Example usage for com.google.common.collect Iterators cycle

Introduction

In this page you can find the example usage for com.google.common.collect Iterators cycle.

Prototype

public static <T> Iterator<T> cycle(T... elements)

Source Link

Document

Returns an iterator that cycles indefinitely over the provided elements.

Usage

From source file:runtime.intrinsic._listsets.java

public static ListValue invoke(final ListValue list, final ListValue indexes, final ListValue vals) {
    ListValue result = list;//w  ww  .  j  a  va  2s  .  c  o m

    final Iterator<?> valiter = vals.size() >= indexes.size() ? vals.iterator() : Iterators.cycle(vals);

    for (final Object index : indexes)
        result = result.update((Integer) index, valiter.next());

    return result;
}

From source file:runtime.intrinsic._mapsets.java

public static MapValue invoke(final MapValue map, final ListValue keys, final ListValue vals) {
    MapValue result = map;//  w  w  w .  j av  a  2  s  .  c  o m

    final Iterator<?> valiter = vals.size() >= keys.size() ? vals.iterator() : Iterators.cycle(vals);

    for (final Object key : keys)
        result = result.assoc(key, valiter.next());

    return result;
}

From source file:runtime.intrinsic._assoc.java

public static MapValue invoke(final ListValue keys, final ListValue vals) {
    if (vals.size() == 0)
        return PersistentMap.EMPTY;

    final PersistentMap result = PersistentMap.fresh();

    final Iterator<?> valiter = vals.size() >= keys.size() ? vals.iterator() : Iterators.cycle(vals);

    for (final Object key : keys)
        result.assocUnsafe(key, valiter.next());

    return result;
}

From source file:runtime.intrinsic._group.java

public static MapValue invoke(final ListValue keys, final ListValue vals) {
    if (vals.size() == 0)
        return PersistentMap.EMPTY;

    final PersistentMap result = PersistentMap.fresh();

    final Iterator<?> keyiter = keys.size() >= vals.size() ? keys.iterator() : Iterators.cycle(keys);

    for (final Object val : vals) {
        final Object key = keyiter.next();

        final PersistentList keyvals = (PersistentList) result.get(key);

        if (keyvals == null) {
            result.assocUnsafe(key, PersistentList.single(val));
        } else {//from w w  w  . j av a  2s .com
            result.assocUnsafe(key, keyvals.appendUnsafe(val));
        }
    }

    return result;
}

From source file:runtime.intrinsic._take.java

public static ListValue invoke(final int n, final ListValue list) {
    final int size = list.size();

    if (size == 0) {
        return list;
    } else {/*from  w  w  w  . java 2 s.co  m*/
        final int extent = Math.abs(n);

        if (extent == size) {
            return list;
        } else if (extent < size) {
            // sublist cases
            return n >= 0 ? (ListValue) list.subList(0, n) : (ListValue) list.subList(size + n, size);
        } else {
            // rollover cases
            if (n >= 0) {
                return PersistentList.init(Iterators.cycle(list), n);
            } else {
                final PersistentList result = PersistentList.alloc(extent);

                int ri = 0;
                for (int i = n + 1; i <= 0; i++)
                    result.updateUnsafe(ri++, list.get(size + (i % size) - 1));

                return result;
            }
        }
    }
}

From source file:com.ibm.og.supplier.Suppliers.java

/**
 * Creates a supplier that returns values in a cycle
 * /*from w w  w .ja va2  s  . co m*/
 * @param values the values to supply
 * @return a supplier which supplies values in a cycle
 * @throws NullPointerException if values is null or contains null elements
 */
public static <T> Supplier<T> cycle(final List<T> values) {
    final List<T> copy = ImmutableList.copyOf(values);
    checkArgument(!copy.isEmpty(), "values must not be empty");
    final Iterator<T> it = Iterators.cycle(copy);
    return new Supplier<T>() {
        @Override
        public T get() {
            return it.next();
        }

        @Override
        public String toString() {
            return String.format("cycle %s", copy);
        }
    };
}

From source file:runtime.intrinsic._zip.java

public static ListValue invoke(final Tuple lists) {
    final int wid = lists.size();

    // fast implementation of common case (pair of lists)
    if (wid == 2)
        return invoke2((ListValue) lists.get(0), (ListValue) lists.get(1));

    // variable-width cases

    int size = 0;
    boolean even = true;
    for (int i = 0; i < wid; i++) {
        final int listsize = ((ListValue) lists.get(i)).size();

        // note early bailout
        if (listsize == 0)
            return PersistentList.EMPTY;

        if (size < listsize) {
            size = listsize;/*from  ww  w  . j a v  a2s  .com*/
            even = false;
        }
    }

    final PersistentList result = PersistentList.alloc(size);

    final Iterator<?>[] iters = new Iterator<?>[wid];
    for (int j = 0; j < wid; j++) {
        final ListValue list = (ListValue) lists.get(j);
        iters[j] = even ? list.iterator() : Iterators.cycle(list);
    }

    for (int i = 0; i < size; i++) {
        final Object[] vals = new Object[wid];

        for (int j = 0; j < wid; j++)
            vals[j] = iters[j].next();

        result.updateUnsafe(i, Tuple.from(vals));
    }

    return result;
}

From source file:com.bfd.harpc.loadbalance.RoundRobinStrategy.java

@Override
protected Collection<S> onBackendsOffered(Set<S> targets) {
    List<S> newTargets = Lists.newArrayList(targets);
    Collections.shuffle(newTargets);
    iterator = Iterators.cycle(newTargets);
    return newTargets;
}

From source file:runtime.intrinsic._mapz.java

public static ListValue invoke(final Tuple lists, final Lambda func) {
    final int wid = lists.size();

    // fast implementation of common case (pair of lists)
    if (wid == 2)
        return invoke2((ListValue) lists.get(0), (ListValue) lists.get(1), func);

    int size = 0;
    boolean ragged = false;

    if (wid > 0) {
        size = ((ListValue) lists.get(0)).size();

        // early bailout--any empty component list yields empty zip
        if (size == 0)
            return PersistentList.EMPTY;

        for (int i = 1; i < wid; i++) {
            final int listsize = ((ListValue) lists.get(i)).size();

            // early bailout--any empty component list yields empty zip
            if (listsize == 0)
                return PersistentList.EMPTY;

            if (listsize != size) {
                // ragged lists must use a slower iterator
                ragged = true;/*from  ww w.j a  v a  2s .  c o m*/

                // size of zipped list is size of longest list
                size = Math.max(size, listsize);
            }
        }
    }

    final PersistentList result = PersistentList.alloc(size);

    final Iterator<?>[] iters = new Iterator<?>[wid];
    for (int j = 0; j < wid; j++) {
        final ListValue list = (ListValue) lists.get(j);
        iters[j] = ragged ? Iterators.cycle(list) : list.iterator();
    }

    for (int i = 0; i < size; i++) {
        final Object[] vals = new Object[wid];

        for (int j = 0; j < wid; j++)
            vals[j] = iters[j].next();

        result.updateUnsafe(i, func.apply(Tuple.from(vals)));
    }

    return result;
}

From source file:org.opendaylight.openflowplugin.api.openflow.md.util.PollableQueuesZipper.java

/**
 * @return next common product of polling member groups
 *//* w  w  w. ja  v a 2 s .co  m*/
public T poll() {
    T item = null;
    if (cursor == null) {
        cursor = Iterators.cycle(sources);
    }

    Queue<T> queue;
    for (int i = 0; i < sources.size(); i++) {
        queue = cursor.next();
        item = queue.poll();
        if (item != null) {
            break;
        }
    }

    return item;
}