

gcache.Cache对象结构定义如下：

// Cache struct.
type Cache struct {
    Adapter // Adapter for cache features.
}

Adapter接口定义如下：

https://godoc.org/github.com/gogf/gf/os/gcache#Adapter

// Adapter is the adapter for cache features implements.
type Adapter interface {
    // Set sets cache with <key>-<value> pair, which is expired after <duration>.
    //
    // It does not expire if <duration> == 0.
    // It deletes the <key> if <duration> < 0.
    Set(key interface{}, value interface{}, duration time.Duration) error

    // Sets batch sets cache with key-value pairs by <data>, which is expired after <duration>.
    //
    // It does not expire if <duration> == 0.
    // It deletes the keys of <data> if <duration> < 0 or given <value> is nil.
    Sets(data map[interface{}]interface{}, duration time.Duration) error

    // SetIfNotExist sets cache with <key>-<value> pair which is expired after <duration>
    // if <key> does not exist in the cache. It returns true the <key> dose not exist in the
    // cache and it sets <value> successfully to the cache, or else it returns false.
    //
    // The parameter <value> can be type of <func() interface{}>, but it dose nothing if its
    // result is nil.
    //
    // It does not expire if <duration> == 0.
    // It deletes the <key> if <duration> < 0 or given <value> is nil.
    SetIfNotExist(key interface{}, value interface{}, duration time.Duration) (bool, error)

    // Get retrieves and returns the associated value of given <key>.
    // It returns nil if it does not exist or its value is nil.
    Get(key interface{}) (interface{}, error)

    // GetOrSet retrieves and returns the value of <key>, or sets <key>-<value> pair and
    // returns <value> if <key> does not exist in the cache. The key-value pair expires
    // after <duration>.
    //
    // It does not expire if <duration> == 0.
    // It deletes the <key> if <duration> < 0 or given <value> is nil, but it does nothing
    // if <value> is a function and the function result is nil.
    GetOrSet(key interface{}, value interface{}, duration time.Duration) (interface{}, error)

    // GetOrSetFunc retrieves and returns the value of <key>, or sets <key> with result of
    // function <f> and returns its result if <key> does not exist in the cache. The key-value
    // pair expires after <duration>.
    //
    // It does not expire if <duration> == 0.
    // It deletes the <key> if <duration> < 0 or given <value> is nil, but it does nothing
    // if <value> is a function and the function result is nil.
    GetOrSetFunc(key interface{}, f func() (interface{}, error), duration time.Duration) (interface{}, error)

    // GetOrSetFuncLock retrieves and returns the value of <key>, or sets <key> with result of
    // function <f> and returns its result if <key> does not exist in the cache. The key-value
    // pair expires after <duration>.
    //
    // It does not expire if <duration> == 0.
    // It does nothing if function <f> returns nil.
    //
    // Note that the function <f> should be executed within writing mutex lock for concurrent
    // safety purpose.
    GetOrSetFuncLock(key interface{}, f func() (interface{}, error), duration time.Duration) (interface{}, error)

    // Contains returns true if <key> exists in the cache, or else returns false.
    Contains(key interface{}) (bool, error)

    // GetExpire retrieves and returns the expiration of <key> in the cache.
    //
    // It returns 0 if the <key> does not expire.
    // It returns -1 if the <key> does not exist in the cache.
    GetExpire(key interface{}) (time.Duration, error)

    // Remove deletes one or more keys from cache, and returns its value.
    // If multiple keys are given, it returns the value of the last deleted item.
    Remove(keys ...interface{}) (value interface{}, err error)

    // Update updates the value of <key> without changing its expiration and returns the old value.
    // The returned value <exist> is false if the <key> does not exist in the cache.
    //
    // It deletes the <key> if given <value> is nil.
    // It does nothing if <key> does not exist in the cache.
    Update(key interface{}, value interface{}) (oldValue interface{}, exist bool, err error)

    // UpdateExpire updates the expiration of <key> and returns the old expiration duration value.
    //
    // It returns -1 and does nothing if the <key> does not exist in the cache.
    // It deletes the <key> if <duration> < 0.
    UpdateExpire(key interface{}, duration time.Duration) (oldDuration time.Duration, err error)

    // Size returns the number of items in the cache.
    Size() (size int, err error)

    // Data returns a copy of all key-value pairs in the cache as map type.
    // Note that this function may leads lots of memory usage, you can implement this function
    // if necessary.
    Data() (map[interface{}]interface{}, error)

    // Keys returns all keys in the cache as slice.
    Keys() ([]interface{}, error)

    // Values returns all values in the cache as slice.
    Values() ([]interface{}, error)

    // Clear clears all data of the cache.
    // Note that this function is sensitive and should be carefully used.
    Clear() error

    // Close closes the cache if necessary.
    Close() error
}

适配器的注册方法：

// SetAdapter changes the adapter for this cache.
// Be very note that, this setting function is not concurrent-safe, which means you should not call
// this setting function concurrently in multiple goroutines.
func (c *Cache) SetAdapter(adapter Adapter)

具体示例请参考【Redis缓存】章节。