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 long[] toLongArray(List<Long> list) {
    if (list == null || list.isEmpty())
        return null;
    long[] arr = new long[list.size()];
    for (int i = 0; i < list.size(); i++) {
        arr[i] = list.get(i).longValue();
    }/*from   www.  j a v  a 2 s  . c  o  m*/
    return arr;
}

From source file:Main.java

/**
 * Returns the index of the maximum element in the list, using the elements'
 * natural ordering, or -1 if the list is empty.
 * @param list a list//from  www. j ava  2 s .  c o  m
 * @return the index of the maximum element
 */
public static <T extends Comparable<? super T>> int maxIndex(List<T> list) {
    if (list.isEmpty())
        return -1;
    if (list.size() == 1)
        return 0;
    int best = 0;
    //TODO: alternative implementation for non-RandomAccess lists?
    for (int i = 1; i < list.size(); ++i)
        if (list.get(i).compareTo(list.get(best)) > 0)
            best = i;
    return best;
}

From source file:Main.java

/**
 * Returns first item in the list if list is not empty.
 *
 * @param list The list to get first item from.
 *///from w ww.j  a v a 2 s.  c o  m
@Nullable
public static <T> T first(@Nullable final List<T> list) {
    return (list == null || list.isEmpty() ? null : list.get(0));
}

From source file:Main.java

public static int getAllListViewSectionCounts(ListView lv, List dataSource) {
    if (null == lv || dataSource == null || dataSource.isEmpty()) {
        return 0;
    }/*  w  w  w. j  a  v  a 2s. c o m*/
    return dataSource.size() + lv.getHeaderViewsCount() + lv.getFooterViewsCount();
}

From source file:Main.java

/**
 * Returns the index of the minimum element in the list, using the elements'
 * natural ordering, or -1 if the list is empty.
 * @param list a list// w  ww  .jav a  2  s. co  m
 * @return the index of the minimum element
 */
public static <T extends Comparable<? super T>> int minIndex(List<T> list) {
    if (list.isEmpty())
        return -1;
    if (list.size() == 1)
        return 0;
    int best = 0;
    //TODO: alternative implementation for non-RandomAccess lists?
    for (int i = 1; i < list.size(); ++i)
        if (list.get(i).compareTo(list.get(best)) < 0)
            best = i;
    return best;
}

From source file:Main.java

public static <T extends Comparator<T>> Boolean isEmpty(List<T> collection) {
    return collection == null || collection.isEmpty();
}

From source file:Main.java

public static <T> String listToString(List<T> list) {
    if (null == list || list.isEmpty()) {
        return "";
    }/*from  w  w w  . ja  va  2 s  . c o m*/
    StringBuilder sb = new StringBuilder();
    for (T i : list) {
        sb.append(i.toString());
        sb.append(",");
    }
    int index = sb.lastIndexOf(",");
    if (-1 != index) {
        sb.deleteCharAt(index);
    }
    return sb.toString();
}

From source file:Main.java

public static Double listAvg(List<Double> list) {
    if (list == null || list.isEmpty()) {
        return null;
    }/* w  w w  .ja  v a2s . c  o m*/

    Double listSum = listSum(list);

    return listSum / list.size();
}

From source file:Main.java

public static <T> T getSingleResult(List<T> results) {
    return (results == null || results.isEmpty()) ? null : results.get(0);
}

From source file:Main.java

private static String extract(Uri uri, int index) {
    List<String> pathSegments = uri.getPathSegments();
    if (pathSegments.isEmpty() || pathSegments.size() < index)
        return null;
    return pathSegments.get(index);
}