[BridgeAbstract] Replace getCacheDuration() with CACHE_TIMEOUT

BridgeAbstract.md

@@ -5,7 +5,6 @@ To create a new Bridge extending `BridgeAbstract` you must specify some [basic m
 - [`collectData`](#the-collectdata-function) (**required**)
 - [`getName`](#the-getname-function)
 - [`getURI`](#the-geturi-function)
-- [`getCacheDuration`](#the-getcacheduration-function)
 
 Find a [template](#template) at the end of this file.
 
@@ -19,6 +18,7 @@ const URI // URI to the target website of the bridge ("http://....")
 const DESCRIPTION // A brief description of the Bridge
 const MAINTAINER // Name of the maintainer
 const PARAMETERS // (optional) Definition of additional parameters
+const CACHE_TIMEOUT // (optional) Defines the maximum duration for the cache in seconds (default: 3600)
 ```
 
 Find a description of `const PARAMETERS` [below](#parameters)
@@ -191,18 +191,6 @@ This function returns the URI to the destination site of the bridge. It will be
 	}
 ```
 
-## The `getCacheDuration` function
-
-This function returns the time in **seconds** during which rss-bridge will output cached values instead of re-generating a RSS feed.
-
-**Notice:** **RSS-Bridge** will return `3600` seconds (1 hour) by default, so you only have to implement this function if you require different timing!
-
-```PHP
-	public function getCacheDuration(){
-		return 3600; // 1 hour
-	}
-```
-
 # Bridge Abstract functions
 
 All bridges extend from `BridgeAbstract` and therefore are able to make use of functions defined in `BridgeAbstract`. 
@@ -277,6 +265,7 @@ class MySiteBridge extends BridgeAbstract {
 	const DESCRIPTION = 'No description provided';
 	const MAINTAINER = 'No maintainer';
 	const PARAMETERS = array();
+	const CACHE_TIMEOUT = 3600;
 
 	public function collectData(){
 		// Implement your bridge here!