add: method logparser tests

28-methods/logparser-nopkg/summary.go

@@ -0,0 +1,67 @@
+// 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 (
+	"sort"
+)
+
+// summary aggregates the parsing results
+type summary struct {
+	sum     map[string]result // metrics per domain
+	domains []string          // unique domain names
+	total   result            // total visits for all domains
+}
+
+// newSummary constructs and initializes a new summary
+// You can't use its methods without pointer mechanics
+func newSummary() *summary {
+	return &summary{sum: make(map[string]result)}
+}
+
+// Update updates the report for the given parsing result
+func (s *summary) update(r result) {
+	domain := r.domain
+	if _, ok := s.sum[domain]; !ok {
+		s.domains = append(s.domains, domain)
+	}
+
+	// let the result handle the addition
+	// this allows us to manage the result in once place
+	// and this way it becomes easily extendable
+	s.total = s.total.add(r)
+	s.sum[domain] = r.add(s.sum[domain])
+}
+
+// Iterator returns `next()` to detect when the iteration ends,
+// and a `cur()` to return the current result.
+// iterator iterates sorted by domains.
+func (s *summary) iterator() (next func() bool, cur func() result) {
+	sort.Strings(s.domains)
+
+	// remember the last iterated result
+	var last int
+
+	next = func() bool {
+		defer func() { last++ }()
+		return len(s.domains) > last
+	}
+
+	cur = func() result {
+		// returns a copy so the caller cannot change it
+		name := s.domains[last-1]
+		return s.sum[name]
+	}
+
+	return
+}
+
+// totals returns the total metrics
+func (s *summary) totals() result {
+	return s.total
+}