本文整理了Java中java.util.stream.IntStream.findFirst()方法的一些代码示例，展示了IntStream.findFirst()的具体用法。这些代码示例主要来源于Github/Stackoverflow/Maven等平台，是从一些精选项目中提取出来的代码，具有较强的参考意义，能在一定程度帮忙到你。IntStream.findFirst()方法的具体详情如下：
包路径：java.util.stream.IntStream
类名称：IntStream
方法名：findFirst

IntStream.findFirst介绍

[英]Returns an OptionalInt describing the first element of this stream, or an empty OptionalInt if the stream is empty. If the stream has no encounter order, then any element may be returned.

This is a short-circuiting terminal operation.
[中]返回描述此流的第一个元素的Optionant，如果流为空，则返回空Optionant。如果流没有遭遇顺序，那么可以返回任何元素。
这是一个short-circuiting terminal operation。

代码示例

代码示例来源：origin: jdbi/jdbi

private int indexOfBatchChunkSizeParameter(Method method) {
  Annotation[][] parameterAnnotations = method.getParameterAnnotations();
  return IntStream.range(0, parameterAnnotations.length)
      .filter(i -> Stream.of(parameterAnnotations[i]).anyMatch(BatchChunkSize.class::isInstance))
      .findFirst()
      .orElse(-1);
}

代码示例来源：origin: biezhi/30-seconds-of-java8

public static <T extends Comparable<? super T>> int sortedIndex(T[] arr, T el) {
  boolean isDescending = arr[0].compareTo(arr[arr.length - 1]) > 0;
  return IntStream.range(0, arr.length)
      .filter(i -> isDescending ? el.compareTo(arr[i]) >= 0 : el.compareTo(arr[i]) <= 0)
      .findFirst()
      .orElse(arr.length);
}

代码示例来源：origin: apache/hbase

/**
 * Creates a deterministic hash code for store file collection.
 */
public static OptionalInt getDeterministicRandomSeed(Collection<HStoreFile> files) {
 return files.stream().mapToInt(f -> f.getPath().getName().hashCode()).findFirst();
}

代码示例来源：origin: biezhi/30-seconds-of-java8

/**
 * Find index of element in the array. Return -1 in case element does not exist.
 * <p>
 * Uses IntStream.range().filter() to find index of the element in the array.
 *
 * @param elements input array
 * @param el       element to find
 * @return index of the element
 */
public static int indexOf(int[] elements, int el) {
  return IntStream.range(0, elements.length)
      .filter(idx -> elements[idx] == el)
      .findFirst()
      .orElse(-1);
}

代码示例来源：origin: speedment/speedment

@Override
  public OptionalInt execute() {
    try (final IntStream stream = buildPrevious()) {
      return stream.findFirst();
    }
  }
}

代码示例来源：origin: twosigma/beakerx

@Override
public void saveProfile(Map<String, Object> profile) {
 int idx = IntStream.range(0, profiles.size())
     .filter(i -> profile.get("name").equals(profiles.get(i).get("name")))
     .findFirst().orElse(-1);
 if (idx == -1) {
  profiles.add(profile);
 } else {
  profiles.set(idx, profile);
 }
 saveSparkConf(profiles);
}

代码示例来源：origin: jooby-project/jooby

static List<Map<String, Object>> frames(final ClassLoader loader, final SourceLocator locator,
  final Throwable cause) {
 List<StackTraceElement> stacktrace = Arrays.asList(cause.getStackTrace());
 int limit = IntStream.range(0, stacktrace.size())
   .filter(i -> stacktrace.get(i).getClassName().equals(HANDLER)).findFirst()
   .orElse(stacktrace.size());
 return stacktrace.stream()
   // trunk stack at HttpHandlerImpl (skip servers stack)
   .limit(limit)
   .map(e -> frame(loader, locator, cause, e))
   .collect(Collectors.toList());
}

代码示例来源：origin: apache/geode

public synchronized int getAvailablePort() {
  int result = IntStream.generate(supplier)
    .filter(port -> !usedPorts.contains(port))
    .findFirst()
    .getAsInt();

  usedPorts.add(result);
  return result;
 }
}

代码示例来源：origin: speedment/speedment

private int driverVersion() {
    return
      Stream.of(
        driver(NEW_DRIVER),
        driver(OLD_DRIVER)
      )
      .filter(Optional::isPresent)
      .map(Optional::get)
      .mapToInt(Driver::getMajorVersion)
      .findFirst()
      .orElse(5);  // Fallback. There is no driver so we just make up a version
  }
}

代码示例来源：origin: stackoverflow.com

Random r = new Random();
int[] fiveRandomNumbers = r.ints(5, 0, 11).toArray();
int randomNumber = r.ints(1, 0, 11).findFirst().getAsInt();

