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Commit c40448f

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Merge branch 'main' into fix_test_for_crazy_generics_strict_processor_order_24
2 parents fedd095 + 84eb88a commit c40448f

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3 files changed

+66
-6
lines changed

3 files changed

+66
-6
lines changed

‎1-0-java-basics/1-3-1-crazy-generics/src/test/java/com/bobocode/basics/CrazyGenericsTest.java‎

Lines changed: 2 additions & 3 deletions
Original file line numberDiff line numberDiff line change
@@ -187,7 +187,7 @@ void maxHolderClassTypeParameterShouldBeBoundByComparableT() {
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var typeParam = typeParameters[0];
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var boundType = typeParam.getBounds()[0];
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190-
var expectedBoundTypeName = String.format("%s<%s>", Comparable.class.getTypeName(), TYPE_PARAMETER_NAME);
190+
var expectedBoundTypeName = String.format("%s<? super %s>", Comparable.class.getTypeName(), TYPE_PARAMETER_NAME);
191191
assertThat(boundType.getTypeName()).isEqualTo(expectedBoundTypeName);
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}
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@@ -288,12 +288,11 @@ void strictProcessorTypeParameterIsCalledT() {
288288
void strictProcessorTypeParameterIsBoundBySerializableAndComparable() {
289289
var typeParameters = StrictProcessor.class.getTypeParameters();
290290
var typeParam = typeParameters[0];
291-
292291
assertThat(typeParam.getBounds())
293292
.hasSize(2)
294293
.extracting(Type::getTypeName)
295294
.containsExactlyInAnyOrder(Serializable.class.getTypeName(),
296-
String.format("%s<%s>", Comparable.class.getTypeName(), TYPE_PARAMETER_NAME));
295+
String.format("%s<? super %s>", Comparable.class.getTypeName(), TYPE_PARAMETER_NAME));
297296
}
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@Test

‎5-0-functional-programming/5-1-1-crazy-lambdas/src/main/java/com/bobocode/fp/CrazyLambdas.java‎

Lines changed: 39 additions & 0 deletions
Original file line numberDiff line numberDiff line change
@@ -3,6 +3,7 @@
33
import com.bobocode.util.ExerciseNotCompletedException;
44

55
import java.math.BigDecimal;
6+
import java.util.Comparator;
67
import java.util.Map;
78
import java.util.function.*;
89

@@ -190,6 +191,44 @@ public static BiFunction<Map<String, IntUnaryOperator>, String, IntUnaryOperator
190191
throw new ExerciseNotCompletedException();
191192
}
192193

194+
/**
195+
* Returns a comparator of type T that is comparing values extracted using the provided mapper function.
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* <p>
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* E.g. imagine you need to compare accounts by their balance values.
198+
* <pre>{@code
199+
* Comparator<Account> balanceComparator = comparing(Account::getBalance);
200+
* }</pre>
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* <p>
202+
* PLEASE NOTE, that @{@link Comparator} is a functional interface, and you should manually write a lambda expression
203+
* to implement it.
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*
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* @param mapper a mapper function that allows to map an object to a comparable value
206+
* @return a comparator instance
207+
*/
208+
public static <T, U extends Comparable<? super U>> Comparator<T> comparing(Function<? super T, ? extends U> mapper) {
209+
throw new ExerciseNotCompletedException();
210+
}
211+
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/**
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* Returns a comparator of type T that uses a provided comparator to compare objects, and only if they are equal
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* it's comparing values extracted using the provided mapper function.
215+
* <p>
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* E.g. suppose you want to compare accounts by balance, but in case two people have the same balance you want to
217+
* compare their first names:
218+
* <pre>{@code
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* Comparator<Account> accountComparator = thenComparing(balanceComparator, Account::getFirstName);
220+
* }</pre>
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* <p>
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*
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* @param comparator an initial comparator
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* @param mapper a mapper function that is used to extract values when initial comparator returns zero
225+
* @return a comparator instance
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*/
227+
public static <T, U extends Comparable<? super U>> Comparator<T> thenComparing(
228+
Comparator<? super T> comparator, Function<? super T, ? extends U> mapper) {
229+
throw new ExerciseNotCompletedException();
230+
}
231+
193232
/**
194233
* Returns {@link Supplier} of {@link Supplier} of {@link Supplier} of {@link String} "WELL DONE!".
195234
*

‎5-0-functional-programming/5-1-1-crazy-lambdas/src/test/java/com/bobocode/fp/CrazyLambdasTest.java‎

Lines changed: 25 additions & 3 deletions
Original file line numberDiff line numberDiff line change
@@ -6,12 +6,11 @@
66
import org.junit.jupiter.api.TestMethodOrder;
77

88
import java.math.BigDecimal;
9-
import java.util.HashMap;
10-
import java.util.Map;
11-
import java.util.Queue;
9+
import java.util.*;
1210
import java.util.concurrent.ConcurrentLinkedQueue;
1311
import java.util.function.*;
1412

13+
import static org.assertj.core.api.Assertions.assertThat;
1514
import static org.junit.jupiter.api.Assertions.*;
1615

1716
/**
@@ -252,6 +251,29 @@ void functionLoader() {
252251

253252
@Test
254253
@Order(18)
254+
void comparing() {
255+
var strLengthComparator = CrazyLambdas.comparing(String::length);
256+
var stringList = new ArrayList<>(List.of("Me", "I", "All of us", "They", "She"));
257+
258+
stringList.sort(strLengthComparator);
259+
260+
assertThat(stringList).isEqualTo(List.of("I", "Me", "She", "They", "All of us"));
261+
}
262+
263+
@Test
264+
@Order(19)
265+
void thenComparing() {
266+
var strLengthComparator = Comparator.comparing(String::length);
267+
var lengthThenNaturalComparator = CrazyLambdas.thenComparing(strLengthComparator, s -> s);
268+
var stringList = new ArrayList<>(List.of("Me", "I", "All of us", "They", "She", "He"));
269+
270+
stringList.sort(lengthThenNaturalComparator);
271+
272+
assertThat(stringList).isEqualTo(List.of("I", "He", "Me", "She", "They", "All of us"));
273+
}
274+
275+
@Test
276+
@Order(20)
255277
void trickyWellDoneSupplier() {
256278
Supplier<Supplier<Supplier<String>>> wellDoneSupplier = CrazyLambdas.trickyWellDoneSupplier();
257279

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