Example usage for java.util Collection iterator

Introduction

In this page you can find the example usage for java.util Collection iterator.

Prototype

Iterator<E> iterator();

Source Link

Document

Returns an iterator over the elements in this collection.

Usage

From source file:Main.java

public static String toString(Collection<?> list, String split) {
    if (list == null) {
        return null;
    }/*from   ww w  . j  av  a2s .  c  o m*/
    StringBuffer rs = new StringBuffer();
    Iterator<?> it = list.iterator();
    while (it.hasNext()) {
        rs.append(it.next());
        if (it.hasNext()) {
            rs.append(split);
        }
    }
    return rs.toString();
}

From source file:Main.java

/**
 * Converts the given collection to a <code>java.util.List</code>.
 * @param collection The collection to convert to a list.
 * @return A <code>java.util.List</code> containing all of the elements from the
 *         supplied collection.//from  ww w . ja  v  a  2 s . com
 */
public static List toList(Collection collection) {
    if (collection instanceof List)
        return (List) collection;

    List list = new ArrayList();
    Iterator iterator = collection.iterator();
    while (iterator.hasNext()) {
        list.add(iterator.next());
    }
    return list;
}

From source file:Main.java

public static <T> T last(Collection<T> collection) {
    if (collection == null || collection.isEmpty()) {
        return null;
    }/*from   w  ww.ja v a 2  s .  c  o  m*/
    Iterator<T> iterator = collection.iterator();
    T elem = null;
    while (iterator.hasNext()) {
        elem = iterator.next();
    }
    return elem;
}

From source file:Main.java

/**
 * Computes the array of element indices which where added to a collection.
 *
 * @param smallCollection//from   w  w w.  ja  v  a 2 s  . c o  m
 *          the original collection.
 * @param bigCollection
 *          the collection with added elements.
 * @return the the array of element indices which where added to the original
 *         collection
 */
public static int[] computeDifferenceIndices(Collection<?> smallCollection, Collection<?> bigCollection) {
    List<Integer> addedIndices = new ArrayList<>();
    int index = 0;
    for (Iterator<?> ite = bigCollection.iterator(); ite.hasNext(); index++) {
        if (smallCollection == null || !smallCollection.contains(ite.next())) {
            if (smallCollection == null) {
                ite.next();
            }
            addedIndices.add(index);
        }
    }
    int[] result = new int[addedIndices.size()];
    for (int i = 0; i < addedIndices.size(); i++) {
        result[i] = addedIndices.get(i);
    }
    return result;
}

From source file:Main.java

/**
 * Returns the element at the specified position in the 
 * collection. // w  ww  . j av a2s  .co  m
 * Shifts any subsequent elements to the left 
 * (subtracts one from their indices). 
 * Returns the element that was removed from the Collection.
 * @param p_collection a Collection
 * @param p_index index of element to return.
 * @returns the element at the specified position in the 
 * collection.
 */
public static Object get(Collection p_collection, int p_index) {
    if (p_collection == null) {
        return null;
    }
    Iterator it = p_collection.iterator();
    for (int i = 0; it.hasNext(); i++) {
        if (i == p_index) {
            return it.next();
        }
    }
    return null;
}

From source file:Main.java

public static <A> Set<A> makeSet(Collection<A> xs) {
    if (xs.size() == 0)
        return Collections.<A>emptySet();
    else if (xs.size() == 1)
        return Collections.singleton(xs.iterator().next());
    else {/*from  w w  w  .  ja v a 2 s  . c o m*/
        Set<A> set = new HashSet<A>(xs.size());
        set.addAll(xs);
        return set;
    }
}

From source file:org.apache.bigtop.bigpetstore.qstream.Utils.java

/**
 * Borrowed from apache StringUtils./*from   w w  w  . j  av  a  2 s  . com*/
 */
public static String join(Collection var0, Object var1) {
    StringBuffer var2 = new StringBuffer();

    for (Iterator var3 = var0.iterator(); var3.hasNext(); var2.append(var3.next())) {
        if (var2.length() != 0) {
            var2.append(var1);
        }
    }

    return var2.toString();
}

From source file:Main.java

/**
 * Determine whether the given collection only contains a
 * single unique object./* w ww.j  a v  a  2s .  c om*/
 * @param coll the collection to check
 * @return <code>true</code> if the collection contains a
 * single reference or multiple references to the same
 * instance, <code>false</code> else
 */
public static boolean hasUniqueObject(Collection<?> coll) {
    if (coll.isEmpty()) {
        return false;
    }
    Object candidate = null;
    for (Iterator<?> it = coll.iterator(); it.hasNext();) {
        Object elem = it.next();
        if (candidate == null) {
            candidate = elem;
        } else if (candidate != elem) {
            return false;
        }
    }
    return true;
}

From source file:com.enonic.cms.core.structure.menuitem.MenuItemKey.java

public static String convertToCommaSeparatedString(Collection<MenuItemKey> keys) {
    StringBuffer s = new StringBuffer();
    for (Iterator<MenuItemKey> it = keys.iterator(); it.hasNext();) {
        MenuItemKey menuItemKey = it.next();
        s.append(menuItemKey);//  ww w  .  j ava  2s. c  om
        if (it.hasNext()) {
            s.append(",");
        }
    }
    return s.toString();
}

From source file:Main.java

public static <T extends Object> T remove(final int index, final Collection<T> collection) {
    if (!isEmptyOrNull(collection)) {
        int i = 0;
        for (Iterator<T> it = collection.iterator(); it.hasNext();) {
            final T removed = it.next();
            if (i == index) {
                it.remove();//from   ww  w. j  av a  2 s .  co m
                return removed;
            }
            i++;
        }
    }
    return null;
}