13.1. Collection Class

To add, update, delete, or retrieve elements against the collection of multiple elements, use the Collection class.

There are 4 types of collection classes in SophiaFramework UNIVERSE as follows: array, stack, list, and hashmap.

Table 13.1. Collection Class

Class Name	Description
`SFXArray`	Data structure for processing a multiple of the elements as an array. The array size is variable.
`SFXStack`	Data structure for processing a multiple of the elements as a stack. The stack size is variable.
`SFXList`	Data structure for processing a multiple of the elements as a two-way linked list.
`SFXLinkedHashMap`	Data structure for operating a multiple of the key-value pairs as a hashmap. This class internally contains the two-way linked list where the elements are linked in the insertion order. `SFXHashmap` is an alias of `SFXLinkedHashMap`.
`SFXFlatHashMap`	Data structure for operating a multiple of the key-value pairs as a hashmap. This class does not contain the two-way linked list like `SFXLinkedHashMap`.

Limitation on the Collection Class

	Limitation on the Collection Class
Each element of the collection must not exceed 4 byte in length. In case of the more than 4 byte data such as the class instance or the UIint64 / SInt64 / Float64 data, its pointer should be stored into the collection as an element. However, the `SFXAnsiString` or `SFXWideString` instance can be stored into the element as the key in case of `SFXLinkedHashMap` / `SFXFlatHashMap`. But, it cannot be stored into the element as the value. Reference: How to Handle Class Instance As Element

Each element of the collection must not exceed 4 byte in length. In case of the more than 4 byte data such as the class instance or the UIint64 / SInt64 / Float64 data, its pointer should be stored into the collection as an element.

However, the SFXAnsiString or SFXWideString instance can be stored into the element as the key in case of SFXLinkedHashMap / SFXFlatHashMap. But, it cannot be stored into the element as the value.

Reference: How to Handle Class Instance As Element