All/Any/One/None Predicate - allow construction with zero or one predicates

rfe 37979, implemented by Matt Benson

git-svn-id: https://svn.apache.org/repos/asf/jakarta/commons/proper/collections/trunk@377508 13f79535-47bb-0310-9956-ffa450edef68

RELEASE-NOTES.html

@@ -80,6 +80,7 @@ If this causes major headaches to anyone please contact commons-dev at jakarta.a
 <li>ListOrderedMap - additional method, put(int,Object,Object)</li>
 <li>PriorityBuffer - now Serializable [36163]</li>
 <li>IfClosure - add single argument constructor [38495]</li>
+<li>All/Any/One/None Predicate - allow construction with zero or one predicates [37979]</li>
 </ul>
 
 <center><h3>BUG FIXES</h3></center>

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

@@ -1,5 +1,5 @@
 /*
- *  Copyright 2002-2004 The Apache Software Foundation
+ *  Copyright 2002-2004,2006 The Apache Software Foundation
  *
  *  Licensed under the Apache License, Version 2.0 (the "License");
  *  you may not use this file except in compliance with the License.
@@ -264,13 +264,13 @@ public class PredicateUtils {
     /**
      * Create a new Predicate that returns true only if all of the specified
      * predicates are true.
+     * If the array of predicates is empty, then this predicate returns true.
      * 
      * @see org.apache.commons.collections.functors.AllPredicate
      * 
      * @param predicates  an array of predicates to check, may not be null
      * @return the <code>all</code> predicate
      * @throws IllegalArgumentException if the predicates array is null
-     * @throws IllegalArgumentException if the predicates array has less than 2 elements
      * @throws IllegalArgumentException if any predicate in the array is null
      */
     public static Predicate allPredicate(Predicate[] predicates) {
@@ -280,13 +280,13 @@ public class PredicateUtils {
     /**
      * Create a new Predicate that returns true only if all of the specified
      * predicates are true. The predicates are checked in iterator order.
+     * If the collection of predicates is empty, then this predicate returns true.
      * 
      * @see org.apache.commons.collections.functors.AllPredicate
      * 
      * @param predicates  a collection of predicates to check, may not be null
      * @return the <code>all</code> predicate
      * @throws IllegalArgumentException if the predicates collection is null
-     * @throws IllegalArgumentException if the predicates collection has less than 2 elements
      * @throws IllegalArgumentException if any predicate in the collection is null
      */
     public static Predicate allPredicate(Collection predicates) {
@@ -311,13 +311,13 @@ public class PredicateUtils {
     /**
      * Create a new Predicate that returns true if any of the specified
      * predicates are true.
+     * If the array of predicates is empty, then this predicate returns false.
      * 
      * @see org.apache.commons.collections.functors.AnyPredicate
      * 
      * @param predicates  an array of predicates to check, may not be null
      * @return the <code>any</code> predicate
      * @throws IllegalArgumentException if the predicates array is null
-     * @throws IllegalArgumentException if the predicates array has less than 2 elements
      * @throws IllegalArgumentException if any predicate in the array is null
      */
     public static Predicate anyPredicate(Predicate[] predicates) {
@@ -327,13 +327,13 @@ public class PredicateUtils {
     /**
      * Create a new Predicate that returns true if any of the specified
      * predicates are true. The predicates are checked in iterator order.
+     * If the collection of predicates is empty, then this predicate returns false.
      * 
      * @see org.apache.commons.collections.functors.AnyPredicate
      * 
      * @param predicates  a collection of predicates to check, may not be null
      * @return the <code>any</code> predicate
      * @throws IllegalArgumentException if the predicates collection is null
-     * @throws IllegalArgumentException if the predicates collection has less than 2 elements
      * @throws IllegalArgumentException if any predicate in the collection is null
      */
     public static Predicate anyPredicate(Collection predicates) {
@@ -358,13 +358,13 @@ public class PredicateUtils {
     /**
      * Create a new Predicate that returns true if only one of the specified
      * predicates are true.
+     * If the array of predicates is empty, then this predicate returns false.
      * 
      * @see org.apache.commons.collections.functors.OnePredicate
      * 
      * @param predicates  an array of predicates to check, may not be null
      * @return the <code>one</code> predicate
      * @throws IllegalArgumentException if the predicates array is null
-     * @throws IllegalArgumentException if the predicates array has less than 2 elements
      * @throws IllegalArgumentException if any predicate in the array is null
      */
     public static Predicate onePredicate(Predicate[] predicates) {
@@ -374,13 +374,13 @@ public class PredicateUtils {
     /**
      * Create a new Predicate that returns true if only one of the specified
      * predicates are true. The predicates are checked in iterator order.
+     * If the collection of predicates is empty, then this predicate returns false.
      * 
      * @see org.apache.commons.collections.functors.OnePredicate
      * 
      * @param predicates  a collection of predicates to check, may not be null
      * @return the <code>one</code> predicate
      * @throws IllegalArgumentException if the predicates collection is null
-     * @throws IllegalArgumentException if the predicates collection has less than 2 elements
      * @throws IllegalArgumentException if any predicate in the collection is null
      */
     public static Predicate onePredicate(Collection predicates) {
@@ -405,13 +405,13 @@ public class PredicateUtils {
     /**
      * Create a new Predicate that returns true if none of the specified
      * predicates are true.
+     * If the array of predicates is empty, then this predicate returns true.
      * 
      * @see org.apache.commons.collections.functors.NonePredicate
      * 
      * @param predicates  an array of predicates to check, may not be null
      * @return the <code>none</code> predicate
      * @throws IllegalArgumentException if the predicates array is null
-     * @throws IllegalArgumentException if the predicates array has less than 2 elements
      * @throws IllegalArgumentException if any predicate in the array is null
      */
     public static Predicate nonePredicate(Predicate[] predicates) {
@@ -421,13 +421,13 @@ public class PredicateUtils {
     /**
      * Create a new Predicate that returns true if none of the specified
      * predicates are true. The predicates are checked in iterator order.
+     * If the collection of predicates is empty, then this predicate returns true.
      * 
      * @see org.apache.commons.collections.functors.NonePredicate
      * 
      * @param predicates  a collection of predicates to check, may not be null
      * @return the <code>none</code> predicate
      * @throws IllegalArgumentException if the predicates collection is null
-     * @throws IllegalArgumentException if the predicates collection has less than 2 elements
      * @throws IllegalArgumentException if any predicate in the collection is null
      */
     public static Predicate nonePredicate(Collection predicates) {

