From 9ead169b9090c4dd973ab06409f5cf09f61a68b1 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?F=E5=98=89=E9=98=B3?= <fjy8018@qq.com>
Date: Thu, 27 Sep 2018 17:16:26 +0800
Subject: [PATCH] =?UTF-8?q?=E8=A3=85=E9=A5=B0=E5=99=A8=E6=A8=A1=E5=BC=8F?=
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---
 .../decorator/after/ABattercake.java          | 17 ++++++++
 .../decorator/after/AbstractBattercake.java   | 15 +++++++
 .../after/AbstractBattercakeDecorator.java    | 34 ++++++++++++++++
 .../decorator/after/EggBattercake.java        | 30 ++++++++++++++
 .../decorator/after/SausageBattercake.java    | 29 ++++++++++++++
 .../decorator/before/Battercake.java          | 21 ++++++++++
 .../decorator/before/BattercakeWithEgg.java   | 19 +++++++++
 .../before/BattercakeWithEggSausage.java      | 17 ++++++++
 .../decorator/before/BattercakeTest.java      | 40 +++++++++++++++++++
 9 files changed, 222 insertions(+)
 create mode 100644 src/main/java/top/fjy8018/designpattern/pattern/structural/decorator/after/ABattercake.java
 create mode 100644 src/main/java/top/fjy8018/designpattern/pattern/structural/decorator/after/AbstractBattercake.java
 create mode 100644 src/main/java/top/fjy8018/designpattern/pattern/structural/decorator/after/AbstractBattercakeDecorator.java
 create mode 100644 src/main/java/top/fjy8018/designpattern/pattern/structural/decorator/after/EggBattercake.java
 create mode 100644 src/main/java/top/fjy8018/designpattern/pattern/structural/decorator/after/SausageBattercake.java
 create mode 100644 src/main/java/top/fjy8018/designpattern/pattern/structural/decorator/before/Battercake.java
 create mode 100644 src/main/java/top/fjy8018/designpattern/pattern/structural/decorator/before/BattercakeWithEgg.java
 create mode 100644 src/main/java/top/fjy8018/designpattern/pattern/structural/decorator/before/BattercakeWithEggSausage.java
 create mode 100644 src/test/java/top/fjy8018/designpattern/pattern/structural/decorator/before/BattercakeTest.java

diff --git a/src/main/java/top/fjy8018/designpattern/pattern/structural/decorator/after/ABattercake.java b/src/main/java/top/fjy8018/designpattern/pattern/structural/decorator/after/ABattercake.java
new file mode 100644
index 0000000..a347151
--- /dev/null
+++ b/src/main/java/top/fjy8018/designpattern/pattern/structural/decorator/after/ABattercake.java
@@ -0,0 +1,17 @@
+package top.fjy8018.designpattern.pattern.structural.decorator.after;
+
+/**
+ * @author F嘉阳
+ * @date 2018-09-27 17:04
+ */
+public class ABattercake extends AbstractBattercake {
+    @Override
+    public String getDesc() {
+        return "煎饼";
+    }
+
+    @Override
+    public int cost() {
+        return 8;
+    }
+}
diff --git a/src/main/java/top/fjy8018/designpattern/pattern/structural/decorator/after/AbstractBattercake.java b/src/main/java/top/fjy8018/designpattern/pattern/structural/decorator/after/AbstractBattercake.java
new file mode 100644
index 0000000..388e2da
--- /dev/null
+++ b/src/main/java/top/fjy8018/designpattern/pattern/structural/decorator/after/AbstractBattercake.java
@@ -0,0 +1,15 @@
+package top.fjy8018.designpattern.pattern.structural.decorator.after;
+
+/**
+ * 装饰器模式按照业务场景一般有两层抽象，
+ * 一层是所有类的抽象，一层是所有装饰器的抽象，
+ * 所有装饰器的抽象可以为实现类提供实现额外功能的能力
+ *
+ * @author F嘉阳
+ * @date 2018-09-27 17:02
+ */
+public abstract class AbstractBattercake {
+    public abstract String getDesc();
+
+    public abstract int cost();
+}
diff --git a/src/main/java/top/fjy8018/designpattern/pattern/structural/decorator/after/AbstractBattercakeDecorator.java b/src/main/java/top/fjy8018/designpattern/pattern/structural/decorator/after/AbstractBattercakeDecorator.java
new file mode 100644
index 0000000..df5748b
