decorator

Documentation

Index

• func DecorateRegistry(registry storage.Registry, decorator Decorator) storage.Registry
• type Decorator
• type Func
  • func (df Func) Decorate(v interface{}) interface{}

Functions

func DecorateRegistry

func DecorateRegistry(registry storage.Registry, decorator Decorator) storage.Registry

DecorateRegistry the provided registry with decorator. Registries may be decorated multiple times.

Types

type Decorator

type Decorator interface {
	Decorate(v interface{}) interface{}
}

Decorator provides an interface for intercepting object creation within a registry. The single method accepts an registry storage object, such as a Layer, optionally replacing it upon with an alternative object or a wrapper.

For example, if one wants to intercept the instantiation of a layer, an implementation might be as follows:

func (md *DecoratorImplementation) Decorate(v interface{}) interface{} {
	switch v := v.(type) {
	case Layer:
		return wrapLayer(v)
	}

	// Make sure to return the object or nil if the decorator doesn't require
	// replacement.
	return v
}

Such a decorator can be used to intercept calls to support implementing complex features outside of the storage package.

type Func

type Func func(v interface{}) interface{}

Func provides a shortcut handler for decorators that only need a function. Use is similar to http.HandlerFunc.

func (Func) Decorate

func (df Func) Decorate(v interface{}) interface{}

Decorate allows DecoratorFunc to implement the Decorator interface.