filter

Documentation

Overview

Package filter provides structures that represent filters. This package is primarily used by driver implementors.

Index

• type Condition
• type Filter
  • func New(conds []Condition) *Filter
  • func Optimize(f *Filter) *Filter
  • func (f *Filter) Accept(v Visitor) (bool, error)
  • func (f *Filter) IsSatisfiedBy(doc *document.Document) bool
• type HasKeys
  • func (c *HasKeys) Accept(v Visitor) (bool, error)
  • func (c *HasKeys) IsSatisfiedBy(doc *document.Document) bool
• type HasUniqueKeyIn
  • func (c *HasUniqueKeyIn) Accept(v Visitor) (bool, error)
  • func (c *HasUniqueKeyIn) IsSatisfiedBy(doc *document.Document) bool
• type IsOneOf
  • func (c *IsOneOf) Accept(v Visitor) (bool, error)
  • func (c *IsOneOf) IsSatisfiedBy(doc *document.Document) bool
• type Set
  • func NewSet(members ...string) Set
  • func (s Set) Copy() Set
  • func (s Set) IntersectInPlace(x Set)
  • func (s Set) UnionInPlace(x Set)
• type Visitor

Types

type Condition

type Condition interface {
	IsSatisfiedBy(*document.Document) bool
	Accept(Visitor) (bool, error)
}

Condition is a predicate that checks if a document meets a certain criteria.

type Filter

type Filter struct {
	Conditions []Condition
}

Filter is a collection of zero or more conditions. A filter with no conditions does not match any documents.

func New

func New(conds []Condition) *Filter

New returns a new filter with the given conditions.

func Optimize

func Optimize(f *Filter) *Filter

Optimize performs basic optimization of the given filter.

func (*Filter) Accept

func (f *Filter) Accept(v Visitor) (bool, error)

Accept calls c.Accept(v) for each condition in f.

If f is nil, Accept() returns true. If f is non-nil, but contains no matchers it returns false. The behavior is useful for building custom matchers.

func (*Filter) IsSatisfiedBy

func (f *Filter) IsSatisfiedBy(doc *document.Document) bool

IsSatisfiedBy returns true if doc meets this all of the conditions in the filter.

type HasKeys

type HasKeys struct {
	Values Set
}

HasKeys is a condition that matches documents that have all of a given set of keys.

func (*HasKeys) Accept

func (c *HasKeys) Accept(v Visitor) (bool, error)

Accept calls v.HasKeys(c).

func (*HasKeys) IsSatisfiedBy

func (c *HasKeys) IsSatisfiedBy(doc *document.Document) bool

IsSatisfiedBy returns true if doc meets this condition.

type HasUniqueKeyIn

type HasUniqueKeyIn struct {
	Values Set
}

HasUniqueKeyIn is a condition that matches documents with unique keys in given set.

func (*HasUniqueKeyIn) Accept

func (c *HasUniqueKeyIn) Accept(v Visitor) (bool, error)

Accept calls v.HasUniqueKeyIn(c).

func (*HasUniqueKeyIn) IsSatisfiedBy

func (c *HasUniqueKeyIn) IsSatisfiedBy(doc *document.Document) bool

IsSatisfiedBy returns true if doc meets this condition.

type IsOneOf

type IsOneOf struct {
	Values Set
}

IsOneOf is a condition that matches documents with IDs in a specific set.

func (*IsOneOf) Accept

func (c *IsOneOf) Accept(v Visitor) (bool, error)

Accept calls v.IsOneOf(c).

func (*IsOneOf) IsSatisfiedBy

func (c *IsOneOf) IsSatisfiedBy(doc *document.Document) bool

IsSatisfiedBy returns true if doc meets this condition.

type Set

type Set map[string]struct{}

Set is a set of strings.

func NewSet

func NewSet(members ...string) Set

NewSet returns a string set from a slice of its members.

func (Set) Copy

func (s Set) Copy() Set

Copy returns a copy of s.

func (Set) IntersectInPlace

func (s Set) IntersectInPlace(x Set)

IntersectInPlace updates s to the intersection of x and itself.

func (Set) UnionInPlace

func (s Set) UnionInPlace(x Set)

UnionInPlace updates s to the union of x and itself.

type Visitor

type Visitor interface {
	IsOneOf(*IsOneOf) (bool, error)
	HasUniqueKeyIn(*HasUniqueKeyIn) (bool, error)
	HasKeys(*HasKeys) (bool, error)
}

Visitor an interface for performing operations with filter conditions.