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 double[] toDoubleArray(Collection<? extends Number> c) {
    double arr[] = new double[c.size()];
    int i = 0;//from   ww w . j a va  2 s.c o m
    for (Number item : c)
        arr[i++] = item.doubleValue();
    return arr;
}

From source file:Main.java

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

From source file:Main.java

public static String collectionToSlashString(Collection<?> collection) {
    if (collection != null && collection.size() > 0) {
        StringBuilder sb = new StringBuilder();
        Object obj = null;/* w  w w  .  ja v  a  2  s .  c  om*/
        for (Iterator<?> iterator = collection.iterator(); iterator.hasNext();) {
            obj = iterator.next();
            sb.append(obj.toString());
            if (iterator.hasNext()) {
                sb.append("/");
            }
        }
        return sb.toString();
    } else {
        return "";
    }
}

From source file:Main.java

private static <E> boolean fallBackToStandardImplementation(final Collection<E> coll, final int limit) {
    return limit >= coll.size() || limit < 0 || coll.isEmpty();
}

From source file:Main.java

/**
 * Modify the specified Collection so that only the first <code>limit</code> elements
 * remain, as determined by iteration order. If the Collection is smaller than limit,
 * it is unmodified.//from   w w w.  j a  v  a2s.c  o  m
 */
public static void limit(Collection<?> col, int limit) {
    int size = col.size();
    if (size > limit) {
        if (col instanceof List<?>) {
            ((List<?>) col).subList(limit, size).clear();

        } else {
            Iterator<?> itr = col.iterator();
            for (int ii = 0; ii < limit; ii++) {
                itr.next();
            }
            while (itr.hasNext()) {
                itr.next();
                itr.remove();
            }
        }
    }
}

From source file:Main.java

public static <T> boolean collectionEquals(Collection<T> col1, Collection<T> col2) {
    if (col1.size() != col2.size()) {
        return false;
    }/*from   w  ww  .ja  va  2s  .  c  o  m*/

    for (T item : col1) {
        if (!col2.contains(item)) {
            return false;
        }
    }

    return true;
}

From source file:Main.java

public static long[] toArray(Collection<Long> collection) {
    long[] array = new long[collection.size()];
    Iterator<Long> it = collection.iterator();
    int i = 0;//ww  w . j  a v  a  2 s .co  m
    while (it.hasNext()) {
        array[i++] = it.next();
    }
    return array;
}

From source file:Main.java

/**
 * Create new {@link HashMap} having same size of given base collection.
 *
 * @param base collection which size will be referred
 * @param <K>  keyType// w  w w.ja  v  a2 s.  c o  m
 * @param <V>  valueType
 * @return created {@link HashMap} instance
 */
public static <K, V> HashMap<K, V> newHashMap(Collection<?> base) {
    return new HashMap<K, V>(base.size());
}

From source file:Main.java

public static Boolean isEmpty(Collection<?> collection) {
    if (collection == null || collection.size() < 1) {
        return Boolean.TRUE;
    }//from   www.  j a  v  a2s . c  om
    return Boolean.FALSE;
}

From source file:Main.java

public static <T extends Object> T getFirst(Collection<T> items, T otherwise) {
    if (items == null || items.size() == 0)
        return otherwise;
    return items.iterator().next();
}