Map Class

Map (Foundation class) consist of a data set that contains a key and a corresponding value, where the key is unique. The key and the value need not be from the same data type.

A Map is always sorted on the key value.

Define
Map m = new Map(Types::STRING, Types::INTEGER); or Map m = new Map(typeId2Type(typeid(recId)), Types::Record);

Insert a value
m.insert("Wassini", 37); m.insert("Eric", 102);

Exists value
To see if a value already is added, use the exists method: if (m.exists("Wassini")) print "Yes!"; else print "No!";

Lookup value
To get the value linked to a specific key use the lookup method: Integer i;

i = m.lookup("Wassini")) If key don't exist in map lookup function throw error so is better to test before is key exist

Getting values
There are several ways to get the values in the map.


 * 1) Using a MapIterator
 * 2) Using a MapEnumerator
 * 3) Using a direct method

MapIterator
The MapIterator loops throug the complete map:

MapIterator mi;

mi = new MapIterator(m);

while (mi.more) { print mi.key; print mi.value;

mi.next; }

MapEnumerator
MapEnumerator Class is like MapIterator Class, but does not allow the deletion of elements during enumeration. MapEnumerator Class automatically created on the same tier as the Map Class, and MapIterator does not. MapEnumerator me = m.getEnumerator;

while (me.moveNext) { print me.currentKey; print me.currentValue; }

Direct method
It is possible to get find a specific value from the key:

print m.lookup("Wassini");

Removing values
Just use the remove method to remove the active key/value pair.

m.remove("Wassini");

Updating values
It is not possible to update a value directly: int age; str keyid = "Wassini";

age = m.exists(keyid) ? m.lookup(keyid) : 0; m.insert(keyid, age + 1);

Other methods
// Get number of elements: print m.elements;

// Get the used types: print m.definitionString;

// Dump the whole map as a string: print m.toString;

Passing across tiers
As with other foundation classes, the Map can be passed across tiers by converting it to a container. The pack method converts it to a container: container packedMap = m.pack; To convert the packed container back to a Map, call the static create method of the Map class: Map map = Map::create(packedMap);