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：

    1. // Cache struct.
    2. type Cache struct {
    3.     Adapter // Adapter for cache features.
    4. }

    Adapter接口定义如下：
    https://godoc.org/github.com/gogf/gf/os/gcache#Adapter

    1. // Adapter is the adapter for cache features implements.
    2. type Adapter interface {
    3.     // Set sets cache with <key>-<value> pair, which is expired after <duration>.
    4.     //
    5.     // It does not expire if <duration> == 0.
    6.     // It deletes the <key> if <duration> < 0.
    7.     Set(ctx context.Context, key interface{}, value interface{}, duration time.Duration) error
    9.     // Sets batch sets cache with key-value pairs by <data>, which is expired after <duration>.
    10.     //
    11.     // It does not expire if <duration> == 0.
    12.     // It deletes the keys of <data> if <duration> < 0 or given <value> is nil.
    13.     Sets(ctx context.Context, data map[interface{}]interface{}, duration time.Duration) error
    15.     // SetIfNotExist sets cache with <key>-<value> pair which is expired after <duration>
    16.     // if <key> does not exist in the cache. It returns true the <key> dose not exist in the
    17.     // cache and it sets <value> successfully to the cache, or else it returns false.
    18.     //
    19.     // The parameter <value> can be type of <func() interface{}>, but it dose nothing if its
    20.     // result is nil.
    21.     //
    22.     // It does not expire if <duration> == 0.
    23.     // It deletes the <key> if <duration> < 0 or given <value> is nil.
    24.     SetIfNotExist(ctx context.Context, key interface{}, value interface{}, duration time.Duration) (bool, error)
    26.     // Get retrieves and returns the associated value of given <key>.
    27.     // It returns nil if it does not exist, its value is nil or it's expired.
    28.     Get(ctx context.Context, key interface{}) (interface{}, error)
    30.     // GetOrSet retrieves and returns the value of <key>, or sets <key>-<value> pair and
    31.     // returns <value> if <key> does not exist in the cache. The key-value pair expires
    32.     // after <duration>.
    33.     //
    34.     // It does not expire if <duration> == 0.
    35.     // It deletes the <key> if <duration> < 0 or given <value> is nil, but it does nothing
    36.     // if <value> is a function and the function result is nil.
    37.     GetOrSet(ctx context.Context, key interface{}, value interface{}, duration time.Duration) (interface{}, error)
    39.     // GetOrSetFunc retrieves and returns the value of <key>, or sets <key> with result of
    40.     // function <f> and returns its result if <key> does not exist in the cache. The key-value
    41.     // pair expires after <duration>.
    42.     //
    43.     // It does not expire if <duration> == 0.
    44.     // It deletes the <key> if <duration> < 0 or given <value> is nil, but it does nothing
    45.     // if <value> is a function and the function result is nil.
    46.     GetOrSetFunc(ctx context.Context, key interface{}, f func() (interface{}, error), duration time.Duration) (interface{}, error)
    48.     // GetOrSetFuncLock retrieves and returns the value of <key>, or sets <key> with result of
    49.     // function <f> and returns its result if <key> does not exist in the cache. The key-value
    50.     // pair expires after <duration>.
    51.     //
    52.     // It does not expire if <duration> == 0.
    53.     // It does nothing if function <f> returns nil.
    54.     //
    55.     // Note that the function <f> should be executed within writing mutex lock for concurrent
    56.     // safety purpose.
    57.     GetOrSetFuncLock(ctx context.Context, key interface{}, f func() (interface{}, error), duration time.Duration) (interface{}, error)
    59.     // Contains returns true if <key> exists in the cache, or else returns false.
    60.     Contains(ctx context.Context, key interface{}) (bool, error)
    62.     // GetExpire retrieves and returns the expiration of <key> in the cache.
    63.     //
    64.     // It returns 0 if the <key> does not expire.
    65.     // It returns -1 if the <key> does not exist in the cache.
    66.     GetExpire(ctx context.Context, key interface{}) (time.Duration, error)
    68.     // Remove deletes one or more keys from cache, and returns its value.
    69.     // If multiple keys are given, it returns the value of the last deleted item.
    70.     Remove(ctx context.Context, keys ...interface{}) (value interface{}, err error)
    72.     // Update updates the value of <key> without changing its expiration and returns the old value.
    73.     // The returned value <exist> is false if the <key> does not exist in the cache.
    74.     //
    75.     // It deletes the <key> if given <value> is nil.
    76.     // It does nothing if <key> does not exist in the cache.
    77.     Update(ctx context.Context, key interface{}, value interface{}) (oldValue interface{}, exist bool, err error)
    79.     // UpdateExpire updates the expiration of <key> and returns the old expiration duration value.
    80.     //
    81.     // It returns -1 and does nothing if the <key> does not exist in the cache.
    82.     // It deletes the <key> if <duration> < 0.
    83.     UpdateExpire(ctx context.Context, key interface{}, duration time.Duration) (oldDuration time.Duration, err error)
    85.     // Size returns the number of items in the cache.
    86.     Size(ctx context.Context) (size int, err error)
    88.     // Data returns a copy of all key-value pairs in the cache as map type.
    89.     // Note that this function may leads lots of memory usage, you can implement this function
    90.     // if necessary.
    91.     Data(ctx context.Context) (map[interface{}]interface{}, error)
    93.     // Keys returns all keys in the cache as slice.
    94.     Keys(ctx context.Context) ([]interface{}, error)
    96.     // Values returns all values in the cache as slice.
    97.     Values(ctx context.Context) ([]interface{}, error)
    99.     // Clear clears all data of the cache.
    100.     // Note that this function is sensitive and should be carefully used.
    101.     Clear(ctx context.Context) error
    103.     // Close closes the cache if necessary.
    104.     Close(ctx context.Context) error
    105. }

    适配器的注册方法：

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