diff --git a/interfaces/log-parser/oop/analysis.go b/interfaces/log-parser/oop/analysis.go
index 84cc24b..ac0ba1d 100644
--- a/interfaces/log-parser/oop/analysis.go
+++ b/interfaces/log-parser/oop/analysis.go
@@ -10,8 +10,8 @@ package main
 import "sort"
 
 type analysis struct {
-	sum      map[string]result // metrics per domain
-	keys     []string          // unique keys
+	sum      map[string]result // metrics per group key
+	keys     []string          // unique group keys
 	groupKey groupFunc
 	filter   filterFunc
 }
@@ -24,6 +24,31 @@ func newAnalysis() *analysis {
 	}
 }
 
+// transform the result
+func (a *analysis) transform(r result) {
+	if !a.filter(r) {
+		return
+	}
+
+	key := a.groupKey(r)
+	if _, ok := a.sum[key]; !ok {
+		a.keys = append(a.keys, key)
+	}
+
+	a.sum[key] = r.add(a.sum[key])
+}
+
+// each yields an analysis result
+func (a *analysis) each(yield resultFn) error {
+	sort.Strings(a.keys)
+
+	for _, key := range a.keys {
+		yield(a.sum[key])
+	}
+
+	return nil
+}
+
 func (a *analysis) groupBy(g groupFunc) {
 	if g != nil {
 		a.groupKey = g
@@ -35,26 +60,3 @@ func (a *analysis) filterBy(f filterFunc) {
 		a.filter = f
 	}
 }
-
-// analyse the given result
-func (a *analysis) analyse(r result) {
-	if !a.filter(r) {
-		return
-	}
-
-	key := a.groupKey(r)
-	if _, ok := a.sum[key]; !ok {
-		a.keys = append(a.keys, key)
-	}
-
-	a.sum[key] = r.add(a.sum[key])
-}
-
-// each sends an analysis result to `handle`
-func (a *analysis) each(handle resultFn) {
-	sort.Strings(a.keys)
-
-	for _, domain := range a.keys {
-		handle(a.sum[domain])
-	}
-}
diff --git a/interfaces/log-parser/oop/chartsummary.go b/interfaces/log-parser/oop/chartreport.go
similarity index 88%
rename from interfaces/log-parser/oop/chartsummary.go
rename to interfaces/log-parser/oop/chartreport.go
index 2e6a6de..a878215 100644
--- a/interfaces/log-parser/oop/chartsummary.go
+++ b/interfaces/log-parser/oop/chartreport.go
@@ -10,12 +10,12 @@ import (
 // You need to run:
 // go get -u github.com/wcharczuk/go-chart
 
-type chartSummary struct {
+type chartReport struct {
 	title         string
 	width, height int
 }
 
-func (s *chartSummary) summarize(results iterator) error {
+func (s *chartReport) report(results iterator) error {
 	w := os.Stdout
 
 	donut := c.DonutChart{
diff --git a/interfaces/log-parser/oop/jsonparser.go b/interfaces/log-parser/oop/jsonlog.go
similarity index 62%
rename from interfaces/log-parser/oop/jsonparser.go
rename to interfaces/log-parser/oop/jsonlog.go
index 97dc04f..1789e44 100644
--- a/interfaces/log-parser/oop/jsonparser.go
+++ b/interfaces/log-parser/oop/jsonlog.go
@@ -1,4 +1,4 @@
-// For more tutorials: https://bp.learngoprogramming.com
+// For more tutorials: https://bj.learngoprogramming.com
 //
 // Copyright © 2018 Inanc Gumus
 // Learn Go Programming Course
@@ -14,26 +14,26 @@ import (
 	"io/ioutil"
 )
 
-type jsonParser struct {
-	r io.Reader
+type jsonLog struct {
+	reader io.Reader
 }
 
-func newJSONParser(r io.Reader) *jsonParser {
-	return &jsonParser{r: r}
+func newJSONLog(r io.Reader) *jsonLog {
+	return &jsonLog{reader: r}
 }
 
-func (p *jsonParser) parse(handle resultFn) error {
-	defer readClose(p.r)
+func (j *jsonLog) each(yield resultFn) error {
+	defer readClose(j.reader)
 
-	bytes, err := ioutil.ReadAll(p.r)
+	bytes, err := ioutil.ReadAll(j.reader)
 	if err != nil {
 		return err
 	}
 
-	return parseJSON(bytes, handle)
+	return extractJSON(bytes, yield)
 }
 
-func parseJSON(bytes []byte, handle resultFn) error {
+func extractJSON(bytes []byte, yield resultFn) error {
 	var rs []struct {
 		Domain  string
 		Page    string
@@ -49,7 +49,7 @@ func parseJSON(bytes []byte, handle resultFn) error {
 	}
 
 	for _, r := range rs {
-		handle(result{
+		yield(result{
 			domain:  r.Domain,
 			page:    r.Page,
 			visits:  r.Visits,
diff --git a/interfaces/log-parser/oop/main.go b/interfaces/log-parser/oop/main.go
index c8a9b16..ffe93fc 100644
--- a/interfaces/log-parser/oop/main.go
+++ b/interfaces/log-parser/oop/main.go
@@ -14,20 +14,23 @@ import (
 )
 
 func main() {
-	a := newAnalysis()
-	// a.filterBy(notUsing(domainExtFilter("io", "com")))
-	// a.groupBy(domainGrouper)
+	an := newAnalysis()
+	// an.filterBy(notUsing(domainExtFilter("io", "com")))
+	// an.filterBy(domainFilter("org"))
+	// an.groupBy(domainGrouper)
 
