add containsAny(Collection,Collection) and tests

git-svn-id: https://svn.apache.org/repos/asf/jakarta/commons/proper/collections/trunk@130811 13f79535-47bb-0310-9956-ffa450edef68

src/java/org/apache/commons/collections/CollectionUtils.java

@@ -1,7 +1,7 @@
 /*
- * $Header: /home/jerenkrantz/tmp/commons/commons-convert/cvs/home/cvs/jakarta-commons//collections/src/java/org/apache/commons/collections/CollectionUtils.java,v 1.15 2002/08/18 20:11:37 pjack Exp $
+ * $Header: /home/jerenkrantz/tmp/commons/commons-convert/cvs/home/cvs/jakarta-commons//collections/src/java/org/apache/commons/collections/CollectionUtils.java,v 1.16 2002/09/07 19:49:49 rwaldhoff Exp $
- * $Revision: 1.15 $
+ * $Revision: 1.16 $
- * $Date: 2002/08/18 20:11:37 $
+ * $Date: 2002/09/07 19:49:49 $
  *
  * ====================================================================
  *
@@ -83,7 +83,7 @@ import org.apache.commons.collections.iterators.EnumerationIterator;
  * @author Rodney Waldhoff
  * @author Paul Jack
  * @author <a href="mailto:scolebourne@joda.org">Stephen Colebourne</a>
- * @version $Id: CollectionUtils.java,v 1.15 2002/08/18 20:11:37 pjack Exp $
+ * @version $Revision: 1.16 $ $Date: 2002/09/07 19:49:49 $
  */
 public class CollectionUtils {
 
@@ -134,6 +134,7 @@ public class CollectionUtils {
      * in the two given {@link Collection}s.
      *
      * @see Collection#retainAll
+     * @see #containsAny
      */
     public static Collection intersection(final Collection a, final Collection b) {
         ArrayList list = new ArrayList();
@@ -197,6 +198,30 @@ public class CollectionUtils {
         return list;
     }
 
+    /**
+     * Returns <code>true</code> iff some element of <i>a</i>
+     * is also an element of <i>b</i> (or, equivalently, if 
+     * some element of <i>b</i> is also an element of <i>a</i>).
+     * In other words, this method returns <code>true</code>
+     * iff the {@link #intersection} of <i>a</i> and <i>b</i>
+     * is not empty.
+     * @since 2.1
+     * @param a a non-<code>null</code> Collection
+     * @param b a non-<code>null</code> Collection
+     * @return <code>true</code> iff the intersection of <i>a</i> and <i>b</i> is non-empty
+     * @see #intersection
+     */
+    public static boolean containsAny(final Collection a, final Collection b) {
+        // TO DO: we may be able to optimize this by ensuring either a or b
+        // is the larger of the two Collections, but I'm not sure which.
+        for(Iterator iter = a.iterator(); iter.hasNext();) {
+            if(b.contains(iter.next())) {
+                return true;
+            }
+        }
+        return false;
+    }
+
     /**
      * Returns a {@link Map} mapping each unique element in
      * the given {@link Collection} to an {@link Integer}
@@ -689,6 +714,7 @@ public class CollectionUtils {
             i++;
         }
     }
+
     private static final int getFreq(final Object obj, final Map freqMap) {
         try {
             return ((Integer)(freqMap.get(obj))).intValue();
@@ -700,7 +726,6 @@ public class CollectionUtils {
         return 0;
     }
 
-
     /**
      *  Base class for collection decorators.  I decided to do it this way
      *  because it seemed to result in the most reuse.  

src/test/org/apache/commons/collections/TestCollectionUtils.java

@@ -1,7 +1,7 @@
 /*
- * $Header: /home/jerenkrantz/tmp/commons/commons-convert/cvs/home/cvs/jakarta-commons//collections/src/test/org/apache/commons/collections/TestCollectionUtils.java,v 1.5 2002/08/18 15:26:43 scolebourne Exp $
+ * $Header: /home/jerenkrantz/tmp/commons/commons-convert/cvs/home/cvs/jakarta-commons//collections/src/test/org/apache/commons/collections/TestCollectionUtils.java,v 1.6 2002/09/07 19:49:49 rwaldhoff Exp $
- * $Revision: 1.5 $
+ * $Revision: 1.6 $
- * $Date: 2002/08/18 15:26:43 $
+ * $Date: 2002/09/07 19:49:49 $
  *
  * ====================================================================
  *
@@ -66,7 +66,7 @@ import java.util.*;
 
 /**
  * @author Rodney Waldhoff
- * @version $Id: TestCollectionUtils.java,v 1.5 2002/08/18 15:26:43 scolebourne Exp $
+ * @version $Id: TestCollectionUtils.java,v 1.6 2002/09/07 19:49:49 rwaldhoff Exp $
  */
 public class TestCollectionUtils extends TestCase {
     public TestCollectionUtils(String testName) {
@@ -141,6 +141,47 @@ public class TestCollectionUtils extends TestCase {
         assertEquals(1,CollectionUtils.cardinality("e",_b));
     }
 
+    public void testContainsAny() {
+        Collection empty = new ArrayList(0);
+        Collection one = new ArrayList(1);
+        one.add("1");
+        Collection two = new ArrayList(1);
+        two.add("2");
+        Collection three = new ArrayList(1);
+        three.add("3");
+        Collection odds = new ArrayList(2);
+        odds.add("1");
+        odds.add("3");
+        
+        assertTrue("containsAny({1},{1,3}) should return true.",
+            CollectionUtils.containsAny(one,odds));
+        assertTrue("containsAny({1,3},{1}) should return true.",
+            CollectionUtils.containsAny(odds,one));
+        assertTrue("containsAny({3},{1,3}) should return true.",
+            CollectionUtils.containsAny(three,odds));
+        assertTrue("containsAny({1,3},{3}) should return true.",
+            CollectionUtils.containsAny(odds,three));
+        assertTrue("containsAny({2},{2}) should return true.",
+            CollectionUtils.containsAny(two,two));
+        assertTrue("containsAny({1,3},{1,3}) should return true.",
+            CollectionUtils.containsAny(odds,odds));
+        
+        assertTrue("containsAny({2},{1,3}) should return false.",
+            !CollectionUtils.containsAny(two,odds));
+        assertTrue("containsAny({1,3},{2}) should return false.",
+            !CollectionUtils.containsAny(odds,two));
+        assertTrue("containsAny({1},{3}) should return false.",
+            !CollectionUtils.containsAny(one,three));
+        assertTrue("containsAny({3},{1}) should return false.",
+            !CollectionUtils.containsAny(three,one));
+        assertTrue("containsAny({1,3},{}) should return false.",
+            !CollectionUtils.containsAny(odds,empty));
+        assertTrue("containsAny({},{1,3}) should return false.",
+            !CollectionUtils.containsAny(empty,odds));
+        assertTrue("containsAny({},{}) should return false.",
+            !CollectionUtils.containsAny(empty,empty));
+    }
+
     public void testUnion() {
         Collection col = CollectionUtils.union(_a,_b);
         Map freq = CollectionUtils.getCardinalityMap(col);