From ca981f2d2701aaaf3b5f6a2152619568f3cacbc6 Mon Sep 17 00:00:00 2001
From: duandazhi <ab601026460@163.com>
Date: Fri, 26 Aug 2022 17:20:34 +0800
Subject: [PATCH] =?UTF-8?q?Opt=E5=A2=9E=E5=8A=A0=EF=BC=9AifPresent?=
 =?UTF-8?q?=EF=BC=88fun,=20default=EF=BC=89=E6=96=B9=E6=B3=95=EF=BC=8C?=
 =?UTF-8?q?=E9=9D=9E=E5=B8=B8=E9=AB=98=E9=A2=91=E7=9A=84=E6=96=B9=E6=B3=95?=
 =?UTF-8?q?=EF=BC=8C=E8=A6=81=E5=A4=9A=E8=B0=A2=E4=B8=80=E4=B8=AAorElse?=
 =?UTF-8?q?=E6=98=AF=E5=9C=A8=E4=B8=8D=E4=BC=98=E9=9B=85?=
MIME-Version: 1.0
Content-Type: text/plain; charset=UTF-8
Content-Transfer-Encoding: 8bit

---
 .../main/java/cn/hutool/core/lang/Opt.java    | 24 +++++++++++++++++++
 .../java/cn/hutool/core/lang/OptTest.java     | 14 +++++++++++
 2 files changed, 38 insertions(+)

diff --git a/hutool-core/src/main/java/cn/hutool/core/lang/Opt.java b/hutool-core/src/main/java/cn/hutool/core/lang/Opt.java
index 6a349256e3..6af6f9a24b 100644
--- a/hutool-core/src/main/java/cn/hutool/core/lang/Opt.java
+++ b/hutool-core/src/main/java/cn/hutool/core/lang/Opt.java
@@ -229,6 +229,30 @@ public class Opt<T> {
 		return this;
 	}
 
+	/**
+	 * 如果包裹里的值存在，就执行传入的操作, 如果不存在直接给一个默认值({@link Function#apply(Object)})
+	 *
+	 * <p>
+	 *     作用：简化api,如此高频api ifPresent没有返回、没有默认值用起来不方便，
+	 * 设置默认还得写ifPresent OrElse ({@link Optional#orElse(Object)})
+	 * <pre>{@code Opt.ofNullable(xxxObj).ifPresent(xxxObj::yyMethod, DEFAULT_ZZZ)}</pre>
+	 * </p>
+	 *
+	 * @param mapper 值存在时执行的操作
+	 * @param defaultValue 值不存在时的默认值
+	 * @param <U> 操作返回值的类型
+	 * @return 返回包裹<U>类型的Opt
+	 * @throws NullPointerException 如果给定的mapper操作为 {@code null}，抛出 {@code NPE}
+	 */
+	public <U> Opt<U> ifPresent(Function<? super T, ? extends U> mapper, T defaultValue) {
+		Objects.requireNonNull(mapper);
+		if (isPresent()) {
+			return Opt.ofNullable(mapper.apply(value));
+		} else {
+			return Opt.ofNullable(mapper.apply(defaultValue));
+		}
+	}
+
 	/**
 	 * 判断包裹里的值存在并且与给定的条件是否满足 ({@link Predicate#test}执行结果是否为true)
 	 * 如果满足条件则返回本身
diff --git a/hutool-core/src/test/java/cn/hutool/core/lang/OptTest.java b/hutool-core/src/test/java/cn/hutool/core/lang/OptTest.java
index f1542d46a0..be859d36d0 100644
--- a/hutool-core/src/test/java/cn/hutool/core/lang/OptTest.java
+++ b/hutool-core/src/test/java/cn/hutool/core/lang/OptTest.java
@@ -31,6 +31,15 @@ public class OptTest {
 		Assert.assertEquals("hutool", hutool);
 	}
 
+	@Test
+	public void ifPresentAndDefaultTest() {
+		String username = null;
+		final User user = new User();
+		// 相当于ifPresent的链式调用
+		Opt<User> opt = Opt.ofNullable(username).ifPresent(user::name, "hutool");
+		Assert.assertEquals("hutool", opt.get().getUsername());
+	}
+
 	@Test
 	public void getTest() {
 		// 和原版Optional有区别的是，get不会抛出NoSuchElementException
@@ -199,5 +208,10 @@ public class OptTest {
 	static class User {
 		private String username;
 		private String nickname;
+
+		public User name(String username) {
+			this.username = username;
+			return this;
+		}
 	}
 }
-- 
Gitee