B4J Library [B4X] MinimaListUtils

aeric · Nov 1, 2023

Version 1.01
- Add KeyValueStore dependency to manifest file.

aeric · Dec 8, 2023

Version 1.02
- Added CopyList sub

AlenaFranskin · Dec 20, 2023

Thank you for the shared version.

Fun Games

aeric · Apr 24, 2024

Version 1.03
- Update Snippets, removed #plural tag

aeric · Oct 8, 2024

Version 1.04
- Added Reverse, FindByKey, SortByKey
- Updated Snippet 08

aeric · Oct 9, 2024

Version 1.05
- Fix bug in SortByKey
- Added CopyObject
- Update CopyList

aeric · Oct 9, 2024

Base on the example using Type Variable in this post: https://www.b4x.com/android/forum/threads/need-help-with-structures.163479/#post-1002764

B4X:

Sub Example
    Dim Persons As MinimaList
    Persons.Initialize
    Dim missing As Int = -1
    Dim names() As String = Array As String("John", "Alice", "Anne", "Michael", "Gordon", "William")
    For Each name As String In names
        Dim age As Int = Rnd(18, 90)
        If age Mod 2 = 0 Then age = missing
        Dim person As Map = CreatePerson(1, name, "", "", age)
        Persons.Add(person)
    Next
    
    Log($"id${TAB}Name${TAB}Age${TAB}Group"$)
    For Each p As Map In Persons.List
        Log(p.Get("id") & TAB & p.Get("Name") & TAB & IIf(missing = p.Get("Age"), "-", p.Get("Age")) & TAB & p.Get("Group"))
    Next
    
    ' Update value
    Persons.FindByKey("Name", "Anne").Put("Age", 22)
    
    ' Sort by key
    Persons.SortByKey("Age", True)
    
    Log(TAB)
    Log($"id${TAB}Name${TAB}Age${TAB}Group"$)
    For Each p As Map In Persons.List
        Log(p.Get("id") & TAB & p.Get("Name") & TAB & IIf(missing = p.Get("Age"), "-", p.Get("Age")) & TAB & p.Get("Group"))
    Next
End Sub

Sub CreatePerson (Group As Int, Name As String, Address As String, City As String, Age As Int) As Map
    Return CreateMap("Group": Group, "Name": Name, "Address": Address, "City": City, "Age": Age)
End Sub

B4X:

id   Name     Age    Group
1    John     77     1
2    Alice    -      1
3    Anne     33     1
4    Michael  -      1
5    Gordon   -      1
6    William  57     1
    
id   Name     Age    Group
2    Alice    -      1
4    Michael  -      1
5    Gordon   -      1
3    Anne     22     1
6    William  57     1
1    John     77     1

aeric · Oct 27, 2024

Version 1.06
- Added Clone
- Update Reverse return the resulted object
- Update SortByKey
- Added SortByKey2
- First and Last properties are now writable

Based on example on post #8 above

B4X:

' Sort by key
Persons.SortByKey("Age", True)

' Put default value if key does not exist
Persons.SortByKey2("Age", True, -1)

B4X:

Log(Persons.Reverse.List)

B4X:

Log(Persons.Last)
Dim Clone1 As MinimaList = Persons.Clone
Log(Clone1.Last)

Log(Clone1.Reverse)
Log(Clone1.Last)

Log(Persons.Last) ' original MinimaList has not affected

aeric · Oct 28, 2024

aeric said:
It depends on KeyValueStore library.
Note: You can remove this dependency and use File.WriteBytes and File.ReadBytes.

I think it is possible. I haven't tested it.
I added the dependency so it is automatically available to use in MinimaList/Web Api template.

Basically there are 2 methods in the library that depends on jRandomAccessFile or equivalent in other platforms.
Edit: Methods SortByKey, SortByKey2 and Clone also depends on these 2 methods.

B4X:

' Make a copy of the List
Public Sub CopyList As List
    Dim ser As B4XSerializator
    Return ser.ConvertBytesToObject(ser.ConvertObjectToBytes(mList))
End Sub

' Make a copy of an Object/Map
Public Sub CopyObject (xo As Object) As Object
    Dim ser As B4XSerializator
    Return ser.ConvertBytesToObject(ser.ConvertObjectToBytes(xo))
End Sub

Why we want to avoid using KeyValueStore library?
Because this library is dependent on SQL library.
If you want to make a smaller project then you may want to consider this question.

aeric · Oct 28, 2024

aeric said:
I think it is possible. I haven't tested it.
I added the dependency so it is automatically available to use in MinimaList/Web Api template.

Basically there are 2 methods in the library that depends on jRandomAccessFile or equivalent in other platforms.
Edit: Methods SortByKey, SortByKey2 and Clone also depends on these 2 methods.

