Add $.and(predicates) and $.or(predicates) methods.

Author: javadev

src/main/java/com/github/underscore/$.java

@@ -2792,6 +2792,16 @@ public static <T> T checkNotNull(T reference) {
         return reference;
     }
 
+    public static <T> List<T> checkNotNullElements(List<T> references) {
+        if (references == null) {
+            throw new NullPointerException();
+        }
+        for (T reference : references) {
+            checkNotNull(reference);
+        }
+        return references;
+    }
+
     public static <T> T checkNotNull(T reference, Object errorMessage) {
         if (reference == null) {
             throw new NullPointerException(String.valueOf(errorMessage));
@@ -2862,6 +2872,54 @@ protected static <K, E> Map<K, E> newLinkedHashMap() {
         return new LinkedHashMap<K, E>();
     }
 
+    public static <T> Predicate<T> and(
+            final Predicate<? super T> pred1,
+            final Predicate<? super T> pred2,
+        final Predicate<? super T>... rest) {
+        checkNotNull(pred1);
+        checkNotNull(pred2);
+        checkNotNullElements(Arrays.asList(rest));
+        return new Predicate<T>() {
+            @Override
+            public boolean test(T value) {
+                boolean result = pred1.test(value) && pred2.test(value);
+                if (!result) {
+                    return false;
+                }
+                for (Predicate<? super T> predicate : rest) {
+                    if (!predicate.test(value)) {
+                        return false;
+                    }
+                }
+                return true;
+            }
+        };
+    }
+
+    public static <T> Predicate<T> or(
+            final Predicate<? super T> pred1,
+            final Predicate<? super T> pred2,
+            final Predicate<? super T>... rest) {
+        checkNotNull(pred1);
+        checkNotNull(pred2);
+        checkNotNullElements(Arrays.asList(rest));
+        return new Predicate<T>() {
+            @Override
+            public boolean test(T value) {
+                boolean result = pred1.test(value) || pred2.test(value);
+                if (result) {
+                    return true;
+                }
+                for (Predicate<? super T> predicate : rest) {
+                    if (predicate.test(value)) {
+                        return true;
+                    }
+                }
+                return false;
+            }
+        };
+    }
+
     public static void main(String ... args) {
         final String message = "Underscore-java is a java port of Underscore.js.\n\n"
             + "In addition to porting Underscore's functionality, Underscore-java includes matching unit tests.\n\n"

src/test/java/com/github/underscore/UnderscoreTest.java

@@ -432,11 +432,77 @@ public void checkNotNullWithMessage() {
         $.checkNotNull(null, "Error message");
     }
 
+    @Test(expected = NullPointerException.class)
+    public void checkNotNull2() {
+        $.checkNotNullElements(null);
+    }
+
     @Test
     public void checkNotNullWithObjectAndMessage() {
         assertEquals("123", $.checkNotNull("123", "Error message"));
     }
 
+    @Test
+    @SuppressWarnings("unchecked")
+    public void and() {
+        Predicate<Integer> predicate = $.and(
+            new Predicate<Object>() {
+                @Override
+                public boolean test(Object value) {
+                    return value != null;
+                }
+            },
+            new Predicate<Number>() {
+                @Override
+                public boolean test(Number value) {
+                    return value.intValue() > 0;
+                }
+            },
+            new Predicate<Integer>() {
+                @Override
+                public boolean test(Integer value) {
+                    return (50 <= value) && (value <= 60);
+                }
+            });
+        assertTrue(predicate.test(50));
+        assertFalse(predicate.test(null));
+        assertFalse(predicate.test(-56));
+        assertTrue(predicate.test(60));
+        assertFalse(predicate.test(62));
+        assertFalse(predicate.test(1002));
+    }
+
+    @Test
+    @SuppressWarnings("unchecked")
+    public void or() {
+        Predicate<Integer> predicate = $.or(
+            new Predicate<Object>() {
+                @Override
+                public boolean test(Object value) {
+                    return value == null;
+                }
+            },
+            new Predicate<Number>() {
+                @Override
+                public boolean test(Number value) {
+                    return value.intValue() > 2000;
+                }
+            },
+            new Predicate<Integer>() {
+                @Override
+                public boolean test(Integer value) {
+                    return (50 <= value) && (value <= 60);
+                }
+            });
+        assertTrue(predicate.test(50));
+        assertTrue(predicate.test(55));
+        assertTrue(predicate.test(60));
+        assertTrue(predicate.test(null));
+        assertFalse(predicate.test(1001));
+        assertFalse(predicate.test(1001));
+        assertTrue(predicate.test(2001));
+    }
+
     @Test
     @SuppressWarnings("unchecked")
     public void stackoverflow() {