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Golubev Nikita - Part2 #84

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31221f8
Generator
Jul 11, 2017
7e9c98a
part2
Jul 13, 2017
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5 changes: 3 additions & 2 deletions src/main/java/data/Generator.java
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Original file line number Diff line number Diff line change
Expand Up @@ -60,7 +60,8 @@ public static Employee generateEmployee() {
}

public static List<Employee> generateEmployeeList() {
// TODO
throw new UnsupportedOperationException();
return Stream.generate(Generator::generateEmployee)
.limit(15)
.collect(toList());
}
}
90 changes: 85 additions & 5 deletions src/test/java/part2/exercise/CollectorsExercise1.java
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Expand Up @@ -23,7 +23,6 @@ public class CollectorsExercise1 {
@Test
public void getTheCoolestOne() {
final Map<String, Person> coolestByPosition = getCoolestByPosition(getEmployees());

coolestByPosition.forEach((position, person) -> System.out.println(position + " -> " + person));
}

Expand Down Expand Up @@ -61,8 +60,78 @@ private Map<String, Person> getCoolestByPosition(List<Employee> employees) {
// Second option
// Collectors.toMap
// iterate twice: stream...collect(...).stream()...
// TODO
throw new UnsupportedOperationException();
final Map<String,Person> result;

employees.stream()
.flatMap(CollectorsExercise1::employeeInfo)
.collect(Collectors.groupingBy(PersonPositionDuration::getPosition, Collectors.collectingAndThen(
Collectors.maxBy(
Comparator.comparingInt(PersonPositionDuration::getDuration)),
info -> info.get().getPerson())));
employees.stream()
.flatMap(CollectorsExercise1::employeeInfo)
.collect(new Collector<PersonPositionDuration, Map<String,PersonPositionDuration>, Map<String,Person>>() {
@Override
public Supplier<Map<String, PersonPositionDuration>> supplier() {
return HashMap::new;
}

@Override
public BiConsumer<Map<String, PersonPositionDuration>, PersonPositionDuration> accumulator() {
return (map, info) -> map.merge(
info.getPosition(),
info,
(ppd1,ppd2) -> ppd2.getDuration() > ppd1.getDuration() ? ppd2 : ppd1);
}

@Override
public BinaryOperator<Map<String, PersonPositionDuration>> combiner() {
return (map1,map2) -> {
for (PersonPositionDuration info : map2.values()){
PersonPositionDuration mapInfo = map1.get(info.getPosition());
if (mapInfo == null || info.getDuration() > mapInfo.getDuration()){
map1.put(info.getPosition(),info);
}
}
return map1;
};
}

@Override
public Function<Map<String, PersonPositionDuration>, Map<String, Person>> finisher() {
return mapInfo -> mapInfo
.entrySet()
.stream()
.map(Map.Entry::getValue)
.collect(Collectors.toMap(
PersonPositionDuration::getPosition,
PersonPositionDuration::getPerson));
}

@Override
public Set<Characteristics> characteristics() {
return Collections.emptySet();
}
});

result = getCoolestByPositionFromStream(employees.stream().flatMap(CollectorsExercise1::employeeInfo));
return result;
}

private static Stream<PersonPositionDuration> employeeInfo(Employee employee) {
return employee.getJobHistory().stream()
.map(entry -> new PersonPositionDuration(employee.getPerson(),
entry.getPosition(),
entry.getDuration()));
}

private static Map<String,Person> getCoolestByPositionFromStream(Stream<PersonPositionDuration> upstream){
return upstream
.collect(Collectors.toMap(PersonPositionDuration::getPosition,Function.identity(),
(ppd1,ppd2) -> ppd2.getDuration() > ppd1.getDuration() ? ppd2 : ppd1))
.entrySet()
.stream()
.collect(Collectors.toMap(Map.Entry::getKey,entry -> entry.getValue().getPerson()));
}

