Example usage for java.util List isEmpty

Introduction

In this page you can find the example usage for java.util List isEmpty.

Prototype

boolean isEmpty();

Source Link

Document

Returns true if this list contains no elements.

Usage

From source file:Main.java

public static boolean isEmpty(List list) {
    if (list == null) {
        return true;
    } else {/*  w  w w.jav a2  s  .  co  m*/
        return list.isEmpty();
    }
}

From source file:Main.java

/**
 * Splits list into several sub-lists according to predicate.
 * @param <T>/* w  w w. ja v a2s  .  c  om*/
 * @param list
 * @param predicate
 * @return 
 */
public static final <T> List<List<T>> split(List<T> list, Predicate<T> predicate) {
    if (list.isEmpty()) {
        return Collections.EMPTY_LIST;
    }
    List<List<T>> lists = new ArrayList<>();
    boolean b = predicate.test(list.get(0));
    int len = list.size();
    int start = 0;
    for (int ii = 1; ii < len; ii++) {
        boolean t = predicate.test(list.get(ii));
        if (b != t) {
            lists.add(list.subList(start, ii));
            start = ii;
            b = t;
        }
    }
    lists.add(list.subList(start, len));
    return lists;
}

From source file:Main.java

@SuppressWarnings("rawtypes")
public static boolean isEmpty(Object array) {
    if (null != array) {
        if (array instanceof List) {
            List list = (List) array;
            if (!list.isEmpty()) {
                return false;
            }/*w ww. j av a 2s .  c  o m*/
        } else if (array instanceof Map) {
            Map map = (Map) array;
            if (!map.isEmpty()) {
                return false;
            }
        } else if (array instanceof Object[]) {
            Object[] arr = (Object[]) array;
            if (arr.length > 0) {
                return false;
            }
        }
    }

    return true;
}

From source file:Main.java

/** Credit Victor from StackOverflow
 * Combines several collections of elements and create permutations of all of them, taking one element from each
 * collection, and keeping the same order in resultant lists as the one in original list of collections.
 *
 * <ul>Example/*from w  w  w  . ja v  a2 s . co m*/
 * <li>Input  = { {a,b,c} , {1,2,3,4} }</li>
 * <li>Output = { {a,1} , {a,2} , {a,3} , {a,4} , {b,1} , {b,2} , {b,3} , {b,4} , {c,1} , {c,2} , {c,3} , {c,4} }</li>
 * </ul>
 *
 * @param collections Original list of collections which elements have to be combined.
 * @return Resultant collection of lists with all permutations of original list.
 */
public static <T> Collection<List<T>> permutations(List<Collection<T>> collections) {
    if (collections == null || collections.isEmpty()) {
        return Collections.emptyList();
    } else {
        Collection<List<T>> res = Lists.newLinkedList();
        permutationsImpl(collections, res, 0, new LinkedList<T>());
        return res;
    }
}

From source file:Main.java

public static boolean isApplicationBroughtToBackground(final Context context) {
    try {// ww  w . jav  a 2s .  c  o  m
        ActivityManager am = (ActivityManager) context.getSystemService(Context.ACTIVITY_SERVICE);
        List<ActivityManager.RunningTaskInfo> tasks = am.getRunningTasks(1);
        if (!tasks.isEmpty()) {
            ComponentName topActivity = tasks.get(0).topActivity;
            if (!topActivity.getPackageName().equals(context.getPackageName())) {
                return true;
            }
        }
    } catch (Exception ex) {
        ex.printStackTrace();
    }
    return false;
}

From source file:Main.java

@Nullable
static <T> List<T> nonEmptyOrNull(Collection<T> collection) {
    List<T> list = Collections.unmodifiableList(new ArrayList<>(collection));
    return list.isEmpty() ? null : list;
}

From source file:Main.java

/**
 * Used to know if Apollo was sent into the background
 * /* w  w  w  .  j  ava2  s.  c om*/
 * @param context The {@link Context} to use
 */
public static final boolean isApplicationSentToBackground(final Context context) {
    final ActivityManager activityManager = (ActivityManager) context
            .getSystemService(Context.ACTIVITY_SERVICE);
    final List<RunningTaskInfo> tasks = activityManager.getRunningTasks(1);
    if (!tasks.isEmpty()) {
        final ComponentName topActivity = tasks.get(0).topActivity;
        if (!topActivity.getPackageName().equals(context.getPackageName())) {
            return true;
        }
    }
    return false;
}

From source file:Main.java

/**
 * Returns the first element of the collection.
 * //  w w  w  . jav a  2  s.c om
 * @param <T>
 *            the element type
 * @param iterable
 *            the collection
 * @return the first element or null if the list is empty
 */
public static <T> T first(Iterable<T> iterable) {
    if (iterable instanceof Deque<?>)
        return ((Deque<T>) iterable).getFirst();
    if (iterable instanceof List<?>) {
        List<T> list = (List<T>) iterable;
        return list.isEmpty() ? null : list.get(0);
    }
    Iterator<T> iterator = iterable.iterator();
    return iterator.hasNext() ? iterator.next() : null;
}

From source file:Main.java

public static Element element(Element element) {
    Element onlyChild = null;//w w  w  .  j  a  v  a2  s  . c  o m
    List elements = elements(element);
    if (!elements.isEmpty()) {
        onlyChild = (Element) elements.get(0);
    }
    return onlyChild;
}

From source file:Main.java

public static int hashCode(List list) {
    if (list == null) {
        return 0;
    }/*from ww  w.j  av  a  2 s  . c o m*/
    if (list.isEmpty()) {
        return 1;
    }
    ArrayList<?> tmp = new ArrayList<>(list);
    Collections.sort(tmp, (o1, o2) -> Integer.compare(o1.hashCode(), o2.hashCode()));
    return tmp.hashCode();
}