Introduction

A map container with a concurrent safety switch option, the most commonly used data structure. This module includes map containers with multiple data structures: HashMap, TreeMap, and ListMap.

Type	Data Structure	Average Complexity	Supports Sorting	Ordered Traversal	Description
HashMap	Hash Table	O(1)	No	No	High performance read/write operation, high memory usage, random traversal
ListMap	Hash Table + Doubly Linked List	O(2)	No	Yes	Supports traversal in the order of insertion, high memory usage
TreeMap	Red Black Tree	O(log N)	Yes	Yes	Compact memory usage, supports key name sorting and ordered traversal

tip

Additionally, the gmap module supports defining common types of map with hash table as the underlying data structure: IntIntMap, IntStrMap, IntAnyMap, StrIntMap, StrStrMap, StrAnyMap.

Usage Scenarios:

Any map/hash table/associative array usage scenario, particularly in concurrent safety scenarios.

Usage Method:

import "github.com/gogf/gf/v2/container/gmap"

Interface Documentation:

https://pkg.go.dev/github.com/gogf/gf/v2/container/gmap

NilChecker and Typed Nil Support

• Feature Overview: Starting from the generic version, gmap provides NilChecker functions for generic map types (such as KVMap[K, V], ListKVMap[K, V]) to customize "which values should be considered nil", primarily used to solve typed nil determination issues when containing pointers, interfaces, and other types.
• Usage: You can specify via constructors like NewKVMapWithChecker, NewListKVMapWithChecker, or register at runtime by calling RegisterNilChecker with a func(V) bool determination function. Lazy loading/conditional write methods (such as GetOrSet* series) will call this function before actually writing, and usually won't write the key-value pair when it returns true.
• Compatibility: If NilChecker is not set, it maintains consistency with historical versions, defaulting to any(v) == nil for determination, and typed nil behavior won't change.

Example:

type Student struct {
    Name string
}

// Treat *Student(nil) as "no value", won't write to map
m := gmap.NewListKVMapWithChecker[int, *Student](func(s *Student) bool {
    return s == nil
}, true)

v := m.GetOrSetFuncLock(1, func() *Student {
    return nil
})
fmt.Println(v == nil)       // true
fmt.Println(m.Contains(1)) // false, key not written

Documentation

📄️ Map - Usage

Basic usage of the gmap module under the GoFrame framework, including switching operations of concurrent security features, setting, querying, and deleting key-value pairs, as well as ordered traversal, serialization and deserialization of data structures, with detailed code examples and execution results.

📄️ Map - Performance

Detailed testing and analysis of the performance of dictionary types. By comparing the performance of gmap in the GoFrame framework with the standard library's sync.Map, the efficiency in different scenarios of concurrent safety and non-concurrent safety is revealed. Includes performance benchmarking of different types of maps such as HashMap, ListMap, and TreeMap, providing developers with real-time reference for optimizing applications.

📄️ Map - Methods

Various methods of the AnyAnyMap in the GoFrame framework, including operations such as creation, cloning, iteration, setting, deletion, and merging. Code examples are provided to help understand the use of these methods to ensure concurrency safety. For more detailed information, refer to the GoFrame Framework documentation.