Collection (#170)

* generic examle

* update collection

* update checkstyle

* change to jdk 14

* fixed build error

* udpate formatter version

* Formatted with Google Java Formatter

Co-authored-by: github-actions <${GITHUB_ACTOR}@users.noreply.github.com>

Author: realDuYuanChao

.github/workflows/checkstyle.yml

@@ -8,12 +8,13 @@ jobs:
     steps:
       - uses: actions/checkout@v2
       - uses: actions/setup-python@v2
-      - name: Set up JDK 16
+      - name: Set up JDK 12
         uses: actions/setup-java@v1
         with:
-          java-version: 16
-      - run: wget https://github.com/google/google-java-format/releases/download/v1.11.0/google-java-format-1.11.0-all-deps.jar -O formatter.jar
-      - run: java --add-exports jdk.compiler/com.sun.tools.javac.api=ALL-UNNAMED --add-exports jdk.compiler/com.sun.tools.javac.file=ALL-UNNAMED --add-exports jdk.compiler/com.sun.tools.javac.parser=ALL-UNNAMED --add-exports jdk.compiler/com.sun.tools.javac.tree=ALL-UNNAMED --add-exports jdk.compiler/com.sun.tools.javac.util=ALL-UNNAMED -jar formatter.jar --replace --set-exit-if-changed $(find . -type f -name "*.java" | grep ".*/src/.*java")
+          java-version: 12
+      - run: wget https://github.com/google/google-java-format/releases/download/google-java-format-1.9/google-java-format-1.9-all-deps.jar -O formatter.jar
+#      - run: java --add-exports jdk.compiler/com.sun.tools.javac.api=ALL-UNNAMED --add-exports jdk.compiler/com.sun.tools.javac.file=ALL-UNNAMED --add-exports jdk.compiler/com.sun.tools.javac.parser=ALL-UNNAMED --add-exports jdk.compiler/com.sun.tools.javac.tree=ALL-UNNAMED --add-exports jdk.compiler/com.sun.tools.javac.util=ALL-UNNAMED -jar formatter.jar --replace --set-exit-if-changed $(find . -type f -name "*.java" | grep ".*/src/.*java")
+      - run: java -jar formatter.jar --replace --set-exit-if-changed $(find . -type f -name "*.java" | grep ".*/src/.*java")
       - name: Commit Format changes
         if: failure()
         run: |

.github/workflows/maven.yml

@@ -12,9 +12,9 @@ jobs:
 
     steps:
       - uses: actions/checkout@v2
-      - name: Set up JDK 16
+      - name: Set up JDK 14
         uses: actions/setup-java@v1
         with:
-          java-version: 16
+          java-version: 14
       - name: Build with Maven
         run: mvn clean test

pom.xml

@@ -8,8 +8,8 @@
     <artifactId>untitled</artifactId>
     <version>1.0-SNAPSHOT</version>
     <properties>
-        <maven.compiler.source>16</maven.compiler.source>
-        <maven.compiler.target>16</maven.compiler.target>
+        <maven.compiler.source>14</maven.compiler.source>
+        <maven.compiler.target>14</maven.compiler.target>
     </properties>
     <dependencies>
         <dependency>
@@ -30,8 +30,8 @@
                 <groupId>org.apache.maven.plugins</groupId>
                 <artifactId>maven-compiler-plugin</artifactId>
                 <configuration>
-                    <source>16</source>
-                    <target>16</target>
+                    <source>14</source>
+                    <target>14</target>
                 </configuration>
             </plugin>
         </plugins>

src/main/java/com/examplehub/basics/ArrayListExample.java

@@ -0,0 +1,3 @@
+package com.examplehub.basics.generic;
+
+public class GenericClass {}

src/main/java/com/examplehub/basics/HashMapExample.java

@@ -0,0 +1,3 @@
+package com.examplehub.basics.generic;
+
+public class GenericExample {}

src/main/java/com/examplehub/basics/generic/GenericClass.java

@@ -0,0 +1,3 @@
+package com.examplehub.basics.map;
+
+public class EnumMapExample {}

src/main/java/com/examplehub/basics/generic/GenericExample.java

@@ -0,0 +1,3 @@
+package com.examplehub.basics.map;
+
+public class HashMapExample {}

src/main/java/com/examplehub/basics/map/EnumMapExample.java

@@ -0,0 +1,3 @@
+package com.examplehub.basics.map;
+
+public class PropertiesExample {}

src/main/java/com/examplehub/basics/map/HashMapExample.java

@@ -0,0 +1,3 @@
+package com.examplehub.basics.map;
+
+public class TreeMapExample {}

src/main/java/com/examplehub/basics/map/PropertiesExample.java

@@ -0,0 +1,3 @@
+package com.examplehub.basics.queue;
+
+public class DequeExample {}

