We have a map, whose key may be Integer, String or whatever else is a Primitive type. We want to sort it, in ascending or descending order.
Here's a quick method:
public Map<Key_object, Value_object> sortMap (Map<Key_object, Value_object> theMap, String theOrder) {
    //create the return map
    Map<Key_object, Value_object> returnMap = new Map<Key_object, Value_object>();
    //get the set of the keys of the map we want to sort
    Set<Key_object> keySet = theMap.keySet();
    //create a list and add all the keys from the set
    //a small workaround needed because we can't sort a set
    List<Key_object> keyList = new List<Key_object>();
    keyList.addAll(keySet);
    //sort the list ascending (predefined behaviour)
    keyList.sort();
    if (theOrder == 'DESC')
        //iterate from the last to the first key over the ascending ordered key list
        for (Integer i = (keyList.size() - 1); i >= 0; i--)
            returnMap.put(keyList[i], theMap.get(keyList[i]));
    else
        //iterate from the first to the last key over the ascending ordered key list
        for (Integer i = 0; i < keyList.size(); i++)
            returnMap.put(keyList[i], theMap.get(keyList[i]));
    //return the sorted map
    return returnMap;
}
Of course we can omit the part regarding the order (if we want only ascending or descending order) or create two different methods for this.
 
Sort this map
ReplyDeletetheMap.put('Uiyt',5);
theMap.put('jkiyt',10);
theMap.put('sgd',1);
theMap.put('ajsgdajs',1);
theMap.put('sgd',9);
Thanks a lot, here I copy the (String, Integer) version.
ReplyDeletepublic static Map sortMap (Map theMap, String theOrder) {
//create the return map
Map returnMap = new Map();
//get the set of the keys of the map we want to sort
Set keySet = theMap.keySet();
//create a list and add all the keys from the set
//a small workaround needed because we can't sort a set
List keyList = new List();
keyList.addAll(keySet);
//sort the list ascending (predefined behaviour)
keyList.sort();
if (theOrder == 'DESC')
//iterate from the last to the first key over the ascending ordered key list
for (Integer i = (keyList.size() - 1); i >= 0; i--)
returnMap.put(keyList[i], theMap.get(keyList[i]));
else
//iterate from the first to the last key over the ascending ordered key list
for (Integer i = 0; i < keyList.size(); i++)
returnMap.put(keyList[i], theMap.get(keyList[i]));
//return the sorted map
return returnMap;
}