src/java/org/apache/commons/collections/functors/AllPredicate.java

@@ -1,5 +1,5 @@
 /*
- *  Copyright 2001-2004 The Apache Software Foundation
+ *  Copyright 2001-2004,2006 The Apache Software Foundation
  *
  *  Licensed under the Apache License, Version 2.0 (the "License");
  *  you may not use this file except in compliance with the License.
@@ -21,12 +21,15 @@ import java.util.Collection;
 import org.apache.commons.collections.Predicate;
 
 /**
- * Predicate implementation that returns true if all the predicates return true.
+ * Predicate implementation that returns true if all the
+ * predicates return true.
+ * If the array of predicates is empty, then this predicate returns true.
  * 
  * @since Commons Collections 3.0
  * @version $Revision$ $Date$
  *
  * @author Stephen Colebourne
+ * @author Matt Benson
  */
 public final class AllPredicate implements Predicate, PredicateDecorator, Serializable {
 
@@ -42,11 +45,10 @@ public final class AllPredicate implements Predicate, PredicateDecorator, Serial
      * @param predicates  the predicates to check, cloned, not null
      * @return the <code>all</code> predicate
      * @throws IllegalArgumentException if the predicates array is null
-     * @throws IllegalArgumentException if the predicates array has less than 2 elements
      * @throws IllegalArgumentException if any predicate in the array is null
      */
     public static Predicate getInstance(Predicate[] predicates) {
-        FunctorUtils.validateMin2(predicates);
+        FunctorUtils.validate(predicates);
         predicates = FunctorUtils.copy(predicates);
         return new AllPredicate(predicates);
     }
@@ -58,7 +60,6 @@ public final class AllPredicate implements Predicate, PredicateDecorator, Serial
      * @return the <code>all</code> predicate
      * @throws IllegalArgumentException if the predicates array is null
      * @throws IllegalArgumentException if any predicate in the array is null
-     * @throws IllegalArgumentException if the predicates array has less than 2 elements
      */
     public static Predicate getInstance(Collection predicates) {
         Predicate[] preds = FunctorUtils.validate(predicates);

src/java/org/apache/commons/collections/functors/AnyPredicate.java

@@ -1,5 +1,5 @@
 /*
- *  Copyright 2001-2004 The Apache Software Foundation
+ *  Copyright 2001-2004,2006 The Apache Software Foundation
  *
  *  Licensed under the Apache License, Version 2.0 (the "License");
  *  you may not use this file except in compliance with the License.
@@ -21,12 +21,15 @@ import java.util.Collection;
 import org.apache.commons.collections.Predicate;
 
