The `FormatInterface`interface defines functions that need to be implemented by all formats:
* [display](#the-display-function)
* [stringify](#the-stringify-function)
* [setItems](#the-setitems-function)
* [getItems](#the-getitems-function)
* [setCharset](#the-setcharset-function)
* [getCharset](#the-getcharset-function)
* [setExtraInfos](#the-setextrainfos-function)
* [getExtraInfos](#the-getextrainfos-function)
* [getMimeType](#the-getmimetype-function)
Find a [template](#template) at the end of this file
# Functions
## The `stringify` function
The `stringify` function returns the items received by [`setItems`](#the-setitem-function) as string.
```PHP
stringify(): string
```
## The `setItems` function
The `setItems` function receives an array of items generated by the bridge and must return the object instance. Each item represents an entry in the feed. For more information refer to the [collectData](../05_Bridge_API/02_BridgeAbstract.md#collectdata) function.
```PHP
setItems(array $items): self
```
## The `getItems` function
The `getItems` function returns the items previously set by the [`setItems`](#the-setitems-function) function. If no items where set previously this function returns an error.
```PHP
getItems(): array
```
## The `setCharset` function
The `setCharset` function receives the character set value as string and returns the object instance.
```PHP
setCharset(string): self
```
## The `getCharset` function
The `getCharset` function returns the character set value.
```PHP
getCharset(): string
```
## The `setExtraInfos` function
The `setExtraInfos` function receives an array of elements with additional information to generate format outputs and must return the object instance.
```PHP
setExtraInfos(array $infos): self
```
Currently supported information are:
Name | Description
-----|------------
`name` | Defines the name as generated by the bridge
`uri` | Defines the URI of the feed as generated by the bridge
## The `getExtraInfos` function
The `getExtraInfos` function returns the information previously set via the [`setExtraInfos`](#the-setextrainfos-function) function.
```PHP
getExtraInfos(): array
```
## The `getMimeType` function
The `getMimeType` function returns the expected [MIME type](https://en.wikipedia.org/wiki/Media_type#Common_examples) of the format's output.