list-ops: add to track

config.json

@@ -55,7 +55,8 @@
     "wordy",
     "palindrome-products",
     "twelve-days",
-    "sublist"
+    "sublist",
+    "list-ops"
   ],
   "exercises": [
     {
@@ -317,6 +318,11 @@
       "slug": "sublist",
       "difficulty": 1,
       "topics": []
+    },
+    {
+      "slug": "list-ops",
+      "difficulty": 1,
+      "topics": []
     }
   ],
   "deprecated": [

exercises/list-ops/build.gradle

@@ -0,0 +1,18 @@
+apply plugin: "java"
+apply plugin: "eclipse"
+apply plugin: "idea"
+
+repositories {
+    mavenCentral()
+}
+
+dependencies {
+    testCompile "junit:junit:4.12"
+}
+
+test {
+    testLogging {
+        exceptionFormat = 'full'
+        events = ["passed", "failed", "skipped"]
+    }
+}

exercises/list-ops/src/example/java/ListOps.java

@@ -0,0 +1,56 @@
+
+import java.util.ArrayList;
+import java.util.Collection;
+import java.util.Collections;
+import java.util.List;
+import java.util.function.BiFunction;
+import java.util.function.BinaryOperator;
+import java.util.function.Predicate;
+import java.util.function.UnaryOperator;
+import java.util.stream.Collectors;
+import java.util.stream.Stream;
+
+public class ListOps {
+
+    private ListOps() {
+    }
+
+    public static <T> int length(final List<T> list) {
+        return list.size();
+    }
+
+    public static <T> List<T> reverse(final List<T> list) {
+        List<T> result = new ArrayList(list);
+        Collections.reverse(result);
+        return result;
+    }
+
+    public static <T> List<T> map(final List<T> list,
+            UnaryOperator<T> mapper) {
+        return list.stream().map(mapper).collect(Collectors.toList());
+    }
+
+    public static <T> List<T> filter(final List<T> list,
+            Predicate<T> predicate) {
+        return list.stream().filter(predicate).collect(Collectors.toList());
+    }
+
+    public static <U, T> U reduce(final List<T> list,
+            U identity,
+            BiFunction<U, T, U> accumulator,
+            BinaryOperator<U> combiner) {
+        return list.stream().reduce(identity, accumulator, combiner);
+    }
+
+    public static <T> boolean append(final List<T> listTo,
+            List<T> listFrom) {
+        return listTo.addAll(listFrom);
+    }
+
+    public static <T> List<T> concat(final List<T>... lists) {
+        return Stream.of(lists)
+                .flatMap(Collection::stream)
+                .collect(Collectors.toList());
+    }
+
+}