diff --git a/iterator/pom.xml b/iterator/pom.xml
new file mode 100644
index 0000000..89fcfde
--- /dev/null
+++ b/iterator/pom.xml
@@ -0,0 +1,51 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<!--
+
+        MIT License
+
+        Copyright (c) 2017 James
+
+        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:
+
+        The above copyright notice and this permission notice shall be included in all
+        copies or substantial portions of the Software.
+
+        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.
+
+        -->
+<project xmlns="http://maven.apache.org/POM/4.0.0"
+         xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
+         xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd">
+    <parent>
+        <artifactId>java_design_patterns</artifactId>
+        <groupId>com.github.JamesZBL</groupId>
+        <version>1.11.9-SNAPSHOT</version>
+    </parent>
+    <modelVersion>4.0.0</modelVersion>
+
+    <artifactId>iterator</artifactId>
+    <dependencies>
+        <dependency>
+            <groupId>junit</groupId>
+            <artifactId>junit</artifactId>
+            <scope>test</scope>
+        </dependency>
+        <dependency>
+            <groupId>org.mockito</groupId>
+            <artifactId>mockito-core</artifactId>
+            <scope>test</scope>
+        </dependency>
+    </dependencies>
+
+</project>
\ No newline at end of file
diff --git a/iterator/src/main/java/Application.java b/iterator/src/main/java/Application.java
new file mode 100644
index 0000000..fb2a681
--- /dev/null
+++ b/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());
+    }
+  }
+}
diff --git a/iterator/src/main/java/BookShelf.java b/iterator/src/main/java/BookShelf.java
new file mode 100644
index 0000000..239ef48
--- /dev/null
+++ b/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;
+  }
+}
diff --git a/iterator/src/main/java/BookShelfIterator.java b/iterator/src/main/java/BookShelfIterator.java
new file mode 100644
index 0000000..418ec16
--- /dev/null
+++ b/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;
+  }
+}
diff --git a/iterator/src/main/java/Item.java b/iterator/src/main/java/Item.java
new file mode 100644
index 0000000..7c5fa39
--- /dev/null
+++ b/iterator/src/main/java/Item.java
@@ -0,0 +1,50 @@
+/**
+ * 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.
+ */
+
+/**
+ * 元素
+ */
+public class Item {
+
+  private ItemType type;
+  private String name;
+
+  public Item(ItemType type, String name) {
+    this.type = type;
+    this.name = name;
+  }
+
+  public final void setType(ItemType type) {
+    this.type = type;
+  }
+
+  public ItemType getType() {
+    return type;
+  }
+
+  @Override
+  public String toString() {
+    return name;
+  }
+}
diff --git a/iterator/src/main/java/ItemIterator.java b/iterator/src/main/java/ItemIterator.java
new file mode 100644
index 0000000..c308452
--- /dev/null
+++ b/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();
+}
diff --git a/iterator/src/main/java/ItemType.java b/iterator/src/main/java/ItemType.java
new file mode 100644
index 0000000..2b7a9c3
--- /dev/null
+++ b/iterator/src/main/java/ItemType.java
@@ -0,0 +1,31 @@
+/**
+ * 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.
+ */
+
+/**
+ * 元素类型
+ */
+public enum ItemType {
+
+  IT, FICTION, CARTOON
+}
diff --git a/mediator/pom.xml b/mediator/pom.xml
new file mode 100644
index 0000000..d94879f
--- /dev/null
+++ b/mediator/pom.xml
@@ -0,0 +1,51 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<!--
+
+        MIT License
+
+        Copyright (c) 2017 James
+
+        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:
+
+        The above copyright notice and this permission notice shall be included in all
+        copies or substantial portions of the Software.
+
+        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.
+
+        -->
+<project xmlns="http://maven.apache.org/POM/4.0.0"
+         xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
+         xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd">
+    <parent>
+        <artifactId>java_design_patterns</artifactId>
+        <groupId>com.github.JamesZBL</groupId>
+        <version>1.11.9-SNAPSHOT</version>
+    </parent>
+    <modelVersion>4.0.0</modelVersion>
+
+    <artifactId>mediator</artifactId>
+    <dependencies>
+        <dependency>
+            <groupId>junit</groupId>
+            <artifactId>junit</artifactId>
+            <scope>test</scope>
+        </dependency>
+        <dependency>
+            <groupId>org.mockito</groupId>
+            <artifactId>mockito-core</artifactId>
+            <scope>test</scope>
+        </dependency>
+    </dependencies>
+
+</project>
\ No newline at end of file
diff --git a/mediator/src/main/java/me/zbl/mediator/AbstractPartyMember.java b/mediator/src/main/java/me/zbl/mediator/AbstractPartyMember.java
new file mode 100644
index 0000000..c7080a3
--- /dev/null
+++ b/mediator/src/main/java/me/zbl/mediator/AbstractPartyMember.java
@@ -0,0 +1,59 @@
+/**
+ * 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.
