Add single argument constructor for IfClosure

bug 38495, from Matt Benson

git-svn-id: https://svn.apache.org/repos/asf/jakarta/commons/proper/collections/trunk@375766 13f79535-47bb-0310-9956-ffa450edef68

RELEASE-NOTES.html

@@ -79,6 +79,7 @@ If this causes major headaches to anyone please contact commons-dev at jakarta.a
 <li>ListOrderedMap - additional list-like method, setValue(int,Object)</li>
 <li>ListOrderedMap - additional method, put(int,Object,Object)</li>
 <li>PriorityBuffer - now Serializable [36163]</li>
+<li>IfClosure - add single argument constructor [38495]</li>
 </ul>
 
 <center><h3>BUG FIXES</h3></center>

src/java/org/apache/commons/collections/ClosureUtils.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.
@@ -51,6 +51,7 @@ import org.apache.commons.collections.functors.WhileClosure;
  * @version $Revision$ $Date$
  *
  * @author Stephen Colebourne
+ * @author Matt Benson
  */
 public class ClosureUtils {
 
@@ -226,6 +227,23 @@ public class ClosureUtils {
         return ChainedClosure.getInstance(closures);
     }
 
+    /**
+     * Create a new Closure that calls another closure based on the
+     * result of the specified predicate.
+     * 
+     * @see org.apache.commons.collections.functors.IfClosure
+     * 
+     * @param predicate  the validating predicate
+     * @param trueClosure  the closure called if the predicate is true
+     * @return the <code>if</code> closure
+     * @throws IllegalArgumentException if the predicate is null
+     * @throws IllegalArgumentException if the closure is null
+     * @since Commons Collections 3.2
+     */
+    public static Closure ifClosure(Predicate predicate, Closure trueClosure) {
+        return IfClosure.getInstance(predicate, trueClosure);
+    }
+
     /**
      * Create a new Closure that calls one of two closures depending 
      * on the specified predicate.

src/java/org/apache/commons/collections/functors/IfClosure.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.
@@ -28,6 +28,7 @@ import org.apache.commons.collections.Predicate;
  * @version $Revision$ $Date$
  *
  * @author Stephen Colebourne
+ * @author Matt Benson
  */
 public class IfClosure implements Closure, Serializable {
 
@@ -41,6 +42,22 @@ public class IfClosure implements Closure, Serializable {
     /** The closure to use if false */
     private final Closure iFalseClosure;
 
+    /**
+     * Factory method that performs validation.
+     * <p>
+     * This factory creates a closure that performs no action when
+     * the predicate is false.
+     * 
+     * @param predicate  predicate to switch on
+     * @param trueClosure  closure used if true
+     * @return the <code>if</code> closure
+     * @throws IllegalArgumentException if either argument is null
+     * @since Commons Collections 3.2
+     */
+    public static Closure getInstance(Predicate predicate, Closure trueClosure) {
+        return getInstance(predicate, trueClosure, NOPClosure.INSTANCE);
+    }
+
     /**
      * Factory method that performs validation.
      * 
@@ -60,6 +77,21 @@ public class IfClosure implements Closure, Serializable {
         return new IfClosure(predicate, trueClosure, falseClosure);
     }
 
+    /**
+     * Constructor that performs no validation.
+     * Use <code>getInstance</code> if you want that.
+     * <p>
+     * This constructor creates a closure that performs no action when
+     * the predicate is false.
+     * 
+     * @param predicate  predicate to switch on, not null
+     * @param trueClosure  closure used if true, not null
+     * @since Commons Collections 3.2
+     */
+    public IfClosure(Predicate predicate, Closure trueClosure) {
+        this(predicate, trueClosure, NOPClosure.INSTANCE);
+    }
+
     /**
      * Constructor that performs no validation.
      * Use <code>getInstance</code> if you want that.

src/test/org/apache/commons/collections/TestClosureUtils.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.
@@ -37,9 +37,7 @@ import org.apache.commons.collections.functors.NOPClosure;
  */
 public class TestClosureUtils extends junit.framework.TestCase {
 
-    private static final Object cObject = new Object();
     private static final Object cString = "Hello";
-    private static final Object cInteger = new Integer(6);
 
     /**
      * Construct
@@ -244,12 +242,21 @@ public class TestClosureUtils extends junit.framework.TestCase {
         } catch (IllegalArgumentException ex) {}
     }
     
-    // switchClosure
+    // ifClosure
     //------------------------------------------------------------------
 
-    public void testSwitchClosure() {
+    public void testIfClosure() {
         MockClosure a = new MockClosure();
-        MockClosure b = new MockClosure();
+        MockClosure b = null;
+        ClosureUtils.ifClosure(PredicateUtils.truePredicate(), a).execute(null);
+        assertEquals(1, a.count);
+
+        a = new MockClosure();
+        ClosureUtils.ifClosure(PredicateUtils.falsePredicate(), a).execute(null);
+        assertEquals(0, a.count);
+
+        a = new MockClosure();
+        b = new MockClosure();
         ClosureUtils.ifClosure(PredicateUtils.truePredicate(), a, b).execute(null);
         assertEquals(1, a.count);
         assertEquals(0, b.count);
@@ -259,9 +266,14 @@ public class TestClosureUtils extends junit.framework.TestCase {
         ClosureUtils.ifClosure(PredicateUtils.falsePredicate(), a, b).execute(null);
         assertEquals(0, a.count);
         assertEquals(1, b.count);
-        
+    }        
-        a = new MockClosure();
+
-        b = new MockClosure();
+    // switchClosure
+    //------------------------------------------------------------------
+
+    public void testSwitchClosure() {
+        MockClosure a = new MockClosure();
+        MockClosure b = new MockClosure();
         ClosureUtils.switchClosure(
             new Predicate[] {PredicateUtils.equalPredicate("HELLO"), PredicateUtils.equalPredicate("THERE")}, 
             new Closure[] {a, b}).execute("WELL");