Example usage for java.util.stream Stream filter

Introduction

In this page you can find the example usage for java.util.stream Stream filter.

Prototype

Stream<T> filter(Predicate<? super T> predicate);

Source Link

Document

Returns a stream consisting of the elements of this stream that match the given predicate.

Usage

From source file:Main.java

public static void main(String[] args) {
    List<String> names = Arrays.asList("Chris", "HTML", "XML", "CSS", "");

    Stream<String> s = names.stream().filter(name -> name.startsWith("C"));

    List<String> collect = s.filter(Objects::nonNull).collect(Collectors.toList());
    System.out.println(collect);/*from  w w  w  .  jav a  2s .c  o m*/
}

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From source file:Main.java

public static void main(String[] args) {
    List<String> names = Arrays.asList("Chris", "HTML", "XML", "CSS", "");

    Stream<String> s = names.stream();

    Predicate<String> isEmpty = String::isEmpty;
    Predicate<String> notEmpty = isEmpty.negate();

    System.out.println(s.filter(notEmpty).collect(Collectors.toList()));
}

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From source file:com.liferay.ide.core.util.FileListing.java

public static List<IPath> getFileListing(File dir, String fileType) {
    Collection<File> files = FileUtils.listFiles(dir, new String[] { fileType }, true);

    Stream<File> stream = files.stream();

    return stream.filter(file -> file.exists()).map(file -> new Path(file.getPath()))
            .collect(Collectors.toList());
}

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From source file:Main.java

private static <T> List<T> where(Stream<T> stream, Predicate<T> filter) {
    return stream.filter(filter).collect(Collectors.toList());
}

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From source file:Main.java

/**
 * This is a shortcut for {@code (Stream<O>) s.filter(o -> clazz.isInstance(o))}.
 *
 * @param s     stream that's elements are filtered by type {@code clazz}. Must not be {@code null}.
 * @param clazz Type the elements of the input stream should be of to be part of the returned result stream.
 *              Must not be {@code null}.
 * @param <I>   Type of elements in input stream
 * @param <O>   Type of element remaining in the output stream
 * @return input stream filtered by type {@code O}
 * @throws NullPointerException when {@code clazz} or {@code s} is {@code null}.
 *//*from   ww  w.  j a v  a2s  . co  m*/
@SuppressWarnings("unchecked") // we know the cast is safe, since all elements are of type O
public static <I, O> Stream<O> filter(Stream<I> s, Class<O> clazz) throws NullPointerException {
    Objects.requireNonNull(clazz);
    Objects.requireNonNull(s);
    return (Stream<O>) s.filter(clazz::isInstance);
}

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From source file:com.ikanow.aleph2.core.shared.utils.TimeSliceDirUtils.java

/** Filters out non matching directories
 * @param in/*from   w  w  w.ja va  2  s  .c o  m*/
 * @param filter
 * @return
 */
public static Stream<String> filterTimedDirectories(final Stream<Tuple3<String, Date, Date>> in,
        final Tuple2<Optional<Date>, Optional<Date>> filter) {
    return in.filter(t3 -> filter._1().map(tmin -> { //lower bound
        return tmin.getTime() < t3._3().getTime(); // just has to be smaller than the largest time in the group
    }).orElse(true)).filter(t3 -> filter._2().map(tmax -> { //lower bound
        return tmax.getTime() >= t3._2().getTime(); // just has to be larger than the smallest time in the group
    }).orElse(true)).map(t3 -> t3._1());
}

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From source file:edumsg.core.PostgresConnection.java

public static void readConfFile() throws Exception {
    String file = System.getProperty("user.dir") + "/Postgres.conf";
    java.util.List<String> lines = new ArrayList<String>();
    //extract string between square brackets and compile regex for faster performance
    Pattern pattern = Pattern.compile("\\[(.+)\\]");
    Matcher matcher;/*  ww  w. jav  a2s.c  o m*/
    Exception e;
    Stream<String> stream = Files.lines(Paths.get(file));
    lines = stream.filter(line -> !line.startsWith("#")).collect(Collectors.toList());

