Example usage for java.util Collections emptyList

Introduction

In this page you can find the example usage for java.util Collections emptyList.

Prototype

@SuppressWarnings("unchecked")
public static final <T> List<T> emptyList()

Source Link

Document

Returns an empty list (immutable).

Usage

From source file:Main.java

private static List<String> split(String input, String delimiter) {
    if (input == null || input.isEmpty()) {
        return Collections.emptyList();
    }//from  ww  w .  j  a  v a2 s . c om
    return new ArrayList<String>(Arrays.asList(input.split(delimiter)));
}

From source file:Main.java

/**
 * convert to List<T> from Enumeration<T>
 * //from  w  w  w.j a v a2s.co  m
 * @param enumeration
 * @return
 */
public static <T> List<T> convert(Enumeration<T> enumeration) {
    if (enumeration == null) {
        return Collections.emptyList();
    }
    ArrayList<T> result = new ArrayList<T>();
    while (enumeration.hasMoreElements()) {
        result.add(enumeration.nextElement());
    }
    return result;
}

From source file:Main.java

public static <V> List<V> uniteCollectionArray(Collection<V[]> values) {
    if (isEmpty(values)) {
        return Collections.emptyList();
    }//from w ww . j a v a2 s. c  o m
    List<V> copy = new ArrayList<V>();
    for (V[] collections : values) {
        copy.addAll(Arrays.asList(collections));
    }
    return copy;
}

From source file:Main.java

/**
 * /*  www .  j av a 2  s  .com*/
 * @param c1
 * @param s1
 * @return c1 - s1
 * 
 */
public static <T> List<T> minius(Collection<T> c1, Collection<T> s1) {

    if (c1 == null) {
        return Collections.emptyList();
    }

    if (s1 == null || s1.size() == 0) {
        return new ArrayList<T>(c1);
    }
    List<T> list = new ArrayList<T>();
    for (T t : c1) {
        if (!s1.contains(t)) {
            list.add(t);
        }
    }
    return list;
}

From source file:Main.java

public static <T> List<T> immutableList(T... list) {
    if (list == null)
        return Collections.emptyList();
    return immutableList(Arrays.asList(list));
}

From source file:Main.java

public static <T> List<T> toImmutableList(List<T> list) {
    switch (list.size()) {
    case 0:// w ww  .  jav  a 2 s . com
        return Collections.emptyList();
    case 1:
        return Collections.singletonList(list.get(0));
    default:
        return Collections.unmodifiableList(list);
    }
}

From source file:Main.java

/**
 * Returns an non null value based on the giving {@link List}
 *
 * @param list/* w  w  w .  ja v a2 s  . co  m*/
 *            value to evaluate
 * @return the original value or an empty {@link List}
 * @since 4.2
 */
public static <T> List<T> nonNullList(@Nullable final List<T> list) {
    return list == null ? Collections.emptyList() : list;
}

From source file:Main.java

public static <T> List<T> innerJoin(List<List<T>> list, BiFunction<T, T, T> function) {
    if (list == null || function == null) {
        throw new NullPointerException("list or function must not be null");
    }/*from  www  .  j a v a  2 s.c o m*/
    if (list.isEmpty()) {
        return Collections.emptyList();
    }
    if (list.size() == 1) {
        return list.get(0);
    }

    List<List<T>> result = innerJoin(list.get(0), list.get(1), function);
    if (list.size() == 2) {
        return merge(result);
    } else {
        for (int i = 2; i < list.size(); i++) {
            List<T> l1 = list.get(i);
            List<List<T>> temp = new ArrayList<>();
            result.stream().forEach(l -> temp.addAll(innerJoin(l, l1, function)));
            result = temp;
        }
        return merge(result);
    }
}

From source file:Main.java

/**
 * Returns an non null value based on the giving {@link Collection}
 *
 * @param collection/*from w w w.j a v a2 s .  c  o m*/
 *            value to evaluate
 * @return the original value or an empty {@link Collection}
 * @since 4.2
 */
public static <T> Collection<T> nonNullCollection(@Nullable final Collection<T> collection) {
    return collection == null ? Collections.emptyList() : collection;
}

From source file:Main.java

public static <T> List<T> toImmutableList(final Collection<T> c) {
    if (c.isEmpty()) {
        return Collections.emptyList();
    } else {/*from  ww w.  jav  a2s  .  c  o m*/
        return Collections.unmodifiableList(new ArrayList<T>(c));
    }
}