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

From source file:Main.java

/**
 * Splits a collection in <tt>n</tt> new collections. The last collection may contain more elements than the others
 * if {@code set.size() % n != 0}.// w ww  .j ava  2  s .  c o m
 *
 * @param set the input collection
 * @param n   the number of new collections
 * @param <T> the element type
 * @return a list containing the new collections
 */
public static <T> List<T>[] split(Collection<T> set, int n) {
    if (set.size() >= n) {
        @SuppressWarnings("unchecked")
        List<T>[] arrays = new List[n];
        int minSegmentSize = (int) Math.floor(set.size() / (double) n);

        int start = 0;
        int stop = minSegmentSize;

        Iterator<T> it = set.iterator();

        for (int i = 0; i < n - 1; i++) {
            int segmentSize = stop - start;
            List<T> segment = new ArrayList<T>(segmentSize);
            for (int k = 0; k < segmentSize; k++) {
                segment.add(it.next());
            }
            arrays[i] = segment;
            start = stop;
            stop += segmentSize;
        }

        int segmentSize = set.size() - start;
        List<T> segment = new ArrayList<T>(segmentSize);
        for (int k = 0; k < segmentSize; k++) {
            segment.add(it.next());
        }
        arrays[n - 1] = segment;

        return arrays;
    } else {
        throw new IllegalArgumentException("n must not be smaller set size!");
    }
}

From source file:Main.java

public static int getSize(final Collection<?> collection) {
    if (collection == null) {
        return 0;
    }//from   w ww  .ja v  a2  s . c  o m
    return collection.size();
}

From source file:edu.northwestern.bioinformatics.studycalendar.web.taglibs.Functions.java

public static Collection pluck(Collection collection, String property) {
    Collection result = new ArrayList(collection.size());
    for (Object o : collection) {
        try {//from w ww .j  a  v a 2  s . c  om
            Object plucked = new Expression(o, "get" + capitalize(property), null).getValue();
            result.add(plucked);
        } catch (Exception e) {
            throw new StudyCalendarError("Unable to get the '" + property + "' property", e);
        }

    }
    return result;
}

From source file:Main.java

/**
 * clone all elements/*from   w  ww  .ja va 2s . c o m*/
 * 
 * @param inputCollection
 *            the collection to get the input from, may not be null
 * @return all elements (new list)
 * @throws NullPointerException
 *             if the input collection is null
 */
public static <E> Collection<E> cloneEx(Collection<E> inputCollection) {
    final ArrayList<E> outputCollection = new ArrayList<E>(inputCollection.size());
    for (Iterator<E> iter = inputCollection.iterator(); iter.hasNext();) {
        outputCollection.add(iter.next());
    }
    return outputCollection;
}

From source file:Main.java

/**
 * Returns the number of items in the given collection.
 *
 * @param collection    The collection to return the length of.
 * @param <E>           The component type of the items stored in the collection.
 * @return              The number of items in the given collection.
 */// ww  w  . ja  va2 s . c  om
public static <E> int length(Collection<E> collection) {
    if (collection == null)
        return 0;
    return collection.size();
}

From source file:Main.java

public static Collection<String> convertLongsToStrings(Collection<Long> longs) {
    if (longs != null) {
        Collection<String> strings = new ArrayList<String>(longs.size());
        for (long longNumber : longs) {
            strings.add(String.valueOf(longNumber));
        }/*  w w w.j  a va  2 s . co m*/
        return strings;
    }
    return null;
}

From source file:com.nec.strudel.bench.test.EntityAssert.java

public static <E> void assertSameEntitySets(Collection<E> expected, Collection<E> actual) {
    assertEquals(expected.size(), actual.size());
    for (E e : actual) {
        assertContains(e, expected);/*from ww w.j  av  a 2s  .c  om*/
    }
}

From source file:Main.java

/**
 * Returns an array containing all of the elements in the given collection. This is a
 * compile-time type-safe alternative to {@link Collection#toArray(Object[])}.
 * /*w w  w .j  av  a2s .  c  o m*/
 * @param collection the source collection
 * @param clazz the type of the array elements
 * @param <A> the type of the array elements
 * @return an array of type <code>A</code> containing all of the elements in the given
 *         collection
 * 
 * @throws NullPointerException if the specified collection or class is null
 * 
 * @see <a href="http://bugs.sun.com/bugdatabase/view_bug.do?bug_id=7023484">Sun bug 7023484</a>
 */
public static <A> A[] toArray(Collection<? extends A> collection, Class<A> clazz) {
    Object array = Array.newInstance(clazz, collection.size());
    @SuppressWarnings("unchecked")
    A[] typedArray = collection.toArray((A[]) array);
    return typedArray;
}

From source file:Main.java

public static int[] toArray(Collection<Integer> col) {
    if (col == null)
        return null;
    int[] arr = new int[col.size()];
    int i = 0;//from  w  w w.  j av a2  s  . c  o m
    for (Integer v : col)
        arr[i++] = v.intValue();
    return arr;
}