- TreeBidiMap iterator implemented (with tests)

maps/treebidimap/iterator.go

@@ -0,0 +1,77 @@
+// Copyright (c) 2015, Emir Pasic. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+package treebidimap
+
+import (
+	"github.com/emirpasic/gods/containers"
+	rbt "github.com/emirpasic/gods/trees/redblacktree"
+)
+
+func assertIteratorImplementation() {
+	var _ containers.ReverseIteratorWithKey = (*Iterator)(nil)
+}
+
+// Iterator holding the iterator's state
+type Iterator struct {
+	iterator rbt.Iterator
+}
+
+// Iterator returns a stateful iterator whose elements are key/value pairs.
+func (m *Map) Iterator() Iterator {
+	return Iterator{iterator: m.forwardMap.Iterator()}
+}
+
+// Next moves the iterator to the next element and returns true if there was a next element in the container.
+// If Next() returns true, then next element's key and value can be retrieved by Key() and Value().
+// If Next() was called for the first time, then it will point the iterator to the first element if it exists.
+// Modifies the state of the iterator.
+func (iterator *Iterator) Next() bool {
+	return iterator.iterator.Next()
+}
+
+// Prev moves the iterator to the previous element and returns true if there was a previous element in the container.
+// If Prev() returns true, then previous element's key and value can be retrieved by Key() and Value().
+// Modifies the state of the iterator.
+func (iterator *Iterator) Prev() bool {
+	return iterator.iterator.Prev()
+}
+
+// Value returns the current element's value.
+// Does not modify the state of the iterator.
+func (iterator *Iterator) Value() interface{} {
+	return iterator.iterator.Value().(*data).value
+}
+
+// Key returns the current element's key.
+// Does not modify the state of the iterator.
+func (iterator *Iterator) Key() interface{} {
+	return iterator.iterator.Key()
+}
+
+// Begin resets the iterator to its initial state (one-before-first)
+// Call Next() to fetch the first element if any.
+func (iterator *Iterator) Begin() {
+	iterator.iterator.Begin()
+}
+
+// End moves the iterator past the last element (one-past-the-end).
+// Call Prev() to fetch the last element if any.
+func (iterator *Iterator) End() {
+	iterator.iterator.End()
+}
+
+// First moves the iterator to the first element and returns true if there was a first element in the container.
+// If First() returns true, then first element's key and value can be retrieved by Key() and Value().
+// Modifies the state of the iterator
+func (iterator *Iterator) First() bool {
+	return iterator.iterator.First()
+}
+
+// Last moves the iterator to the last element and returns true if there was a last element in the container.
+// If Last() returns true, then last element's key and value can be retrieved by Key() and Value().
+// Modifies the state of the iterator.
+func (iterator *Iterator) Last() bool {
+	return iterator.iterator.Last()
+}

maps/treebidimap/treebidimap_test.go

@@ -170,6 +170,157 @@ func sameElements(a []interface{}, b []interface{}) bool {
 	return true
 }
 