-	p := newTextParser(os.Stdin)
-	s := newTextSummary()
+	src := newTextLog(os.Stdin)
+	dst := newTextReport()
 
-	// s := &chartSummary{
-  	//  title:  "visits per domain",
-  	//  width:  1920,
-  	//  height: 800,
-  	// }
+	// s := &chartReport{
+	//  title:  "visits per domain",
+	//  width:  1920,
+	//  height: 800,
+	// }
 
-	if err := report(p, a, s); err != nil {
+	pipe := newPipeline(src, dst, an)
+
+	if err := pipe.run(); err != nil {
 		log.Fatalln(err)
 	}
 
diff --git a/interfaces/log-parser/oop/pipeline.go b/interfaces/log-parser/oop/pipeline.go
new file mode 100644
index 0000000..481df94
--- /dev/null
+++ b/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)
+}
diff --git a/interfaces/log-parser/oop/report.go b/interfaces/log-parser/oop/report.go
deleted file mode 100644
index 4375b3b..0000000
--- a/interfaces/log-parser/oop/report.go
+++ /dev/null
@@ -1,63 +0,0 @@
-// 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 (
-	"errors"
-	"os"
-	"strings"
-)
-
-type resultFn func(result)
-
-type parser interface {
-	parse(resultFn) error
-}
-
-type analyser interface {
-	analyse(result)
-}
-
-type iterator interface {
-	each(resultFn)
-}
-
-type summarizer interface {
-	summarize(iterator) error
-}
-
-func report(p parser, a analyser, s summarizer) error {
-	if err := p.parse(a.analyse); err != nil {
-		return err
-	}
-
-	it, ok := a.(iterator)
-	if !ok {
-		return errors.New("cannot iterate on analyser")
-	}
-
-	return s.summarize(it)
-}
-
-// reportFromFile generates a default report
-func reportFromFile(path string) (err error) {
-	f, err := os.Open(path)
-	if err != nil {
-		return err
-	}
-
-	var p parser
-	switch {
-	case strings.HasSuffix(path, ".txt"):
-		p = newTextParser(f)
-	case strings.HasSuffix(path, ".json"):
-		p = newJSONParser(f)
-	}
-
-	return report(p, newAnalysis(), newTextSummary())
-}
diff --git a/interfaces/log-parser/oop/textparser.go b/interfaces/log-parser/oop/textlog.go
similarity index 72%
rename from interfaces/log-parser/oop/textparser.go
rename to interfaces/log-parser/oop/textlog.go
index 9894494..7137194 100644
--- a/interfaces/log-parser/oop/textparser.go
+++ b/interfaces/log-parser/oop/textlog.go
@@ -15,36 +15,36 @@ import (
 	"strings"
 )
 
-type textParser struct {
-	r io.Reader
+type textLog struct {
+	reader io.Reader
 }
 
-func newTextParser(r io.Reader) *textParser {
-	return &textParser{r: r}
+func newTextLog(r io.Reader) *textLog {
+	return &textLog{reader: r}
 }
 
-func (p *textParser) parse(handle resultFn) error {
-	defer readClose(p.r)
+func (p *textLog) each(yield resultFn) error {
+	defer readClose(p.reader)
 
 	var (
 		l  = 1
-		in = bufio.NewScanner(p.r)
+		in = bufio.NewScanner(p.reader)
 	)
 
 	for in.Scan() {
-		r, err := parseFields(in.Text())
+		r, err := extractFields(in.Text())
 		if err != nil {
 			return fmt.Errorf("line %d: %v", l, err)
 		}
 
-		handle(r)
+		yield(r)
 		l++
 	}
 
 	return in.Err()
 }
 
-func parseFields(s string) (r result, err error) {
+func extractFields(s string) (r result, err error) {
 	fields := strings.Fields(s)
 	if len(fields) != fieldsLength {
 		return r, fmt.Errorf("wrong number of fields %q", fields)
diff --git a/interfaces/log-parser/oop/textsummary.go b/interfaces/log-parser/oop/textreport.go
similarity index 84%
rename from interfaces/log-parser/oop/textsummary.go
rename to interfaces/log-parser/oop/textreport.go
index e20376e..9cc98b9 100644
--- a/interfaces/log-parser/oop/textsummary.go
+++ b/interfaces/log-parser/oop/textreport.go
@@ -21,13 +21,13 @@ const (
 	flags    = 0
 )
 
-type textSummary struct{}
+type textReport struct{}
 
-func newTextSummary() *textSummary {
-	return new(textSummary)
+func newTextReport() *textReport {
+	return new(textReport)
 }
 
-func (s *textSummary) summarize(results iterator) error {
+func (s *textReport) report(results iterator) error {
 	w := tabwriter.NewWriter(os.Stdout, minWidth, tabWidth, padding, ' ', flags)
 
 	write := fmt.Fprintf