Adds default methods for Commands (#238) (#238)

Closes #235

wpilibc/shared/include/Commands/Command.h

@@ -81,45 +81,13 @@ class Command : public ErrorBase, public NamedSendable, public ITableListener {
   bool IsTimedOut() const;
   bool AssertUnlocked(const std::string& message);
   void SetParent(CommandGroup* parent);
-  /**
-   * The initialize method is called the first time this Command is run after
-   * being started.
-   */
-  virtual void Initialize() = 0;
-  /**
-   * The execute method is called repeatedly until this Command either finishes
-   * or is canceled.
-   */
-  virtual void Execute() = 0;
-  /**
-   * Returns whether this command is finished.
-   * If it is, then the command will be removed and {@link Command#end() end()}
-   * will be called.
-   *
-   * <p>It may be useful for a team to reference the {@link Command#isTimedOut()
-   * isTimedOut()} method for time-sensitive commands.</p>
-   * @return whether this command is finished.
-   * @see Command#isTimedOut() isTimedOut()
-   */
-  virtual bool IsFinished() = 0;
-  /**
-   * Called when the command ended peacefully.  This is where you may want
-   * to wrap up loose ends, like shutting off a motor that was being used
-   * in the command.
-   */
-  virtual void End() = 0;
-  /**
-   * Called when the command ends because somebody called
-   * {@link Command#cancel() cancel()} or another command shared the same
-   * requirements as this one, and booted it out.
-   *
-   * <p>This is where you may want to wrap up loose ends, like shutting off a
-   * motor that was being used in the command.</p>
-   *
-   * <p>Generally, it is useful to simply call the {@link Command#end() end()}
-   * method within this method</p>
-   */
-  virtual void Interrupted() = 0;
+
+  virtual void Initialize();
+  virtual void Execute();
+  virtual bool IsFinished();
+  virtual void End();
+  virtual void Interrupted();
+
   virtual void _Initialize();
   virtual void _Interrupted();
   virtual void _Execute();

wpilibc/shared/include/Commands/InstantCommand.h

@@ -0,0 +1,26 @@
+/*----------------------------------------------------------------------------*/
+/* Copyright (c) FIRST 2016. All Rights Reserved.                             */
+/* Open Source Software - may be modified and shared by FRC teams. The code   */
+/* must be accompanied by the FIRST BSD license file in the root directory of */
+/* the project.                                                               */
+/*----------------------------------------------------------------------------*/
+
+#pragma once
+
+#include <string>
+
+#include "Commands/Command.h"
+
+namespace frc {
+
+class InstantCommand : public Command {
+ public:
+  explicit InstantCommand(const std::string& name);
+  InstantCommand() = default;
+  virtual ~InstantCommand() = default;
+
+ protected:
+  virtual bool IsFinished();
+};
+
+}  // namespace frc

wpilibc/shared/include/Commands/PrintCommand.h

@@ -9,21 +9,17 @@
 
 #include <string>
 
-#include "Commands/Command.h"
+#include "Commands/InstantCommand.h"
 
 namespace frc {
 
-class PrintCommand : public Command {
+class PrintCommand : public InstantCommand {
  public:
   explicit PrintCommand(const std::string& message);
   virtual ~PrintCommand() = default;
 
  protected:
   virtual void Initialize();
-  virtual void Execute();
-  virtual bool IsFinished();
-  virtual void End();
-  virtual void Interrupted();
 
  private:
   std::string m_message;

wpilibc/shared/include/Commands/StartCommand.h

@@ -7,21 +7,17 @@
 
 #pragma once
 
-#include "Commands/Command.h"
+#include "Commands/InstantCommand.h"
 
 namespace frc {
 
-class StartCommand : public Command {
+class StartCommand : public InstantCommand {
  public:
   explicit StartCommand(Command* commandToStart);
   virtual ~StartCommand() = default;
 
  protected:
   virtual void Initialize();
-  virtual void Execute();
-  virtual bool IsFinished();
-  virtual void End();
-  virtual void Interrupted();
 
  private:
   Command* m_commandToFork;

wpilibc/shared/include/Commands/TimedCommand.h

@@ -0,0 +1,26 @@
+/*----------------------------------------------------------------------------*/
+/* Copyright (c) FIRST 2016. All Rights Reserved.                             */
+/* Open Source Software - may be modified and shared by FRC teams. The code   */
+/* must be accompanied by the FIRST BSD license file in the root directory of */
+/* the project.                                                               */
+/*----------------------------------------------------------------------------*/
+
+#pragma once
+
+#include <string>
+
+#include "Commands/Command.h"
+
+namespace frc {
+
+class TimedCommand : public Command {
+ public:
+  TimedCommand(const std::string& name, double timeout);
+  explicit TimedCommand(double timeout);
+  virtual ~TimedCommand() = default;
+
+ protected:
+  virtual bool IsFinished();
+};
+
+}  // namespace frc

wpilibc/shared/include/Commands/WaitCommand.h

@@ -9,22 +9,15 @@
 
 #include <string>
 
-#include "Commands/Command.h"
+#include "Commands/TimedCommand.h"
 
 namespace frc {
 
-class WaitCommand : public Command {
+class WaitCommand : public TimedCommand {
  public:
   explicit WaitCommand(double timeout);
   WaitCommand(const std::string& name, double timeout);
   virtual ~WaitCommand() = default;
-
- protected:
-  virtual void Initialize();
-  virtual void Execute();
-  virtual bool IsFinished();
-  virtual void End();
-  virtual void Interrupted();
 };
 
 }  // namespace frc

wpilibc/shared/include/Commands/WaitForChildren.h

@@ -20,11 +20,7 @@ class WaitForChildren : public Command {
   virtual ~WaitForChildren() = default;
 
  protected:
-  virtual void Initialize();
-  virtual void Execute();
   virtual bool IsFinished();
-  virtual void End();
-  virtual void Interrupted();
 };
 
 }  // namespace frc

wpilibc/shared/include/Commands/WaitUntilCommand.h

@@ -20,11 +20,7 @@ class WaitUntilCommand : public Command {
   virtual ~WaitUntilCommand() = default;
 
  protected:
-  virtual void Initialize();
-  virtual void Execute();
   virtual bool IsFinished();
-  virtual void End();
-  virtual void Interrupted();
 
  private:
   double m_time;