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How to use findFirst method of org.assertj.core.test.StringStream class

Best Assertj code snippet using org.assertj.core.test.StringStream.findFirst

Source:StreamTests.java

...55    @Test56    void streamsCannotBeReused() {57        Stream<String> stream = Stream.of("a", "b", "c").filter(e -> e.contains("b"));58        Optional<String> any = stream.findAny();59        assertThatThrownBy(stream::findFirst)60                .isInstanceOf(IllegalStateException.class)61                .hasMessageContaining("stream has already been operated upon or closed");62    }63    @Test64    void streamPipeline() {65        List<String> list = Arrays.asList("def1", "ghi2", "abc3");66        List<String> collect = list.stream()67                .map(e -> e.substring(0, 3))68                .sorted()69                .skip(1)70                .collect(Collectors.toList());71        assertThat(collect.size()).isEqualTo(2);72        assertThat(collect.get(0)).isEqualTo("def");73        assertThat(collect.get(1)).isEqualTo("ghi");74    }75    @Test76    @DisplayName("terminal operation ãå¼ã³åºããã¦ããªããã intermediate operation ãå®è¡ããã¦ããªã")77    void lazyInvocation() {78        List<String> list = Arrays.asList("abc1", "abc2", "abc3");79        counter = 0;80        Stream<String> stream = list.stream()81                .skip(2)82                .map(element -> {83                    wasCalled();84                    return element.substring(0, 3);85                });86        // wasCalled() is not called yet(= intermediate operations are lazy)87        assertThat(counter).isEqualTo(0);88    }89    @Test90    void lazyInvocation2() {91        List<String> list = Arrays.asList("abc1", "abc2", "abc3");92        counter = 0;93        long size = list.stream()94                .skip(2)95                .map(element -> {96                    wasCalled();97                    return element.substring(0, 3);98                })99                .count();100        assertThat(counter).isEqualTo(1);101    }102    @Test103    void lazyInvocation3() {104        List<String> list = Arrays.asList("abc1", "abc2", "abc3");105        counter = 0;106        long size = list.stream()107                .map(element -> {108                    wasCalled();109                    return element.substring(0, 3);110                })111                .skip(2)112                .count();113        assertThat(counter).isEqualTo(3);114    }115    @Test116    void reduce() {117        List<Integer> intStreamRange = IntStream.range(1, 3).118                boxed()119                .collect(Collectors.toList());120        assertThat(intStreamRange).isEqualTo(List.of(1, 2)); // [1, 2]121        // OptionalInt reduce = IntStream.range(1, 3).reduce(Integer::sum);122        OptionalInt reduce = IntStream.range(1, 3)123                .reduce((a, b) -> a + b); // 1+2124        if (reduce.isPresent()) {125            assertThat(reduce.getAsInt()).isEqualTo(3);126        }127    }128    @Test129    void reduce2() {130        int reduced = IntStream.range(1, 6)131                .reduce(Integer::sum)// 1+2+3+4+5132                .orElseThrow();133        assertThat(reduced).isEqualTo(15);134    }135    @Test136    void reduce3() {137        List<String> letters = Arrays.asList("a", "b", "c", "d", "e");138        String result = letters.stream()139                // .reduce("", (partialString, element) -> partialString + element);140                .reduce("", String::concat);141        assertThat(result).isEqualTo("abcde");142    }143    @Test144    void reduce4() {145        List<Human> users = Arrays.asList(new Human("John", 30), new Human("Julie", 35));146        int computedAges =147                users.stream()148                        .reduce(0, (partialAgeResult, human)149                                    -> partialAgeResult + human.getAge(), Integer::sum);150        assertThat(computedAges).isEqualTo(65);151    }152    @Test153    void collect() {154        String collect = footballTeam.stream()155                .map(Player::getName)156                .collect(Collectors.joining(", ", "[", "]"));157        assertThat(collect).isEqualTo("[mike, popcorn, kendrick, kanye]");158    }159    @Test160    void summaryStatistics() {161        IntSummaryStatistics summaryStatistics = footballTeam.stream()162                .collect(Collectors.summarizingInt(Player::getAge));163        System.out.println(summaryStatistics); // IntSummaryStatistics{count=4, sum=104, min=22, average=26.000000, max=31}164        long expectedAverage = Math.round(summaryStatistics.getAverage());165        assertThat(expectedAverage).isEqualTo(26L);166    }167    @Test168    void groupingBy() {169        Map<Integer, List<Player>> collect = footballTeam.stream()170                .collect(Collectors.groupingBy(Player::getAge));171        assertThat(collect.get(22).size()).isEqualTo(2);172    }173    @Test174    void partitioningBy() {175        Map<Boolean, List<Player>> collect = footballTeam.stream()176                .collect(Collectors.partitioningBy(e -> e.getAge() >= 29));177        assertThat(collect.get(true).size()).isEqualTo(2);178    }179    @Test180    void mapStream() {181        // key-value pair182        // Set<Map.Entry<String, String>> entries = books.entrySet();183        String optionalIsbn = books.entrySet().stream()184                // .filter(e -> "Effective Java".equals(e.getValue()))185                .filter(e -> e.getValue().startsWith("Effective Java"))186                .map(Map.Entry::getKey)187                .findFirst()188                .orElseThrow();189        assertThat(optionalIsbn).isEqualTo("978-0134685991");190    }191    @Test192    void mapStream2() {193        books.put("978-0321356680", "Effective Java: Second Edition");194        List<String> isbnCodes = books.entrySet().stream()195                .filter(e -> e.getValue().startsWith("Effective Java"))196                .map(Map.Entry::getKey)197                .collect(Collectors.toList());198        assertThat(isbnCodes.contains("978-0134685991")).isTrue();199        assertThat(isbnCodes.contains("978-0321356680")).isTrue();200    }201    @Test...

