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github.com/patrickmn/go-cache

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v1.0.0
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Published: Mar 3, 2015 | License: MIT | Module: github.com/patrickmn/go-cache

Index

Constants

const (
	// For use with functions that take an expiration time.
	NoExpiration time.Duration = -1
	// For use with functions that take an expiration time. Equivalent to
	// passing in the same expiration duration as was given to New() or
	// NewFrom() when the cache was created (e.g. 5 minutes.)
	DefaultExpiration time.Duration = 0
)

type Cache

type Cache struct {
	// contains filtered or unexported fields
}

func New

func New(defaultExpiration, cleanupInterval time.Duration) *Cache

Return a new cache with a given default expiration duration and cleanup interval. If the expiration duration is less than one (or NoExpiration), the items in the cache never expire (by default), and must be deleted manually. If the cleanup interval is less than one, expired items are not deleted from the cache before calling c.DeleteExpired().

func NewFrom

func NewFrom(defaultExpiration, cleanupInterval time.Duration, items map[string]*Item) *Cache

Return a new cache with a given default expiration duration and cleanup interval. If the expiration duration is less than one (or NoExpiration), the items in the cache never expire (by default), and must be deleted manually. If the cleanup interval is less than one, expired items are not deleted from the cache before calling c.DeleteExpired().

NewFrom() also accepts an items map which will serve as the underlying map for the cache. This is useful for starting from a deserialized cache (serialized using e.g. gob.Encode() on c.Items()), or passing in e.g. make(map[string]*Item, 500) to improve startup performance when the cache is expected to reach a certain minimum size.

Only the cache's methods synchronize access to this map, so it is not recommended to keep any references to the map around after creating a cache. If need be, the map can be accessed at a later point using c.Items() (subject to the same caveat.)

Note regarding serialization: When using e.g. gob, make sure to gob.Register() the individual types stored in the cache before encoding a map retrieved with c.Items(), and to register those same types before decoding a blob containing an items map.

func (Cache) Add

func (c Cache) Add(k string, x interface{}, d time.Duration) error

Add an item to the cache only if an item doesn't already exist for the given key, or if the existing item has expired. Returns an error otherwise.

func (Cache) Decrement

func (c Cache) Decrement(k string, n int64) error

Decrement an item of type int, int8, int16, int32, int64, uintptr, uint, uint8, uint32, or uint64, float32 or float64 by n. Returns an error if the item's value is not an integer, if it was not found, or if it is not possible to decrement it by n. To retrieve the decremented value, use one of the specialized methods, e.g. DecrementInt64.

func (Cache) DecrementFloat

func (c Cache) DecrementFloat(k string, n float64) error

Decrement an item of type float32 or float64 by n. Returns an error if the item's value is not floating point, if it was not found, or if it is not possible to decrement it by n. Pass a negative number to decrement the value. To retrieve the decremented value, use one of the specialized methods, e.g. DecrementFloat64.

func (Cache) DecrementFloat32

func (c Cache) DecrementFloat32(k string, n float32) (float32, error)

Decrement an item of type float32 by n. Returns an error if the item's value is not an float32, or if it was not found. If there is no error, the decremented value is returned.

func (Cache) DecrementFloat64

func (c Cache) DecrementFloat64(k string, n float64) (float64, error)

Decrement an item of type float64 by n. Returns an error if the item's value is not an float64, or if it was not found. If there is no error, the decremented value is returned.

func (Cache) DecrementInt

func (c Cache) DecrementInt(k string, n int) (int, error)

Decrement an item of type int by n. Returns an error if the item's value is not an int, or if it was not found. If there is no error, the decremented value is returned.

func (Cache) DecrementInt16

func (c Cache) DecrementInt16(k string, n int16) (int16, error)

Decrement an item of type int16 by n. Returns an error if the item's value is not an int16, or if it was not found. If there is no error, the decremented value is returned.

func (Cache) DecrementInt32

func (c Cache) DecrementInt32(k string, n int32) (int32, error)

Decrement an item of type int32 by n. Returns an error if the item's value is not an int32, or if it was not found. If there is no error, the decremented value is returned.

func (Cache) DecrementInt64

func (c Cache) DecrementInt64(k string, n int64) (int64, error)

