Java Utililty Methods Collection Flatten

List of utility methods to do Collection Flatten

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Description

The list of methods to do Collection Flatten are organized into topic(s).

Method

Listflatten(Collection colOfCols)
flatten 
int size = 0;
for (C col : colOfCols) {
    size += col.size();
ArrayList<T> list = new ArrayList<T>(size);
for (C col : colOfCols) {
    list.addAll(col);
return list;
Collectionflatten(Class cls, Collection> collections)
flatten 
try {
    Collection<T> flatCollection = cls.newInstance();
    for (Collection<T> collection : collections) {
        flatCollection.addAll(collection);
    return flatCollection;
} catch (RuntimeException re) {
    throw re;
...
Listflatten(Collection> collections)
flatten 
List<E> result = new ArrayList<E>();
for (Collection<E> list : collections) {
    result.addAll(list);
return result;
Collectionflatten(Collection> cols)
flatten 
if (cols.size() == 0) {
    return Collections.emptyList();
} else if (cols.size() == 1) {
    return cols.iterator().next();
} else {
    Collection<V> result = new ArrayList<V>();
    for (Collection<V> c : cols) {
        for (V v : c) {
...
Listflatten(Collection l)
flatten 
boolean hasCollection = false;
for (Object o : l) {
    if (o instanceof Collection) {
        hasCollection = true;
        break;
if (!hasCollection && (l instanceof List)) {
...
Listflatten(Collection list, Class type)
flatten 
List<Object> retVal = new ArrayList<Object>();
flatten(list, retVal);
return (List<T>) retVal;
Listflatten(Collection> nestedList)
combines all the lists in a collection to a single list 
List<T> result = new ArrayList<T>();
for (List<T> list : nestedList) {
    result.addAll(list);
return result;
Listflatten(Collection> collOfLists)
This method is NOT intended as a part of public API and should not be used outside the library! 
List<U> res = new ArrayList<U>();
for (List<U> l : collOfLists) {
    res.addAll(l);
return res;
Stringflatten(Collection collection, char separator)
flatten 
StringBuilder buf = new StringBuilder(""); 
if (!isEmptyCollection(collection)) {
    Iterator<T> iter = collection.iterator();
    buf.append(String.valueOf(iter.next()));
    while (iter.hasNext()) {
        buf.append(separator).append(String.valueOf(iter.next()));
return buf.toString();
Collectionflatten(Collection original)
flatten 
boolean hasNested = false;
for (Object o : original) {
    if (o instanceof Collection) {
        hasNested = true;
        break;
if (!hasNested)
...