package enum_example | |
import ( | |
"bytes" | |
"encoding/json" | |
) | |
// TaskState represents the state of task, moving through Created, Running then Finished or Errorred | |
type TaskState int | |
const ( | |
// Created represents the task has been created but not started yet | |
Created TaskState = iota | |
//Running represents the task has started | |
Running | |
// Finished represents the task is complete | |
Finished | |
// Errorred represents the task has encountered a problem and is no longer running | |
Errorred | |
) | |
func (s TaskState) String() string { | |
return toString[s] | |
} | |
var toString = map[TaskState]string{ | |
Created: "Created", | |
Running: "Running", | |
Finished: "Finished", | |
Errorred: "Errorred", | |
} | |
var toID = map[string]TaskState{ | |
"Created": Created, | |
"Running": Running, | |
"Finished": Finished, | |
"Errorred": Errorred, | |
} | |
// MarshalJSON marshals the enum as a quoted json string | |
func (s TaskState) MarshalJSON() ([]byte, error) { | |
buffer := bytes.NewBufferString(`"`) | |
buffer.WriteString(toString[s]) | |
buffer.WriteString(`"`) | |
return buffer.Bytes(), nil | |
} | |
// UnmarshalJSON unmashals a quoted json string to the enum value | |
func (s *TaskState) UnmarshalJSON(b []byte) error { | |
var j string | |
err := json.Unmarshal(b, &j) | |
if err != nil { | |
return err | |
} | |
// Note that if the string cannot be found then it will be set to the zero value, 'Created' in this case. | |
*s = toID[j] | |
return nil | |
} |
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Really helpful, thanks for sharing! |
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Cheers |
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For me, MarshalJSON only works when its receiver is a func (s TaskState) MarshalJSON() ([]byte, error) |
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Good spot, thanks I'd replaced the original gist with a cleaner example and introduced that bug |
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Very Cool, |
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Thanks, very helpful! |
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cool |
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Very useful, thanks. It is also nice to know that editors support regex replace which allows you to generate the contents of For example |
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So cooooool |
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Another option is:
The one disadvantage is that if you do a bunch a comparisons in Go, they will be string comparisons instead of int. This could effect performance, but for most cases is probably insignificant. |
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Thank you! |
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thanks |
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WOW. Thanks for this.