Decrement an item of type int64 by n. Returns an error if the item's value is not an int64, or if it was not found. If there is no error, the decremented value is returned.

func (Cache) DecrementInt8

func (c Cache) DecrementInt8(k string, n int8) (int8, error)

Decrement an item of type int8 by n. Returns an error if the item's value is not an int8, or if it was not found. If there is no error, the decremented value is returned.

func (Cache) DecrementUint

func (c Cache) DecrementUint(k string, n uint) (uint, error)

Decrement an item of type uint by n. Returns an error if the item's value is not an uint, or if it was not found. If there is no error, the decremented value is returned.

func (Cache) DecrementUint16

func (c Cache) DecrementUint16(k string, n uint16) (uint16, error)

Decrement an item of type uint16 by n. Returns an error if the item's value is not an uint16, or if it was not found. If there is no error, the decremented value is returned.

func (Cache) DecrementUint32

func (c Cache) DecrementUint32(k string, n uint32) (uint32, error)

Decrement an item of type uint32 by n. Returns an error if the item's value is not an uint32, or if it was not found. If there is no error, the decremented value is returned.

func (Cache) DecrementUint64

func (c Cache) DecrementUint64(k string, n uint64) (uint64, error)

Decrement an item of type uint64 by n. Returns an error if the item's value is not an uint64, or if it was not found. If there is no error, the decremented value is returned.

func (Cache) DecrementUint8

func (c Cache) DecrementUint8(k string, n uint8) (uint8, error)

Decrement an item of type uint8 by n. Returns an error if the item's value is not an uint8, or if it was not found. If there is no error, the decremented value is returned.

func (Cache) DecrementUintptr

func (c Cache) DecrementUintptr(k string, n uintptr) (uintptr, error)

Decrement an item of type uintptr by n. Returns an error if the item's value is not an uintptr, or if it was not found. If there is no error, the decremented value is returned.

func (Cache) Delete

func (c Cache) Delete(k string)

Delete an item from the cache. Does nothing if the key is not in the cache.

func (Cache) DeleteExpired

func (c Cache) DeleteExpired()

Delete all expired items from the cache.

func (Cache) Flush

func (c Cache) Flush()

Delete all items from the cache.

func (Cache) Get

func (c Cache) Get(k string) (interface{}, bool)

Get an item from the cache. Returns the item or nil, and a bool indicating whether the key was found.

func (Cache) Increment

func (c Cache) Increment(k string, n int64) error

Increment an item of type int, int8, int16, int32, int64, uintptr, uint, uint8, uint32, or uint64, float32 or float64 by n. Returns an error if the item's value is not an integer, if it was not found, or if it is not possible to increment it by n. To retrieve the incremented value, use one of the specialized methods, e.g. IncrementInt64.

func (Cache) IncrementFloat

func (c Cache) IncrementFloat(k string, n float64) error

Increment an item of type float32 or float64 by n. Returns an error if the item's value is not floating point, if it was not found, or if it is not possible to increment it by n. Pass a negative number to decrement the value. To retrieve the incremented value, use one of the specialized methods, e.g. IncrementFloat64.

func (Cache) IncrementFloat32

func (c Cache) IncrementFloat32(k string, n float32) (float32, error)

Increment an item of type float32 by n. Returns an error if the item's value is not an float32, or if it was not found. If there is no error, the incremented value is returned.

func (Cache) IncrementFloat64

func (c Cache) IncrementFloat64(k string, n float64) (float64, error)

Increment an item of type float64 by n. Returns an error if the item's value is not an float64, or if it was not found. If there is no error, the incremented value is returned.

func (Cache) IncrementInt

func (c Cache) IncrementInt(k string, n int) (int, error)

Increment an item of type int by n. Returns an error if the item's value is not an int, or if it was not found. If there is no error, the incremented value is returned.

func (Cache) IncrementInt16

func (c Cache) IncrementInt16(k string, n int16) (int16, error)

Increment an item of type int16 by n. Returns an error if the item's value is not an int16, or if it was not found. If there is no error, the incremented value is returned.

func (Cache) IncrementInt32

func (c Cache) IncrementInt32(k string, n int32) (int32, error)

Increment an item of type int32 by n. Returns an error if the item's value is not an int32, or if it was not found. If there is no error, the incremented value is returned.

