test(exp/sync): add example test case for NewLRU and NewFixedPool.

go/exp/sync/example_fixedpool_test.go

@@ -0,0 +1,76 @@
+// Copyright 2024 The searKing Author. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+package sync_test
+
+import (
+	"bytes"
+	"fmt"
+	"time"
+
+	sync_ "github.com/searKing/golang/go/exp/sync"
+)
+
+var bufFixedPool = sync_.NewFixedPool[*bytes.Buffer](func() *bytes.Buffer {
+	// The Pool's New function should generally only return pointer
+	// types, since a pointer can be put into the return interface
+	// value without an allocation:
+	fmt.Println("allocating new buffer")
+	return new(bytes.Buffer)
+}, 1)
+
+var bufCachedPool = sync_.NewCachedPool[*bytes.Buffer](func() *bytes.Buffer {
+	// The Pool's New function should generally only return pointer
+	// types, since a pointer can be put into the return interface
+	// value without an allocation:
+	fmt.Println("allocating new buffer")
+	return new(bytes.Buffer)
+})
+var bufTempPool = sync_.NewTempPool[*bytes.Buffer](nil)
+
+// timeNow is a fake version of time.Now for tests.
+func timeNow() time.Time {
+	return time.Unix(1136214245, 0)
+}
+
+func Log(bufPool *sync_.FixedPool[*bytes.Buffer], key, val string) {
+	be := bufPool.Get()
+	{
+		b := be.Value
+		b.Reset()
+		// Replace this with time.Now() in a real logger.
+		b.WriteString(timeNow().UTC().Format(time.RFC3339))
+		b.WriteByte(' ')
+		b.WriteString(key)
+		b.WriteByte('=')
+		b.WriteString(val)
+		fmt.Println(b.String())
+	}
+	bufPool.Put(be)
+}
+func ExampleNewFixedPool() {
+	Log(bufFixedPool, "path", "/search?q=flowers")
+	Log(bufFixedPool, "path", "/search?q=vegetables")
+	// Output:
+	// 2006-01-02T15:04:05Z path=/search?q=flowers
+	// 2006-01-02T15:04:05Z path=/search?q=vegetables
+}
+
+func ExampleNewCachedPool() {
+	Log(bufCachedPool, "path", "/search?q=flowers")
+	Log(bufCachedPool, "path", "/search?q=vegetables")
+	// Output:
+	// allocating new buffer
+	// 2006-01-02T15:04:05Z path=/search?q=flowers
+	// 2006-01-02T15:04:05Z path=/search?q=vegetables
+}
+
+func ExampleNewTempPool() {
+	bufTempPool.Emplace(new(bytes.Buffer))
+	Log(bufTempPool, "path", "/search?q=flowers")
+	Log(bufTempPool, "path", "/search?q=vegetables")
+	// Output:
+	// 2006-01-02T15:04:05Z path=/search?q=flowers
+	// 2006-01-02T15:04:05Z path=/search?q=vegetables
+}

go/exp/sync/example_lru_test.go

@@ -0,0 +1,60 @@
+// Copyright 2024 The searKing Author. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+package sync_test
+
+import (
+	"fmt"
+
+	sync_ "github.com/searKing/golang/go/exp/sync"
+)
+
+func ExampleNewLRU() {
+	l := sync_.NewLRU[int, int](2)
+	var evictCounter int
+	l.SetEvictCallback(func(k int, v int) {
+		evictCounter++
+		fmt.Printf("{%d,%d} evicted as oldest: %d\n", k, v, evictCounter)
+	})
+	printAll := func() {
+		fmt.Printf("lru: ")
+		first := true
+		for k, v := range l.All() {
+			if !first {
+				fmt.Printf(", ")
+			}
+			first = false
+			fmt.Printf("{%d,%d}", k, v)
+		}
+		fmt.Println()
+	}
+	l.Add(1, 1)
+	l.Add(2, 2)
+	l.Add(3, 3) // evict 1, that's the oldest
+	printAll()
+
+	fmt.Println("try to refresh {2,22}")
+	l.Add(2, 22) // refresh 2; Now 3 is the oldest
+	printAll()
+
+	fmt.Println("try to remove oldest")
+	l.RemoveOldest() // evict 2, that's the oldest
+	printAll()
+
+	fmt.Println("try to purge all elements")
+	l.Purge()
+	printAll()
+
+	// Output:
+	// {1,1} evicted as oldest: 1
+	// lru: {2,2}, {3,3}
+	// try to refresh {2,22}
+	// lru: {3,3}, {2,22}
+	// try to remove oldest
+	// {3,3} evicted as oldest: 2
+	// lru: {2,22}
+	// try to purge all elements
+	// {2,22} evicted as oldest: 3
+	// lru:
+}