Check if one collection contains Some from another collection

Description

Demo Code

/*/*from  w  ww  .  j ava2s  .co  m*/
 *******************************************************************************
 * Copyright (C) 1996-2015, International Business Machines Corporation and    *
 * others. All Rights Reserved.                                                *
 *******************************************************************************
 */
import java.util.Collection;
import java.util.Comparator;
import java.util.HashMap;
import java.util.Iterator;
import java.util.Map;
import java.util.Map.Entry;
import java.util.Set;
import java.util.SortedSet;
import java.util.TreeSet;
import java.util.regex.Matcher;
import android.icu.text.UTF16;
import android.icu.text.UnicodeSet;
import android.icu.text.UnicodeSetIterator;

public class Main{
    /**
     * @param a
     * @param b
     * @return
     */
    public static boolean containsSome(Collection a, Collection b) {
        // fast paths
        if (a.size() == 0 || b.size() == 0)
            return false;
        if (a == b)
            return true; // must test after size test.

        if (a instanceof SortedSet && b instanceof SortedSet) {
            SortedSet aa = (SortedSet) a;
            SortedSet bb = (SortedSet) b;
            Comparator bbc = bb.comparator();
            Comparator aac = aa.comparator();
            if (bbc == null && aac == null) {
                Iterator ai = aa.iterator();
                Iterator bi = bb.iterator();
                Comparable ao = (Comparable) ai.next(); // these are ok, since the sizes are != 0
                Comparable bo = (Comparable) bi.next();
                while (true) {
                    int rel = ao.compareTo(bo);
                    if (rel < 0) {
                        if (!ai.hasNext())
                            return false;
                        ao = (Comparable) ai.next();
                    } else if (rel > 0) {
                        if (!bi.hasNext())
                            return false;
                        bo = (Comparable) bi.next();
                    } else {
                        return true;
                    }
                }
            } else if (bbc.equals(a)) {
                Iterator ai = aa.iterator();
                Iterator bi = bb.iterator();
                Object ao = ai.next(); // these are ok, since the sizes are != 0
                Object bo = bi.next();
                while (true) {
                    int rel = aac.compare(ao, bo);
                    if (rel < 0) {
                        if (!ai.hasNext())
                            return false;
                        ao = ai.next();
                    } else if (rel > 0) {
                        if (!bi.hasNext())
                            return false;
                        bo = bi.next();
                    } else {
                        return true;
                    }
                }
            }
        }
        for (Iterator it = a.iterator(); it.hasNext();) {
            if (b.contains(it.next()))
                return true;
        }
        return false;
    }
    /**
     * Get the size of an iterator (number of items in it).
     * @param source
     * @return
     */
    public static int size(Iterator source) {
        int result = 0;
        while (source.hasNext()) {
            source.next();
            ++result;
        }
        return result;
    }
    /**
     * Compare, allowing nulls
     * @param a
     * @param b
     * @return
     */
    public static <T> boolean equals(T a, T b) {
        return a == null ? b == null : b == null ? false : a.equals(b);
    }
    /**
     * Compare, allowing nulls and putting them first
     * @param a
     * @param b
     * @return
     */
    public static <T extends Comparable> int compare(T a, T b) {
        return a == null ? b == null ? 0 : -1 : b == null ? 1 : a
                .compareTo(b);
    }
    /**
     * Compare iterators
     * @param iterator1
     * @param iterator2
     * @return
     */
    public static <T extends Comparable> int compare(Iterator<T> iterator1,
            Iterator<T> iterator2) {
        int diff;
        while (true) {
            if (!iterator1.hasNext()) {
                return iterator2.hasNext() ? -1 : 0;
            } else if (!iterator2.hasNext()) {
                return 1;
            }
            diff = CollectionUtilities.compare(iterator1.next(),
                    iterator2.next());
            if (diff != 0) {
                return diff;
            }
        }
    }
    /**
     * Compare, with shortest first, and otherwise lexicographically
     * @param a
     * @param b
     * @return
     */
    public static <T extends Comparable, U extends Collection<T>> int compare(
            U o1, U o2) {
        int diff = o1.size() - o2.size();
        if (diff != 0) {
            return diff;
        }
        Iterator<T> iterator1 = o1.iterator();
        Iterator<T> iterator2 = o2.iterator();
        return compare(iterator1, iterator2);
    }
    /**
     * Compare, with shortest first, and otherwise lexicographically
     * @param a
     * @param b
     * @return
     */
    public static <T extends Comparable, U extends Set<T>> int compare(
            U o1, U o2) {
        int diff = o1.size() - o2.size();
        if (diff != 0) {
            return diff;
        }
        Collection<T> x1 = SortedSet.class.isInstance(o1) ? o1
                : new TreeSet<T>(o1);
        Collection<T> x2 = SortedSet.class.isInstance(o2) ? o2
                : new TreeSet<T>(o2);
        return compare(x1, x2);
    }
    /**
     * Compare, allowing nulls and putting them first
     * @param a
     * @param b
     * @return
     */
    public static <K extends Comparable, V extends Comparable, T extends Entry<K, V>> int compare(
            T a, T b) {
        if (a == null) {
            return b == null ? 0 : -1;
        } else if (b == null) {
            return 1;
        }
        int diff = compare(a.getKey(), b.getKey());
        if (diff != 0) {
            return diff;
        }
        return compare(a.getValue(), b.getValue());
    }
}
Check if one collection contains Some from another collection - Android java.util

Description

Demo Code

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