'update'

vw2019 · vw2019 · commit fff8cba6c670 · 2018-09-28T20:24:21.000+08:00
diff --git a/src/main/java/lambdasinaction/chap3/Demo342.java b/src/main/java/lambdasinaction/chap3/Demo342.java
@@ -0,0 +1,22 @@
+package lambdasinaction.chap3;
+
+import java.util.Arrays;
+import java.util.List;
+import java.util.function.Consumer;
+
+/**
+ * @author vector
+ * @date: 2018/9/28 0028 14:00
+ */
+public class Demo342 {
+    public static <T> void forEach(List<T> list, Consumer<T> consumer) {
+        for (T t : list) {
+            consumer.accept(t);
+        }
+    }
+
+    public static void main(String[] args) {
+
+        forEach(Arrays.asList(1,2,3,4,5,6),(Integer i)-> System.out.println(i));
+    }
+}
diff --git a/src/main/java/lambdasinaction/chap3/Demo343.java b/src/main/java/lambdasinaction/chap3/Demo343.java
@@ -0,0 +1,25 @@
+package lambdasinaction.chap3;
+
+import java.util.ArrayList;
+import java.util.Arrays;
+import java.util.List;
+import java.util.function.Function;
+
+/**
+ * @author vector
+ * @date: 2018/9/28 0028 14:21
+ */
+public class Demo343 {
+    public static <T, R> List<R> map(List<T> list, Function<T, R> function) {
+        List<R> result = new ArrayList<>();
+        for (T t : list) {
+            result.add(function.apply(t));
+        }
+        return result;
+    }
+
+    public static void main(String[] args) {
+        List<Integer> map = map(Arrays.asList("ladf", "in", "action"), (String s) -> s.length());
+        System.out.println(map);
+    }
+}
diff --git a/src/main/java/lambdasinaction/chap3/demo341.java b/src/main/java/lambdasinaction/chap3/demo341.java
@@ -0,0 +1,30 @@
+package lambdasinaction.chap3;
+
+import java.util.ArrayList;
+import java.util.Arrays;
+import java.util.List;
+import java.util.function.Predicate;
+
+/**
+ * @author vector
+ * @date: 2018/9/28 0028 13:51
+ */
+public class demo341 {
+    public static <T> List<T> filter(List<T> list, Predicate<T> p) {
+        List<T> result = new ArrayList<>();
+        for (T t : list) {
+            if (p.test(t)) {
+                result.add(t);
+            }
+        }
+        return result;
+    }
+
+    public static void main(String[] args) {
+        Predicate<String> nonEmptyStringPredicate = (String s) -> !s.isEmpty();
+        List<String> filter = filter(Arrays.asList("123","","asv","^&*"), nonEmptyStringPredicate);
+        System.out.println(filter);
+    }
+
+
+}