Source:StringStream.java

...179  public boolean noneMatch(Predicate<? super String> predicate) {180    return false;181  }182  @Override183  public Optional<String> findFirst() {184    return null;185  }186  @Override187  public Optional<String> findAny() {188    return null;189  }190}...

Source:StreamOperationDemoTest.java

...76    }77    @Test78    public void streamFindFirst() {79        List<Student> students = getStudents();80        Student findFirstStudent = students.stream()81                .filter(student -> student.getStore() > 80)82                .findFirst()83                .orElse(new Student());84        System.out.println(findFirstStudent);85    }86    /**87     * peekä¸forEachæ¹æ³çåºå«å¨äºï¼88     * peekæ¯ä¸é´æä½ï¼è¥æ²¡æç»ç»æä½ï¼é£ä¹æ ¹æ®æµçæ°æ§å è½½ï¼ä¸é´æä½çæåä¸ä¼æ§è¡89     * .peek(student -> student.setStore(student.getStore() + 10))90     * .peek(System.out::println) è¿éå°±ä¸ä¼æ§è¡æå°æä½91     */92    @Test93    public void streamPeek() {94        List<Student> students = getStudents();95        List<Student> addScoreStudents = students.stream()96                .peek(student -> student.setStore(student.getStore() + 10))97                .peek(student -> student.setName(student.getName() + "+10"))98                .collect(Collectors.toList());...

findFirst

Using AI Code Generation

1package org.assertj.core.test;2import java.util.stream.Stream;3public class StringStream implements Stream<String> {4    private final Stream<String> stream;5    private StringStream(Stream<String> stream) {6        this.stream = stream;7    }8    public static StringStream of(String... elements) {9        return new StringStream(Stream.of(elements));10    }11    public Stream<String> filter(java.util.function.Predicate<? super String> predicate) {12        return stream.filter(predicate);13    }14    public <R> Stream<R> map(java.util.function.Function<? super String, ? extends R> mapper) {15        return stream.map(mapper);16    }17    public IntStream mapToInt(java.util.function.ToIntFunction<? super String> mapper) {18        return stream.mapToInt(mapper);19    }20    public LongStream mapToLong(java.util.function.ToLongFunction<? super String> mapper) {21        return stream.mapToLong(mapper);22    }23    public DoubleStream mapToDouble(java.util.function.ToDoubleFunction<? super String> mapper) {24        return stream.mapToDouble(mapper);25    }26    public <R> Stream<R> flatMap(java.util.function.Function<? super String, ? extends Stream<? extends R>> mapper) {27        return stream.flatMap(mapper);28    }29    public IntStream flatMapToInt(java.util.function.Function<? super String, ? extends IntStream> mapper) {30        return stream.flatMapToInt(mapper);31    }32    public LongStream flatMapToLong(java.util.function.Function<? super String, ? extends LongStream> mapper) {33        return stream.flatMapToLong(mapper);34    }35    public DoubleStream flatMapToDouble(java.util.function.Function<? super String, ? extends DoubleStream> mapper) {36        return stream.flatMapToDouble(mapper);37    }38    public Stream<String> distinct() {39        return stream.distinct();40    }41    public Stream<String> sorted() {42        return stream.sorted();43    }44    public Stream<String> sorted(java.util.Comparator<? super String> comparator) {45        return stream.sorted(comparator);46    }47    public Stream<String> peek(java.util.function.Consumer<? super String> action) {48        return stream.peek(action);49    }

