apply changes from review iluwatar#69

Author: robertkasperczyk

guarded-suspension/README.md

@@ -10,12 +10,12 @@ tags:
 ---
 
 ## Intent
-Use Guareded suspension pattern to handle a situation when you want to execute a method on object which is not in a proper state.
+Use Guarded suspension pattern to handle a situation when you want to execute a method on object which is not in a proper state.
 
 ![Guarded Suspension diagram](./etc/guarded-suspension.png)
 
 ## Applicability
-Use Guareded Suspension pattern when:
-
-* the developer knows that the method execution will be blocked for a finite period of time
+Use Guarded Suspension pattern when the developer knows that the method execution will be blocked for a finite period of time
 
+## Related patterns
+* Balking 

guarded-suspension/etc/guarded-suspension.png

@@ -38,6 +38,7 @@
     <dependency>
       <groupId>junit</groupId>
       <artifactId>junit</artifactId>
+      <scope>test</scope>
     </dependency>
   </dependencies>
 </project>

guarded-suspension/pom.xml

@@ -0,0 +1,76 @@
+/**
+ * The MIT License
+ * Copyright (c) 2014 Ilkka Seppälä
+ *
+ * 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.
+ */
+/**
+ * Guarded-suspension is a concurrent design pattern for handling situation when to execute some action we need
+ * condition to be satisfied.
+ * <p>
+ * Implementation is based on GuardedQueue, which has two methods: get and put,
+ * the condition is that we cannot get from empty queue so when thread attempt
+ * to break the condition we invoke Object's wait method on him and when other thread put an element
+ * to the queue he notify the waiting one that now he can get from queue.
+ */
+package com.iluwatar.guarded.suspension;
+
+import java.util.concurrent.ExecutorService;
+import java.util.concurrent.Executors;
+import java.util.concurrent.TimeUnit;
+
+/**
+ * Created by robertt240 on 1/26/17.
+ */
+public class App {
+  /**
+   * Example pattern execution
+   *
+   * @param args - command line args
+   */
+  public static void main(String[] args) {
+    GuardedQueue guardedQueue = new GuardedQueue();
+    ExecutorService executorService = Executors.newFixedThreadPool(3);
+
+    //here we create first thread which is supposed to get from guardedQueue
+    executorService.execute(() -> {
+          guardedQueue.get();
+        }
+    );
+
+    //here we wait two seconds to show that the thread which is trying to get from guardedQueue will be waiting
+    try {
+      Thread.sleep(2000);
+    } catch (InterruptedException e) {
+      e.printStackTrace();
+    }
+    //now we execute second thread which will put number to guardedQueue and notify first thread that it could get
+    executorService.execute(() -> {
+          guardedQueue.put(20);
+        }
+    );
+    executorService.shutdown();
+    try {
+      executorService.awaitTermination(30, TimeUnit.SECONDS);
+    } catch (InterruptedException e) {
+      e.printStackTrace();
+    }
+  }
+
+}

guarded-suspension/src/main/java/com/iluwatar/guarded/suspension/App.java

@@ -31,7 +31,7 @@
 
 public class GuardedQueue {
   private static final Logger LOGGER = LoggerFactory.getLogger(GuardedQueue.class);
-  private Queue<Integer> sourceList;
+  private final Queue<Integer> sourceList;
 
   public GuardedQueue() {
     this.sourceList = new LinkedList<>();
@@ -49,17 +49,17 @@ public synchronized Integer get() {
         e.printStackTrace();
       }
     }
-
+    LOGGER.info("getting");
     return sourceList.peek();
   }
 
   /**
    * @param e number which we want to put to our queue
    */
   public synchronized void put(Integer e) {
+    LOGGER.info("putting");
     sourceList.add(e);
-    notify();
     LOGGER.info("notifying");
-
+    notify();
   }
 }

guarded-suspension/src/main/java/com/iluwatar/guarded/suspension/GuardedQueue.java

@@ -47,4 +47,12 @@ public void testGet() {
     Assert.assertEquals(Integer.valueOf(10), value);
   }
 
+  @Test
+  public void testPut() {
+    GuardedQueue g = new GuardedQueue();
+    g.put(12);
+    Assert.assertEquals(Integer.valueOf(12), g.get());
+
+  }
+
 }

guarded-suspension/src/test/java/com/iluwatar/guarded/suspension/GuardedQueueTest.java

@@ -121,7 +121,7 @@
         <module>factory-kit</module>
         <module>feature-toggle</module>
         <module>value-object</module>
-		<module>module</module>
+		    <module>module</module>
         <module>monad</module>
         <module>mute-idiom</module>
         <module>mutex</module>
@@ -134,6 +134,8 @@
         <module>event-asynchronous</module>
         <module>queue-load-leveling</module>
         <module>object-mother</module>
+        <module>guarded-suspension</module>
+
     </modules>
 
     <dependencyManagement>