159 lines
3.0 KiB
Go
159 lines
3.0 KiB
Go
package annotation
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import (
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"fmt"
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"reflect"
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"strings"
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)
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const (
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AnnotationTag = "annotation"
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AnnotationChar = "@"
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AnnotationStartChar = "("
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AnnotationEndChar = ")"
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AnnotationSpliter = ";"
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AnnotationAttributeSpliter = ","
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AnnotationKeyValueSpliter = "="
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)
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var annotationRegistry map[string]reflect.Type
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func init() {
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annotationRegistry = make(map[string]reflect.Type, 0)
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}
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func registerAnnotation(name string, t reflect.Type) {
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annotationRegistry[name] = t
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}
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type Annotation interface {
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parseAttribute(attributes map[string]string) error
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}
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// @Inject(name? string)
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// @Resource(name? string)
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func ParseAnnotation(tag reflect.StructTag) (map[string]Annotation, error) {
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s := strings.Trim(tag.Get(AnnotationTag), " ")
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if "" == s {
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return nil, nil
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}
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annotations := strings.Split(s, AnnotationSpliter)
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if nil == annotations || 0 == len(annotations) {
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return nil, nil
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}
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rKVs := make(map[string]Annotation, 0)
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for _, a := range annotations {
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a = strings.Trim(a, " ")
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if "" == a {
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continue
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}
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aName, attributes, err := ParseAnnotationItem(a)
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if nil != err {
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return nil, err
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}
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if "" == aName {
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continue
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}
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annotation, err := NewAnnotation(aName, attributes)
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if nil != err {
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return nil, err
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}
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rKVs[aName] = annotation
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}
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return rKVs, nil
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}
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func NewAnnotation(name string, attributes map[string]string) (Annotation, error) {
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t, ok := annotationRegistry[name]
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if !ok {
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return nil, fmt.Errorf("There is no annotation[%s]", name)
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}
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v := reflect.New(t.Elem())
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i := v.Interface().(Annotation)
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if nil != attributes {
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i.parseAttribute(attributes)
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}
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return i, nil
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}
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func ParseAnnotationItem(a string) (name string, attributes map[string]string, err error) {
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s := strings.Trim(a, " ")
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if "" == s {
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return
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}
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i := strings.Index(s, AnnotationChar)
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if -1 == i {
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err = fmt.Errorf("Syntax error: annotation must be started %s", AnnotationChar)
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return
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}
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aStart := strings.Index(s, AnnotationStartChar)
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if -1 == aStart {
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// This is pure annotation ex)@Resource
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name = s
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return
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}
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name = s[:aStart]
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aEnd := strings.Index(s, AnnotationEndChar)
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if -1 == aEnd {
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// This is syntax error ex)@Resource(
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err = fmt.Errorf("Syntax error: annotation must be ended %s", AnnotationEndChar)
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return
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}
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if 1 >= aEnd-aStart {
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return
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}
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attr := s[aStart+1 : aEnd]
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attr = strings.Trim(attr, " ")
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if "" == attr {
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return
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}
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attrs, pErr := ParseAttribute(s[aStart+1 : aEnd])
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if nil != pErr {
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err = pErr
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return
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}
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attributes = attrs
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return
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}
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func ParseAttribute(s string) (map[string]string, error) {
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attr := strings.Trim(s, " ")
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if "" == attr {
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return nil, nil
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}
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kvs := strings.Split(attr, AnnotationAttributeSpliter)
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if nil == kvs || 0 == len(kvs) {
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return nil, nil
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}
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rKVs := make(map[string]string)
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for i := 0; i < len(kvs); i++ {
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s := strings.Trim(kvs[i], " ")
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if "" == s {
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continue
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}
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kv := strings.Split(s, AnnotationKeyValueSpliter)
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k := strings.Trim(kv[0], " ")
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v := strings.Trim(kv[1], " ")
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rKVs[k] = v
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}
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return rKVs, nil
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}
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