public static void main(String[] args) throws IOException {
DB db = DBMaker.newMemoryDB().make();
//
// TreeMap has build in support for lazily loaded values.
// In that case each value are not stored inside node,
// but in separate record.
//
// use DB.createTreeMap to create TreeMap with non-default parameters
Map map = db.createTreeMap("name").valuesOutsideNodesEnable().make();
map.put("key", "this string is loaded lazily with 'map.get(key)' ");
//
// Other option for lazily loaded record is to use Atomic.Var.
// In this case you have singleton record with name.
// As bonus you can update reference in thread-safe atomic manner.
//
Atomic.Var<String> record = db.createAtomicVar("lazyRecord", "aaa", db.getDefaultSerializer());
record.set("some value");
System.out.println(record.get());
// Last option is to use low level Engine storage directly.
// Each stored record gets assigned unique recid (record id),
// which is latter used to get or update record.
// Your code should store only recid as reference to object.
// All MapDB collections are written this way.
// insert new record
long recid = db.getEngine().put("something", SerializerBase.STRING_NOSIZE);
// load record
String lazyString = db.getEngine().get(recid, SerializerBase.STRING_NOSIZE);
// update record
db.getEngine().update(recid, "new value", SerializerBase.STRING_NOSIZE);
// I hope this example helped!
db.close();
}
