siegfriedix / hw7 Goto Github PK

Task
To better understand how the stream operations work, we suggest
you to implement such methods:
package com.geekhub.collections;
import java.util.Comparator;
import java.util.List;
import java.util.Map;
import java.util.Optional;
import java.util.function.Bin aryOperator;
import java.util.function.Con sumer;
import java.util.function.Fun ction;
import java.util.function.Pre dicate;
public class CollectionUtils {
private CollectionUtils() {
}
public static < E > List< E > filter(List< E > elements, Predicate< E > filter) {
//TODO Implement me
return null ;
}
public static < E > boolean anyMatch(List< E > elements, Predicate< E > predicate) {
//TODO Implement me
return false ;
}
public static < E > boolean allMatch(List< E > elements, Predicate< E > predicate) {
//TODO Implement me
return false ;
}
public static < E > boolean noneMatch(List< E > elements, Predicate< E > predicate) {
//TODO Implement me
return false ;
}
public static < T , R > List< R > map(List< T > elements, Function< T , R > mappingFunction) {
//TODO Implement me
return null ;
}
public static < E > Optional< E > max(List< E > elements, Comparator< E > comparator) {
//TODO Implement me
return null ;
}
public static < E > Optional< E > min(List< E > elements, Comparator< E > comparator) {
//TODO Implement me
return null ;
}
public static < E > List< E > distinct(List< E > elements) {
//TODO Implement me
return null ;
}
public static < E > void forEach(List< E > elements, Consumer< E > consumer) {
//TODO Implement me
}
public static < E > Optional< E > reduce(List< E > elements, BinaryOper ator< E > accumulator) {
//TODO Implement me
return null ;
}
public static < E > E reduce( E seed, List< E > elements, BinaryOperat or< E > accumulator) {
//TODO Implement me
return null ;
}
public static < E > Map<Boolean, List< E >> partitionBy(List< E > elements, Predicate< E > predicate) {
//TODO Implement me
return null ;
}
public static < T , K > Map< K , List< T >> groupBy(List< T > elements, Fu nction< T , K > classifier) {
//TODO Implement me
return null ;
}
public static < T , K , U > Map< K , U > toMap(List< T > elements,
Function< T , K > keyFunction,
Function< T , U > valueFunction,
BinaryOperator< U > mergeFunction) {
//TODO Implement me
return null ;
}
}
You are NOT supposed to use the stream API inside these
methods.