代码示例来源：origin: jooby-project/jooby

public Optional<DocItem> pop(final String classname, String method, String pattern) {
 try {
  List<DocItem> javadoc = javadoc(classname);
  int pos = IntStream.range(0, javadoc.size())
    .filter(i -> javadoc.get(i).matches(method, pattern))
    .findFirst()
    .orElse(-1);
  if (pos >= 0) {
   return Optional.ofNullable(javadoc.remove(pos));
  }
 } catch (Exception x) {
  log.debug("Parsing of javadoc resulted in exception: {}", classname, x);
 }
 return Optional.empty();
}

代码示例来源：origin: speedment/speedment

default OptionalInt findFirst(IntPipeline pipeline) {
  requireNonNull(pipeline);
  return optimize(pipeline).getAsIntStream().findFirst();
}

代码示例来源：origin: biezhi/30-seconds-of-java8

/**
 * Find last index of element in the array. Return -1 in case element does not exist.
 * <p>
 * Uses IntStream.iterate().limit().filter() to find index of the element in the array.
 *
 * @param elements input array
 * @param el       element to find
 * @return index of the element
 */
public static int lastIndexOf(int[] elements, int el) {
  return IntStream.iterate(elements.length - 1, i -> i - 1)
      .limit(elements.length)
      .filter(idx -> elements[idx] == el)
      .findFirst()
      .orElse(-1);
}

代码示例来源：origin: neo4j/neo4j

private static Integer token( String name, Map<Integer,String> tokens )
{
  IntSupplier allocateFromMap = () ->
  {
    int newIndex = tokens.size();
    tokens.put( newIndex, name );
    return newIndex;
  };
  return tokens.entrySet().stream()
         .filter( entry -> entry.getValue().equals( name ) )
         .mapToInt( Map.Entry::getKey )
         .findFirst().orElseGet( allocateFromMap );
}

代码示例来源：origin: spring-cloud/spring-cloud-gateway

private static int findOpenPort(final int startInclusive, final int endExclusive) {
  return range(startInclusive, endExclusive)
      .filter(RedisRule::testPort)
      .findFirst()
      .orElseThrow(() ->new IllegalStateException(format(
          "No open port found in the range [%d, %d]", startInclusive, endExclusive)));
}

代码示例来源：origin: jooby-project/jooby

public String name(final Parameter parameter) {
 String name = RequestParam.nameFor(parameter);
 if (name != null) {
  return name;
 }
 // asm
 Executable exec = parameter.getDeclaringExecutable();
 Parameter[] params = exec.getParameters();
 int idx = IntStream.range(0, params.length)
   .filter(i -> params[i].equals(parameter))
   .findFirst()
   .getAsInt();
 String[] names = nameProvider.names(exec);
 return names[idx];
}

代码示例来源：origin: jooby-project/jooby

/**
 * Parse application bytecode, build route methods from it and merge output with the given routes.
 *
 * @param application Application to parse.
 * @param routes Application routes.
 * @return List of route methods.
 * @throws Exception If something goes wrong.
 */
public List<RouteMethod> parseFully(String application, List<Route.Definition> routes)
  throws Exception {
 List<RouteMethod> methods = parse(application);
 BiFunction<String, String, OptionalInt> routeIndex = (verb, pattern) -> {
  RouteMethod it = new RouteMethod(verb, pattern, new RouteResponse(void.class));
  return IntStream.range(0, methods.size())
    .filter(i -> methods.get(i).equals(it))
    .findFirst();
 };
 List<RouteMethod> result = new ArrayList<>(routes.size());
 for (Route.Definition route : routes) {
  routeIndex.apply(route.method(), route.pattern())
    .ifPresent(i -> result.add(complement(route, methods.remove(i))));
 }
 customizer.entrySet().forEach(it ->
   result.stream()
     .filter(it.getKey())
     .forEach(it.getValue())
 );
 return result;
}

代码示例来源：origin: jooby-project/jooby

AtomicInteger count = new AtomicInteger(IntStream.range(0, args.size())
  .filter(i -> !args.get(i).getClassName().equals(String.class.getName()))
  .findFirst()
  .orElse(0));
int from = 0;

代码示例来源：origin: apache/ignite

/** */
private static int keyInSamePartition(Ignite ignite, String cacheName, int key) {
  Affinity<Object> affinity = ignite.affinity(cacheName);
  return IntStream.iterate(key + 1, i -> i + 1)
    .filter(i -> affinity.partition(i) == affinity.partition(key))
    .findFirst().getAsInt();
}

代码示例来源：origin: apache/ignite

/** */
  private static int keyInDifferentPartition(Ignite ignite, String cacheName, int key) {
    Affinity<Object> affinity = ignite.affinity(cacheName);

    return IntStream.iterate(key + 1, i -> i + 1)
      .filter(i -> affinity.partition(i) != affinity.partition(key))
      .findFirst().getAsInt();
  }
}