fix 2 bug of ConcurrentLinkedQueue

collections/ArrayList.go

@@ -27,6 +27,27 @@ func NewArrayListByCapacity[T lang.Object](cap int) *ArrayList[T] {
 	}
 }
 
+// NewArrayListFrom create a new ArrayList from list by index from [from] until [to]
+func NewArrayListFrom[T lang.Object](list List[T], from, to int) *ArrayList[T] {
+	newList := NewArrayListByCapacity[T](to - from)
+	iterator, err := SkipIterator[T](list.ListIterator(), to-from)
+	if err != nil {
+		panic(err)
+	}
+
+	for i := 0; i < to-from; i++ {
+		next, err := iterator.Next()
+		if err != nil {
+			panic(err)
+		}
+
+		// newList wont throw any exception in this place
+		_ = newList.Add(next)
+	}
+
+	return newList
+}
+
 func (a *ArrayList[T]) String() string {
 	return String[T](a)
 }

collections/ArrayList_test.go

@@ -2,11 +2,29 @@ package collections
 
 import (
 	"fmt"
+	"testing"
+
 	"github.com/tursom/GoCollections/exceptions"
 	"github.com/tursom/GoCollections/lang"
-	"testing"
 )
 
+func Test_NewArrayListByCapacity(t *testing.T) {
+	capacity := 10
+	list := NewArrayListByCapacity[lang.Int](capacity)
+	if len(list.array) != 0 && cap(list.array) != capacity {
+		t.Fail()
+	}
+}
+
+func Test_NewArrayListFrom(t *testing.T) {
+	list := NewArrayList[lang.Int]()
+	for i := 0; i < 10; i++ {
+		list.Add(lang.Int(i))
+	}
+	newList := NewArrayListFrom[lang.Int](list, 5, 6)
+	fmt.Println(newList)
+}
+
 func TestArrayListAdd(t *testing.T) {
 	list := NewArrayList[lang.Int]()
 	for i := 0; i < 10; i++ {
@@ -39,7 +57,8 @@ func TestLinkedList(t *testing.T) {
 					return nil, nil, nil
 				},
 			)
-			fmt.Println(exceptions.Exec2r1((*LinkedList[lang.Int]).Get, list, j).AsInt())
+			//get := (*LinkedList[lang.Int]).Get
+			//fmt.Println(exceptions.Exec2r1[func(int) (int, exceptions.Exception), List[int], int](get, list, j).AsInt())
 		}
 	}
 	for i := 0; i < 10; i++ {

collections/Iterable.go

@@ -161,3 +161,19 @@ func Clear[T any](l MutableIterable[T]) exceptions.Exception {
 		return iterator.Remove()
 	})
 }
+
+// SkipIterator skip [skip] items of [iterator]
+// returns [iterator] itself
+func SkipIterator[T any](iterator Iterator[T], skip int) (Iterator[T], exceptions.Exception) {
+	for i := 0; i < skip; i++ {
+		if iterator.HasNext() {
+			_, err := iterator.Next()
+			if err != nil {
+				return nil, err
+			}
+		} else {
+			break
+		}
+	}
+	return iterator, nil
+}

collections/LinkedList.go

@@ -33,6 +33,26 @@ func NewLinkedList[T lang.Object]() *LinkedList[T] {
 	return &LinkedList[T]{lang.NewBaseObject(), tail, 0}
 }
 
+func NewLinkedListFrom[T lang.Object](list List[T], from, to int) *LinkedList[T] {
+	newList := NewLinkedList[T]()
+	iterator, err := SkipIterator[T](list.ListIterator(), to-from)
+	if err != nil {
+		panic(err)
+	}
+
+	for i := 0; i < to-from; i++ {
+		next, err := iterator.Next()
+		if err != nil {
+			panic(err)
+		}
+
+		// newList wont throw any exception in this place
+		_ = newList.Add(next)
+	}
+
+	return newList
+}
+
 func (l *LinkedList[T]) Size() int {
 	return l.size
 }
@@ -161,6 +181,7 @@ func (l *LinkedList[T]) SubMutableList(from, to int) MutableList[T] {
 		list.Add(node.value)
 	}
 	return list
+	return NewArrayListFrom[T](l, from, to)
 }
 
 func (l *LinkedList[T]) Get(index int) (T, exceptions.Exception) {

concurrent/collections/ConcurrentLinkedQueue.go

@@ -8,6 +8,8 @@ import (
 )
 
 type (
+	// ConcurrentLinkedQueue FIFO data struct, impl by linked list.
+	// in order to reuse ConcurrentLinkedStack, element will offer on queue's end, and poll on queue's head.
 	ConcurrentLinkedQueue[T lang.Object] struct {
 		lang.BaseObject
 		ConcurrentLinkedStack[T]
@@ -45,12 +47,21 @@ func (q *ConcurrentLinkedQueue[T]) OfferAndGetNode(element T) (collections.Queue
 	return &linkedQueueIterator[T]{queue: q, node: newNode}, nil
 }
 