func (Cache) IncrementInt64

func (c Cache) IncrementInt64(k string, n int64) (int64, error)

Increment an item of type int64 by n. Returns an error if the item's value is not an int64, or if it was not found. If there is no error, the incremented value is returned.

func (Cache) IncrementInt8

func (c Cache) IncrementInt8(k string, n int8) (int8, error)

Increment an item of type int8 by n. Returns an error if the item's value is not an int8, or if it was not found. If there is no error, the incremented value is returned.

func (Cache) IncrementUint

func (c Cache) IncrementUint(k string, n uint) (uint, error)

Increment an item of type uint by n. Returns an error if the item's value is not an uint, or if it was not found. If there is no error, the incremented value is returned.

func (Cache) IncrementUint16

func (c Cache) IncrementUint16(k string, n uint16) (uint16, error)

Increment an item of type uint16 by n. Returns an error if the item's value is not an uint16, or if it was not found. If there is no error, the incremented value is returned.

func (Cache) IncrementUint32

func (c Cache) IncrementUint32(k string, n uint32) (uint32, error)

Increment an item of type uint32 by n. Returns an error if the item's value is not an uint32, or if it was not found. If there is no error, the incremented value is returned.

func (Cache) IncrementUint64

func (c Cache) IncrementUint64(k string, n uint64) (uint64, error)

Increment an item of type uint64 by n. Returns an error if the item's value is not an uint64, or if it was not found. If there is no error, the incremented value is returned.

func (Cache) IncrementUint8

func (c Cache) IncrementUint8(k string, n uint8) (uint8, error)

Increment an item of type uint8 by n. Returns an error if the item's value is not an uint8, or if it was not found. If there is no error, the incremented value is returned.

func (Cache) IncrementUintptr

func (c Cache) IncrementUintptr(k string, n uintptr) (uintptr, error)

Increment an item of type uintptr by n. Returns an error if the item's value is not an uintptr, or if it was not found. If there is no error, the incremented value is returned.

func (Cache) ItemCount

func (c Cache) ItemCount() int

Returns the number of items in the cache. This may include items that have expired, but have not yet been cleaned up. Equivalent to len(c.Items()).

func (Cache) Items

func (c Cache) Items() map[string]*Item

Returns the items in the cache. This may include items that have expired, but have not yet been cleaned up. If this is significant, the Expiration fields of the items should be checked. Note that explicit synchronization is needed to use a cache and its corresponding Items() return value at the same time, as the map is shared.

func (Cache) Load

func (c Cache) Load(r io.Reader) error

Add (Gob-serialized) cache items from an io.Reader, excluding any items with keys that already exist (and haven't expired) in the current cache.

NOTE: This method is deprecated in favor of c.Items() and NewFrom() (see the documentation for NewFrom().)

func (Cache) LoadFile

func (c Cache) LoadFile(fname string) error

Load and add cache items from the given filename, excluding any items with keys that already exist in the current cache.

NOTE: This method is deprecated in favor of c.Items() and NewFrom() (see the documentation for NewFrom().)

func (Cache) Replace

func (c Cache) Replace(k string, x interface{}, d time.Duration) error

Set a new value for the cache key only if it already exists, and the existing item hasn't expired. Returns an error otherwise.

func (Cache) Save

func (c Cache) Save(w io.Writer) (err error)

Write the cache's items (using Gob) to an io.Writer.

NOTE: This method is deprecated in favor of c.Items() and NewFrom() (see the documentation for NewFrom().)

func (Cache) SaveFile

func (c Cache) SaveFile(fname string) error

Save the cache's items to the given filename, creating the file if it doesn't exist, and overwriting it if it does.

NOTE: This method is deprecated in favor of c.Items() and NewFrom() (see the documentation for NewFrom().)

func (Cache) Set

func (c Cache) Set(k string, x interface{}, d time.Duration)

Add an item to the cache, replacing any existing item. If the duration is 0 (DefaultExpiration), the cache's default expiration time is used. If it is -1 (NoExpiration), the item never expires.

type Item

type Item struct {
	Object     interface{}
	Expiration *time.Time
}

func (*Item) Expired

func (item *Item) Expired() bool

Returns true if the item has expired.

Package Files

Documentation was rendered with GOOS=linux and GOARCH=amd64.

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