code refactor as per SOLID principal without changing functionality.

java/pom.xml

@@ -5,8 +5,10 @@
     <artifactId>tasks</artifactId>
     <version>0.1</version>
 
+    <packaging>jar</packaging>
     <name>Task List</name>
 
+
     <dependencies>
         <dependency>
             <groupId>junit</groupId>

java/src/main/java/com/codurance/training/actions/TaskActions.java

@@ -0,0 +1,19 @@
+package com.codurance.training.actions;
+
+ public interface TaskActions {
+     void show();
+
+     void add(String commnandLine);
+
+     void addProject(String name);
+
+     void setDone(String idString,boolean done);
+
+     void check(String idString);
+
+     void uncheck(String idString);
+
+     void help();
+
+     void error(String command);
+}

java/src/main/java/com/codurance/training/actions/impl/TaskActionsImpl.java

@@ -0,0 +1,94 @@
+package com.codurance.training.actions.impl;
+
+import com.codurance.training.actions.TaskActions;
+import com.codurance.training.tasks.Task;
+
+import java.io.PrintWriter;
+import java.util.ArrayList;
+import java.util.LinkedHashMap;
+import java.util.List;
+import java.util.Map;
+
+public class TaskActionsImpl implements TaskActions {
+    private final PrintWriter out = new PrintWriter(System.out);
+
+    private static long lastId = 0;
+
+    private static final Map<String, List<Task>> tasksMap= new LinkedHashMap<>();
+    @Override
+    public void show() {
+        for (Map.Entry<String, List<Task>> project : tasksMap.entrySet()) {
+            out.println(project.getKey());
+            for (Task task : project.getValue()) {
+                out.printf("    [%c] %d: %s%n", (task.isDone() ? 'x' : ' '), task.getId(), task.getDescription());
+            }
+            out.println();
+        }
+    }
+    @Override
+    public void add(String commandLine) {
+        String[] subcommandRest = commandLine.split(" ", 2);
+        String subcommand = subcommandRest[0];
+        if (subcommand.equals("project")) {
+            addProject(subcommandRest[1]);
+        } else if (subcommand.equals("task")) {
+            String[] projectTask = subcommandRest[1].split(" ", 2);
+            addTask(projectTask[0], projectTask[1]);
+        }
+    }
+    @Override
+    public void addProject(String name) {
+        tasksMap.put(name, new ArrayList<Task>());
+    }
+
+    private void addTask(String project, String description) {
+        List<Task> projectTasks = tasksMap.get(project);
+        if (projectTasks == null) {
+            out.printf("Could not find a project with the name \"%s\".", project);
+            out.println();
+            return;
+        }
+        projectTasks.add(new Task(nextId(), description, false));
+    }
+    @Override
+    public void check(String idString) {
+        setDone(idString, true);
+    }
+    @Override
+    public void uncheck(String idString) {
+        setDone(idString, false);
+    }
+    @Override
+    public void setDone(String idString, boolean done) {
+        int id = Integer.parseInt(idString);
+        for (Map.Entry<String, List<Task>> project : tasksMap.entrySet()) {
+            for (Task task : project.getValue()) {
+                if (task.getId() == id) {
+                    task.setDone(done);
+                    return;
+                }
+            }
+        }
+        out.printf("Could not find a task with an ID of %d.", id);
+        out.println();
+    }
+    @Override
+    public void help() {
+        out.println("Commands:");
+        out.println("  show");
+        out.println("  add project <project name>");
+        out.println("  add task <project name> <task description>");
+        out.println("  check <task ID>");
+        out.println("  uncheck <task ID>");
+        out.println();
+    }
+    @Override
+    public void error(String command) {
+        out.printf("I don't know what the command \"%s\" is.", command);
+        out.println();
+    }
+
+    public long nextId() {
+        return ++lastId;
+    }
+}

java/src/main/java/com/codurance/training/executioner/TaskExecutioner.java

@@ -0,0 +1,5 @@
+package com.codurance.training.executioner;
+
+public interface TaskExecutioner {
+    void execute(String commandLine);
+}

java/src/main/java/com/codurance/training/executioner/impl/TaskExecutionerImpl.java

@@ -0,0 +1,32 @@
+package com.codurance.training.executioner.impl;
+
+import com.codurance.training.actions.impl.TaskActionsImpl;
+import com.codurance.training.executioner.TaskExecutioner;
+
+public class TaskExecutionerImpl implements TaskExecutioner {
+    TaskActionsImpl taskActions = new TaskActionsImpl();
+    public void execute(String commandLine) {
+        String[] commandRest = commandLine.split(" ", 2);
+        String command = commandRest[0];
+        switch (command) {
+            case "show":
+                taskActions.show();
+                break;
+            case "add":
+                taskActions.add(commandRest[1]);
+                break;
+            case "check":
+                taskActions.check(commandRest[1]);
+                break;
+            case "uncheck":
+                taskActions.uncheck(commandRest[1]);
+                break;
+            case "help":
+                taskActions.help();
+                break;
+            default:
+                taskActions.error(command);
+                break;
+        }
+    }
+}

