/** Under development. * Need to add charts */ import java.util.*; import java.util.stream.*; public class Program { public static void main(String[] args) { TableClient client = new TableClient(); TableClient.Table myTable = client.getTableReference("language"); TableEntity cPlusPlus = new TableEntity("2018", "c++"); cPlusPlus.setValue(1.5); TableOperation op1 = new InsertOperation(cPlusPlus); myTable.setOperation(op1); myTable.execute(); TableEntity java = new TableEntity("2018", "java"); java.setValue(2.5); TableOperation op2 = new InsertOperation(java); myTable.setOperation(op2); myTable.execute(); Filtery myFilter = new Filtery(null, "c++"); TableOperation op3 = new SelectOperation(myFilter); myTable.setOperation(op3); List result = myTable.executeQuery(); for (TableEntity te : result) { System.out.println(te); } } } /////// MAIN LOGIC ////////////////// /////// API FOR STORAGE //////////// //*** outter **** class TableClient { //inner class class Table { private String name; private ArrayList entities = new ArrayList<>(); private TableOperation operation; protected Table(String name) { this.name = name; } public String getName() { return name; } public void setOperation(TableOperation operation) { this.operation = operation; } public void execute() { operation.doWork(entities); } public List executeQuery() { return operation.executeQuery(entities); } }// end inner class private ArrayList tables = new ArrayList<>(); public Table getTableReference(String tableName) { var entity = tables.stream() .filter(t -> t.getName().equals(tableName)) .findFirst(); if (entity.isPresent()) return entity.get(); else return createIfNotExists(tableName); } private Table createIfNotExists(String tableName) { Table table = new Table(tableName); tables.add(table); return table; } } // end outter class //*** entity for data *** class TableEntity { String first; String second; double value; public TableEntity(String first, String second) { this.first = first; this.second = second; } public void setValue(double value) { this.value = value; } public String getFirst() { return first; } public String getSecond() { return second; } public double getValue() { return value; } @Override public String toString() { return String.format("Year: %s Tech: %s Value: %.2f", first, second, value); } } // end entity //**** operation section ***** interface TableOperation { void doWork(ArrayList entities); List executeQuery(ArrayList entities); } class InsertOperation implements TableOperation { private TableEntity entity; public InsertOperation(TableEntity entity) { this.entity = entity; } public void doWork(ArrayList entities) { entities.add(entity); } public List executeQuery(ArrayList entities) { return null; } } class SelectOperation implements TableOperation { private Filtery filtery; public SelectOperation(Filtery filtery) { this.filtery = filtery; } public void doWork(ArrayList entities) { // empty // } public List executeQuery(ArrayList entities) { var tmp = entities.stream() .filter(e -> (e.first.equals(filtery.getFirstKey()) && e.second.equals(filtery.getSecondKey())) || (filtery.getFirstKey() == null && filtery.getSecondKey() == null) || e.first.equals(filtery.getFirstKey()) || e.second.equals(filtery.getSecondKey())) .collect(Collectors.toList()); return tmp; } } //**** end operation section // for filtration class Filtery { private String firstKey; private String secondKey; public Filtery(String firstKey, String secondKey) { this.firstKey = firstKey; this.secondKey = secondKey; } public String getFirstKey() { return firstKey; } public String getSecondKey() { return secondKey; } } // end

My API for storage