@Test
Expand All @@ -75,8 +144,19 @@ public void getTheCoolestOne2() {
// With the longest sum duration on this position
// { John Doe, [{dev, google, 4}, {dev, epam, 4}] } предпочтительнее, чем { A B, [{dev, google, 6}, {QA, epam, 100}]}
private Map<String, Person> getCoolestByPosition2(List<Employee> employees) {
// TODO
throw new UnsupportedOperationException();
return getCoolestByPositionFromStream(employees.stream()
.flatMap(CollectorsExercise1::employeeInfoDuration));
}

private static Stream<PersonPositionDuration> employeeInfoDuration(Employee employee) {
return employeeInfo(employee)
.collect(Collectors.groupingBy(PersonPositionDuration::getPosition))
.entrySet()
.stream()
.map(entry -> new PersonPositionDuration(
employee.getPerson(),
entry.getKey(),
entry.getValue().stream().mapToInt(PersonPositionDuration::getDuration).sum()));
}

private List<Employee> getEmployees() {
Expand Down
176 changes: 92 additions & 84 deletions src/test/java/part2/exercise/CollectorsExercise2.java
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Original file line number Diff line number Diff line change
Expand Up @@ -16,10 +16,12 @@
import java.util.stream.IntStream;
import java.util.stream.Stream;

import static java.util.stream.Collectors.toList;
import static java.util.stream.Collectors.*;
import static org.junit.Assert.assertEquals;

public class CollectorsExercise2 {


private static String generateString() {
final String letters = "ABCDEFGHIJKLMNOPQRSTUVWXYZ";
final int maxLength = 10;
Expand Down Expand Up @@ -131,15 +133,15 @@ public Map<String, List<Key>> getKnownKeys() {
}
}

private static class MapPair {
public static class MapPair {
private final Map<String, Key> keyById;
private final Map<String, List<Value>> valueById;
private final Map<String, Set<Value>> valueById;

public MapPair() {
this(new HashMap<>(), new HashMap<>());
}

public MapPair(Map<String, Key> keyById, Map<String, List<Value>> valueById) {
public MapPair(Map<String, Key> keyById, Map<String, Set<Value>> valueById) {
this.keyById = keyById;
this.valueById = valueById;
}
Expand All @@ -148,17 +150,67 @@ public Map<String, Key> getKeyById() {
return keyById;
}

public Map<String, List<Value>> getValueById() {
public Map<String, Set<Value>> getValueById() {
return valueById;
}
}

private static <K, V, M extends Map<K, V>>
static class MapPairCollector implements Collector<Pair, MapPair, MapPair> {

@Override
public Supplier<MapPair> supplier() {
return MapPair::new;
}

@Override
public BiConsumer<MapPair, Pair> accumulator() {
return (MapPair mapPair, Pair pair) -> {
mapPair.getKeyById().put(pair.getKey().getId(), pair.getKey());
mapPair.getValueById()
.merge(
pair.getValue().getKeyId(),
new HashSet<>(Collections.singletonList(pair.getValue())),
(values, values2) -> {
values.addAll(values2);
return values;
});
};
}

@Override
public BinaryOperator<MapPair> combiner() {
return (mapPair, mapPair2) -> {
BinaryOperator<Map<String, Key>> keyMerger = mapMerger((key, key2) -> key);
Map<String, Key> keyMap = keyMerger.apply(mapPair.getKeyById(), mapPair2.getKeyById());

BinaryOperator<Map<String, Set<Value>>> valueMerger = mapMerger((values, values2) -> {
values.addAll(values2);
return values;
});
Map<String, Set<Value>> valueMap = valueMerger.apply(mapPair.getValueById(), mapPair2.getValueById());

return new MapPair(keyMap, valueMap);
};
}

@Override
public Function<MapPair, MapPair> finisher() {
return Function.identity();
}

@Override
public Set<Characteristics> characteristics() {
return Collections.unmodifiableSet(EnumSet.of(
Characteristics.UNORDERED,
Characteristics.IDENTITY_FINISH));
}
}

public static <K, V, M extends Map<K, V>>
BinaryOperator<M> mapMerger(BinaryOperator<V> mergeFunction) {
return (m1, m2) -> {
for (Map.Entry<K, V> e : m2.entrySet()) {
for (Map.Entry<K, V> e : m2.entrySet())
m1.merge(e.getKey(), e.getValue(), mergeFunction);
}
return m1;
};
}
Expand All @@ -168,90 +220,46 @@ public void collectKeyValueMap() {
final List<Pair> pairs = generatePairs(10, 100);

// В два прохода
// final Map<String, Key> keyMap1 = pairs.stream()...

