Java Collection Intersect hasIntersection(Collection a, Collection b)

License

Parameter

Return

Declaration

public static boolean hasIntersection(Collection<?> a, Collection<?> b) 

Method Source Code

//package com.java2s;
/*//w  w w  .  j av  a2 s.c  o  m
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *    http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

import java.util.Collection;

public class Main {
    /**
     * Returns true if <tt>Collection</CODE>s have intersection.
     *
     * @param a <tt>Collection</tt> to be examined.
     * @param b the other <tt>Collection</tt> to be examined.
     *
     * @return true if given <tt>Collection</tt>s have common element
     */
    public static boolean hasIntersection(Collection<?> a, Collection<?> b) {
        return !isDisjoint(a, b);
    }

    /**
     * Returns true if <tt>Collection</CODE>s are disjoint each other.
     *
     * @param a <tt>Collection</tt> to be examined.
     * @param b the other <tt>Collection</tt> to be examined.
     *
     * @return true if given <tt>Collection</tt>s are disjoint each other
     */
    public static boolean isDisjoint(Collection<?> a, Collection<?> b) {
        if (a == null || b == null)
            return true;

        Collection<?> tester = (a.size() < b.size()) ? a : b;
        Collection<?> testant = (a.size() < b.size()) ? b : a;

        for (Object o : tester) {
            if (testant.contains(o))
                return false;
        }

        return true;
    }
}

Related

1. getIntersection( final Collection> collections)
2. getIntersection(Collection collection1, Collection collection2)
3. hasIntersection(Collection s1, Collection s2)
4. hasIntersection(Collection c1, Collection c2)
5. hasIntersection(Collection col1, Collection col2)
6. hasIntersection(final Collection a, final Collection b)
7. intersect(Collection c1, Collection c2)