refactor: oop log parser

interfaces/log-parser/oop/pipeline.go

@@ -0,0 +1,68 @@
+// For more tutorials: https://blog.learngoprogramming.com
+//
+// Copyright © 2018 Inanc Gumus
+// Learn Go Programming Course
+// License: https://creativecommons.org/licenses/by-nc-sa/4.0/
+//
+
+package main
+
+import (
+	"os"
+	"strings"
+)
+
+type resultFn func(result)
+
+type iterator interface {
+	each(resultFn) error
+}
+
+type transformer interface {
+	transform(result)
+	iterator
+}
+
+type reporter interface {
+	report(iterator) error
+}
+
+type pipeline struct {
+	src  iterator
+	dst  reporter
+	tran transformer
+}
+
+func newPipeline(source iterator, r reporter, t transformer) *pipeline {
+	return &pipeline{
+		src:  source,
+		dst:  r,
+		tran: t,
+	}
+}
+
+// fromFile generates a default report
+func fromFile(path string) (err error) {
+	f, err := os.Open(path)
+	if err != nil {
+		return err
+	}
+
+	var src iterator
+	switch {
+	case strings.HasSuffix(path, ".txt"):
+		src = newTextLog(f)
+	case strings.HasSuffix(path, ".json"):
+		src = newJSONLog(f)
+	}
+
+	p := newPipeline(src, newTextReport(), newAnalysis())
+	return p.run()
+}
+
+func (p *pipeline) run() error {
+	if err := p.src.each(p.tran.transform); err != nil {
+		return err
+	}
+	return p.dst.report(p.tran)
+}