Example usage for java.util.stream Collectors toCollection

Introduction

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

Prototype

public static <T, C extends Collection<T>> Collector<T, ?, C> toCollection(Supplier<C> collectionFactory)

Source Link

Document

Returns a Collector that accumulates the input elements into a new Collection , in encounter order.

Usage

From source file:Main.java

public static void main(String[] args) {
    Stream<String> s = Stream.of("a", "b", "c");

    Collection<String> names = s.collect(Collectors.toCollection(TreeSet::new));

    System.out.println(names);/*w ww.ja  va  2 s .c o  m*/
}

From source file:Main.java

public static void main(String[] args) {
    // collect as typed array
    Stream<String> words = Stream.of("All", "men", "are", "created", "equal");
    Set<String> wordsSet = words.collect(Collectors.toCollection(TreeSet::new));

    wordsSet.forEach(n -> System.out.println(n));
}

From source file:Main.java

public static void main(String[] args) {
    SortedSet<String> uniqueSortedNames = Employee.persons().stream().map(Employee::getName)
            .collect(Collectors.toCollection(TreeSet::new));
    System.out.println(uniqueSortedNames);
    System.out.println(uniqueSortedNames);
}

From source file:Main.java

public static <T> Set<T> asSet(T... values) {
    return Arrays.stream(values).collect(Collectors.toCollection(LinkedHashSet::new));
}

From source file:Main.java

public static <T, K, V> HashMap<K, HashSet<V>> group(Collection<T> entities, Function<T, K> keyMapper,
        Function<T, V> valueMapper) {
    return entities.stream().collect(Collectors.groupingBy(keyMapper, HashMap::new,
            Collectors.mapping(valueMapper, Collectors.toCollection(HashSet::new))));
}

From source file:Main.java

/**
 * Transform the source collection using the mapping function to convert the elements to the output type. The result
 * is written to a set.//from  ww w.j  a v a2s . com
 *
 * @param <T>
 *            the source type type
 * @param <R>
 *            the result type
 * @param source
 *            the source
 * @param mapping
 *            the mapping used for the value transformation
 * @return the sets the
 */
public static <T, R> Set<R> transformToSet(Collection<T> source, Function<T, R> mapping) {
    return source.stream().map(mapping)
            .collect(Collectors.toCollection(() -> createLinkedHashSet(source.size())));
}

From source file:Main.java

/**
 * Returns a {@code Collector} that accumulates the input elements into a new {@code List}, in encounter order. If
 * the provided size is greater than zero then {@link ArrayList} with the given size will be created otherwise a
 * {@link LinkedList} will be created for undermined size.
 *
 * @param <T>/*from   w  ww.  j av  a2 s  . co m*/
 *            the type of the input elements
 * @param <C>
 *            the type of the resulting {@code Collection}
 * @param expectedSize
 *            the expected size of the collection if known. If not known a -1 could be passed.
 * @return a {@code Collector} which collects all the input elements into a {@code List}, in encounter order
 */
@SuppressWarnings("unchecked")
public static <T, C extends Collection<T>> Collector<T, ?, C> toList(int expectedSize) {
    if (expectedSize > 0) {
        return (Collector<T, ?, C>) Collectors.toCollection(() -> new ArrayList<>(expectedSize));
    }
    return (Collector<T, ?, C>) Collectors.toCollection(LinkedList::new);
}

From source file:org.bunkr.core.inventory.InventoryJSON.java

@SuppressWarnings("unchecked")
public static JSONAware encodeO(Inventory input) {
    JSONObject out = new JSONObject();
    JSONArray files = input.getFiles().stream().map(FileInventoryItemJSON::encodeO)
            .collect(Collectors.toCollection(JSONArray::new));
    out.put("files", files);

    JSONArray folders = input.getFolders().stream().map(FolderInventoryItemJSON::encodeO)
            .collect(Collectors.toCollection(JSONArray::new));
    out.put("folders", folders);
    out.put("defaultEncryptionAlgorithm", input.getDefaultEncryption().toString());
    return out;/*w ww. jav a 2  s .  co m*/
}

From source file:com.yahoo.bard.webservice.util.Utils.java

/**
 * Given a collection of objects which share the same super class, return the subset of objects that share a common
 * sub class.// w  ww.  j a va 2  s.com
 *
 * @param set  Input set
 * @param <T> Input set type
 * @param type  sub class
 * @param <K> sub class type
 *
 * @return ordered subset of objects that share a common sub class
 */
public static <T, K extends T> LinkedHashSet<K> getSubsetByType(Collection<T> set, Class<K> type) {
    return set.stream().filter(member -> type.isAssignableFrom(member.getClass()))
            .map(StreamUtils.uncheckedCast(type)).collect(Collectors.toCollection(LinkedHashSet::new));
}

From source file:org.bunkr.core.inventory.FolderInventoryItemJSON.java

@SuppressWarnings("unchecked")
public static JSONAware encodeO(FolderInventoryItem input) {
    JSONObject out = new JSONObject();

    out.put("name", input.getName());
    out.put("uuid", input.getUuid().toString());

    JSONArray files = input.getFiles().stream().map(FileInventoryItemJSON::encodeO)
            .collect(Collectors.toCollection(JSONArray::new));
    out.put("files", files);

    JSONArray folders = input.getFolders().stream().map(FolderInventoryItemJSON::encodeO)
            .collect(Collectors.toCollection(JSONArray::new));
    out.put("folders", folders);
    return out;/*ww w . j  a v a  2  s  .c  o  m*/
}