组合模式

src/main/java/top/fjy8018/designpattern/pattern/structural/composite/CatalogComponent.java

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+package top.fjy8018.designpattern.pattern.structural.composite;
+
+/**
+ * 课程抽象类
+ * 抽象组件应当多加考虑，哪些参数需要，哪些不需要
+ *
+ * @author F嘉阳
+ * @date 2020/2/28 16:19
+ */
+public abstract class CatalogComponent {
+
+    public void add(CatalogComponent catalogComponent) {
+        throw new UnsupportedOperationException("不支持添加操作");
+    }
+
+    public void remove(CatalogComponent catalogComponent) {
+        throw new UnsupportedOperationException("不支持删除操作");
+    }
+
+    public String getName(CatalogComponent catalogComponent) {
+        throw new UnsupportedOperationException("不支持获取名称操作");
+    }
+
+    public Double getPrice(CatalogComponent catalogComponent) {
+        throw new UnsupportedOperationException("不支持获取价格操作");
+    }
+
+    public void print() {
+        throw new UnsupportedOperationException("不支持获取打印操作");
+    }
+}

src/main/java/top/fjy8018/designpattern/pattern/structural/composite/Course.java

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+package top.fjy8018.designpattern.pattern.structural.composite;
+
+import lombok.AllArgsConstructor;
+import lombok.extern.slf4j.Slf4j;
+
+/**
+ * 课程
+ * 重写抽象类需要充分考虑业务逻辑
+ *
+ * @author F嘉阳
+ * @date 2020/2/28 16:24
+ */
+@Slf4j
+@AllArgsConstructor
+public class Course extends CatalogComponent {
+
+    private String name;
+
+    private Double price;
+
+    @Override
+    public String getName(CatalogComponent catalogComponent) {
+        return this.name;
+    }
+
+    @Override
+    public Double getPrice(CatalogComponent catalogComponent) {
+        return this.price;
+    }
+
+    @Override
+    public void print() {
+        log.info("课程名称：{}，价格：{}", name, price);
+    }
+}

src/main/java/top/fjy8018/designpattern/pattern/structural/composite/CourseCatalog.java

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+package top.fjy8018.designpattern.pattern.structural.composite;
+
+import lombok.extern.slf4j.Slf4j;
+
+import java.util.ArrayList;
+import java.util.List;
+
+/**
+ * 课程目录
+ * 可以添加目录节点
+ *
+ * @author F嘉阳
+ * @date 2020/2/28 16:34
+ */
+@Slf4j
+public class CourseCatalog extends CatalogComponent {
+
+    private List<CatalogComponent> items = new ArrayList<>();
+
+    private String name;
+
+    public CourseCatalog(String name) {
+        this.name = name;
+    }
+
+    @Override
+    public void add(CatalogComponent catalogComponent) {
+        items.add(catalogComponent);
+    }
+
+    @Override
+    public void remove(CatalogComponent catalogComponent) {
+        items.remove(catalogComponent);
+    }
+
+    @Override
+    public void print() {
+        log.info("课程目录名称：{}", name);
+        items.forEach(CatalogComponent::print);
+    }
+}

src/test/java/top/fjy8018/designpattern/pattern/structural/composite/CatalogComponentTest.java

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+package top.fjy8018.designpattern.pattern.structural.composite;
+
+import lombok.extern.slf4j.Slf4j;
+import org.junit.jupiter.api.Test;
+
+/**
+ * @author F嘉阳
+ * @date 2020/2/28 16:37
+ */
+@Slf4j
+class CatalogComponentTest {
+
+    @Test
+    void add() {
+        // 将课程与课程目录都认为是同一个类型，进行统一处理
+        CatalogComponent linuxCourse = new Course("Linux课程", 35.0);
+        CatalogComponent windowsCourse = new Course("windows课程", 61.0);
+        CatalogComponent macOsCourse = new Course("macOs课程", 20.0);
+
+        CatalogComponent springCourse = new Course("spring课程", 55.0);
+        CatalogComponent servletCourse = new Course("servlet课程", 11.0);
+
+        // 课程目录
+        CatalogComponent javaCourseCatalog = new CourseCatalog("java课程目录");
+        CatalogComponent schoolCourseCatalog = new CourseCatalog("学校课程主目录");
+
+        javaCourseCatalog.add(springCourse);
+        javaCourseCatalog.add(servletCourse);
+
+        // 既可以添加课程，也可以添加目录
+        schoolCourseCatalog.add(linuxCourse);
+        schoolCourseCatalog.add(windowsCourse);
+        schoolCourseCatalog.add(macOsCourse);
+        schoolCourseCatalog.add(javaCourseCatalog);
+
+        schoolCourseCatalog.print();
+
+
+    }
+}