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, String prefix, String suffix) {
    return objects.stream().map(String::valueOf).collect(joining(delimiter, prefix, suffix));
}

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

public static <T> Set<T> conjunctCollectionsToSet(Collection<T> list1, Collection<T> list2) {
    Set<T> set = new HashSet<>(list2);
    return list1.stream().filter(set::contains).collect(Collectors.toSet());
}

From source file:com.github.horrorho.inflatabledonkey.cloudkitty.operations.ZoneRetrieveRequestOperations.java

static List<RequestOperation> operations(Collection<String> zones, String cloudKitUserId) {
    return zones.stream().map(u -> operation(u, cloudKitUserId)).collect(Collectors.toList());
}

From source file:Main.java

public static <T> List<T> conjunctCollections(Collection<T> list1, Collection<T> list2) {
    Set<T> set = new HashSet<>(list2);
    return list1.stream().filter(set::contains).collect(Collectors.toList());
}

From source file:com.github.horrorho.inflatabledonkey.cloudkitty.operations.RecordRetrieveRequestOperations.java

static List<RequestOperation> operations(String zone, Collection<String> recordNames, String cloudKitUserId) {
    return recordNames.stream().map(u -> operation(zone, u, cloudKitUserId)).collect(Collectors.toList());
}

From source file:Main.java

public static <T> Set<T> conjunctCollectionsToSet(Collection<T> list1, Collection<T> list2) {
    Set<T> set = new HashSet<>(list2);
    return list1.stream().filter(set::contains).collect(toSet());
}

From source file:Main.java

public static <T> List<T> conjunctCollections(Collection<T> list1, Collection<T> list2) {
    Set<T> set = new HashSet<>(list2);
    return list1.stream().filter(set::contains).collect(toList());
}

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 w w w  .j  av  a 2s  .c om
 *
 * @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

public static <T, K, M extends Map<K, T>> M toMap(Collection<T> entities, Function<T, K> keyMapper,
        Supplier<M> supplier) {
    return entities.stream().collect(Collectors.toMap(keyMapper, Function.identity(), (a, b) -> b, supplier));
}