// final Map<String, List<Value>> valuesMap1 = pairs.stream()...
final Map<String, Key> keyMap1 = pairs.stream()
.collect(
toMap(
p -> p.getKey().getId(),
Pair::getKey,
(key, key2) -> key)
);

final Map<String, Set<Value>> valuesMap1 = pairs.stream()
.collect(
groupingBy(
p -> p.getValue().getKeyId(),
mapping(Pair::getValue, toSet())
)
);

// В каждом Map.Entry id ключа должно совпадать с keyId для каждого значения в списке
// final Map<Key, List<Value>> keyValuesMap1 = valueMap1.entrySet().stream()...
final Map<Key, Set<Value>> keyValuesMap1 = valuesMap1.entrySet().stream()
.filter(entry -> keyMap1.containsKey(entry.getKey()))
.collect(
toMap(
entry -> keyMap1.get(entry.getKey()),
Map.Entry::getValue)
);

// В 1 проход в 2 Map с использованием MapPair и mapMerger
final MapPair res2 = pairs.stream()
.collect(new Collector<Pair, MapPair, MapPair>() {
@Override
public Supplier<MapPair> supplier() {
// TODO
throw new UnsupportedOperationException();
}

@Override
public BiConsumer<MapPair, Pair> accumulator() {
// TODO add key and value to maps
throw new UnsupportedOperationException();
}

@Override
public BinaryOperator<MapPair> combiner() {
// TODO use mapMerger
throw new UnsupportedOperationException();
}

@Override
public Function<MapPair, MapPair> finisher() {
return Function.identity();
}

@Override
public Set<Characteristics> characteristics() {
return Collections.unmodifiableSet(EnumSet.of(
Characteristics.UNORDERED,
Characteristics.IDENTITY_FINISH));
}
});

.collect(new MapPairCollector());
final Map<String, Key> keyMap2 = res2.getKeyById();
final Map<String, List<Value>> valuesMap2 = res2.getValueById();

// final Map<Key, List<Value>> keyValuesMap2 = valueMap2.entrySet().stream()...

// Получение результата сразу:

final SubResult res3 = pairs.stream()
.collect(new Collector<Pair, SubResult, SubResult>() {
@Override
public Supplier<SubResult> supplier() {
// TODO
throw new UnsupportedOperationException();
}

@Override
public BiConsumer<SubResult, Pair> accumulator() {
// TODO add key to map, then check value.keyId and add it to one of maps
throw new UnsupportedOperationException();
}

@Override
public BinaryOperator<SubResult> combiner() {
// TODO use mapMerger, then check all valuesWithoutKeys
throw new UnsupportedOperationException();
}

@Override
public Function<SubResult, SubResult> finisher() {
// TODO use mapMerger, then check all valuesWithoutKeys
throw new UnsupportedOperationException();
}

@Override
public Set<Characteristics> characteristics() {
return Collections.unmodifiableSet(EnumSet.of(
Characteristics.UNORDERED));
}
});
final Map<String, Set<Value>> valuesMap2 = res2.getValueById();

final Map<Key, List<Value>> keyValuesMap3 = res3.getSubResult();
final Map<Key, Set<Value>> keyValuesMap2 = valuesMap2.entrySet().stream()
.filter(entry -> keyMap2.containsKey(entry.getKey()))
.collect(
toMap(
entry -> keyMap2.get(entry.getKey()),
Map.Entry::getValue)
);

// compare results
assertEquals(keyValuesMap1, keyValuesMap2);
}

}