Documentation
¶
Index ¶
- Constants
- func WithAbsoluteExpiration(value time.Duration) options.Opt
- func WithExpirationProvider(expirationProvider ExpirationProvider, expiryType ExpirationType) options.Opt
- func WithFinalizer(finalizer Finalizer) options.Opt
- func WithIdleExpiration(value time.Duration) options.Opt
- func WithRefreshInterval(initialInit, refreshPeriod time.Duration) options.Opt
- type ExpirationProvider
- type ExpirationType
- type Finalizer
- type Initializer
- type InitializerWithData
- type Reference
- func (r *Reference) Close()
- func (r *Reference) Get(data ...interface{}) (interface{}, error)
- func (r *Reference) IsClosed() bool
- func (r *Reference) MustGet() interface{}
- func (p *Reference) SetAbsoluteExpiration(expiration time.Duration)
- func (p *Reference) SetExpirationProvider(expirationProvider ExpirationProvider, expiryType ExpirationType)
- func (p *Reference) SetFinalizer(value Finalizer)
- func (p *Reference) SetIdleExpiration(expiration time.Duration)
- func (p *Reference) SetRefreshInterval(initialInit, refreshPeriod time.Duration)
Examples ¶
Constants ¶
const ( // InitOnFirstAccess specifies that the reference should be initialized the first time it is accessed InitOnFirstAccess time.Duration = time.Duration(-1) // InitImmediately specifies that the reference should be initialized immediately after it is created InitImmediately time.Duration = time.Duration(0) )
Variables ¶
This section is empty.
Functions ¶
func WithAbsoluteExpiration ¶
WithAbsoluteExpiration sets the expiration time for the reference. It will expire after this time period, regardless of whether or not it has been recently accessed.
func WithExpirationProvider ¶
func WithExpirationProvider(expirationProvider ExpirationProvider, expiryType ExpirationType) options.Opt
WithExpirationProvider sets the expiration provider, which determines the expiration time of the reference
func WithFinalizer ¶
WithFinalizer sets a finalizer function that is called when the reference is closed or if it expires
func WithIdleExpiration ¶
WithIdleExpiration sets the idle-time expiration for the reference. The reference is expired after not being accessed for the given duration.
func WithRefreshInterval ¶
WithRefreshInterval specifies that the reference should be proactively refreshed. Argument, initialInit, if greater than or equal to 0, indicates that the reference should be initialized after this duration. If less than 0, the reference will be initialized on first access. Argument, refreshPeriod, is the period at which the reference will be refreshed. Note that the Finalizer will not be invoked each time the value is refreshed.
Types ¶
type ExpirationProvider ¶
ExpirationProvider is a function that returns the expiration time of a reference
func NewGraduatingExpirationProvider ¶
func NewGraduatingExpirationProvider(initialExpiry, increments, maxExpiry time.Duration) ExpirationProvider
NewGraduatingExpirationProvider returns an expiration provider that has an initial expiration and then expires in graduated increments with a maximum expiration time.
func NewSimpleExpirationProvider ¶
func NewSimpleExpirationProvider(expiry time.Duration) ExpirationProvider
NewSimpleExpirationProvider returns an expiration provider that sets the given expiration period
type ExpirationType ¶
type ExpirationType uint
ExpirationType indicates how to handle expiration of the reference
const ( // LastAccessed specifies that the expiration time is calculated // from the last access time LastAccessed ExpirationType = iota // LastInitialized specifies that the expiration time is calculated // from the time the reference was initialized LastInitialized // Refreshing indicates that the reference should be periodically refreshed Refreshing )
type Finalizer ¶
type Finalizer func(value interface{})
Finalizer is a function that is called when the reference is closed
type Initializer ¶
type Initializer func() (interface{}, error)
Initializer is a function that initializes the value
type InitializerWithData ¶
type InitializerWithData func(data interface{}) (interface{}, error)
InitializerWithData is a function that initializes the value using the optional data.
type Reference ¶
type Reference struct {
// contains filtered or unexported fields
}
Reference holds a value that is initialized on first access using the provided Initializer function. The Reference has an optional expiring feature wherin the value is reset after the provided period of time. A subsequent call to Get or MustGet causes the Initializer function to be invoked again. The Reference also has a proactive refresh capability, in which the Initializer function is periodically called out of band (out of band means that the caller of Get or MustGet does not need to wait for the initializer function to complete: the old value will be used until the new value has finished initializing). An optional Finalizer function may be provided to be invoked whenever the Reference is closed (via a call to Close) or if it expires. (Note: The Finalizer function is not called every time the value is refreshed with the periodic refresh feature.)
Example ¶
ref := New(func() (interface{}, error) {
return "Value1", nil
})
fmt.Println(ref.MustGet())
Output: Value1
Example (Expiring) ¶
sequence := 0
ref := New(
func() (interface{}, error) {
sequence++
return fmt.Sprintf("Data_%d", sequence), nil
},
WithIdleExpiration(200*time.Millisecond),
)
for i := 0; i < 5; i++ {
fmt.Println(ref.MustGet())
time.Sleep(100 * time.Millisecond)
}
Output:
Example (Refreshing) ¶
This example demonstrates a refreshing reference. The reference is initialized immediately after creation and every 2 seconds thereafter.
sequence := 0
ref := New(
func() (interface{}, error) {
sequence++
return fmt.Sprintf("Data_%d", sequence), nil
},
WithRefreshInterval(InitImmediately, 200*time.Millisecond),
)
for i := 0; i < 5; i++ {
fmt.Println(ref.MustGet())
time.Sleep(300 * time.Millisecond)
}
Output:
func New ¶
func New(initializer Initializer, opts ...options.Opt) *Reference
New creates a new reference
func NewWithData ¶
func NewWithData(initializer InitializerWithData, opts ...options.Opt) *Reference
NewWithData creates a new reference where data is passed from the Get function to the initializer. This is useful for refreshing the reference with dynamic data.
func (*Reference) Close ¶
func (r *Reference) Close()
Close ensures that the finalizer (if provided) is called. Close should be called for expiring references and rerences that specify finalizers.
func (*Reference) MustGet ¶
func (r *Reference) MustGet() interface{}
MustGet returns the value. If an error is returned during initialization of the value then this function will panic.
func (*Reference) SetAbsoluteExpiration ¶
func (*Reference) SetExpirationProvider ¶
func (p *Reference) SetExpirationProvider(expirationProvider ExpirationProvider, expiryType ExpirationType)
func (*Reference) SetFinalizer ¶
func (p *Reference) SetFinalizer(value Finalizer)
Source Files