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

/**
 * @return size of collection if not null, otherwise 0.
 *///from  ww w.ja  v  a  2 s .co  m
public static int size(final Collection<?> col) {
    return col != null ? col.size() : 0;
}

From source file:Main.java

/**
 * Returns the size of the collection. If the collection is null, 0 will be returned.
 */// ww w  .j av  a2 s  .  co  m
public static int getSize(Collection<?> collection) {
    return collection != null ? collection.size() : 0;
}

From source file:Main.java

public static boolean isEmpty(Collection<?> collection) {

    if (null == collection || collection.isEmpty() || collection.size() <= 0)
        return true;
    return false;
}

From source file:Main.java

/**
 * Checks if the given array is null or its length is empty
 * //from  w ww. j  a  v a2 s.c o m
 * @param collection
 * @return
 */
public static boolean isEmpty(Collection collection) {
    if (collection == null)
        return true;
    if (collection.size() == 0)
        return true;
    return false;
}

From source file:Main.java

/**
 * Convert a Collection of Numbers to an array of primitive longs
 * Null values will be skipped in the array 
 * @param items/*w  w  w .j  a v  a  2s.c  o m*/
 * @return
 */
public static long[] toLongArray(Collection<? extends Number> items) {
    long ret[] = new long[items.size()];
    int idx = 0;
    for (Number n : items) {
        if (n != null)
            ret[idx] = n.longValue();
        idx += 1;
    } // FOR
    return (ret);
}

From source file:Main.java

/**
 * Returns the size of the specified collection. If the specified collection is null, this method returns the specified default size.
 *
 * @param c           Collection of Objects referencing the collection to retrieve the size from.
 * @param defaultSize int referencing the size to be returned when the collection is null.
 * @return int referencing the size of the collection, or the default size when the collection is null.
 *//*from  w w w  . ja va 2s.com*/
public static int defaultSizeIfNull(Collection c, int defaultSize) {
    return (c == null ? defaultSize : c.size());
}

From source file:Main.java

/**
 * Creates a new {@link ArrayList} with the inferred type
 * using the given elements./* w  w w.  j a  va2  s.  com*/
 */
public static <T> ArrayList<T> alist(Collection<T> vals) {
    ArrayList<T> ret = new ArrayList<T>(vals.size());
    for (T v : vals)
        ret.add(v);
    return ret;
}

From source file:Main.java

public static int size(Collection<?>... collections) {
    int size = 0;
    if (collections != null) {
        for (Collection<?> c : collections) {
            if (c != null) {
                size += c.size();
            }/*  ww  w.  ja va  2 s  . c om*/
        }
    }

    return size;
}

From source file:Main.java

/**
 * Converts a collection into an array./*from www.j  a  v a2  s  . co m*/
 * @param collection the collection to convert
 * @param clazz the class of the items in the collections
 * @return a non-null array
 */
public static <T> T[] convertToArray(Collection<T> collection, Class<T> clazz) {
    T[] result = (T[]) Array.newInstance(clazz, collection.size());
    return collection.toArray(result);
}

From source file:Main.java

public static int size(Collection collection) {
    if (isEmpty(collection)) {
        return 0;
    }/*from  w  w w .  j  ava  2  s . c om*/
    return collection.size();
}