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 byte[] toByteArray(Collection<? extends Number> c) {
    byte arr[] = new byte[c.size()];
    int i = 0;/*from 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

/**
 * @param coll//from   w  ww . jav  a  2  s  .  c o m
 * @postcondition (coll == null) --> (result == 0)
 * @postcondition (coll != null) --> (result == coll.size())
 */
public static int size(Collection<?> coll) {
    return (coll == null) ? 0 : coll.size();
}

From source file:Main.java

public static <T> List<T> shallowCopyToList(Collection<T> collection) {
    ArrayList<T> copied = new ArrayList<T>(collection.size());
    for (T element : collection) {
        copied.add(element);//from   ww w.j a v a 2  s  . c  o m
    }
    return copied;
}

From source file:Main.java

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

From source file:Main.java

public static void trimCollection(Collection collection, int numberOfElements) {
    if (collection.size() < numberOfElements) {
        return;/*from  w  w w  .  j a  v  a  2 s.  c  o m*/
    }

    numberOfElements = collection.size() - numberOfElements;
    Iterator it = collection.iterator();
    int counter = 0;

    while (it.hasNext()) {
        if (counter <= numberOfElements) {
            it.next();
            counter++;
        }
        it.remove();
    }
}

From source file:Main.java

public static Integer sum(Collection<Integer> collection) {
    if (collection == null || collection.size() == 0) {
        return 0;
    }// w w w  . j  av a  2 s  .  com

    Integer answer = 0;

    for (Integer value : collection) {
        answer += value;
    }

    return answer;
}

From source file:Main.java

public static short[] toShortArray(Collection<? extends Number> c) {
    short arr[] = new short[c.size()];
    int i = 0;// www .  j  a va 2s.  c om
    for (Number item : c)
        arr[i++] = item.shortValue();
    return arr;
}

From source file:Main.java

public static float[] toFloatArray(Collection<? extends Number> c) {
    float arr[] = new float[c.size()];
    int i = 0;//w ww. j  a va2s  .c om
    for (Number item : c)
        arr[i++] = item.floatValue();
    return arr;
}

From source file:Main.java

/**
 * Cast a collection to an array/*  w ww.  j  a  v a  2 s .c o m*/
 *
 * @param collection the collection to cast
 * @param <T>        the type of the collection contents
 * @return an array of type T
 */
public static <T> T[] toArray(Collection<T> collection) {
    return (T[]) collection.toArray(new Object[collection.size()]);
}

From source file:Main.java

/**
 * Checks if collection is null or empty
 *
 * @param source collection to check/*from   w w w  .j a va2s.c  om*/
 * @return true if collection is null or empty
 */
public static boolean isEmpty(Collection<?> source) {
    return source == null || source.size() == 0;
}