emirpasic · emirpasic · Sep 20, 2018 · Sep 20, 2018 · Sep 20, 2018 · Sep 20, 2018
diff --git a/examples/linkedhashset/linkedhashset.go b/examples/linkedhashset/linkedhashset.go
@@ -0,0 +1,23 @@
+// 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 main
+
+import "github.com/emirpasic/gods/sets/linkedhashset"
+
+// LinkedHashSetExample to demonstrate basic usage of LinkedHashSet
+func main() {
+	set := linkedhashset.New() // empty
+	set.Add(5)                 // 5
+	set.Add(4, 4, 3, 2, 1)     // 5, 4, 3, 2, 1 (in insertion-order, duplicates ignored)
+	set.Remove(4)              // 5, 3, 2, 1 (in insertion-order)
+	set.Remove(2, 3)           // 5, 1 (in insertion-order)
+	set.Contains(1)            // true
+	set.Contains(1, 5)         // true
+	set.Contains(1, 6)         // false
+	_ = set.Values()           // []int{5, 1} (in insertion-order)
+	set.Clear()                // empty
+	set.Empty()                // true
+	set.Size()                 // 0
+}
diff --git a/lists/arraylist/arraylist.go b/lists/arraylist/arraylist.go
@@ -61,7 +61,7 @@ func (list *List) Get(index int) (interface{}, bool) {
 	return list.elements[index], true
 }
 
-// Remove removes one or more elements from the list with the supplied indices.
+// Remove removes the element at the given index from the list.
 func (list *List) Remove(index int) {
 
 	if !list.withinRange(index) {

diff --git a/lists/doublylinkedlist/doublylinkedlist.go b/lists/doublylinkedlist/doublylinkedlist.go
@@ -100,7 +100,7 @@ func (list *List) Get(index int) (interface{}, bool) {
 	return element.value, true
 }
 
-// Remove removes one or more elements from the list with the supplied indices.
+// Remove removes the element at the given index from the list.
 func (list *List) Remove(index int) {
 
 	if !list.withinRange(index) {

diff --git a/lists/singlylinkedlist/singlylinkedlist.go b/lists/singlylinkedlist/singlylinkedlist.go
@@ -90,7 +90,7 @@ func (list *List) Get(index int) (interface{}, bool) {
 	return element.value, true
 }
 
-// Remove removes one or more elements from the list with the supplied indices.
+// Remove removes the element at the given index from the list.
 func (list *List) Remove(index int) {
 
