Export errors

jsonapi/errors.go

@@ -0,0 +1,44 @@
+package jsonapi
+
+import "errors"
+
+//Error for all errors within this package
+type Error interface {
+	error
+}
+
+//MarshalError interface
+type MarshalError interface {
+	Error
+}
+
+//UnmarshalError interface
+type UnmarshalError interface {
+	Error
+}
+
+// Marshal errors
+var (
+	// ErrInvalidMarshalType is returned if marshal is called with an invalid type
+	ErrInvalidMarshalType MarshalError = errors.New("Marshal only accepts slice, struct or ptr types")
+	// ErrNonHomogenousSlice if any element within a slice does not implement marshal identifier
+	ErrNonHomogenousSlice MarshalError = errors.New("all elements within the slice must implement api2go.MarshalIdentifier")
+	//ErrNonNilElement marshaling a nil type is not possible
+	ErrNonNilElement MarshalError = errors.New("MarshalIdentifier must not be nil")
+)
+
+// Unmarshal errors
+var (
+	// ErrNilTarget if element will be unmarshalled into a nil element
+	ErrNilTarget UnmarshalError = errors.New("target must not be nil")
+	// ErrNonPointerTarget
+	ErrNonPointerTarget UnmarshalError = errors.New("target must be a ptr")
+)
+
+// Semantic errors
+var (
+	ErrInvalidUnmarshalType UnmarshalError = errors.New("target must implement UnmarshalIdentifier interface")
+	ErrEmptySource          UnmarshalError = errors.New(`Source JSON is empty and has no "attributes" payload object`)
+	ErrMissingType          UnmarshalError = errors.New("invalid record, no type was specified")
+	ErrInvalidStruct        UnmarshalError = errors.New("existing structs must implement interface MarshalIdentifier")
+)

jsonapi/marshal.go

@@ -2,7 +2,6 @@ package jsonapi
 
 import (
 	"encoding/json"
-	"errors"
 	"fmt"
 	"reflect"
 	"strings"
@@ -132,7 +131,7 @@ func MarshalToStruct(data interface{}, information ServerInformation) (*Document
 	case reflect.Struct, reflect.Ptr:
 		return marshalStruct(data.(MarshalIdentifier), information)
 	default:
-		return nil, errors.New("Marshal only accepts slice, struct or ptr types")
+		return nil, ErrInvalidMarshalType
 	}
 }
 
@@ -168,7 +167,7 @@ func marshalSlice(data interface{}, information ServerInformation) (*Document, e
 		k := val.Index(i).Interface()
 		element, ok := k.(MarshalIdentifier)
 		if !ok {
-			return nil, errors.New("all elements within the slice must implement api2go.MarshalIdentifier")
+			return nil, ErrNonHomogenousSlice
 		}
 
 		err := marshalData(element, &dataElements[i], information)
@@ -228,7 +227,7 @@ func filterDuplicates(input []MarshalIdentifier, information ServerInformation)
 func marshalData(element MarshalIdentifier, data *Data, information ServerInformation) error {
 	refValue := reflect.ValueOf(element)
 	if refValue.Kind() == reflect.Ptr && refValue.IsNil() {
-		return errors.New("MarshalIdentifier must not be nil")
+		return ErrNonNilElement
 	}
 
 	attributes, err := json.Marshal(element)

jsonapi/unmarshal.go

@@ -2,7 +2,6 @@ package jsonapi
 
 import (
 	"encoding/json"
-	"errors"
 	"fmt"
 	"reflect"
 )
@@ -80,11 +79,11 @@ type EditToManyRelations interface {
 // must implement the `UnmarshalIdentifier` interface.
 func Unmarshal(data []byte, target interface{}) error {
 	if target == nil {
-		return errors.New("target must not be nil")
+		return ErrNilTarget
 	}
 
 	if reflect.TypeOf(target).Kind() != reflect.Ptr {
-		return errors.New("target must be a ptr")
+		return ErrNonPointerTarget
 	}
 
 	ctx := &Document{}
@@ -95,7 +94,7 @@ func Unmarshal(data []byte, target interface{}) error {
 	}
 
 	if ctx.Data == nil {
-		return errors.New(`Source JSON is empty and has no "attributes" payload object`)
+		return ErrEmptySource
 	}
 
 	if ctx.Data.DataObject != nil {
@@ -118,8 +117,9 @@ func Unmarshal(data []byte, target interface{}) error {
 			for i := 0; i < targetValue.Len(); i++ {
 				marshalCasted, ok := targetValue.Index(i).Interface().(MarshalIdentifier)
 				if !ok {
-					return errors.New("existing structs must implement interface MarshalIdentifier")
+					return ErrInvalidStruct
 				}
+
 				if record.ID == marshalCasted.GetID() {
 					targetRecord = targetValue.Index(i).Addr()
 					break
@@ -150,11 +150,11 @@ func Unmarshal(data []byte, target interface{}) error {
 func setDataIntoTarget(data *Data, target interface{}) error {
 	castedTarget, ok := target.(UnmarshalIdentifier)
 	if !ok {
-		return errors.New("target must implement UnmarshalIdentifier interface")
+		return ErrInvalidUnmarshalType
 	}
 
 	if data.Type == "" {
-		return errors.New("invalid record, no type was specified")
+		return ErrMissingType
 	}
 
 	err := checkType(data.Type, castedTarget)