java/src/main/java/com/codurance/training/main/TaskApplicationRunner.java

@@ -0,0 +1,20 @@
+package com.codurance.training.main;
+
+import com.codurance.training.tasks.TaskList;
+
+import java.io.BufferedReader;
+import java.io.InputStreamReader;
+import java.io.PrintWriter;
+
+public class TaskApplicationRunner {
+    public static void main(String[] args) {
+        try{
+            BufferedReader in = new BufferedReader(new InputStreamReader(System.in));
+            PrintWriter out = new PrintWriter(System.out);
+            new TaskList(in,out).run();
+        }catch (Exception e){
+            e.printStackTrace();
+        }
+
+    }
+}

java/src/main/java/com/codurance/training/tasks/TaskList.java

@@ -1,28 +1,21 @@
 package com.codurance.training.tasks;
 
+import com.codurance.training.executioner.impl.TaskExecutionerImpl;
+
 import java.io.BufferedReader;
 import java.io.IOException;
-import java.io.InputStreamReader;
 import java.io.PrintWriter;
-import java.util.ArrayList;
 import java.util.LinkedHashMap;
 import java.util.List;
 import java.util.Map;
 
 public final class TaskList implements Runnable {
     private static final String QUIT = "quit";
 
-    private final Map<String, List<Task>> tasks = new LinkedHashMap<>();
     private final BufferedReader in;
     private final PrintWriter out;
 
-    private long lastId = 0;
-
-    public static void main(String[] args) throws Exception {
-        BufferedReader in = new BufferedReader(new InputStreamReader(System.in));
-        PrintWriter out = new PrintWriter(System.out);
-        new TaskList(in, out).run();
-    }
+    private final TaskExecutionerImpl executioner = new TaskExecutionerImpl();
 
     public TaskList(BufferedReader reader, PrintWriter writer) {
         this.in = reader;
@@ -42,108 +35,11 @@ public void run() {
             if (command.equals(QUIT)) {
                 break;
             }
-            execute(command);
-        }
-    }
-
-    private void execute(String commandLine) {
-        String[] commandRest = commandLine.split(" ", 2);
-        String command = commandRest[0];
-        switch (command) {
-            case "show":
-                show();
-                break;
-            case "add":
-                add(commandRest[1]);
-                break;
-            case "check":
-                check(commandRest[1]);
-                break;
-            case "uncheck":
-                uncheck(commandRest[1]);
-                break;
-            case "help":
-                help();
-                break;
-            default:
-                error(command);
-                break;
-        }
-    }
-
-    private void show() {
-        for (Map.Entry<String, List<Task>> project : tasks.entrySet()) {
-            out.println(project.getKey());
-            for (Task task : project.getValue()) {
-                out.printf("    [%c] %d: %s%n", (task.isDone() ? 'x' : ' '), task.getId(), task.getDescription());
-            }
-            out.println();
-        }
-    }
-
-    private void add(String commandLine) {
-        String[] subcommandRest = commandLine.split(" ", 2);
-        String subcommand = subcommandRest[0];
-        if (subcommand.equals("project")) {
-            addProject(subcommandRest[1]);
-        } else if (subcommand.equals("task")) {
-            String[] projectTask = subcommandRest[1].split(" ", 2);
-            addTask(projectTask[0], projectTask[1]);
+            executioner.execute(command);
         }
     }
 
-    private void addProject(String name) {
-        tasks.put(name, new ArrayList<Task>());
-    }
 
-    private void addTask(String project, String description) {
-        List<Task> projectTasks = tasks.get(project);
-        if (projectTasks == null) {
-            out.printf("Could not find a project with the name \"%s\".", project);
-            out.println();
-            return;
-        }
-        projectTasks.add(new Task(nextId(), description, false));
-    }
 
-    private void check(String idString) {
-        setDone(idString, true);
-    }
-
-    private void uncheck(String idString) {
-        setDone(idString, false);
-    }
 
-    private void setDone(String idString, boolean done) {
-        int id = Integer.parseInt(idString);
-        for (Map.Entry<String, List<Task>> project : tasks.entrySet()) {
-            for (Task task : project.getValue()) {
-                if (task.getId() == id) {
-                    task.setDone(done);
-                    return;
-                }
-            }
-        }
-        out.printf("Could not find a task with an ID of %d.", id);
-        out.println();
-    }
-
-    private void help() {
-        out.println("Commands:");
-        out.println("  show");
-        out.println("  add project <project name>");
-        out.println("  add task <project name> <task description>");
-        out.println("  check <task ID>");
-        out.println("  uncheck <task ID>");
-        out.println();
-    }
-
-    private void error(String command) {
-        out.printf("I don't know what the command \"%s\" is.", command);
-        out.println();
-    }
-
-    private long nextId() {
-        return ++lastId;
-    }
 }