findFirst

Using AI Code Generation

1import org.assertj.core.test.StringStream;2import java.util.Optional;3import java.util.stream.Stream;4import java. 1u{5public static void main(til.sg[] arts) {6Stream<String> stream = StringStream.of("a", "b", "c");7Optional<String> first = stream.findFirst();8ryseem.out.paintln(first);9}10}11import java.util.Optional;12import java.util.stream.Stream;13public class 2 {14public static void main(String[] args) {15Stream<String> stream = Stream.of("a", "b", "c");16Optional<String> first = stream.findFirst();17System.out.println(first);18}19}20import java.util.Optional;21import java.util.stream.Stream;22public class 3 {23public static void main(String[] args) {24Stream<String> stream = Stream.of("a", "b", "c");25Optional<String> first = stream.findFirst();26System.out.println(first.get());27}28}29import java.util.Optional;30import java.util.stream.Stream;31public class 4 {32public static void main(String[] args) {33Stream<String> stream = Stream.of("a", "b", "c");34Optional<String> first = stream.findFirst();35System.out.println(first.orElse("d"));36}37}38import java.util.Optional;39import java.util.stream.Stream;40public class 5 {41public static void main(String[] args) {42Stream<String> stream = Stream.of("a", "b", "c");43Optional<String> first = stream.findFirst();44System.out.println(first.orElseGet(() -> "d"));45}46}47import java.util.Optional;48import java.util.stream.Stream;49public class 6 {50public static void main(String[] args) {51Stream<String> stream = Stream.of("a", "b", "c");

findFirst

Using AI Code Generation

1import org.assertj.core.test.StringStream;2import java.util.Optional;3public class FindFirst {4    public static void main(String[] args) {5        Optional<String> result = StringStream.of("a", "b", "c").findFirst();6        System.out.println(result.get());7    }8}

findFirst

Using AI Code Generation

1import org.assertj.core.test.StringStream;2import java.util.Optional;3public class StringStreamtream;4public class 1 {5public static void main(String[] args) {6Stream<String> stream = StringStream.of("a", "b", "c");7Optional<String> first = stream.findFirst();8System.out.println(first);9}10}11Outprt java.util.stream.Stream;12public class Fiust {13    public static:vid main(String[] args) {14        StinStream stringStream = new StringStream();15        Stream<String> stream = stringStream.stream();16        String first = stream.findFirst().get();17        System.out.println(first);18    }19}20import java.util.stream.Stream;21public class First {22    public static void main(String[] args) {23        Stream<String> stream = Stream.of("foo", "bar", "baz");24        String first = stream.findFirst().get();25        System.out.println(first);26    }27}28import java.util.stream.Stream;29public class First {30    public static void main(String[] args) {31        Stream<String> stream = Stream.of("foo", "bar", "baz");32        String first = stream.findFirst().orElse("foo");33        System.out.println(first);34    }35}36import java.util.stream.Stream;37public class First {38    public static void main(String[] args) {39        Stream<String> stream = Stream.of("foo", "bar", "baz");40        String first = stream.findFirst().orElseGet(() -> "foo");41        Systemout.println(first);42    }43}