+func TestMapIteratorNextOnEmpty(t *testing.T) {
+	m := NewWithStringComparators()
+	it := m.Iterator()
+	it = m.Iterator()
+	for it.Next() {
+		t.Errorf("Shouldn't iterate on empty map")
+	}
+}
+
+func TestMapIteratorPrevOnEmpty(t *testing.T) {
+	m := NewWithStringComparators()
+	it := m.Iterator()
+	it = m.Iterator()
+	for it.Prev() {
+		t.Errorf("Shouldn't iterate on empty map")
+	}
+}
+
+func TestMapIteratorNext(t *testing.T) {
+	m := NewWith(utils.StringComparator, utils.IntComparator)
+	m.Put("c", 3)
+	m.Put("a", 1)
+	m.Put("b", 2)
+
+	it := m.Iterator()
+	count := 0
+	for it.Next() {
+		count++
+		key := it.Key()
+		value := it.Value()
+		switch key {
+		case "a":
+			if actualValue, expectedValue := value, 1; actualValue != expectedValue {
+				t.Errorf("Got %v expected %v", actualValue, expectedValue)
+			}
+		case "b":
+			if actualValue, expectedValue := value, 2; actualValue != expectedValue {
+				t.Errorf("Got %v expected %v", actualValue, expectedValue)
+			}
+		case "c":
+			if actualValue, expectedValue := value, 3; actualValue != expectedValue {
+				t.Errorf("Got %v expected %v", actualValue, expectedValue)
+			}
+		default:
+			t.Errorf("Too many")
+		}
+		if actualValue, expectedValue := value, count; actualValue != expectedValue {
+			t.Errorf("Got %v expected %v", actualValue, expectedValue)
+		}
+	}
+	if actualValue, expectedValue := count, 3; actualValue != expectedValue {
+		t.Errorf("Got %v expected %v", actualValue, expectedValue)
+	}
+}
+
+func TestMapIteratorPrev(t *testing.T) {
+	m := NewWith(utils.StringComparator, utils.IntComparator)
+	m.Put("c", 3)
+	m.Put("a", 1)
+	m.Put("b", 2)
+
+	it := m.Iterator()
+	for it.Next() {
+	}
+	countDown := m.Size()
+	for it.Prev() {
+		key := it.Key()
+		value := it.Value()
+		switch key {
+		case "a":
+			if actualValue, expectedValue := value, 1; actualValue != expectedValue {
+				t.Errorf("Got %v expected %v", actualValue, expectedValue)
+			}
+		case "b":
+			if actualValue, expectedValue := value, 2; actualValue != expectedValue {
+				t.Errorf("Got %v expected %v", actualValue, expectedValue)
+			}
+		case "c":
+			if actualValue, expectedValue := value, 3; actualValue != expectedValue {
+				t.Errorf("Got %v expected %v", actualValue, expectedValue)
+			}
+		default:
+			t.Errorf("Too many")
+		}
+		if actualValue, expectedValue := value, countDown; actualValue != expectedValue {
+			t.Errorf("Got %v expected %v", actualValue, expectedValue)
+		}
+		countDown--
+	}
+	if actualValue, expectedValue := countDown, 0; actualValue != expectedValue {
+		t.Errorf("Got %v expected %v", actualValue, expectedValue)
+	}
+}
+
+func TestMapIteratorBegin(t *testing.T) {
+	m := NewWith(utils.IntComparator, utils.StringComparator)
+	it := m.Iterator()
+	it.Begin()
+	m.Put(3, "c")
+	m.Put(1, "a")
+	m.Put(2, "b")
+	for it.Next() {
+	}
+	it.Begin()
+	it.Next()
+	if key, value := it.Key(), it.Value(); key != 1 || value != "a" {
+		t.Errorf("Got %v,%v expected %v,%v", key, value, 1, "a")
+	}
+}
+
+func TestMapTreeIteratorEnd(t *testing.T) {
+	m := NewWith(utils.IntComparator, utils.StringComparator)
+	it := m.Iterator()
+	m.Put(3, "c")
+	m.Put(1, "a")
+	m.Put(2, "b")
+	it.End()
+	it.Prev()
+	if key, value := it.Key(), it.Value(); key != 3 || value != "c" {
+		t.Errorf("Got %v,%v expected %v,%v", key, value, 3, "c")
+	}
+}
+
+func TestMapIteratorFirst(t *testing.T) {
+	m := NewWith(utils.IntComparator, utils.StringComparator)
+	m.Put(3, "c")
+	m.Put(1, "a")
+	m.Put(2, "b")
+	it := m.Iterator()
+	if actualValue, expectedValue := it.First(), true; actualValue != expectedValue {
+		t.Errorf("Got %v expected %v", actualValue, expectedValue)
+	}
+	if key, value := it.Key(), it.Value(); key != 1 || value != "a" {
+		t.Errorf("Got %v,%v expected %v,%v", key, value, 1, "a")
+	}
+}
+
+func TestMapIteratorLast(t *testing.T) {
+	m := NewWith(utils.IntComparator, utils.StringComparator)
+	m.Put(3, "c")
+	m.Put(1, "a")
+	m.Put(2, "b")
+	it := m.Iterator()
+	if actualValue, expectedValue := it.Last(), true; actualValue != expectedValue {
+		t.Errorf("Got %v expected %v", actualValue, expectedValue)
+	}
+	if key, value := it.Key(), it.Value(); key != 3 || value != "c" {
+		t.Errorf("Got %v,%v expected %v,%v", key, value, 3, "c")
+	}
+}
+
 func BenchmarkMap(b *testing.B) {
 	for i := 0; i < b.N; i++ {
 		m := NewWithIntComparators()