Example usage for java.util Collection stream

Introduction

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

Prototype

default Stream<E> stream()

Source Link

Document

Returns a sequential Stream with this collection as its source.

Usage

From source file:Main.java

public static String join(Collection<?> objects, String delimiter) {
    return objects.stream().map(String::valueOf).collect(joining(delimiter));
}

From source file:Main.java

public static <T> List<T> filterByType(Collection<? super T> objects, Class<T> type) {
    return objects.stream().filter(type::isInstance).map(type::cast).collect(toList());
}

From source file:Main.java

public static <T> List<T> filter(Collection<? extends T> xs, Predicate<? super T> predicate) {
    return xs.stream().filter(predicate).collect(toList());
}

From source file:Main.java

public static String collectionToString(Collection<?> collection) {
    return collection.stream().map(String::valueOf).collect(Collectors.joining(",", "(", ")"));
}

From source file:Main.java

public static <A, B> List<B> map(Collection<? extends A> xs, Function<? super A, ? extends B> mapper) {
    return xs.stream().map(mapper).collect(toList());
}

From source file:Main.java

/**
 * Extract attribute from objects in collection and store them in array and
 * return./*from   ww  w .  j  a va2  s .  co  m*/
 * 
 * @param entities
 * @param keyMapper
 * @param arr
 * @return
 */
public static <T, K> K[] toArray(Collection<T> entities, Function<T, K> keyMapper, K[] arr) {
    return entities.stream().map(keyMapper).toArray(size -> arr);
}

From source file:Main.java

public static <K, V> Map<K, V> asMap(Function<V, K> keySuppler, Collection<V> values) {
    Map<K, V> map = new HashMap<>();
    values.stream().forEach(v -> map.put(keySuppler.apply(v), v));
    return map;/* w w  w  .j  ava  2  s.com*/
}

From source file:Main.java

/**
 * Joins 2 collections into one list.//from   w  w w . jav a 2s  . com
 *
 * @param a Some collection
 * @param b Some other collection
 * @param <T> The type of the elements
 *
 * @return A List that contains all the elements of both collections.
 */
public static <T> List<T> join(Collection<? extends T> a, Collection<? extends T> b) {
    return Stream.concat(a.stream(), b.stream()).collect(Collectors.toList());
}

From source file:Main.java

public static String collectionToString(Collection<?> collection) {
    return collection.stream().map(String::valueOf).collect(joining(",", "(", ")"));
}

From source file:Main.java

/**
 * Returns the given collection as stream.
 *
 * @param <T>/*w w w . jav a 2  s .c  o m*/
 *            the generic type
 * @param source
 *            the source
 * @param parallel
 *            <code>true</code> if the stream should be a parallel stream
 * @return the stream
 */
public static <T> Stream<T> asStream(Collection<T> source, boolean parallel) {
    return parallel ? source.parallelStream() : source.stream();
}