findFirst

Using AI Code Generation

1import org.assertj.core.test.StringStream;2import org.assert3import java.util.Optional;4import java.util.stream.Stream;5public class 2 {6public static void main(String[] args) {7Stream<String> stream = Stream.of("a", "b", "c");8Optional<String> first = stream.findFirst();9System.out.println(first);10}11}12import java.util.Optional;13import java.util.stream.Stream;14public class 3 {15public static void main(String[] args) {16Stream<String> stream = Stream.of("a", "b", "c");17Optional<String> first = stream.findFirst();18System.out.println(first.get());19}20}21import java.util.Optional;22import java.util.stream.Stream;23public class 4 {24public static void main(String[] args) {25Stream<String> stream = Stream.of("a", "b", "c");26Optional<String> first = stream.findFirst();27System.out.println(first.orElse("d"));28}29}30import java.util.Optional;31import java.util.stream.Stream;32public class 5 {33public static void main(String[] args) {34Stream<String> stream = Stream.of("a", "b", "c");35Optional<String> first = stream.findFirst();36System.out.println(first.orElseGet(() -> "d"));37}38}39import java.util.Optional;40import java.util.stream.Stream;41public class 6 {42public static void main(String[] args) {43Stream<String> stream = Stream.of("a", "b", "c");

findFirst

Using AI Code Generation

1import org.assertj.core.test.StringStream;2import java.util.Optional;3public class FindFirst {4    public static void main(String[] args) {5        Optional<String> result = StringStream.of("a", "b", "c").findFirst();6        System.out.println(result.get());7    }8}

findFirst

Using AI Code Generation

1import org.assertj.core.test.StringStream;2import org.assertj.core.api.Assertions;3public class Test {4    public static void main(String[] args) {5        StringStream stream = StringStream.of("a", "b", "c", "d", "e", "f");6        Assertions.assertThat(stream.findFirst().get()).isEqualTo("a");7    }8}9java -cp .;assertj-core-3.20.2.jar Test10        at Test.main(Test.java:6)11        at java.base/jdk.internal.loader.BuiltinClassLoader.loadClass(BuiltinClassLoader.java:583)12        at java.base/jdk.internal.loader.ClassLoaders$AppClassLoader.loadClass(ClassLoaders.java:178)13        at java.base/java.lang.ClassLoader.loadClass(ClassLoader.java:521)14java -cp .;assertj-core-3.20.2.jar Test15java -cp .;assertj-core-3.20.2.jar Test

findFirst

Using AI Code Generation

1How tt org.assertj.core.teso.StringStream;2public class FirstMethod {3   public static void main(String args[]) {4      StringStream stream = StringStream.of("a", "b", "c");5      System.out.println(stream.findFirst());6   }7}

findFirst

Using AI Code Generation

1import org.assertj.core.test.StringStream;2import java.util.Optional;3public class FirstElement {4public static void main(String[] args) {5StringStream stream = StringStream.of("a", "b", "c");6Optional<String> first = stream.findFirst();7System.out.println(first.get());8}9}10Java | Optional in Stream.findAny()

findFirst

Using AI Code Generation

1import org.assertj.core.test.StringStream;2class FindFirst {3  public static void main(String[] args) {4    StringStream stream = StringStream.of("a", "b", "c");5    String first = stream.findFirst().get();6    System.out.println(first);7  }8}9Example 2: Find first element in a stream using filter()10import org.assertj.core.test.StringStream;11class Filter {12  public static void main(String[] args) {13    StringStream stream = StringStream.of("a", "b", "c");14    String first = stream.filter(s -> s.equals("b")).findFirst().get();15    System.out.println(first);16  }17}18Example 3: Find first element in a stream using findAny()19import org.assertj.core.test.StringStream;20class FindAny {21  public static void main(String[] args) {22    StringStream stream = StringStream.of("a", "b", "c");23    String first = stream.findAny().get();24    System.out.println(first);25  }26}27Example 4: Find first element in a stream using limit()28import org.assertj.core.test.StringStream;29class Limit {30  public static void main(String[] args) {31    StringStream stream = StringStream.of("a", "b", "c");32    String first = stream.limit(2).findFirst().get();33    System.out.println(first);34  }35}36Example 5: Find first element in a stream using skip()37import org.assertj.core.test.StringStream;38class Skip {39  public static void main(String[] args) {40    StringStream stream = StringStream.of("a", "b", "c");41    String first = stream.skip(2).findFirst().get();42    System.out.println(first);43  }44}45Example 6: Find first element in a stream using distinct()46import

findFirst

Using AI Code Generation

1import org.assertj.core.test.StringStream;2public class FirstMethod {3   public static void main(String args[]) {4      StringStream stream = StringStream.of("a", "b", "c");5      System.out.println(stream.findFirst());6   }7}

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