forked from kazarena/json-gold
/
id_generator.go
43 lines (38 loc) · 1.29 KB
/
id_generator.go
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package ld
import (
"fmt"
)
// BlankNodeIDGenerator generates IDs for blank nodes
// as specified in http://www.w3.org/TR/json-ld-api/#generate-blank-node-identifier
type BlankNodeIDGenerator struct {
blankNodeIdentifierMap map[string]string
blankNodeCounter int
nodeMap map[string]interface{}
}
// NewBlankNodeIDGenerator creates and returns a new instance of BlankNodeIDGenerator
func NewBlankNodeIDGenerator() *BlankNodeIDGenerator {
return &BlankNodeIDGenerator{
blankNodeIdentifierMap: make(map[string]string),
blankNodeCounter: 0,
}
}
// GenerateBlankNodeIdentifier generates a blank node identifier for the given key
// using the algorithm specified in: http://www.w3.org/TR/json-ld-api/#generate-blank-node-identifier
//
// id: The id, or an empty string to generate a fresh, unused, blank node identifier.
//
// Returns a blank node identifier based on id if it was not an empty string,
// or a fresh, unused, blank node identifier if it was an empty string.
func (bnig *BlankNodeIDGenerator) GenerateBlankNodeIdentifier(id string) string {
if id != "" {
if val, hasID := bnig.blankNodeIdentifierMap[id]; hasID {
return val
}
}
bnid := fmt.Sprintf("_:b%v", bnig.blankNodeCounter)
bnig.blankNodeCounter++
if id != "" {
bnig.blankNodeIdentifierMap[id] = bnid
}
return bnid
}