    //set variables based on matches
    for (int i = 0; i < lines.size(); i++) {
        if (lines.get(i).contains("user")) {
            matcher = pattern.matcher(lines.get(i));
            if (matcher.find())
                setDBUser(matcher.group(1));
            else
                throw e = new Exception("empty user in Postgres.conf");
        }
        if (lines.get(i).contains("database")) {
            matcher = pattern.matcher(lines.get(i));
            if (matcher.find())
                setDBName(matcher.group(1));
            else
                throw e = new Exception("empty database name in Postgres.conf");
        }
        if (lines.get(i).contains("pass")) {
            matcher = pattern.matcher(lines.get(i));
            matcher.find();
            setDBPassword(matcher.group(1));
        }
        if (lines.get(i).contains("host")) {
            matcher = pattern.matcher(lines.get(i));
            if (matcher.find())
                setDBHost(matcher.group(1));
            else
                setDBHost("localhost");
        }
        if (lines.get(i).contains("port")) {
            matcher = pattern.matcher(lines.get(i));
            if (matcher.find())
                setDBPort(matcher.group(1));
            else
                setDBPort("5432");
        }
    }
    if (!formatURL()) {
        e = new Exception("Wrong Format in Postgres.conf");
        throw e;
    }
}

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From source file:io.promagent.internal.HookMetadataParser.java

/**
 * Convert class file paths to class names and add them to result.
 */// w w  w  .j  a  va2s.c  o  m
private static void addClassNames(Stream<String> paths, Collection<String> result,
        Predicate<String> classNameFilter) {
    paths.filter(name -> name.endsWith(".class"))
            .map(name -> name.substring(0, name.length() - ".class".length()))
            .map(name -> name.startsWith("/") ? name.substring(1) : name).map(name -> name.replace("/", "."))
            .filter(classNameFilter).collect(Collectors.toCollection(() -> result));
}

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From source file:com.github.robozonky.app.events.SessionEvents.java

@SuppressWarnings("unchecked")
static <T extends Event> Class<T> getImplementingEvent(final Class<T> original) {
    final Stream<Class<?>> provided = ClassUtils.getAllInterfaces(original).stream();
    final Stream<Class<?>> interfaces = original.isInterface() ? // interface could be extending it directly
            Stream.concat(Stream.of(original), provided) : provided;
    final String apiPackage = "com.github.robozonky.api.notifications";
    return (Class<T>) interfaces.filter(i -> Objects.equals(i.getPackage().getName(), apiPackage))
            .filter(i -> i.getSimpleName().endsWith("Event"))
            .filter(i -> !Objects.equals(i.getSimpleName(), "Event")).findFirst()
            .orElseThrow(() -> new IllegalStateException("Not an event:" + original));
}

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From source file:de.fosd.jdime.Main.java

/**
 * Returns a <code>File</code> (possibly <code>f</code>) that does not exist in the parent directory of
 * <code>f</code>. If <code>f</code> exists an increasing number is appended to the name of <code>f</code> until
 * a <code>File</code> is found that does not exist.
 *
 * @param f//from  w  w w  . j  ava 2  s.c om
 *         the <code>File</code> to find a non existent version of
 * @return a <code>File</code> in the parent directory of <code>f</code> that does not exist
 */
private static File findNonExistent(File f) {

    if (!f.exists()) {
        return f;
    }

    String fullName = f.getName();
    String name;
    String extension;

    int pos = fullName.lastIndexOf('.');

    if (pos != -1) {
        name = fullName.substring(0, pos);
        extension = fullName.substring(pos, fullName.length());
    } else {
        name = fullName;
        extension = "";
    }

    File parent = f.getParentFile();

    Stream<File> files = IntStream.range(0, Integer.MAX_VALUE).mapToObj(v -> {
        String fileName = String.format("%s_%d%s", name, v, extension);
        return new File(parent, fileName);
    });

    File nextFree = files.filter(file -> !file.exists()).findFirst()
            .orElseThrow(() -> new RuntimeException("Can not find a file that does not exist."));

    return nextFree;
}

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