Merge pull request #49 from Code-Hex/bn-jbowers/main

Add a GetDefault method.

Author: Code-Hex

cache.go

@@ -222,6 +222,23 @@ func (c *Cache[K, V]) Get(key K) (zero V, ok bool) {
 	return item.Value, true
 }
 
+// GetOrSet atomically gets a key's value from the cache, or if the
+// key is not present, sets the given value.
+// The loaded result is true if the value was loaded, false if stored.
+func (c *Cache[K, V]) GetOrSet(key K, val V, opts ...ItemOption) (actual V, loaded bool) {
+	c.mu.Lock()
+	defer c.mu.Unlock()
+	item, ok := c.cache.Get(key)
+
+	if !ok || item.Expired() {
+		item := newItem(key, val, opts...)
+		c.cache.Set(key, item)
+		return val, false
+	}
+
+	return item.Value, true
+}
+
 // DeleteExpired all expired items from the cache.
 func (c *Cache[K, V]) DeleteExpired() {
 	c.mu.Lock()

example_test.go

@@ -7,6 +7,7 @@ import (
 
 	cache "github.com/Code-Hex/go-generics-cache"
 	"github.com/Code-Hex/go-generics-cache/policy/lfu"
+	"github.com/Code-Hex/go-generics-cache/policy/lru"
 )
 
 func ExampleCache() {
@@ -143,6 +144,19 @@ func ExampleCache_Contains() {
 	// false
 }
 
+func ExampleCache_GetOrSet() {
+	c := cache.New(cache.AsLRU[string, int](lru.WithCapacity(10)))
+	c.Set("a", 1)
+
+	val1, ok1 := c.GetOrSet("b", 2)
+	fmt.Println(val1, ok1)
+	val2, ok2 := c.GetOrSet("a", 3)
+	fmt.Println(val2, ok2)
+	// Output:
+	// 2 false
+	// 1 true
+}
+
 func ExampleNewNumber() {
 	nc := cache.NewNumber[string, int]()
 	nc.Set("a", 1)