 /**
- * Predicate implementation that returns true if any of the predicates return true.
+ * Predicate implementation that returns true if any of the
+ * predicates return true.
+ * If the array of predicates is empty, then this predicate returns false.
  * 
  * @since Commons Collections 3.0
  * @version $Revision$ $Date$
  *
  * @author Stephen Colebourne
+ * @author Matt Benson
  */
 public final class AnyPredicate implements Predicate, PredicateDecorator, Serializable {
 
@@ -42,11 +45,10 @@ public final class AnyPredicate implements Predicate, PredicateDecorator, Serial
      * @param predicates  the predicates to check, cloned, not null
      * @return the <code>any</code> predicate
      * @throws IllegalArgumentException if the predicates array is null
-     * @throws IllegalArgumentException if the predicates array has less than 2 elements
      * @throws IllegalArgumentException if any predicate in the array is null
      */
     public static Predicate getInstance(Predicate[] predicates) {
-        FunctorUtils.validateMin2(predicates);
+        FunctorUtils.validate(predicates);
         predicates = FunctorUtils.copy(predicates);
         return new AnyPredicate(predicates);
     }
@@ -58,7 +60,6 @@ public final class AnyPredicate implements Predicate, PredicateDecorator, Serial
      * @return the <code>all</code> predicate
      * @throws IllegalArgumentException if the predicates array is null
      * @throws IllegalArgumentException if any predicate in the array is null
-     * @throws IllegalArgumentException if the predicates array has less than 2 elements
      */
     public static Predicate getInstance(Collection predicates) {
         Predicate[] preds = FunctorUtils.validate(predicates);

src/java/org/apache/commons/collections/functors/FunctorUtils.java

@@ -1,5 +1,5 @@
 /*
- *  Copyright 2001-2004 The Apache Software Foundation
+ *  Copyright 2001-2004,2006 The Apache Software Foundation
  *
  *  Licensed under the Apache License, Version 2.0 (the "License");
  *  you may not use this file except in compliance with the License.
@@ -29,6 +29,7 @@ import org.apache.commons.collections.Transformer;
  * @version $Revision$ $Date$
  *
  * @author Stephen Colebourne
+ * @author Matt Benson
  */
 class FunctorUtils {
     
@@ -68,26 +69,6 @@ class FunctorUtils {
         }
     }
     
-    /**
-     * Validate the predicates to ensure that all is well.
-     * 
-     * @param predicates  the predicates to validate
-     */
-    static void validateMin2(Predicate[] predicates) {
-        if (predicates == null) {
-            throw new IllegalArgumentException("The predicate array must not be null");
-        }
-        if (predicates.length < 2) {
-            throw new IllegalArgumentException(
-                "At least 2 predicates must be specified in the predicate array, size was " + predicates.length);
-        }
-        for (int i = 0; i < predicates.length; i++) {
-            if (predicates[i] == null) {
-                throw new IllegalArgumentException("The predicate array must not contain a null predicate, index " + i + " was null");
-            }
-        }
-    }
-
     /**
      * Validate the predicates to ensure that all is well.
      * 
@@ -98,10 +79,6 @@ class FunctorUtils {
         if (predicates == null) {
             throw new IllegalArgumentException("The predicate collection must not be null");
         }
-        if (predicates.size() < 2) {
-            throw new IllegalArgumentException(
-                "At least 2 predicates must be specified in the predicate collection, size was " + predicates.size());
-        }
         // convert to array like this to guarantee iterator() ordering
         Predicate[] preds = new Predicate[predicates.size()];
         int i = 0;

src/java/org/apache/commons/collections/functors/NonePredicate.java

@@ -1,5 +1,5 @@
 /*
- *  Copyright 2001-2004 The Apache Software Foundation
+ *  Copyright 2001-2004,2006 The Apache Software Foundation
  *
  *  Licensed under the Apache License, Version 2.0 (the "License");
  *  you may not use this file except in compliance with the License.
@@ -21,12 +21,15 @@ import java.util.Collection;
 import org.apache.commons.collections.Predicate;
 
 /**
- * Predicate implementation that returns true if none of the predicates return true.
+ * Predicate implementation that returns true if none of the
+ * predicates return true.
+ * If the array of predicates is empty, then this predicate returns true.
  * 
  * @since Commons Collections 3.0
  * @version $Revision$ $Date$
  *
  * @author Stephen Colebourne
+ * @author Matt Benson
  */
 public final class NonePredicate implements Predicate, PredicateDecorator, Serializable {
 