+// offerAndGetNode offer an element on q.end
 func (q *ConcurrentLinkedQueue[T]) offerAndGetNode(element T) (*linkedStackNode[T], exceptions.Exception) {
 	newNode := &linkedStackNode[T]{value: element}
 	q.size.Add(1)
 
 	var next **linkedStackNode[T]
 	ref := q.end
+
+	// bug fix
+	// buf caused by delete q.end but not update it's reference
+	for ref != nil && ref.deleted {
+		ref = ref.next
+	}
+
+	// q.end is nil when queue just created
 	switch {
 	case ref == nil:
 		next = &q.head
@@ -67,6 +78,12 @@ func (q *ConcurrentLinkedQueue[T]) offerAndGetNode(element T) (*linkedStackNode[
 			}
 			next = &ref.next
 		}
+
+		// bug fix
+		// q.head may be deleted on async env
+		for *next != nil {
+			next = &(*next).next
+		}
 	}
 	q.end = newNode
 	return newNode, nil
@@ -80,6 +97,8 @@ func (q *ConcurrentLinkedQueue[T]) MutableIterator() collections.MutableIterator
 	return &linkedQueueIterator[T]{queue: q, node: q.head}
 }
 
+// Size size of queue
+// it may not correct on concurrent environment, to check it's empty, use func IsEmpty
 func (q *ConcurrentLinkedQueue[T]) Size() int {
 	return int(q.size.Load())
 }

concurrent/collections/ConcurrentLinkedQueue_test.go

@@ -2,11 +2,13 @@ package collections
 
 import (
 	"fmt"
+	"math/rand"
 	"sync"
 	"testing"
 	"time"
 	"unsafe"
 
+	"github.com/tursom/GoCollections/collections"
 	"github.com/tursom/GoCollections/exceptions"
 	"github.com/tursom/GoCollections/lang"
 )
@@ -83,16 +85,59 @@ func TestConcurrentLinkedQueue_ThreadSafe(t *testing.T) {
 
 func Test_concurrentLinkedQueueIterator_Remove(t *testing.T) {
 	queue := NewLinkedQueue[lang.Int]()
-	nodes := make([]QueueNode[lang.Int], 0)
+
-	for i := 0; i < 1000; i++ {
+	for i := 0; i < 16; i++ {
+		testConcurrentLinkedQueueIteratorRemove(t, queue, 1000)
+		t.Logf("Test_concurrentLinkedQueueIterator_Remove passed on %d loop", i+1)
+	}
+}
+
+func testConcurrentLinkedQueueIteratorRemove(t *testing.T, queue *ConcurrentLinkedQueue[lang.Int], nodeNumber int) {
+	nodes := make(chan collections.StackNode[lang.Int], nodeNumber)
+	nodesIndex := make([]bool, nodeNumber)
+	b := rand.Int()&1 == 1
+	if b {
+		for i := 0; i < 4; i++ {
+			go func() {
+				for node := range nodes {
+					index := exceptions.Exec0r1(node.RemoveAndGet)
+					if nodesIndex[index] {
+						t.Fatalf("TODO Fatalf")
+					}
+					nodesIndex[index] = true
+				}
+			}()
+		}
+	}
+
+	for i := 0; i < nodeNumber; i++ {
 		node, _ := queue.OfferAndGetNode(lang.Int(i))
-		nodes = append(nodes, node)
+		nodes <- node
-		//fmt.Println(queue)
 	}
-	for _, node := range nodes {
+
-		fmt.Println(exceptions.Exec0r1(node.RemoveAndGet))
+	close(nodes)
+
+	if !b {
+		for i := 0; i < 4; i++ {
+			go func() {
+				for node := range nodes {
+					index := exceptions.Exec0r1(node.RemoveAndGet)
+					if nodesIndex[index] {
+						t.Fatalf("TODO Fatalf")
 					}
-	if queue.Size() != 0 {
+					nodesIndex[index] = true
+				}
+			}()
+		}
+	}
+
+	time.Sleep(time.Second / 5)
+
+	head := queue.head
+	if head != nil && head.deleted {
+		head = head.next
+	}
+	if head != nil {
 		t.Fatalf(fmt.Sprintf("queue remain %d element, is not thread safe", queue.Size()))
 	}
 }

concurrent/collections/ConcurrentLinkedStack.go

@@ -73,6 +73,7 @@ func (s *ConcurrentLinkedStack[T]) Pop() (T, exceptions.Exception) {
 	return node.value, nil
 }
 
+// CleanDeleted tell stack that may clean deleted nodes
 func (s *ConcurrentLinkedStack[T]) CleanDeleted() {
 	if s.deleted.Load() <= s.size.Load() {
 		return