+ */
+package me.zbl.mediator;
+
+import org.slf4j.Logger;
+import org.slf4j.LoggerFactory;
+
+/**
+ * 派对成员抽象类
+ */
+public abstract class AbstractPartyMember implements PartyMember {
+
+  private static final Logger LOGGER = LoggerFactory.getLogger(AbstractPartyMember.class);
+
+  private Party party;
+
+  @Override
+  public void joinParty(Party party) {
+    LOGGER.info("{}加入了派对", this);
+    this.party = party;
+  }
+
+  @Override
+  public void act(Activity activity) {
+    if (null != activity) {
+      LOGGER.info("{}提议进行{}活动", this, activity);
+      party.letAct(this, activity);
+    }
+  }
+
+  @Override
+  public void partyActivity(Activity activity) {
+    LOGGER.info("进行派对活动，名称：{}，介绍：{}", activity, activity.getDescription());
+  }
+
+  @Override
+  public abstract String toString();
+}
diff --git a/mediator/src/main/java/me/zbl/mediator/Activity.java b/mediator/src/main/java/me/zbl/mediator/Activity.java
new file mode 100644
index 0000000..9a1d8b7
--- /dev/null
+++ b/mediator/src/main/java/me/zbl/mediator/Activity.java
@@ -0,0 +1,48 @@
+/**
+ * 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.
+ */
+package me.zbl.mediator;
+
+/**
+ * 活动
+ */
+public enum Activity {
+  SHOOT("射击", "Shooting"), GUESS("猜灯谜", "Guess"), DESKTOP_GAME("桌游", "Desktop games"), SING("唱歌", "singing");
+
+  private String name;
+  private String description;
+
+  Activity(String name, String description) {
+    this.name = name;
+    this.description = description;
+  }
+
+  public String getDescription() {
+    return description;
+  }
+
+  @Override
+  public String toString() {
+    return name;
+  }
+}
diff --git a/mediator/src/main/java/me/zbl/mediator/Application.java b/mediator/src/main/java/me/zbl/mediator/Application.java
new file mode 100644
index 0000000..9448607
--- /dev/null
+++ b/mediator/src/main/java/me/zbl/mediator/Application.java
@@ -0,0 +1,53 @@
+/**
+ * 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.
+ */
+package me.zbl.mediator;
+
+import org.slf4j.Logger;
+import org.slf4j.LoggerFactory;
+
+/**
+ * Mediator
+ */
+public class Application {
+
+  private static final Logger LOGGER = LoggerFactory.getLogger(Application.class);
+
+  public static void main(String[] args) {
+    Party party = new PartyImpl();
+    Student student = new Student();
+    Officer officer = new Officer();
+    Businessman businessman = new Businessman();
+    Oldman oldman = new Oldman();
+
+    party.addMember(student);
+    party.addMember(officer);
+    party.addMember(businessman);
+    party.addMember(oldman);
+
+    student.act(Activity.DESKTOP_GAME);
+    officer.act(Activity.GUESS);
+    businessman.act(Activity.SHOOT);
+    oldman.act(Activity.SING);
+  }
+}
diff --git a/mediator/src/main/java/me/zbl/mediator/Businessman.java b/mediator/src/main/java/me/zbl/mediator/Businessman.java
new file mode 100644
index 0000000..9ac7bdf
--- /dev/null
+++ b/mediator/src/main/java/me/zbl/mediator/Businessman.java
@@ -0,0 +1,35 @@
+/**
+ * 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.
