/**
* BPlusTree<K,E>
* K is the genericity of entry that need to be comparable
* E is the genericity of data item that can be any object
*/
BPlusTree<Integer,String> bPlusTree = new BPlusTree<>(16);//instance B+Tree with specific order

//instance B+Tree with default order
BPlusTree<Integer,String> bPlusTree = new BPlusTree<>(); //default order is 9

bPlusTree.insert(0, "data record 1");
bPlusTree.insert(0, "data record 2");
bPlusTree.insert(1, "data record 3");
bPlusTree.insert(2, "data record 4");
bPlusTree.insert(3, "data record 5");

//query all data records under the entry 0
List<String> queryResult = bPlusTree.query(0);
System.out.println(queryResult); //[data record 2, data record 1]

//query all data records under the entries [0,3)
List<String> queryResult = bPlusTree.rangeQuery(0, 3);
System.out.println(queryResult); //[data record 2, data record 1, data record 3, data record 4]

//return true if update successfully, false otherwise
bPlusTree.update(0, "data record 2", "data record 12");
System.out.println(bPlusTree.query(0)); //[data record 1, data record 12]

/**
* remove all data records under the entry
* return true if remove successfully, false otherwise
*/
bPlusTree.remove(1);
System.out.println(bPlusTree.query(1)); //[]

/**
* remove specific data record under the entry (using ".equals()" to determine whether certain data record is the present)
* return true if remove successfully, false otherwise
*/
bPlusTree.remove(0, "data record 12");
System.out.println(bPlusTree.query(0)); //[data record 1]