--- /dev/null
+++ b/src/main/java/top/fjy8018/designpattern/pattern/structural/decorator/after/AbstractBattercakeDecorator.java
@@ -0,0 +1,34 @@
+package top.fjy8018.designpattern.pattern.structural.decorator.after;
+
+/**
+ * @author F嘉阳
+ * @date 2018-09-27 17:05
+ */
+public abstract class AbstractBattercakeDecorator extends AbstractBattercake {
+
+    private AbstractBattercake abstractBattercake;
+
+    /**
+     * 通过构造器注入待装饰对象
+     *
+     * @param abstractBattercake
+     */
+    public AbstractBattercakeDecorator(AbstractBattercake abstractBattercake) {
+        this.abstractBattercake = abstractBattercake;
+    }
+
+    /**
+     * 实现类可以提供额外能力
+     */
+    protected abstract void doSomething();
+
+    @Override
+    public String getDesc() {
+        return this.abstractBattercake.getDesc();
+    }
+
+    @Override
+    public int cost() {
+        return this.abstractBattercake.cost();
+    }
+}
diff --git a/src/main/java/top/fjy8018/designpattern/pattern/structural/decorator/after/EggBattercake.java b/src/main/java/top/fjy8018/designpattern/pattern/structural/decorator/after/EggBattercake.java
new file mode 100644
index 0000000..4196113
--- /dev/null
+++ b/src/main/java/top/fjy8018/designpattern/pattern/structural/decorator/after/EggBattercake.java
@@ -0,0 +1,30 @@
+package top.fjy8018.designpattern.pattern.structural.decorator.after;
+
+import lombok.extern.slf4j.Slf4j;
+
+/**
+ * @author F嘉阳
+ * @date 2018-09-27 17:08
+ */
+@Slf4j
+public class EggBattercake extends AbstractBattercakeDecorator {
+
+    public EggBattercake(AbstractBattercake abstractBattercake) {
+        super(abstractBattercake);
+    }
+
+    @Override
+    protected void doSomething() {
+        log.info("EggBattercake doSomething...");
+    }
+
+    @Override
+    public String getDesc() {
+        return super.getDesc() + " 加一个鸡蛋";
+    }
+
+    @Override
+    public int cost() {
+        return super.cost() + 1;
+    }
+}
diff --git a/src/main/java/top/fjy8018/designpattern/pattern/structural/decorator/after/SausageBattercake.java b/src/main/java/top/fjy8018/designpattern/pattern/structural/decorator/after/SausageBattercake.java
new file mode 100644
index 0000000..aaee2c5
--- /dev/null
+++ b/src/main/java/top/fjy8018/designpattern/pattern/structural/decorator/after/SausageBattercake.java
@@ -0,0 +1,29 @@
+package top.fjy8018.designpattern.pattern.structural.decorator.after;
+
+import lombok.extern.slf4j.Slf4j;
+
+/**
+ * @author F嘉阳
+ * @date 2018-09-27 17:10
+ */
+@Slf4j
+public class SausageBattercake extends AbstractBattercakeDecorator {
+    public SausageBattercake(AbstractBattercake abstractBattercake) {
+        super(abstractBattercake);
+    }
+
+    @Override
+    protected void doSomething() {
+        log.info("SausageBattercake doSomething...");
+    }
+
+    @Override
+    public String getDesc() {
+        return super.getDesc() + " 加一根香肠";
+    }
+
+    @Override
+    public int cost() {
+        return super.cost() + 2;
+    }
+}
diff --git a/src/main/java/top/fjy8018/designpattern/pattern/structural/decorator/before/Battercake.java b/src/main/java/top/fjy8018/designpattern/pattern/structural/decorator/before/Battercake.java
new file mode 100644
index 0000000..e11ae35
--- /dev/null
+++ b/src/main/java/top/fjy8018/designpattern/pattern/structural/decorator/before/Battercake.java
@@ -0,0 +1,21 @@
+package top.fjy8018.designpattern.pattern.structural.decorator.before;
+
+/**
+ * 装饰器模式：允许向一个现有的对象添加新的功能，同时又不改变其结构。这种类型的设计模式属于结构型模式，它是作为现有的类的一个包装。
+ * 这种模式创建了一个装饰类，用来包装原有的类，并在保持类方法签名完整性的前提下，提供了额外的功能。
+ * 优点：继承的有力补充，比继承灵活，不改变原有对象的情况下给一个对象扩展功能
+ * 通过使用不同装饰器排列组合实现不同效果
+ * 符合开闭原则
+ *
+ * @author F嘉阳
+ * @date 2018-09-27 16:56
