Update Iterables.

Author: gk-brown

README.md

@@ -1140,6 +1140,8 @@ public static <T, K extends Comparable<? super K>> Iterable<Map.Entry<K, List<T>
 
 public static <T> boolean exists(Iterable<T> iterable, Predicate<? super T> predicate) { ... }
 
+public static <T, U> Predicate<T> where(Function<? super T, U> transform, Predicate<U> condition) { ... }
+
 public static <T, U extends Comparable<? super U>> Predicate<T> whereEqualTo(Function<? super T, U> transform, U value) { ... }
 public static <T, U extends Comparable<? super U>> Predicate<T> whereNotEqualTo(Function<? super T, U> transform, U value) { ... }
 public static <T, U extends Comparable<? super U>> Predicate<T> whereGreaterThan(Function<? super T, U> transform, U value) { ... }

kilo-client/src/main/java/org/httprpc/kilo/util/Iterables.java

@@ -221,6 +221,40 @@ public static <T> boolean exists(Iterable<T> iterable, Predicate<? super T> pred
         return firstOf(filter(iterable, predicate)) != null;
     }
 
+    /**
+     * Creates a "where" predicate.
+     *
+     * @param <T>
+     * The element type.
+     *
+     * @param <U>
+     * The value type.
+     *
+     * @param transform
+     * The transform function.
+     *
+     * @param condition
+     * The condition to test.
+     *
+     * @return
+     * The comparison predicate.
+     */
+    public static <T, U> Predicate<T> where(Function<? super T, U> transform, Predicate<U> condition) {
+        if (transform == null || condition == null) {
+            throw new IllegalArgumentException();
+        }
+
+        return element -> {
+            var result = transform.apply(element);
+
+            if (result != null) {
+                return condition.test(result);
+            } else {
+                return false;
+            }
+        };
+    }
+
     /**
      * Creates a "where equal to" predicate.
      *
@@ -385,22 +419,6 @@ public static <T> Predicate<T> whereFalse(Function<? super T, Boolean> transform
         return where(transform, result -> !result);
     }
 
-    private static <T, U> Predicate<T> where(Function<? super T, U> transform, Predicate<U> condition) {
-        if (transform == null) {
-            throw new IllegalArgumentException();
-        }
-
-        return element -> {
-            var result = transform.apply(element);
-
-            if (result != null) {
-                return condition.test(result);
-            } else {
-                return false;
-            }
-        };
-    }
-
     /**
      * Calculates a sum.
      *

kilo-client/src/test/java/org/httprpc/kilo/util/IterablesTest.java

@@ -119,6 +119,15 @@ public void testExists() {
         assertFalse(exists(values, value -> value > 3));
     }
 
+    @Test
+    public void testWhere() {
+        List<Supplier<String>> values = listOf(() -> "a", () -> "b", () -> "c", () -> null);
+
+        var result = countOf(filter(values, where(Supplier::get, value -> value.equalsIgnoreCase("A"))));
+
+        assertEquals(1, result);
+    }
+
     @Test
     public void testWhereEqualTo() {
         var values = listOf("a", "ab", "abc");
@@ -191,15 +200,6 @@ public void testWhereFalse() {
         assertEquals(2, result);
     }
 
-    @Test
-    public void testOptionalPredicate() {
-        List<Supplier<Boolean>> values = listOf(() -> true, () -> false, () -> false, () -> null);
-
-        var result = countOf(filter(values, whereFalse(Supplier::get)));
-
-        assertEquals(2, result);
-    }
-
     @Test
     public void testIsNull() {
         var values = listOf(1, null, 2, null, 3);