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

/**
 * /*  ww w.  ja  v  a 2  s .c o m*/
 * @param collection
 * @return float[]
 */
public static float[] toFloatArray(final Collection<Float> collection) {
    final float[] array = new float[collection == null ? 0 : collection.size()];

    if (collection != null) {
        int i = 0;

        for (Iterator<Float> iterator = collection.iterator(); iterator.hasNext();) {
            array[i++] = iterator.next().floatValue();
        }
    }

    return array;
}

From source file:Main.java

public static String[] toStringArray(Collection<String> collection) {
    if (collection == null) {
        return null;
    }//from w  w  w  .j ava2s  . c  o m
    return collection.toArray(new String[collection.size()]);
}

From source file:Main.java

public static <T> T[] toArray(Collection<T> list, IntFunction<T[]> action) {
    return list.toArray(action.apply(list.size()));
}

From source file:Main.java

public static <O> O getRandom(final Collection<O> pObjects) {
    if (pObjects != null && !pObjects.isEmpty()) {
        int r = Math.abs(random.nextInt() % pObjects.size());
        List<O> objects = !(pObjects instanceof List) ? new ArrayList<O>(pObjects) : (List<O>) pObjects;

        return objects.get(r);
    }// w w  w.j  a  va 2 s. com
    return null;
}

From source file:com.shazam.fork.summary.OutcomeAggregator.java

private static Boolean and(final Collection<Boolean> booleans) {
    return BooleanUtils.and(booleans.toArray(new Boolean[booleans.size()]));
}

From source file:Main.java

/**
 * /*  w w w  .j  av a2 s  .c om*/
 * 
 */
@SuppressWarnings("unchecked")
public static <T> T[] toArray(Collection<T> collection, Class<T> elementClass, int index, int count) {
    int n = collection.size();
    int end = Math.min(index + count, n);
    Object result = Array.newInstance(elementClass, end - index);
    Iterator<T> it = collection.iterator();
    int resultIndex = 0;
    for (int i = 0; i < end; i++) {
        if (!it.hasNext())
            break;
        Object value = it.next();
        if (i < index)
            continue;
        Array.set(result, resultIndex, value);
        resultIndex++;
    }
    return (T[]) result;
}

From source file:Main.java

/**
 * Returns an array of integer values from the set of integer values
 * @param set to return array for//from w  ww. j a  v  a  2 s. c  o  m
 * @return array
 */
public static int[] intArray(Collection<Integer> set) {
    if (set == null) {
        return new int[0];
    }
    int[] result = new int[set.size()];
    int index = 0;
    for (Integer value : set) {
        result[index++] = value;
    }
    return result;
}

From source file:Main.java

public static <T> T get(Collection<T> c, int index) {
    if (isEmpty(c))
        return null;

    if (index < 0 || index >= c.size())
        return null;

    if (c instanceof List)
        return (T) ((List<T>) c).get(index);

    List<? extends T> a = new ArrayList<T>(c);
    return a.get(index);
}

From source file:com.qwazr.utils.ArrayUtils.java

public static double[] toPrimitiveDouble(Collection<Double> collection) {
    double[] array = new double[collection.size()];
    int i = 0;//from  ww w .j ava 2  s  .co m
    for (double val : collection)
        array[i++] = val;
    return array;
}

From source file:Main.java

/**
 * Extract the lone element of the specified Collection.
 * @param <E> collection type/*from w  ww  .j  a  v  a  2s . co m*/
 * @param collection to read
 * @return sole member of collection
 * @throws IllegalArgumentException if collection is null/empty or contains more than one element
 * @since 4.0
 */
public static <E> E extractSingleton(final Collection<E> collection) {
    if (collection == null || collection.size() != 1) {
        throw new IllegalArgumentException("Can extract singleton only when collection size == 1");
    }
    return collection.iterator().next();
}