@@ -42,11 +45,10 @@ public final class NonePredicate implements Predicate, PredicateDecorator, Seria
      * @param predicates  the predicates to check, cloned, not null
      * @return the <code>any</code> predicate
      * @throws IllegalArgumentException if the predicates array is null
-     * @throws IllegalArgumentException if the predicates array has less than 2 elements
      * @throws IllegalArgumentException if any predicate in the array is null
      */
     public static Predicate getInstance(Predicate[] predicates) {
-        FunctorUtils.validateMin2(predicates);
+        FunctorUtils.validate(predicates);
         predicates = FunctorUtils.copy(predicates);
         return new NonePredicate(predicates);
     }
@@ -58,7 +60,6 @@ public final class NonePredicate implements Predicate, PredicateDecorator, Seria
      * @return the <code>one</code> predicate
      * @throws IllegalArgumentException if the predicates array is null
      * @throws IllegalArgumentException if any predicate in the array is null
-     * @throws IllegalArgumentException if the predicates array has less than 2 elements
      */
     public static Predicate getInstance(Collection predicates) {
         Predicate[] preds = FunctorUtils.validate(predicates);

src/java/org/apache/commons/collections/functors/OnePredicate.java

@@ -1,5 +1,5 @@
 /*
- *  Copyright 2001-2004 The Apache Software Foundation
+ *  Copyright 2001-2004,2006 The Apache Software Foundation
  *
  *  Licensed under the Apache License, Version 2.0 (the "License");
  *  you may not use this file except in compliance with the License.
@@ -21,12 +21,15 @@ import java.util.Collection;
 import org.apache.commons.collections.Predicate;
 
 /**
- * Predicate implementation that returns true if only one of the predicates return true.
+ * Predicate implementation that returns true if only one of the
+ * predicates return true.
+ * If the array of predicates is empty, then this predicate returns false.
  * 
  * @since Commons Collections 3.0
  * @version $Revision$ $Date$
  *
  * @author Stephen Colebourne
+ * @author Matt Benson
  */
 public final class OnePredicate implements Predicate, PredicateDecorator, Serializable {
 
@@ -42,11 +45,10 @@ public final class OnePredicate implements Predicate, PredicateDecorator, Serial
      * @param predicates  the predicates to check, cloned, not null
      * @return the <code>any</code> predicate
      * @throws IllegalArgumentException if the predicates array is null
-     * @throws IllegalArgumentException if the predicates array has less than 2 elements
      * @throws IllegalArgumentException if any predicate in the array is null
      */
     public static Predicate getInstance(Predicate[] predicates) {
-        FunctorUtils.validateMin2(predicates);
+        FunctorUtils.validate(predicates);
         predicates = FunctorUtils.copy(predicates);
         return new OnePredicate(predicates);
     }
@@ -58,7 +60,6 @@ public final class OnePredicate implements Predicate, PredicateDecorator, Serial
      * @return the <code>one</code> predicate
      * @throws IllegalArgumentException if the predicates array is null
      * @throws IllegalArgumentException if any predicate in the array is null
-     * @throws IllegalArgumentException if the predicates array has less than 2 elements
      */
     public static Predicate getInstance(Collection predicates) {
         Predicate[] preds = FunctorUtils.validate(predicates);

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

@@ -1,5 +1,5 @@
 /*
- *  Copyright 2001-2004 The Apache Software Foundation
+ *  Copyright 2001-2004,2006 The Apache Software Foundation
  *
  *  Licensed under the Apache License, Version 2.0 (the "License");
  *  you may not use this file except in compliance with the License.
@@ -34,6 +34,7 @@ import junit.textui.TestRunner;
  * @version $Revision$ $Date$
  *
  * @author Stephen Colebourne
+ * @author Matt Benson
  */
 public class TestPredicateUtils extends junit.framework.TestCase {
 
