tasks a-s

Task/Object-serialization/Go/object-serialization.go

@@ -0,0 +1,154 @@
+package main
+
+import (
+    "encoding/gob"
+    "fmt"
+    "os"
+)
+
+type printable interface {
+    print()
+}
+
+func main() {
+    // create instances
+    animals := []printable{
+        &Animal{Alive: true},
+        &Cat{},
+        &Lab{
+            Dog:   Dog{Animal: Animal{Alive: true}},
+            Color: "yellow",
+        },
+        &Collie{Dog: Dog{
+            Animal:           Animal{Alive: true},
+            ObedienceTrained: true,
+        }},
+    }
+
+    // display
+    fmt.Println("created:")
+    for _, a := range animals {
+        a.print()
+    }
+
+    // serialize
+    f, err := os.Create("objects.dat")
+    if err != nil {
+        fmt.Println(err)
+        return
+    }
+    for _, a := range animals {
+        gob.Register(a)
+    }
+    err = gob.NewEncoder(f).Encode(animals)
+    if err != nil {
+        fmt.Println(err)
+        return
+    }
+    f.Close()
+
+    // read
+    f, err = os.Open("objects.dat")
+    if err != nil {
+        fmt.Println(err)
+        return
+    }
+    var clones []printable
+    gob.NewDecoder(f).Decode(&clones)
+    if err != nil {
+        fmt.Println(err)
+        return
+    }
+
+    // display
+    fmt.Println("\nloaded from objects.dat:")
+    for _, c := range clones {
+        c.print()
+    }
+}
+
+type Animal struct {
+    Alive bool
+}
+
+func (a *Animal) print() {
+    if a.Alive {
+        fmt.Println("   live animal, unspecified type")
+    } else {
+        fmt.Println("   dead animal, unspecified type")
+    }
+}
+
+type Dog struct {
+    Animal
+    ObedienceTrained bool
+}
+
+func (d *Dog) print() {
+    switch {
+    case !d.Alive:
+        fmt.Println("   dead dog")
+    case d.ObedienceTrained:
+        fmt.Println("   trained dog")
+    default:
+        fmt.Println("   dog, not trained")
+    }
+}
+
+type Cat struct {
+    Animal
+    LitterBoxTrained bool
+}
+
+func (c *Cat) print() {
+    switch {
+    case !c.Alive:
+        fmt.Println("   dead cat")
+    case c.LitterBoxTrained:
+        fmt.Println("   litter box trained cat")
+    default:
+        fmt.Println("   cat, not litter box trained")
+    }
+}
+
+type Lab struct {
+    Dog
+    Color string
+}
+
+func (l *Lab) print() {
+    var r string
+    if l.Color == "" {
+        r = "lab, color unspecified"
+    } else {
+        r = l.Color + " lab"
+    }
+    switch {
+    case !l.Alive:
+        fmt.Println("   dead", r)
+    case l.ObedienceTrained:
+        fmt.Println("   trained", r)
+    default:
+        fmt.Printf("   %s, not trained\n", r)
+    }
+}
+
+type Collie struct {
+    Dog
+    CatchesFrisbee bool
+}
+
+func (c *Collie) print() {
+    switch {
+    case !c.Alive:
+        fmt.Println("   dead collie")
+    case c.ObedienceTrained && c.CatchesFrisbee:
+        fmt.Println("   trained collie, catches frisbee")
+    case c.ObedienceTrained && !c.CatchesFrisbee:
+        fmt.Println("   trained collie, but doesn't catch frisbee")
+    case !c.ObedienceTrained && c.CatchesFrisbee:
+        fmt.Println("   collie, not trained, but catches frisbee")
+    case !c.ObedienceTrained && !c.CatchesFrisbee:
+        fmt.Println("   collie, not trained, doesn't catch frisbee")
+    }
+}