src/main/java/com/examplehub/basics/map/TreeMapExample.java

@@ -0,0 +1,3 @@
+package com.examplehub.basics.queue;
+
+public class PriorityQueueExample {}

src/main/java/com/examplehub/basics/queue/DequeExample.java

@@ -0,0 +1,3 @@
+package com.examplehub.basics.queue;
+
+public class QueueExample {}

src/main/java/com/examplehub/basics/queue/PriorityQueueExample.java

@@ -0,0 +1,3 @@
+package com.examplehub.basics.queue;
+
+public class StackExample {}

src/main/java/com/examplehub/basics/queue/QueueExample.java

@@ -0,0 +1,4 @@
+package com.examplehub.basics.set;
+
+
+public class ArrayListExample {}

src/main/java/com/examplehub/basics/queue/StackExample.java

@@ -1,4 +1,4 @@
-package com.examplehub.basics;
+package com.examplehub.basics.set;
 
 import java.util.HashSet;
 

src/main/java/com/examplehub/basics/set/ArrayListExample.java

@@ -1,4 +1,4 @@
-package com.examplehub.basics;
+package com.examplehub.basics.set;
 
 import java.util.LinkedList;
 

src/main/java/com/examplehub/basics/HashSetExample.java src/main/java/com/examplehub/basics/set/HashSetExample.java

@@ -0,0 +1,3 @@
+package com.examplehub.basics.set;
+
+public class TreeSetExample {}

src/main/java/com/examplehub/basics/LinkedListExample.java src/main/java/com/examplehub/basics/set/LinkedListExample.java

@@ -17,6 +17,9 @@ void testPut() {
 
     assertNull(hashMap.put("bio", "Github"));
     assertEquals("Github", hashMap.put("bio", "I love coding"));
+
+    hashMap.put("username", "admin_username");
+    assertEquals("admin_username", hashMap.get("username"));
   }
 
   @Test
@@ -61,6 +64,8 @@ void testGet() {
     assertNull(hashMap.get("bio"));
 
     assertEquals("jack", hashMap.getOrDefault("user", "jack"));
+
+    assertNull(hashMap.get("url"));
   }
 
   @Test
@@ -112,10 +117,16 @@ void testKeySet() {
     hashMap.put("password", "abc123");
     assertEquals("[password, username]", hashMap.keySet().toString());
 
-    // password->abc123
-    // username->admin
+    String[][] keyValues =
+        new String[][] {
+          {"password", "abc123"},
+          {"username", "admin"}
+        };
+    int index = 0;
     for (String key : hashMap.keySet()) {
-      System.out.println(key + "->" + hashMap.get(key));
+      assertEquals(keyValues[index][0], key);
+      assertEquals(keyValues[index][1], hashMap.get(key));
+      index++;
     }
   }
 
@@ -141,10 +152,50 @@ void testEntry() {
     HashMap<String, String> hashMap = new HashMap<>();
     hashMap.put("username", "admin");
     hashMap.put("password", "abc123");
-    // password->abc123
-    // username->admin
+    String[][] keyValues =
+        new String[][] {
+          {"password", "abc123"},
+          {"username", "admin"}
+        };
+    int index = 0;
     for (Map.Entry<String, String> entry : hashMap.entrySet()) {
-      System.out.println(entry.getKey() + "->" + entry.getValue());
+      assertEquals(keyValues[index][0], entry.getKey());
+      assertEquals(keyValues[index][1], entry.getValue());
+      index++;
+    }
+  }
+
+  @Test
+  void testStoreObj() {
+    class Student {
+      private String name;
+      private int age;
+
+      public Student(String name, int age) {
+        this.name = name;
+        this.age = age;
+      }
+
+      public String getName() {
+        return name;
+      }
+
+      public void setName(String name) {
+        this.name = name;
+      }
+
+      public int getAge() {
+        return age;
+      }
+
+      public void setAge(int age) {
+        this.age = age;
+      }
     }
+    Student student = new Student("Jack", 25);
+    HashMap<String, Student> hashMap = new HashMap<>();
+    hashMap.put("jack", student);
+    assertEquals("Jack", hashMap.get("jack").getName());
+    assertEquals(25, hashMap.get("jack").getAge());
   }
 }

src/main/java/com/examplehub/basics/set/TreeSetExample.java

@@ -0,0 +1,25 @@
+package com.examplehub.basics.generic;
+
+import static org.junit.jupiter.api.Assertions.*;
+
+import org.junit.jupiter.api.Test;
+
+class GenericClassTest {
+  @Test
+  void testWriteGenericClass() {
+    class MyBean<T> {
+      T value;
+
+      public T getValue() {
+        return value;
+      }
+
+      public void setValue(T value) {
+        this.value = value;
+      }
+    }
+    MyBean<Integer> bean1 = new MyBean<>();
+    bean1.setValue(123);
+    assertEquals(123, bean1.getValue());
+  }
+}