example_text_marshaling_test.go

Documentation: encoding/json

		 1  // Copyright 2018 The Go Authors. All rights reserved.
		 2  // Use of this source code is governed by a BSD-style
		 3  // license that can be found in the LICENSE file.
		 4  
		 5  package json_test
		 6  
		 7  import (
		 8  	"encoding/json"
		 9  	"fmt"
		10  	"log"
		11  	"strings"
		12  )
		13  
		14  type Size int
		15  
		16  const (
		17  	Unrecognized Size = iota
		18  	Small
		19  	Large
		20  )
		21  
		22  func (s *Size) UnmarshalText(text []byte) error {
		23  	switch strings.ToLower(string(text)) {
		24  	default:
		25  		*s = Unrecognized
		26  	case "small":
		27  		*s = Small
		28  	case "large":
		29  		*s = Large
		30  	}
		31  	return nil
		32  }
		33  
		34  func (s Size) MarshalText() ([]byte, error) {
		35  	var name string
		36  	switch s {
		37  	default:
		38  		name = "unrecognized"
		39  	case Small:
		40  		name = "small"
		41  	case Large:
		42  		name = "large"
		43  	}
		44  	return []byte(name), nil
		45  }
		46  
		47  func Example_textMarshalJSON() {
		48  	blob := `["small","regular","large","unrecognized","small","normal","small","large"]`
		49  	var inventory []Size
		50  	if err := json.Unmarshal([]byte(blob), &inventory); err != nil {
		51  		log.Fatal(err)
		52  	}
		53  
		54  	counts := make(map[Size]int)
		55  	for _, size := range inventory {
		56  		counts[size] += 1
		57  	}
		58  
		59  	fmt.Printf("Inventory Counts:\n* Small:				%d\n* Large:				%d\n* Unrecognized: %d\n",
		60  		counts[Small], counts[Large], counts[Unrecognized])
		61  
		62  	// Output:
		63  	// Inventory Counts:
		64  	// * Small:				3
		65  	// * Large:				2
		66  	// * Unrecognized: 3
		67  }
		68
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