Example usage for java.util Collection size

Introduction

In this page you can find the example usage for java.util Collection size.

Prototype

int size();

Source Link

Document

Returns the number of elements in this collection.

Usage

From source file:Main.java

public static int[] toIntArray(Collection<Integer> items) {
    int ret[] = new int[items.size()];
    int idx = 0;/*from w  ww  .  ja  v  a  2  s.  c o m*/
    for (Integer i : items) {
        assert (i != null);
        ret[idx++] = i.intValue();
    } // FOR
    return (ret);
}

From source file:Main.java

public static int[] toIntArray(Collection<? extends Number> c) {
    int arr[] = new int[c.size()];
    int i = 0;//from  ww  w. j  a  va2s.  c  o m
    for (Number item : c)
        arr[i++] = item.intValue();
    return arr;
}

From source file:Utils.java

public static <T> Collection<T> diff(Collection<T> c1, Collection<T> c2) {
    if (c1 == null || c1.size() == 0 || c2 == null || c2.size() == 0) {
        return c1;
    }/*from  w w w  . j ava  2  s.  c o  m*/
    Collection<T> difference = new ArrayList<T>();
    for (T item : c1) {
        if (!c2.contains(item)) {
            difference.add(item);
        }
    }
    return difference;
}

From source file:Main.java

public static <T> List<T> cons(T x, Collection<? extends T> xs) {
    ArrayList<T> result = new ArrayList<>(xs.size() + 1);
    result.add(x);//from ww w .j  a  v a 2s  . co m
    result.addAll(xs);
    return result;
}

From source file:Main.java

/**
 * Returns a slice of a collection, up to maxLen in size
 *
 * @param c      the collection to cut//from ww  w.  j  a  va2 s . c o  m
 * @param maxLen the length of the slice
 * @return a slice of {@code c} {@code maxLen} in size, if {@code maxLen} is less than {@code c.size()}, otherwise, return {@code c}
 */
public static <E> Collection<E> cutMaxLen(Collection<E> c, int maxLen) {
    if (maxLen < c.size()) {
        return new ArrayList<>(c).subList(0, maxLen);
    }
    return c;
}

From source file:Main.java

public static List<String> toStrings(Collection<?> c) {
    List<String> result = new ArrayList<String>(c.size());
    for (Object e : c) {
        result.add(e.toString());// ww w . j  a  v  a  2  s. co m
    }
    return result;
}

From source file:Main.java

public static final long[] collection2longArray(Collection<Object> collection) {
    long[] array = new long[collection.size()];
    int index = 0;
    for (Object value : collection) {
        try {//from  ww w. j av  a 2s . co m
            array[index] = Long.parseLong(String.valueOf(value));
            index++;
        } catch (Exception e) {
        }
    }
    return array;
}

From source file:Main.java

/**
 * Judge whether a collection is null or size is 0
 *
 * @param c/*from w w  w.  j av  a 2 s .c  o  m*/
 * @param <V>
 * @return
 */
public static <V> boolean isEmpty(Collection<V> c) {
    return (c == null || c.size() == 0);
}

From source file:Main.java

public static boolean isNotEmpty(Collection<? extends Object> collection) {
    return collection != null && collection.size() > 0;
}

From source file:Main.java

@SuppressWarnings("unchecked")
public static <E> E fromLast(Collection<E> collection, int fromLast) {
    return (E) collection.toArray()[collection.size() - 1 - fromLast];
}