@@ -237,6 +238,14 @@ public class TestPredicateUtils extends junit.framework.TestCase {
         coll.add(PredicateUtils.falsePredicate());
         coll.add(PredicateUtils.falsePredicate());
         assertEquals(false, PredicateUtils.allPredicate(coll).evaluate(null));
+        coll.clear();
+        coll.add(PredicateUtils.falsePredicate());
+        assertFalse(PredicateUtils.allPredicate(coll).evaluate(null));
+        coll.clear();
+        coll.add(PredicateUtils.truePredicate());
+        assertTrue(PredicateUtils.allPredicate(coll).evaluate(null));
+        coll.clear();
+        assertTrue(PredicateUtils.allPredicate(coll).evaluate(null));
     }
 
     public void testAllPredicateEx1() {
@@ -276,12 +285,7 @@ public class TestPredicateUtils extends junit.framework.TestCase {
     }
     
     public void testAllPredicateEx5() {
-        try {
+        PredicateUtils.allPredicate(Collections.EMPTY_LIST);
-            PredicateUtils.allPredicate(Collections.EMPTY_LIST);
-        } catch (IllegalArgumentException ex) {
-            return;
-        }
-        fail();
     }
     
     public void testAllPredicateEx6() {
@@ -347,6 +351,14 @@ public class TestPredicateUtils extends junit.framework.TestCase {
         coll.add(PredicateUtils.falsePredicate());
         coll.add(PredicateUtils.falsePredicate());
         assertEquals(false, PredicateUtils.anyPredicate(coll).evaluate(null));
+        coll.clear();
+        coll.add(PredicateUtils.falsePredicate());
+        assertFalse(PredicateUtils.anyPredicate(coll).evaluate(null));
+        coll.clear();
+        coll.add(PredicateUtils.truePredicate());
+        assertTrue(PredicateUtils.anyPredicate(coll).evaluate(null));
+        coll.clear();
+        assertFalse(PredicateUtils.anyPredicate(coll).evaluate(null));
     }
 
     public void testAnyPredicateEx1() {
@@ -386,12 +398,7 @@ public class TestPredicateUtils extends junit.framework.TestCase {
     }
     
     public void testAnyPredicateEx5() {
-        try {
+        PredicateUtils.anyPredicate(Collections.EMPTY_LIST);
-            PredicateUtils.anyPredicate(Collections.EMPTY_LIST);
-        } catch (IllegalArgumentException ex) {
-            return;
-        }
-        fail();
     }
     
     public void testAnyPredicateEx6() {
@@ -461,6 +468,14 @@ public class TestPredicateUtils extends junit.framework.TestCase {
         coll.add(PredicateUtils.falsePredicate());
         coll.add(PredicateUtils.falsePredicate());
         assertEquals(false, PredicateUtils.onePredicate(coll).evaluate(null));
+        coll.clear();
+        coll.add(PredicateUtils.falsePredicate());
+        assertFalse(PredicateUtils.onePredicate(coll).evaluate(null));
+        coll.clear();
+        coll.add(PredicateUtils.truePredicate());
+        assertTrue(PredicateUtils.onePredicate(coll).evaluate(null));
+        coll.clear();
+        assertFalse(PredicateUtils.onePredicate(coll).evaluate(null));
     }
 
     public void testOnePredicateEx1() {
@@ -500,12 +515,7 @@ public class TestPredicateUtils extends junit.framework.TestCase {
     }
     
     public void testOnePredicateEx5() {
-        try {
+        PredicateUtils.onePredicate(Collections.EMPTY_LIST);
-            PredicateUtils.onePredicate(Collections.EMPTY_LIST);
-        } catch (IllegalArgumentException ex) {
-            return;
-        }
-        fail();
     }
     
     public void testOnePredicateEx6() {
@@ -571,6 +581,14 @@ public class TestPredicateUtils extends junit.framework.TestCase {
         coll.add(PredicateUtils.falsePredicate());
         coll.add(PredicateUtils.falsePredicate());
         assertEquals(true, PredicateUtils.nonePredicate(coll).evaluate(null));
+        coll.clear();
+        coll.add(PredicateUtils.falsePredicate());
+        assertTrue(PredicateUtils.nonePredicate(coll).evaluate(null));
+        coll.clear();
+        coll.add(PredicateUtils.truePredicate());
+        assertFalse(PredicateUtils.nonePredicate(coll).evaluate(null));
+        coll.clear();
+        assertTrue(PredicateUtils.nonePredicate(coll).evaluate(null));
     }
 
     public void testNonePredicateEx1() {
@@ -610,12 +628,7 @@ public class TestPredicateUtils extends junit.framework.TestCase {
     }
     
     public void testNonePredicateEx5() {
-        try {
+        PredicateUtils.nonePredicate(Collections.EMPTY_LIST);
-            PredicateUtils.nonePredicate(Collections.EMPTY_LIST);
-        } catch (IllegalArgumentException ex) {
-            return;
-        }
-        fail();
     }
     
     public void testNonePredicateEx6() {