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 <T> T checkAndReturnOnlyElement(Collection<T> collection) {
    if (collection == null || collection.size() == 0) {
        return null;
    } else if (collection.size() != 1) {
        throw new IllegalStateException("collection size is " + collection.size());
    }/*w  w  w .j  a  v  a 2s  .co m*/
    return collection.iterator().next();
}

From source file:Main.java

@SuppressWarnings("rawtypes")
public static boolean allIn(Collection source, Collection target) {
    if (target == null || target.size() == 0) {
        return false;
    }/*from   w w w.  ja  va2s . c  om*/

    for (Iterator it = source.iterator(); it.hasNext();) {
        Object object = it.next();
        if (!target.contains(object)) {
            return false;
        }
    }
    return true;
}

From source file:Main.java

/**
 * Retorna true se a colleciton for null ou vazia.
 */// ww w  .  j  a  va  2  s.co m
public static <T> boolean isEmpty(final Collection<T> collection) {
    return collection == null || collection.size() == 0;
}

From source file:Main.java

public static boolean isNonEmpty(Collection c) {
    return (c != null && c.size() > 0);
}

From source file:Main.java

public static long[] toLongArray(Collection<? extends Number> c) {
    long arr[] = new long[c.size()];
    int i = 0;//  w  w  w  . ja  v a 2s. c om
    for (Number item : c) {
        arr[i++] = item.longValue();
    }
    return arr;
}

From source file:Main.java

/**
 * Returns the size of the specified collection or 0 on null.
 * @param <T>//from www . j  a  v  a  2s. c o m
 * @param collection
 * @return
 */
public static <T> int size(Collection<T> collection) {
    return collection == null ? 0 : collection.size();
}

From source file:Main.java

public static byte[] toByteArray(Collection<? extends Number> c) {
    byte arr[] = new byte[c.size()];
    int i = 0;// w  ww .j  a v  a 2  s.  c o  m
    for (Number item : c) {
        arr[i++] = item.byteValue();
    }
    return arr;
}

From source file:Main.java

public static boolean isEmpty(Collection<?> collection) {
    if (collection == null || collection.size() == 0) {
        return true;
    }/*from w  w  w.ja v a  2 s  .co m*/
    return false;
}

From source file:Main.java

/**
 * @param array/*from  w w w .  ja v  a  2s .  c  om*/
 * @return
 */
public static <T> boolean isEmpty(Collection<T> array) {
    if (array == null || array.size() == 0) {
        return true;
    }
    return false;
}

From source file:Main.java

public static <T> boolean isEmpty(Collection<T> collection) {
    return null == collection || collection.size() <= 0;
}