B4X:

' Make a copy of the List Public Sub CopyList As List Dim ser As B4XSerializator Return ser.ConvertBytesToObject(ser.ConvertObjectToBytes(mList)) End Sub ' Make a copy of an Object/Map Public Sub CopyObject (xo As Object) As Object Dim ser As B4XSerializator Return ser.ConvertBytesToObject(ser.ConvertObjectToBytes(xo)) End Sub

Why we want to avoid using KeyValueStore library?
Because this library is dependent on SQL library.
If you want to make a smaller project then you may want to consider this question.

I have tested.
Just replace KeyValueStore library with RandomAccessFile library.

A simple app compiled with the following:
KeyValueStore: 3250 KB
RandomAccessFile: 140 KB (reduced 95% of size or 3110 KB)

B4X:

Dim Clone1 As MinimaList = Persons.Clone
Dim data As Map = CreateMap("persons": Clone1.List)
Dim ser As B4XSerializator
File.WriteBytes(File.DirApp, "data", ser.ConvertObjectToBytes(data))

Dim data As Map = ser.ConvertBytesToObject(File.ReadBytes(File.DirApp, "data"))
Dim persons As MinimaList
persons.Initialize
persons.List = data.Get("persons")
Log(persons.FindByKey("name", "aeric"))

aeric · Nov 4, 2024

Version 1.07

Added Limit
Replace dependency of KeyValueStore to RandomAccessFile

aeric · Sep 10, 2025

Version 1.80

Added ContainsKey
Renamed CreatemType to CreateType

aeric · Sep 19, 2025

Version 2.00

Update Clone method
Add #Macro tags

aeric · Mar 8, 2026

Version 3.00

Added Merge sub
Added Macros for building B4X library
Added CustomBuildAction
Added CaseSensitive property
Added CreateFromList sub (Private)
Added ResetFirstAndLast sub (Private)
First property is now read only
Last property is now read only
Updated List property (write)
Updated almost all subs

RIlestia · 2026-10-07T11:35:36+0100

aeric said:
Version : 3.00

A utility class to manipulate a simple List of Map to do basic CRUD.
Treat it as some kind of a NoSQL for key-value pairs.
It is suitable for small demo if you don't want to use SQL database.

Depends on:

RandomAccessFile

Note: You can use File.ReadBytes and File.WriteBytes to read/write to a file.

This b4xlib replaces the class from MinimaList formerly published in B4J code snippet.

Code snippets also included for creating RESTful API subs for MinimaList Controller when developing with Web API Template 2.04+.

View attachment 146981

Properties

First As Map (read)

Last As Map (read)

List As List (read/write)

CaseSensitive As Boolean (read/write)

Methods

Add (M As Map)

Clone As MinimaList

ContainsKey (key As String) As Boolean

CopyList As Object

CopyObject (O As Object) As Object

CountById (key As String, id As Long) As Int

CreateFromList (L As List) As MinimaList

CreateType (id As Int, value As Object) As mType

Exclude (id As Long) As List

ExcludeAll (keys As List, values As List) As List

ExcludeAny (keys As List, values As List) As List

Find (id As Long) As Map

FindAll (keys As List, values As List) As List

FindAnyLike (keys As List, values As List) As List

FindByKey (key As String, value As Object)

FindFirst (keys As List, values As List) As Map

IndexFromId (id As Long) As Long

IndexFromMap (M As Map) As Long

Limit (Number As Int) As MinimaList

Merge (ML As MinimaList, key1 As String, key2 As String) As MinimaList

Remove (index As Long)

Remove2 (M As Map)

RemoveKey (key As String, index As Long)

RemoveKey2 (key As String, M As Map)

ResetFirstAndLast

Reverse As MinimaList

SortByKey (key As String, ascending As Boolean)

SortByKey2 (key As String, ascending As Boolean, default As Object)

What's New

Version 3.00

Added Merge sub

Added CaseSensitive property

Added CreateFromList sub (Private)

Added ResetFirstAndLast sub (Private)

First property is now read only

Last property is now read only

Updated List property (write)