 	if !list.withinRange(index) {

diff --git a/sets/linkedhashset/enumerable.go b/sets/linkedhashset/enumerable.go
@@ -0,0 +1,79 @@
+// 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 linkedhashset
+
+import "github.com/emirpasic/gods/containers"
+
+func assertEnumerableImplementation() {
+	var _ containers.EnumerableWithIndex = (*Set)(nil)
+}
+
+// Each calls the given function once for each element, passing that element's index and value.
+func (set *Set) Each(f func(index int, value interface{})) {
+	iterator := set.Iterator()
+	for iterator.Next() {
+		f(iterator.Index(), iterator.Value())
+	}
+}
+
+// Map invokes the given function once for each element and returns a
+// container containing the values returned by the given function.
+func (set *Set) Map(f func(index int, value interface{}) interface{}) *Set {
+	newSet := New()
+	iterator := set.Iterator()
+	for iterator.Next() {
+		newSet.Add(f(iterator.Index(), iterator.Value()))
+	}
+	return newSet
+}
+
+// Select returns a new container containing all elements for which the given function returns a true value.
+func (set *Set) Select(f func(index int, value interface{}) bool) *Set {
+	newSet := New()
+	iterator := set.Iterator()
+	for iterator.Next() {
+		if f(iterator.Index(), iterator.Value()) {
+			newSet.Add(iterator.Value())
+		}
+	}
+	return newSet
+}
+
+// Any passes each element of the container to the given function and
+// returns true if the function ever returns true for any element.
+func (set *Set) Any(f func(index int, value interface{}) bool) bool {
+	iterator := set.Iterator()
+	for iterator.Next() {
+		if f(iterator.Index(), iterator.Value()) {
+			return true
+		}
+	}
+	return false
+}
+
+// All passes each element of the container to the given function and
+// returns true if the function returns true for all elements.
+func (set *Set) All(f func(index int, value interface{}) bool) bool {
+	iterator := set.Iterator()
+	for iterator.Next() {
+		if !f(iterator.Index(), iterator.Value()) {
+			return false
+		}
+	}
+	return true
+}
+
+// Find passes each element of the container to the given function and returns
+// the first (index,value) for which the function is true or -1,nil otherwise
+// if no element matches the criteria.
+func (set *Set) Find(f func(index int, value interface{}) bool) (int, interface{}) {
+	iterator := set.Iterator()
+	for iterator.Next() {
+		if f(iterator.Index(), iterator.Value()) {
+			return iterator.Index(), iterator.Value()
+		}
+	}
+	return -1, nil
+}
diff --git a/sets/linkedhashset/iterator.go b/sets/linkedhashset/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 linkedhashset
+
+import (
+	"github.com/emirpasic/gods/containers"
+	"github.com/emirpasic/gods/lists/doublylinkedlist"
+)
+
+func assertIteratorImplementation() {
+	var _ containers.ReverseIteratorWithIndex = (*Iterator)(nil)
+}
+
+// Iterator holding the iterator's state
+type Iterator struct {
+	iterator doublylinkedlist.Iterator
+}
+
+// Iterator returns a stateful iterator whose values can be fetched by an index.
+func (set *Set) Iterator() Iterator {
+	return Iterator{iterator: set.list.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 index and value can be retrieved by Index() 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 index and value can be retrieved by Index() 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()
+}
+
+// Index returns the current element's index.
+// Does not modify the state of the iterator.
+func (iterator *Iterator) Index() int {
+	return iterator.iterator.Index()
+}
+
+// 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 index and value can be retrieved by Index() 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 index and value can be retrieved by Index() and Value().
+// Modifies the state of the iterator.
+func (iterator *Iterator) Last() bool {
+	return iterator.iterator.Last()
+}
diff --git a/sets/linkedhashset/linkedhashset.go b/sets/linkedhashset/linkedhashset.go
@@ -0,0 +1,118 @@
+// 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 linkedhashset implements a set that preserves insertion-order and is backed a hash tables to store values and doubly-linked list to store ordering.
+//
+// Note that insertion-order is not affected if an element is re-inserted into the set.
+//
+// Structure is not thread safe.
+//
+// References: http://en.wikipedia.org/wiki/Set_%28abstract_data_type%29
+package linkedhashset
+
+import (
+	"fmt"
+	"github.com/emirpasic/gods/lists/doublylinkedlist"
+	"github.com/emirpasic/gods/sets"
+	"strings"
+)
+
+func assertSetImplementation() {
+	var _ sets.Set = (*Set)(nil)
+}
+
+// Set holds elements in go's native map
+type Set struct {
+	items map[interface{}]struct{}
+	list  *doublylinkedlist.List
+}
+
+var itemExists = struct{}{}
+
+// New instantiates a new empty set
+func New() *Set {
+	return &Set{
+		items: make(map[interface{}]struct{}),
+		list:  doublylinkedlist.New(),
+	}
+}
+
+// Add adds the items (one or more) to the set.
+// Note that insertion-order is not affected if an element is re-inserted into the set.
+func (set *Set) Add(items ...interface{}) {
+	for _, item := range items {
+
+		if _, contains := set.items[item]; contains {
+			continue
+		}
+
+		set.items[item] = itemExists
+		set.list.Append(item)
+	}
+}
+
+// Remove removes the items (one or more) from the set.
+// Slow operation, worst-case O(n^2).
+func (set *Set) Remove(items ...interface{}) {
+	for _, item := range items {
+
+		if _, contains := set.items[item]; !contains {
+			continue
+		}
+
+		delete(set.items, item)
+		index := set.list.IndexOf(item)
+		set.list.Remove(index)
+	}
+}
+
+// Contains check if items (one or more) are present in the set.
+// All items have to be present in the set for the method to return true.
+// Returns true if no arguments are passed at all, i.e. set is always superset of empty set.
+func (set *Set) Contains(items ...interface{}) bool {
+	for _, item := range items {
+		if _, contains := set.items[item]; !contains {
+			return false
+		}
+	}
+	return true
+}
+
+// Empty returns true if set does not contain any elements.
+func (set *Set) Empty() bool {
+	return set.Size() == 0
+}
+
+// Size returns number of elements within the set.
+func (set *Set) Size() int {
+	return set.list.Size()
+}
+
+// Clear clears all values in the set.
+func (set *Set) Clear() {
+	set.items = make(map[interface{}]struct{})
+	set.list.Clear()
+}
+
+// Values returns all items in the set.
+func (set *Set) Values() []interface{} {
+	values := make([]interface{}, set.Size())
+	it := set.Iterator()
+	for it.Next() {
+		values[it.Index()] = it.Value()
+	}
+	return values
+}
+
+// String returns a string representation of container
+func (set *Set) String() string {
+	str := "LinkedHashSet\n"
+	items := []string{}
+	it := set.Iterator()
+	for it.Next() {
+		items = append(items, fmt.Sprintf("%v", it.Value()))
+	}
+	str += strings.Join(items, ", ")
+	return str
+}