Add support for the takeWhile(), takeRightWile() and at().

Author: javadev

lodash-plugin/src/main/java/com/github/underscore/lodash/$.java

@@ -112,9 +112,21 @@ public Chain<List<T>> takeRight(final Integer n) {
             return new Chain<List<T>>($.takeRight(value(), n));
         }
 
+        public Chain<List<T>> takeWhile(final Predicate<T> pred) {
+            return new Chain<List<T>>($.takeWhile(value(), pred));
+        }
+
+        public Chain<List<T>> takeRightWhile(final Predicate<T> pred) {
+            return new Chain<List<T>>($.takeRightWhile(value(), pred));
+        }
+
         public Chain<List<T>> xor(final List<T> list) {
             return new Chain<List<T>>($.xor(value(), list));
         }
+
+        public Chain<List<T>> at(final Integer ... indexes) {
+            return new Chain<List<T>>($.at(value(), indexes));
+        }
     }
 
     public static Chain chain(final String item) {
@@ -189,7 +201,7 @@ public List<T> dropWhile(final Predicate<T> pred) {
     }
 
     public static <T> List<T> dropRightWhile(final Iterable<T> iterable, final Predicate<T> pred) {
-        return dropWhile(reverse(iterable), pred);
+        return reverse(dropWhile(reverse(iterable), pred));
     }
 
     public List<T> dropRightWhile(final Predicate<T> pred) {
@@ -308,6 +320,22 @@ public List<T> takeRight(final Integer n) {
         return takeRight(getIterable(), n);
     }
 
+    public static <T> List<T> takeWhile(final Iterable<T> iterable, final Predicate<T> pred) {
+        return first(newArrayList(iterable), findIndex(newArrayList(iterable), negate(pred)));
+    }
+
+    public List<T> takeWhile(final Predicate<T> pred) {
+        return takeWhile(getIterable(), pred);
+    }
+
+    public static <T> List<T> takeRightWhile(final Iterable<T> iterable, final Predicate<T> pred) {
+        return reverse(takeWhile(reverse(iterable), pred));
+    }
+
+    public List<T> takeRightWhile(final Predicate<T> pred) {
+        return takeRightWhile(getIterable(), pred);
+    }
+
     public static <T> List<T> xor(final List<T> ... lists) {
         int index = -1;
         int length = lists.length;
@@ -323,6 +351,24 @@ public List<T> xor(final List<T> list) {
         return xor((List<T>) getIterable(), list);
     }
 
+    public static <T> List<T> at(final List<T> list, final Integer ... indexes) {
+        final List<T> result = newArrayList();
+        final List<Integer> indexesList = Arrays.asList(indexes);
+        int index = 0;
+        for (final Iterator<T> iterator = list.iterator(); iterator.hasNext(); ) {
+            final T object = iterator.next();
+            if (indexesList.contains(index)) {
+                result.add(object);
+            }
+            index += 1;
+        }
+        return result;
+    }
+
+    public List<T> at(final Integer ... indexes) {
+        return at((List<T>) getIterable(), indexes);
+    }
+
     public static void main(String ... args) {
         final String message = "Underscore-java-lodash is a lodash plugin for underscore-java.\n\n"
             + "For docs, license, tests, and downloads, see: http://javadev.github.io/underscore-java";

lodash-plugin/src/test/java/com/github/underscore/lodash/LodashTest.java

@@ -128,25 +128,25 @@ public Boolean apply(Integer n) {
 
 /*
 _.dropRightWhile([1, 2, 3], function(n) {
-  return n > 1;
+  return n > 2;
 });
-// → [1]
+// → [1, 2]
 */
     @Test
     public void dropRightWhile() {
-        assertEquals("[1]", $.dropRightWhile(asList(1, 2, 3), new Predicate<Integer>() {
+        assertEquals("[1, 2]", $.dropRightWhile(asList(1, 2, 3), new Predicate<Integer>() {
             public Boolean apply(Integer n) {
-                return n > 1;
+                return n > 2;
             }
         }).toString());
-        assertEquals("[1]", new $(asList(1, 2, 3)).dropRightWhile(new Predicate<Integer>() {
+        assertEquals("[1, 2]", new $(asList(1, 2, 3)).dropRightWhile(new Predicate<Integer>() {
             public Boolean apply(Integer n) {
-                return n > 1;
+                return n > 2;
             }
         }).toString());
-        assertEquals("[1]", $.chain(asList(1, 2, 3)).dropRightWhile(new Predicate<Integer>() {
+        assertEquals("[1, 2]", $.chain(asList(1, 2, 3)).dropRightWhile(new Predicate<Integer>() {
             public Boolean apply(Integer n) {
-                return n > 1;
+                return n > 2;
             }
         }).toString());
     }
@@ -337,6 +337,56 @@ public void takeRight() {
         assertEquals("[]", $.takeRight(asList(1, 2, 3), 0).toString());
     }
 
+/*
+_.takeWhile([1, 2, 3], function(n) {
+  return n < 3;
+});
+// → [1, 2]
+*/
+    @Test
+    public void takeWhile() {
+        assertEquals("[1, 2]", $.takeWhile(asList(1, 2, 3), new Predicate<Integer>() {
+            public Boolean apply(Integer n) {
+                return n < 3;
+            }
+        }).toString());
+        assertEquals("[1, 2]", new $(asList(1, 2, 3)).takeWhile(new Predicate<Integer>() {
+            public Boolean apply(Integer n) {
+                return n < 3;
+            }
+        }).toString());
+        assertEquals("[1, 2]", $.chain(asList(1, 2, 3)).takeWhile(new Predicate<Integer>() {
+            public Boolean apply(Integer n) {
+                return n < 3;
+            }
+        }).toString());
+    }
+
+/*
+_.takeRightWhile([1, 2, 3], function(n) {
+  return n > 1;
+});
+// → [2, 3]
+*/
+    @Test
+    public void takeRightWhile() {
+        assertEquals("[2, 3]", $.takeRightWhile(asList(1, 2, 3), new Predicate<Integer>() {
+            public Boolean apply(Integer n) {
+                return n > 1;
+            }
+        }).toString());
+        assertEquals("[2, 3]", new $(asList(1, 2, 3)).takeRightWhile(new Predicate<Integer>() {
+            public Boolean apply(Integer n) {
+                return n > 1;
+            }
+        }).toString());
+        assertEquals("[2, 3]", $.chain(asList(1, 2, 3)).takeRightWhile(new Predicate<Integer>() {
+            public Boolean apply(Integer n) {
+                return n > 1;
+            }
+        }).toString());
+    }
+
 /*
 _.xor([1, 2], [4, 2]);
 // → [1, 4]
@@ -349,6 +399,17 @@ public void xor() {
     }
 
 
+/*
+_.at(['a', 'b', 'c'], 0, 2);
+// → ['a', 'c']
+*/
+    @Test
+    public void at() {
+        assertEquals("[a, c]", $.at(asList("a", "b", "c"), 0, 2).toString());
+        assertEquals("[a, c]", new $(asList("a", "b", "c")).at(0, 2).toString());
+        assertEquals("[a, c]", $.chain(asList("a", "b", "c")).at(0, 2).value().toString());
+    }
+
     @Test
     public void main() {
         $.main(new String[] {});