List of usage examples for java.util Collection size
int size();
From source file:Main.java
public static String join(Collection<?> collection, String seperator) { Object[] objs = new Object[collection.size()]; collection.toArray(objs);/*from w w w. j a va 2s . co m*/ return join(objs, seperator); }
From source file:Main.java
@SuppressWarnings("unchecked") static <E> Collection<E> reverse(Collection<? extends E> c) { Object[] reverse = new Object[c.size()]; int index = c.size(); for (E e : c) { reverse[--index] = e;//from w w w. j a v a2s.c om } return (List<E>) Arrays.asList(reverse); }
From source file:Main.java
@SuppressWarnings({ "rawtypes", "unchecked" }) public static Collection substract(Collection source, Collection target) { if (source == null || source.size() == 0) { return null; }/* w w w . jav a2s . co m*/ if (target == null || target.size() == 0) { return source; } Collection result = new ArrayList(); for (Iterator it = source.iterator(); it.hasNext();) { Object candidate = it.next(); if (!target.contains(candidate)) { result.add(candidate); } } return result; }
From source file:Main.java
public static Object findSingleObject(Collection c) { if (c == null || c.isEmpty()) return null; if (c.size() > 1) throw new IllegalStateException("found more than one object when single object requested"); return c.iterator().next(); }
From source file:Main.java
public static <E> E extractSingleton(Collection<E> collection) { if (collection != null && collection.size() == 1) { return collection.iterator().next(); } else {// www. j a v a2 s . c om throw new IllegalArgumentException("Can extract singleton only when collection size == 1"); } }
From source file:Main.java
/** * Return true if same objects exist in listA and listB *///from w w w. ja v a 2s.co m public static <T> boolean isEqual(Collection<T> listA, Collection<T> listB) { if (listA.size() != listB.size()) { return false; } if (listA.size() != setIntersection(listA, listB).size()) { return false; } return true; }
From source file:Main.java
/** * Returns the size of the collection or array *//*from w w w .j a va2 s. co m*/ public static int size(Object collection) { if (collection instanceof Collection) { Collection value = (Collection) collection; return value.size(); } else if (collection != null) { if (collection.getClass().isArray()) { return Array.getLength(collection); } } return 0; }
From source file:Main.java
@SuppressWarnings({ "rawtypes", "unchecked" }) public static Collection in(Collection source, Collection target) { if (source == null || source.size() == 0) { return null; }//from w ww . j ava 2 s .com if (target == null || target.size() == 0) { return null; } Collection result = new ArrayList(); for (Iterator it = source.iterator(); it.hasNext();) { Object candidate = it.next(); if (target.contains(candidate)) { result.add(candidate); } } return result; }
From source file:Main.java
public static <T> boolean hasItems(Collection<T> source) { if (source == null) return false; return source.size() > 0; }
From source file:Main.java
/** * @return true if collection has only 1 item (null safe). */// w w w . j a v a 2 s .c om public static boolean hasOneItem(final Collection<?> col) { return col != null && col.size() == 1; }