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BAEL-7: Use Collection interface

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This commit is contained in:
Hector Romero 2016-12-01 08:16:25 -06:00
parent 01d66ecce9
commit de33c9ce0b
1 changed files with 59 additions and 35 deletions
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94
core-java/src/test/java/org/baeldung/java/collections/JoinSplitCollectionsUnitTest.java
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@ -6,9 +6,11 @@ import static org.junit.Assert.assertTrue;
import java.util.ArrayList;
import java.util.Arrays;
import java.util.Collection;
import java.util.HashMap;
import java.util.List;
import java.util.Map;
import java.util.concurrent.atomic.AtomicInteger;
import java.util.stream.Collectors;
import java.util.stream.Stream;
@ -25,14 +27,25 @@ public class JoinSplitCollectionsUnitTest {
assertArrayEquals(result, new String[] { "Dog", "Cat", "Bird", "Cow" });
}
@Test
public void whenJoiningTwoCollections_thenJoined() {
Collection<Integer> collection1 = Arrays.asList(7, 8, 9);
Collection<Integer> collection2 = Arrays.asList(10, 11, 12);
Collection<Integer> result = Stream.concat(collection1.stream(), collection2.stream())
.collect(Collectors.toList());
assertTrue(result.equals(Arrays.asList(7, 8, 9, 10, 11, 12)));
}
@Test
public void whenJoiningTwoListsWithFilter_thenJoined() {
List<Integer> list1 = Arrays.asList(7, 8, 11);
List<Integer> list2 = Arrays.asList(9, 12, 10);
List<Integer> result = Stream.concat(list1.stream(), list2.stream()).filter(next -> next <= 10)
public void whenJoiningTwoCollectionsWithFilter_thenJoined() {
Collection<Integer> collection1 = Arrays.asList(7, 8, 11);
Collection<Integer> collection2 = Arrays.asList(9, 12, 10);
Collection<Integer> result = Stream.concat(collection1.stream(), collection2.stream())
.filter(next -> next <= 10)
.collect(Collectors.toList());
assertTrue(result.equals(Arrays.asList(7, 8, 9, 10)));
}
@ -46,11 +59,11 @@ public class JoinSplitCollectionsUnitTest {
}
@Test
public void whenConvertListToString_thenConverted() {
List<String> directions = Arrays.asList("Left", "Right", "Top", "Bottom");
public void whenConvertCollectionToString_thenConverted() {
Collection<String> directions = Arrays.asList("Left", "Right", "Top", "Bottom");
String result = directions.stream()
.collect(Collectors.joining(", "));
assertEquals(result, "Left, Right, Top, Bottom");
}
@ -68,49 +81,60 @@ public class JoinSplitCollectionsUnitTest {
}
@Test
public void whenConvertNestedListToString_thenConverted() {
List<List<String>> nested = new ArrayList<>();
public void whenConvertNestedCollectionToString_thenConverted() {
Collection<List<String>> nested = new ArrayList<>();
nested.add(Arrays.asList("Left", "Right", "Top", "Bottom"));
nested.add(Arrays.asList("Red", "Blue", "Green", "Yellow"));
String result = nested.stream()
.map(nextList -> nextList.stream()
.collect(Collectors.joining("-")))
.collect(Collectors.joining("; "));
assertEquals(result, "Left-Right-Top-Bottom; Red-Blue-Green-Yellow");
}
@Test
public void whenConvertListToStringAndSkipNull_thenConverted() {
List<String> fruits = Arrays.asList("Apple", "Orange", null, "Grape");
public void whenConvertCollectionToStringAndSkipNull_thenConverted() {
Collection<String> fruits = Arrays.asList("Apple", "Orange", null, "Grape");
String result = fruits.stream()
.filter(next -> next != null)
.collect(Collectors.joining(", "));
assertEquals(result, "Apple, Orange, Grape");
}
@Test
public void whenSplitListGroupOddEven_thenConverted() {
List<Integer> list = Arrays.asList(1, 2, 3, 4, 5, 6, 7, 8, 9, 10);
Map<Boolean, List<Integer>> result = list.stream()
.collect(Collectors.partitioningBy(number -> number % 2 == 0));
public void whenSplitCollectionHalf_thenConverted() {
Collection<Integer> numbers = Arrays.asList(1, 2, 3, 4, 5, 6, 7, 8, 9, 10);
Collection<Integer> result1 = new ArrayList<>();
Collection<Integer> result2 = new ArrayList<>();
AtomicInteger count = new AtomicInteger();
int midpoint = Math.round(numbers.size() / 2);
assertTrue(result.get(true).equals(Arrays.asList(2, 4, 6, 8, 10)));
assertTrue(result.get(false).equals(Arrays.asList(1, 3, 5, 7, 9)));
numbers.forEach(next -> {
int index = count.getAndIncrement();
if(index < midpoint){
result1.add(next);
}else{
result2.add(next);
}
});
assertTrue(result1.equals(Arrays.asList(1, 2, 3, 4, 5)));
assertTrue(result2.equals(Arrays.asList(6, 7, 8, 9, 10)));
}
@Test
public void whenSplitArrayByWordLength_thenConverted() {
String[] words = new String[]{"bye", "cold", "it", "and", "my", "word"};
Map<Integer, List<String>> result = Arrays.stream(words)
.collect(Collectors.groupingBy(word -> word.length()));
assertTrue(result.get(2).equals(Arrays.asList("it", "my")));
assertTrue(result.get(3).equals(Arrays.asList("bye", "and")));
assertTrue(result.get(4).equals(Arrays.asList("cold", "word")));
}
@Test
public void whenSplitArrayByWordLength_thenConverted() {
String[] words = new String[]{"bye", "cold", "it", "and", "my", "word"};
Map<Integer, List<String>> result = Arrays.stream(words)
.collect(Collectors.groupingBy(word -> word.length()));
assertTrue(result.get(2).equals(Arrays.asList("it", "my")));
assertTrue(result.get(3).equals(Arrays.asList("bye", "and")));
assertTrue(result.get(4).equals(Arrays.asList("cold", "word")));
}
@Test
public void whenConvertStringToArray_thenConverted() {
@ -121,9 +145,9 @@ public void whenSplitArrayByWordLength_thenConverted() {
}
@Test
public void whenConvertStringToList_thenConverted() {
public void whenConvertStringToCollection_thenConverted() {
String colors = "Left, Right, Top, Bottom";
List<String> result = Arrays.asList(colors.split(", "));
Collection<String> result = Arrays.asList(colors.split(", "));
assertTrue(result.equals(Arrays.asList("Left", "Right", "Top", "Bottom")));
}
@ -142,10 +166,10 @@ public void whenSplitArrayByWordLength_thenConverted() {
}
@Test
public void whenConvertListToStringMultipleSeparators_thenConverted() {
public void whenConvertCollectionToStringMultipleSeparators_thenConverted() {
String fruits = "Apple. , Orange, Grape. Lemon";
List<String> result = Arrays.stream(fruits.split("[,|.]"))
Collection<String> result = Arrays.stream(fruits.split("[,|.]"))
.map(String::trim).filter(next -> !next.isEmpty())
.collect(Collectors.toList());