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

/**
 * Checks to see if a collection is null or empty.
 * // www.  j a  v  a  2  s.  co m
 * @param collection
 *            Collection to test, may be null.
 * @return true if the collection is null or empty, otherwise false.
 */
public static boolean isEmpty(final Collection<?> collection) {
    return collection == null || collection.size() < 1;
}

From source file:Main.java

public static <K, V> Map<K, V> map(Collection<Entry<K, V>> entries) {
    Map<K, V> map = new LinkedHashMap<>(entries.size());
    for (Entry<K, V> entry : entries) {
        map.put(entry.getKey(), entry.getValue());
    }/*from w  w w. ja va2s. c  o m*/
    return map;
}

From source file:Main.java

public static <T> boolean isSubset(Collection<T> subset, Collection<T> superset) {
    if ((superset == null) || (superset.size() == 0)) {
        return ((subset == null) || (subset.size() == 0));
    }//from  w ww.  j a  va  2  s  .co  m

    HashSet<T> hash = new HashSet<T>(superset);
    for (T t : subset) {
        if (!hash.contains(t)) {
            return false;
        }
    }
    return true;
}

From source file:Main.java

public static String join(Collection<?> input, String sep) {
    if (input == null || input.size() == 0) {
        return "";
    }/*from   ww w  .j a  v  a2  s . co  m*/
    StringBuilder sb = new StringBuilder();
    int index = 0;
    int size = input.size();
    Iterator<?> it = input.iterator();
    while (it.hasNext()) {
        if (index == size - 1) {
            break;
        }
        Object o = it.next();
        sb.append(o).append(sep);
        index++;
    }
    sb.append(it.next());
    return sb.toString();
}

From source file:Main.java

public static <T extends Comparable<T>> T max(final Collection<T> collection) {
    if (collection == null || collection.size() <= 0) {
        return null;
    }/*  w  ww . ja  v a2s .c om*/
    T max = null;
    for (final T elem : collection) {
        if (max == null || elem.compareTo(max) > 0) {
            max = elem;
        }
    }
    return max;
}

From source file:Main.java

public static <T extends Comparable<T>> T min(final Collection<T> collection) {
    if (collection == null || collection.size() <= 0) {
        return null;
    }//from w  ww .  j  ava  2s.  com
    T max = null;
    for (final T elem : collection) {
        if (max == null || elem.compareTo(max) < 0) {
            max = elem;
        }
    }
    return max;
}

From source file:Main.java

public static Collection<?> filterByValue(String propertyName, Object value, Collection<?> collection) {
    List<Object> list = new ArrayList<Object>(collection.size());
    for (Object o : collection) {
        BeanWrapper bw = new BeanWrapperImpl(o);
        Object propertyValue = bw.getPropertyValue(propertyName);
        if (propertyValue.equals(value)) {
            list.add(o);/*from w  w w  .  j a  v  a2s.  c o  m*/
        }
    }
    return list;
}

From source file:Main.java

public static Collection<?> filterByNotValue(String propertyName, Object value, Collection<?> collection) {
    List<Object> list = new ArrayList<Object>(collection.size());
    for (Object o : collection) {
        BeanWrapper bw = new BeanWrapperImpl(o);
        Object propertyValue = bw.getPropertyValue(propertyName);
        if (!propertyValue.equals(value)) {
            list.add(o);/*  w ww. j a  v  a 2s . c  om*/
        }
    }
    return list;
}

From source file:Main.java

public static int countCollectionValues(Map<?, ? extends Collection<?>> map) {
    int counter = 0;
    for (Collection<?> c : map.values()) {
        if (c != null)
            counter += c.size();
    }//from   www  .  j a v  a2  s. co m
    return counter;
}

From source file:Main.java

public static <T> Collection<T> union(Collection<T> a, Collection<T> b) {
    HashSet<T> s = new HashSet<T>(a.size() + b.size());
    s.addAll(a);/*from   w ww.  j av a 2  s  .c  o m*/
    s.addAll(b);
    return s;
}