+ */
+public class Battercake {
+    protected String getDesc() {
+        return "煎饼";
+    }
+
+    protected int cost() {
+        return 8;
+    }
+}
diff --git a/src/main/java/top/fjy8018/designpattern/pattern/structural/decorator/before/BattercakeWithEgg.java b/src/main/java/top/fjy8018/designpattern/pattern/structural/decorator/before/BattercakeWithEgg.java
new file mode 100644
index 0000000..f1e04c0
--- /dev/null
+++ b/src/main/java/top/fjy8018/designpattern/pattern/structural/decorator/before/BattercakeWithEgg.java
@@ -0,0 +1,19 @@
+package top.fjy8018.designpattern.pattern.structural.decorator.before;
+
+/**
+ * 不使用装饰器则只能通过类继承扩展功能，可能引起类爆炸
+ *
+ * @author F嘉阳
+ * @date 2018-09-27 16:59
+ */
+public class BattercakeWithEgg extends Battercake {
+    @Override
+    protected String getDesc() {
+        return super.getDesc() + " 加一个鸡蛋";
+    }
+
+    @Override
+    protected int cost() {
+        return super.cost() + 1;
+    }
+}
diff --git a/src/main/java/top/fjy8018/designpattern/pattern/structural/decorator/before/BattercakeWithEggSausage.java b/src/main/java/top/fjy8018/designpattern/pattern/structural/decorator/before/BattercakeWithEggSausage.java
new file mode 100644
index 0000000..d16d847
--- /dev/null
+++ b/src/main/java/top/fjy8018/designpattern/pattern/structural/decorator/before/BattercakeWithEggSausage.java
@@ -0,0 +1,17 @@
+package top.fjy8018.designpattern.pattern.structural.decorator.before;
+
+/**
+ * @author F嘉阳
+ * @date 2018-09-27 17:00
+ */
+public class BattercakeWithEggSausage extends BattercakeWithEgg {
+    @Override
+    protected String getDesc() {
+        return super.getDesc() + " 加一根香肠";
+    }
+
+    @Override
+    protected int cost() {
+        return super.cost() + 2;
+    }
+}
diff --git a/src/test/java/top/fjy8018/designpattern/pattern/structural/decorator/before/BattercakeTest.java b/src/test/java/top/fjy8018/designpattern/pattern/structural/decorator/before/BattercakeTest.java
new file mode 100644
index 0000000..08fb68b
--- /dev/null
+++ b/src/test/java/top/fjy8018/designpattern/pattern/structural/decorator/before/BattercakeTest.java
@@ -0,0 +1,40 @@
+package top.fjy8018.designpattern.pattern.structural.decorator.before;
+
+import lombok.extern.slf4j.Slf4j;
+import org.junit.jupiter.api.Test;
+import top.fjy8018.designpattern.pattern.structural.decorator.after.ABattercake;
+import top.fjy8018.designpattern.pattern.structural.decorator.after.AbstractBattercake;
+import top.fjy8018.designpattern.pattern.structural.decorator.after.EggBattercake;
+import top.fjy8018.designpattern.pattern.structural.decorator.after.SausageBattercake;
+
+import static org.junit.jupiter.api.Assertions.*;
+
+@Slf4j
+class BattercakeTest {
+
+    /**
+     * 通过继承扩展灵活度低，无法自由组合
+     */
+    @Test
+    void before() {
+        Battercake battercake = new Battercake();
+        log.info(battercake.getDesc() + " 销售价格:" + battercake.cost());
+
+        Battercake battercakeWithEgg = new BattercakeWithEgg();
+        log.info(battercakeWithEgg.getDesc() + " 销售价格:" + battercakeWithEgg.cost());
+
+
+        Battercake battercakeWithEggSausage = new BattercakeWithEggSausage();
+        log.info(battercakeWithEggSausage.getDesc() + " 销售价格:" + battercakeWithEggSausage.cost());
+    }
+
+    @Test
+    void after() {
+        // 自由组合装饰
+        AbstractBattercake battercake = new EggBattercake(new SausageBattercake(new ABattercake()));
+        log.info(battercake.getDesc() + " 销售价格:" + battercake.cost());
+
+        AbstractBattercake battercake2 = new EggBattercake((new ABattercake()));
+        log.info(battercake2.getDesc() + " 销售价格:" + battercake2.cost());
+    }
+}
\ No newline at end of file