From e7f0956a89356e1f841c045bd2b94ae20cafac9c Mon Sep 17 00:00:00 2001
From: Matt Lagrotte <mlagrotte@salesforce.com>
Date: Mon, 26 Feb 2018 14:29:58 -0500
Subject: [PATCH] Add LazyLambdaSingleton example

---
 javapatterns.iml                              |  6 +-
 pom.xml                                       | 30 +++++-----
 .../lazylambda/LazyLambdaSingleton.java       | 24 ++++++++
 .../lazylambda/LazyLambdaSingletonClient.java | 60 +++++++++++++++++++
 4 files changed, 101 insertions(+), 19 deletions(-)
 create mode 100644 src/main/java/org/abqjug/javapatterns/singleton/lazylambda/LazyLambdaSingleton.java
 create mode 100644 src/main/java/org/abqjug/javapatterns/singleton/lazylambda/LazyLambdaSingletonClient.java

diff --git a/javapatterns.iml b/javapatterns.iml
index dfa9d29..9d2270e 100644
--- a/javapatterns.iml
+++ b/javapatterns.iml
@@ -1,9 +1,8 @@
 <?xml version="1.0" encoding="UTF-8"?>
 <module org.jetbrains.idea.maven.project.MavenProjectsManager.isMavenModule="true" type="JAVA_MODULE" version="4">
-  <component name="NewModuleRootManager" LANGUAGE_LEVEL="JDK_1_6" inherit-compiler-output="false">
+  <component name="NewModuleRootManager" LANGUAGE_LEVEL="JDK_1_8" inherit-compiler-output="false">
     <output url="file://$MODULE_DIR$/target/classes" />
     <output-test url="file://$MODULE_DIR$/target/test-classes" />
-    <exclude-output />
     <content url="file://$MODULE_DIR$">
       <sourceFolder url="file://$MODULE_DIR$/src/main/java" isTestSource="false" />
       <excludeFolder url="file://$MODULE_DIR$/target" />
@@ -13,5 +12,4 @@
     <orderEntry type="library" name="Maven: com.google.guava:guava:11.0.2" level="project" />
     <orderEntry type="library" name="Maven: com.google.code.findbugs:jsr305:1.3.9" level="project" />
   </component>
-</module>
-
+</module>
\ No newline at end of file
diff --git a/pom.xml b/pom.xml
index db4b01d..e5ce7c7 100644
--- a/pom.xml
+++ b/pom.xml
@@ -12,8 +12,8 @@
          <plugin>
             <artifactId>maven-compiler-plugin</artifactId>
             <configuration>
-               <source>1.6</source>
-               <target>1.6</target>
+               <source>1.8</source>
+               <target>1.8</target>
                <compilerArgument>-proc:none</compilerArgument>
             </configuration>
          </plugin>
@@ -21,25 +21,25 @@
             <groupId>org.apache.maven.plugins</groupId>
             <artifactId>maven-javadoc-plugin</artifactId>
             <configuration>
-               <source>1.6</source>
-               <aggregate>true</aggregate>
+               <source>1.8</source>
+               <!--<aggregate>true</aggregate>-->
                <doclet>gr.spinellis.umlgraph.doclet.UmlGraphDoc</doclet>
                <docletArtifact>
                   <groupId>gr.spinellis</groupId>
                   <artifactId>UmlGraph</artifactId>
                   <version>4.6</version>
                </docletArtifact>
-               <additionalparam>
-                  -inferrel
-                  -inferdep
-                  -quiet
-                  -constructors
-                  -visibility
-                  -types
-                  -postfixpackage
-                  -nodefontsize 9
-                  -nodefontpackagesize 7
-               </additionalparam>
+               <!--<additionalparam>-->
+                  <!-- -inferrel-->
+                  <!-- -inferdep-->
+                  <!-- -quiet-->
+                  <!-- -constructors-->
+                  <!-- -visibility-->
+                  <!-- -types-->
