import java.nio.ShortBuffer;
import java.nio.charset.Charset;
import java.util.ArrayDeque;
import java.util.Arrays;
import java.util.Collection;
import java.util.Comparator;
import java.util.Currency;
import java.util.Deque;
import java.util.Iterator;
import java.util.List;
import java.util.ListIterator;
import java.util.Locale;
import java.util.Map;
import java.util.NavigableMap;
import java.util.NavigableSet;

import java.nio.ShortBuffer;
import java.nio.charset.Charset;
import java.util.ArrayList;
import java.util.BitSet;
import java.util.Collection;
import java.util.Comparator;
import java.util.Currency;
import java.util.Deque;
import java.util.HashMap;
import java.util.Iterator;
import java.util.LinkedList;
import java.util.List;
import java.util.ListIterator;
import java.util.Locale;
import java.util.Map;

     * meta-iterators rather than letting the nesting get arbitrarily deep.  This keeps each
     * operation O(1).
     */

    @CheckForNull private Iterator<? extends Iterator<? extends T>> topMetaIterator;

    // Only becomes nonnull if we encounter nested concatenations.
    @CheckForNull private Deque<Iterator<? extends Iterator<? extends T>>> metaIterators;

import javax.annotation.CheckForNull;

/**
 * A {@link BlockingDeque} which forwards all its method calls to another {@code BlockingDeque}.
 * Subclasses should override one or more methods to modify the behavior of the backing deque as
 * desired per the <a href="http://en.wikipedia.org/wiki/Decorator_pattern">decorator pattern</a>.
 *
 * <p><b>Warning:</b> The methods of {@code ForwardingBlockingDeque} forward <b>indiscriminately</b>

          + "sollicitudin quam. Praesent neque elit, sodales quis vestibulum vel, pellentesque nec "
          + "erat. Proin cursus commodo lacus eget congue. Aliquam erat volutpat. Fusce ut leo sed "
          + "risus tempor vehicula et a odio. Nam aliquet dolor viverra libero rutrum accumsan "
          + "quis in augue. Suspendisse id dui in lorem tristique placerat eget vel risus. Sed "

     * meta-iterators rather than letting the nesting get arbitrarily deep.  This keeps each
     * operation O(1).
     */

    @CheckForNull private Iterator<? extends Iterator<? extends T>> topMetaIterator;

    // Only becomes nonnull if we encounter nested concatenations.
    @CheckForNull private Deque<Iterator<? extends Iterator<? extends T>>> metaIterators;

          + "sollicitudin quam. Praesent neque elit, sodales quis vestibulum vel, pellentesque nec "
          + "erat. Proin cursus commodo lacus eget congue. Aliquam erat volutpat. Fusce ut leo sed "
          + "risus tempor vehicula et a odio. Nam aliquet dolor viverra libero rutrum accumsan "
          + "quis in augue. Suspendisse id dui in lorem tristique placerat eget vel risus. Sed "