完成 迭代器模式 Sample

Author: JamesZBL

iterator/src/main/java/Application.java

@@ -0,0 +1,60 @@
+/**
+ * MIT License
+ * <p>
+ * Copyright (c) 2017 James
+ * <p>
+ * Permission is hereby granted, free of charge, to any person obtaining a copy
+ * of this software and associated documentation files (the "Software"), to deal
+ * in the Software without restriction, including without limitation the rights
+ * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+ * copies of the Software, and to permit persons to whom the Software is
+ * furnished to do so, subject to the following conditions:
+ * <p>
+ * The above copyright notice and this permission notice shall be included in all
+ * copies or substantial portions of the Software.
+ * <p>
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+ * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+ * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+ * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
+ * SOFTWARE.
+ */
+
+import org.slf4j.Logger;
+import org.slf4j.LoggerFactory;
+
+/**
+ * Iterator
+ */
+public class Application {
+
+  private static final Logger LOGGER = LoggerFactory.getLogger(Application.class);
+
+  public static void main(String[] args) {
+    // 查找小说
+    ItemIterator iterator = new BookShelfIterator(ItemType.FICTION, new BookShelf());
+    LOGGER.info("正在查找小说类图书");
+    while (iterator.hasNext()) {
+      Item nextItem = iterator.next();
+      LOGGER.info("找到了符合条件的图书，书名为：{}", nextItem.toString());
+    }
+
+    // 查找IT
+    ItemIterator iterator2 = new BookShelfIterator(ItemType.IT, new BookShelf());
+    LOGGER.info("正在查找IT类图书");
+    while (iterator2.hasNext()) {
+      Item nextItem = iterator2.next();
+      LOGGER.info("找到了符合条件的图书，书名为：{}", nextItem.toString());
+    }
+
+    // 查找漫画
+    ItemIterator iterator3 = new BookShelfIterator(ItemType.CARTOON, new BookShelf());
+    LOGGER.info("正在查找漫画类图书");
+    while (iterator3.hasNext()) {
+      Item nextItem = iterator3.next();
+      LOGGER.info("找到了符合条件的图书，书名为：{}", nextItem.toString());
+    }
+  }
+}

iterator/src/main/java/BookShelf.java

@@ -0,0 +1,55 @@
+/**
+ * MIT License
+ * <p>
+ * Copyright (c) 2017 James
+ * <p>
+ * Permission is hereby granted, free of charge, to any person obtaining a copy
+ * of this software and associated documentation files (the "Software"), to deal
+ * in the Software without restriction, including without limitation the rights
+ * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+ * copies of the Software, and to permit persons to whom the Software is
+ * furnished to do so, subject to the following conditions:
+ * <p>
+ * The above copyright notice and this permission notice shall be included in all
+ * copies or substantial portions of the Software.
+ * <p>
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+ * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+ * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+ * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
+ * SOFTWARE.
+ */
+
+import java.util.ArrayList;
+import java.util.List;
+
+/**
+ * 书架
+ */
+public class BookShelf {
+
+  private List<Item> items;
+
+  public BookShelf() {
+    items = new ArrayList<>();
+    items.add(new Item(ItemType.FICTION, "西游记"));
+    items.add(new Item(ItemType.FICTION, "水浒传"));
+    items.add(new Item(ItemType.FICTION, "三国演义"));
+    items.add(new Item(ItemType.FICTION, "红楼梦"));
+    items.add(new Item(ItemType.CARTOON, "阿衰"));
+    items.add(new Item(ItemType.CARTOON, "七龙珠"));
+    items.add(new Item(ItemType.CARTOON, "火影忍者"));
+    items.add(new Item(ItemType.IT, "设计模式-可复用面向对象软件的基础"));
+    items.add(new Item(ItemType.IT, "重构-改善既有代码的设计"));
+    items.add(new Item(ItemType.IT, "Effective Java"));
+    items.add(new Item(ItemType.IT, "Java编程思想"));
+  }
+
+  public List<Item> getItemList() {
+    List<Item> list = new ArrayList<>();
+    list.addAll(items);
+    return list;
+  }
+}

iterator/src/main/java/BookShelfIterator.java

@@ -0,0 +1,72 @@
+/**
+ * MIT License
+ * <p>
+ * Copyright (c) 2017 James
+ * <p>
+ * Permission is hereby granted, free of charge, to any person obtaining a copy
+ * of this software and associated documentation files (the "Software"), to deal
+ * in the Software without restriction, including without limitation the rights
+ * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+ * copies of the Software, and to permit persons to whom the Software is
+ * furnished to do so, subject to the following conditions:
+ * <p>
+ * The above copyright notice and this permission notice shall be included in all
+ * copies or substantial portions of the Software.
+ * <p>
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+ * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+ * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+ * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
+ * SOFTWARE.
+ */
+
+import java.util.List;
+
+/**
+ * 图书的迭代器
+ */
+public class BookShelfIterator implements ItemIterator {
+
+  private ItemType type;
+  private BookShelf shelf;
+  private int idx;
+
+  public BookShelfIterator(ItemType type, BookShelf shelf) {
+    this.type = type;
+    this.shelf = shelf;
+    this.idx = -1;
+  }
+
+  @Override
+  public boolean hasNext() {
+    return -1 != getNexIdx();
+  }
+
+  @Override
+  public Item next() {
+    idx = getNexIdx();
+    if (-1 != idx) {
+      return shelf.getItemList().get(idx);
+    }
+    return null;
+  }
+
+  private int getNexIdx() {
+    List<Item> list = shelf.getItemList();
+    int tempIdx = idx;
+    boolean found = false;
+    while (!found) {
+      tempIdx++;
+      if (tempIdx >= list.size()) {
+        tempIdx = -1;
+        break;
+      }
+      if (list.get(tempIdx).getType().equals(type)) {
+        break;
+      }
+    }
+    return tempIdx;
+  }
+}

iterator/src/main/java/Item.java

@@ -45,6 +45,6 @@ public ItemType getType() {
 
   @Override
   public String toString() {
-    return super.toString();
+    return name;
   }
 }

iterator/src/main/java/ItemIterator.java

@@ -0,0 +1,33 @@
+/**
+ * MIT License
+ * <p>
+ * Copyright (c) 2017 James
+ * <p>
+ * Permission is hereby granted, free of charge, to any person obtaining a copy
+ * of this software and associated documentation files (the "Software"), to deal
+ * in the Software without restriction, including without limitation the rights
+ * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+ * copies of the Software, and to permit persons to whom the Software is
+ * furnished to do so, subject to the following conditions:
+ * <p>
+ * The above copyright notice and this permission notice shall be included in all
+ * copies or substantial portions of the Software.
+ * <p>
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+ * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+ * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+ * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
+ * SOFTWARE.
+ */
+
+/**
+ * 迭代器接口
+ */
+public interface ItemIterator {
+
+  boolean hasNext();
+
+  Item next();
+}

iterator/src/main/java/ItemType.java

@@ -27,5 +27,5 @@
  */
 public enum ItemType {
 
-  ANY, VEHICLE, ANIMAL, FOOD;
+  IT, FICTION, CARTOON
 }