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QueryTool.java
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60 lines (46 loc) · 1.42 KB
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import java.util.ArrayList;
import java.util.UUID;
public class QueryTool {
interface Filter {
boolean operation(String item);
}
public ArrayList<String> query(String query)
{
ArrayList<String> results = new ArrayList<String>() ;
// setup a sample list
results.add( "1") ;
results.add( "2") ;
results.add( "3") ;
results.add( "4") ;
results.add( "5") ;
results.add( "6") ;
results.add( "7") ;
results.add( "8") ;
results.add( "9") ;
results.add( "10") ;
// return results
return results ;
}
public ArrayList<String> map(ArrayList<String> rs, Filter f)
{
ArrayList<String> out = new ArrayList<>() ;
rs.forEach( e -> {
String key = UUID.randomUUID().toString();
if ( f.operation(e) ) {
out.add( key + " => " + e ) ;
}
}
) ;
return out ;
}
public static void main(String[] args) {
QueryTool q = new QueryTool() ;
ArrayList<String> dataset = q.query( "select * from test" ) ;
// filters functions
Filter evens = (a) -> ((Integer.parseInt(a)) % 2) == 0;
Filter odds = (a) -> ((Integer.parseInt(a)) % 2) != 0;
// Java's built-in iterator
ArrayList<String> mapset = q.map(dataset, evens) ;
mapset.forEach( e -> System.out.println(e)) ;
}
}