+                  <!-- -postfixpackage-->
+                  <!-- -nodefontsize 9-->
+                  <!-- -nodefontpackagesize 7-->
+               <!--</additionalparam>-->
             </configuration>
          </plugin>
       </plugins>
diff --git a/src/main/java/org/abqjug/javapatterns/singleton/lazylambda/LazyLambdaSingleton.java b/src/main/java/org/abqjug/javapatterns/singleton/lazylambda/LazyLambdaSingleton.java
new file mode 100644
index 0000000..f47cfdd
--- /dev/null
+++ b/src/main/java/org/abqjug/javapatterns/singleton/lazylambda/LazyLambdaSingleton.java
@@ -0,0 +1,24 @@
+package org.abqjug.javapatterns.singleton.lazylambda;
+
+import com.google.common.base.Supplier;
+
+/**
+ * User: Matt Lagrotte (matt@lagrotte.net)
+ * Date: 2/26/18
+ * Time: 2:00 PM
+ */
+public class LazyLambdaSingleton {
+
+    private static LazyLambdaSingleton instance = null;
+
+    private static Supplier<LazyLambdaSingleton> singletonSupplier = () ->
+    {
+        instance = new LazyLambdaSingleton();
+        singletonSupplier = () -> instance;
+        return instance;
+    };
+
+    public static LazyLambdaSingleton getInstance() {
+        return singletonSupplier.get();
+    }
+}
\ No newline at end of file
diff --git a/src/main/java/org/abqjug/javapatterns/singleton/lazylambda/LazyLambdaSingletonClient.java b/src/main/java/org/abqjug/javapatterns/singleton/lazylambda/LazyLambdaSingletonClient.java
new file mode 100644
index 0000000..58dc6a9
--- /dev/null
+++ b/src/main/java/org/abqjug/javapatterns/singleton/lazylambda/LazyLambdaSingletonClient.java
@@ -0,0 +1,60 @@
+package org.abqjug.javapatterns.singleton.lazylambda;
+
+/**
+ * User: Matt Lagrotte (matt@lagrotte.net)
+ * Date: 2/26/18
+ * Time: 2:00 PM
+ */
+public class LazyLambdaSingletonClient {
+    public static class SingletonRunner implements Runnable {
+        private LazyLambdaSingleton instance;
+
+        public LazyLambdaSingleton getInstance() {
+            return instance;
+        }
+
+        public void run() {
+            try {
+                Thread.sleep(1000);
+            } catch (InterruptedException e) {
+                e.printStackTrace();  //To change body of catch statement use File | Settings | File Templates.
+            }
+            instance = LazyLambdaSingleton.getInstance();
+            try {
+                Thread.sleep(1000);
+            } catch (InterruptedException e) {
+                e.printStackTrace();  //To change body of catch statement use File | Settings | File Templates.
+            }
+        }
+    }
+    
+    
+    public static void main(String[] args) throws InterruptedException {
+      SingletonRunner runner1 = new SingletonRunner();
+      SingletonRunner runner2 = new SingletonRunner();
+      SingletonRunner runner3 = new SingletonRunner();
+      SingletonRunner runner4 = new SingletonRunner();
+        
+      Thread t1 = new Thread(runner1);
+      Thread t2 = new Thread(runner2);
+      Thread t3 = new Thread(runner3);
+      Thread t4 = new Thread(runner4);
+
+      t1.start();
+      t2.start();
+      t3.start();
+      t4.start();
+
+      t1.join();
+      t2.join();
+      t3.join();
+      t4.join();
+
+      assert runner1.getInstance() == runner2.getInstance();
+      assert runner2.getInstance() == runner3.getInstance();
+      assert runner3.getInstance() == runner4.getInstance();
+      assert runner4.getInstance() == runner1.getInstance();
+      assert runner2.getInstance() == runner4.getInstance();
+      assert runner3.getInstance() == runner1.getInstance();
+    }
+}