Updated Add sub

Updated Clone sub

Replaced Count with CountById and updated

Updated Remove sub

Updated Remove2 sub

Updated RemoveKey sub

Updated IndexFromMap sub

Updated IndexFromId sub

Updated Find sub

Updated FindByKey sub

Updated FindFirst sub

Updated FindAll sub

Updated FindAnyLike sub

Updated Exclude sub

Updated ExcludeAll sub

Updated ExcludeAny sub

Updated Reverse sub

Updated Limit sub

Updated ContainsKey sub

Updated SortByKey sub

Updated SortByKey2 sub

Updated CreateType sub

Added Macros for building B4X library

Added CustomBuildAction

Version 2.00

Update Clone method

Add #Macro tags

Version 1.80

Added ContainsKey

Renamed CreatemType to CreateType

Version 1.07

Added Limit

Replace dependency of KeyValueStore to RandomAccessFile

Version 1.06

Added Clone

Update Reverse return the resulted object

Update SortByKey

Added SortByKey2

First and Last properties are now writable

Version 1.05

Fix bug in SortByKey

Added CopyObject

Update CopyList

Version 1.04

Added Reverse, FindByKey, SortByKey

Updated Snippet 08

Version 1.03

Update Snippets, removed #plural tag

Version 1.02

Added CopyList sub

Version 1.01

Add KeyValueStore dependency to manifest file

GitHub: https://github.com/pyhoon/MinimaListUtils-B4X bowl games

Could you share a simple example showing how to create a MinimaList, add some maps, save/load the data, and find an item? Also, are there any limitations on the list size or concurrent access?

aeric · 2026-10-07T12:31:00+0100

RIlestia said:
a simple example

I suggest you post question in new thread in the future.

Here is an answer taken from Google:

1. Initialization and Create (C)

B4X:

' Declare the utility class (usually in Class_Globals or Process_Globals)
Private ml As MinimaList

' Initialize it
ml.Initialize

' Create and add some mock data (Map structures)
Dim User1 As Map = CreateMap("id": 1, "name": "Alice", "role": "Admin", "age": 28)
Dim User2 As Map = CreateMap("id": 2, "name": "Bob", "role": "User", "age": 34)
Dim User3 As Map = CreateMap("id": 3, "name": "Charlie", "role": "User", "age": 22)

ml.Add(User1)
ml.Add(User2)
ml.Add(User3)

Log("Total users added: " & ml.List.Size) ' Prints 3

2. Read and Query (R)

B4X:

' Find a specific record using its ID
Dim FoundUser As Map = ml.Find(2)
If FoundUser.IsInitialized Then
    Log("Found User ID 2: " & FoundUser.Get("name")) ' Prints "Bob"
End If

' Filter data: Find all records matching specific criteria
' Example: Find all users whose "role" is "User"
Dim MatchingUsers As List = ml.FindAll(Array As String("role"), Array As Object("User"))
For Each User As Map In MatchingUsers
    Log("Matched User: " & User.Get("name")) ' Prints "Bob" and "Charlie"
Next

' Check if a specific property key exists inside the dataset
If ml.ContainsKey("role") Then
    Log("The dataset contains a 'role' definition.")
End If

3. Update (U)

B4X:

' Grab the reference to the user profile
Dim UserToUpdate As Map = ml.Find(1)
If UserToUpdate.IsInitialized Then
    ' Modify the value directly within the collection
    UserToUpdate.Put("age", 29)
    Log("Alice's updated age: " & ml.Find(1).Get("age")) ' Prints 29
End If

4. Delete (D)

B4X:

' Option A: Remove a record using its explicit Map profile
Dim TargetUser As Map = ml.Find(3)
If TargetUser.IsInitialized Then
    ml.Remove2(TargetUser) ' Charlie is removed
End If

' Option B: Remove an item using its position index
' Let's find index position of Alice (ID: 1)
Dim ItemIndex As Long = ml.IndexFromId(1)
If ItemIndex > -1 Then
    ml.Remove(ItemIndex) ' Alice is removed
End If

5. Bonus Utilities (Sorting & Limiting)

B4X:

' Sort users by their "age" key in ascending order
ml.SortByKey("age", True)

' Limit the list to only return the top 2 elements
Dim LimitedList As MinimaList = ml.Limit(2)

' Quickly peak at the extreme boundary values
Dim TopPerson As Map = ml.First
Dim BottomPerson As Map = ml.Last

Other examples:
https://www.b4x.com/android/forum/threads/b4x-b4xtable-sample-working-with-minimalist.168717/
https://www.b4x.com/android/forum/threads/minimalist-player-scoreboard.164122/

aeric · 2026-10-07T12:35:04+0100

RIlestia said:
are there any limitations on the list size or concurrent access?

The limitation is same as B4X list and maps.
As far as I know, it has great performance.
As I suggested, use it for small apps, not for concurrent access. Do not use it to replace SQLite.

B4J Library [B4X] MinimaListUtils

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1. Initialization and Create (C)​

2. Read and Query (R)​

3. Update (U)​

4. Delete (D)​

5. Bonus Utilities (Sorting & Limiting)​

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Similar Threads

1. Initialization and Create (C)

2. Read and Query (R)

3. Update (U)

4. Delete (D)

5. Bonus Utilities (Sorting & Limiting)