+ */
+package me.zbl.mediator;
+
+/**
+ * 商人
+ */
+public class Businessman extends AbstractPartyMember {
+
+  @Override
+  public String toString() {
+    return "商人";
+  }
+}
diff --git a/mediator/src/main/java/me/zbl/mediator/Officer.java b/mediator/src/main/java/me/zbl/mediator/Officer.java
new file mode 100644
index 0000000..9d8b913
--- /dev/null
+++ b/mediator/src/main/java/me/zbl/mediator/Officer.java
@@ -0,0 +1,35 @@
+/**
+ * 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.
+ */
+package me.zbl.mediator;
+
+/**
+ * 官员
+ */
+public class Officer extends AbstractPartyMember {
+
+  @Override
+  public String toString() {
+    return "官员";
+  }
+}
diff --git a/mediator/src/main/java/me/zbl/mediator/Oldman.java b/mediator/src/main/java/me/zbl/mediator/Oldman.java
new file mode 100644
index 0000000..13f1c3c
--- /dev/null
+++ b/mediator/src/main/java/me/zbl/mediator/Oldman.java
@@ -0,0 +1,35 @@
+/**
+ * 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.
+ */
+package me.zbl.mediator;
+
+/**
+ * 老人
+ */
+public class Oldman extends AbstractPartyMember {
+
+  @Override
+  public String toString() {
+    return "老人";
+  }
+}
diff --git a/mediator/src/main/java/me/zbl/mediator/Party.java b/mediator/src/main/java/me/zbl/mediator/Party.java
new file mode 100644
index 0000000..4d45c95
--- /dev/null
+++ b/mediator/src/main/java/me/zbl/mediator/Party.java
@@ -0,0 +1,34 @@
+/**
+ * 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.
+ */
+package me.zbl.mediator;
+
+/**
+ * 派对
+ */
+public interface Party {
+
+  void addMember(PartyMember member);
+
+  void letAct(PartyMember member, Activity activity);
+}
diff --git a/mediator/src/main/java/me/zbl/mediator/PartyImpl.java b/mediator/src/main/java/me/zbl/mediator/PartyImpl.java
new file mode 100644
index 0000000..dd0d976
--- /dev/null
+++ b/mediator/src/main/java/me/zbl/mediator/PartyImpl.java
@@ -0,0 +1,54 @@
+/**
+ * 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.
+ */
+package me.zbl.mediator;
+
+import java.util.ArrayList;
+import java.util.List;
+
+/**
+ * 派对的实现类
+ */
+public class PartyImpl implements Party {
+
+  private List<PartyMember> members;
+
+  public PartyImpl() {
+    members = new ArrayList<>();
+  }
+
+  @Override
+  public void addMember(PartyMember member) {
+    members.add(member);
+    member.joinParty(this);
+  }
+
+  @Override
+  public void letAct(PartyMember member, Activity activity) {
+    for (PartyMember m : members) {
+      if (!member.equals(m)) {
+        m.partyActivity(activity);
+      }
+    }
+  }
+}
diff --git a/mediator/src/main/java/me/zbl/mediator/PartyMember.java b/mediator/src/main/java/me/zbl/mediator/PartyMember.java
new file mode 100644
index 0000000..ace610d
--- /dev/null
+++ b/mediator/src/main/java/me/zbl/mediator/PartyMember.java
@@ -0,0 +1,36 @@
+/**
+ * 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.
+ */
+package me.zbl.mediator;
+
+/**
+ * 派对成员
+ */
+public interface PartyMember {
+
+  void joinParty(Party party);
+
+  void partyActivity(Activity activity);
+
+  void act(Activity activity);
+}
diff --git a/mediator/src/main/java/me/zbl/mediator/Student.java b/mediator/src/main/java/me/zbl/mediator/Student.java
new file mode 100644
index 0000000..a2160ac
--- /dev/null
+++ b/mediator/src/main/java/me/zbl/mediator/Student.java
@@ -0,0 +1,35 @@
+/**
+ * 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.
+ */
+package me.zbl.mediator;
+
+/**
+ * 学生
+ */
+public class Student extends AbstractPartyMember {
+
+  @Override
+  public String toString() {
+    return "学生";
+  }
+}
diff --git a/pom.xml b/pom.xml
index 75f561a..3bfc3cd 100644
--- a/pom.xml
+++ b/pom.xml
@@ -60,6 +60,8 @@
         <module>chain</module>
         <module>command</module>
         <module>interpreter</module>
+        <module>iterator</module>
+        <module>mediator</module>
     </modules>
 
     <dependencies>