Allow widgets to be added by passing value suppliers (#1690)

wpilibc/src/main/native/cpp/shuffleboard/ShuffleboardContainer.cpp

@@ -141,6 +141,108 @@ SimpleWidget& ShuffleboardContainer::Add(
   return Add(title, nt::Value::MakeStringArray(defaultValue));
 }
 
+SuppliedValueWidget<std::string>& ShuffleboardContainer::AddString(
+    const wpi::Twine& title, std::function<std::string()> supplier) {
+  static auto setter = [](nt::NetworkTableEntry entry, std::string value) {
+    entry.SetString(value);
+  };
+
+  CheckTitle(title);
+  auto widget = std::make_unique<SuppliedValueWidget<std::string>>(
+      *this, title, supplier, setter);
+  auto ptr = widget.get();
+  m_components.emplace_back(std::move(widget));
+  return *ptr;
+}
+
+SuppliedValueWidget<double>& ShuffleboardContainer::AddNumber(
+    const wpi::Twine& title, std::function<double()> supplier) {
+  static auto setter = [](nt::NetworkTableEntry entry, double value) {
+    entry.SetDouble(value);
+  };
+
+  CheckTitle(title);
+  auto widget = std::make_unique<SuppliedValueWidget<double>>(*this, title,
+                                                              supplier, setter);
+  auto ptr = widget.get();
+  m_components.emplace_back(std::move(widget));
+  return *ptr;
+}
+
+SuppliedValueWidget<bool>& ShuffleboardContainer::AddBoolean(
+    const wpi::Twine& title, std::function<bool()> supplier) {
+  static auto setter = [](nt::NetworkTableEntry entry, bool value) {
+    entry.SetBoolean(value);
+  };
+
+  CheckTitle(title);
+  auto widget = std::make_unique<SuppliedValueWidget<bool>>(*this, title,
+                                                            supplier, setter);
+  auto ptr = widget.get();
+  m_components.emplace_back(std::move(widget));
+  return *ptr;
+}
+
+SuppliedValueWidget<std::vector<std::string>>&
+ShuffleboardContainer::AddStringArray(
+    const wpi::Twine& title,
+    std::function<std::vector<std::string>()> supplier) {
+  static auto setter = [](nt::NetworkTableEntry entry,
+                          std::vector<std::string> value) {
+    entry.SetStringArray(value);
+  };
+
+  CheckTitle(title);
+  auto widget = std::make_unique<SuppliedValueWidget<std::vector<std::string>>>(
+      *this, title, supplier, setter);
+  auto ptr = widget.get();
+  m_components.emplace_back(std::move(widget));
+  return *ptr;
+}
+
+SuppliedValueWidget<std::vector<double>>& ShuffleboardContainer::AddNumberArray(
+    const wpi::Twine& title, std::function<std::vector<double>()> supplier) {
+  static auto setter = [](nt::NetworkTableEntry entry,
+                          std::vector<double> value) {
+    entry.SetDoubleArray(value);
+  };
+
+  CheckTitle(title);
+  auto widget = std::make_unique<SuppliedValueWidget<std::vector<double>>>(
+      *this, title, supplier, setter);
+  auto ptr = widget.get();
+  m_components.emplace_back(std::move(widget));
+  return *ptr;
+}
+
+SuppliedValueWidget<std::vector<int>>& ShuffleboardContainer::AddBooleanArray(
+    const wpi::Twine& title, std::function<std::vector<int>()> supplier) {
+  static auto setter = [](nt::NetworkTableEntry entry, std::vector<int> value) {
+    entry.SetBooleanArray(value);
+  };
+
+  CheckTitle(title);
+  auto widget = std::make_unique<SuppliedValueWidget<std::vector<int>>>(
+      *this, title, supplier, setter);
+  auto ptr = widget.get();
+  m_components.emplace_back(std::move(widget));
+  return *ptr;
+}
+
+SuppliedValueWidget<wpi::StringRef>& ShuffleboardContainer::AddRaw(
+    const wpi::Twine& title, std::function<wpi::StringRef()> supplier) {
+  static auto setter = [](nt::NetworkTableEntry entry, wpi::StringRef value) {
+    entry.SetRaw(value);
+  };
+
+  CheckTitle(title);
+  auto widget = std::make_unique<SuppliedValueWidget<wpi::StringRef>>(
+      *this, title, supplier, setter);
+  auto ptr = widget.get();
+  m_components.emplace_back(std::move(widget));
+  return *ptr;
+}
+
 SimpleWidget& ShuffleboardContainer::AddPersistent(
     const wpi::Twine& title, std::shared_ptr<nt::Value> defaultValue) {
   auto& widget = Add(title, defaultValue);

wpilibc/src/main/native/include/frc/shuffleboard/ShuffleboardContainer.h

@@ -7,6 +7,7 @@
 
 #pragma once
 
+#include <functional>
 #include <memory>
 #include <string>
 #include <vector>
@@ -24,6 +25,7 @@
 #include "frc/shuffleboard/LayoutType.h"
 #include "frc/shuffleboard/ShuffleboardComponentBase.h"
 #include "frc/shuffleboard/ShuffleboardValue.h"
+#include "frc/shuffleboard/SuppliedValueWidget.h"
 
 namespace cs {
 class VideoSource;
@@ -262,6 +264,98 @@ class ShuffleboardContainer : public virtual ShuffleboardValue,
   SimpleWidget& Add(const wpi::Twine& title,
                     wpi::ArrayRef<std::string> defaultValue);
 
+  /**
+   * Adds a widget to this container. The widget will display the data provided
+   * by the value supplier. Changes made on the dashboard will not propagate to
+   * the widget object, and will be overridden by values from the value
+   * supplier.
+   *
+   * @param title the title of the widget
+   * @param valueSupplier the supplier for values
+   * @return a widget to display data
+   */
+  SuppliedValueWidget<std::string>& AddString(
+      const wpi::Twine& title, std::function<std::string()> supplier);
+
+  /**
+   * Adds a widget to this container. The widget will display the data provided
+   * by the value supplier. Changes made on the dashboard will not propagate to
+   * the widget object, and will be overridden by values from the value
+   * supplier.
+   *
+   * @param title the title of the widget
+   * @param valueSupplier the supplier for values
+   * @return a widget to display data
+   */
+  SuppliedValueWidget<double>& AddNumber(const wpi::Twine& title,
+                                         std::function<double()> supplier);
+
+  /**
+   * Adds a widget to this container. The widget will display the data provided
+   * by the value supplier. Changes made on the dashboard will not propagate to
+   * the widget object, and will be overridden by values from the value
+   * supplier.
+   *
+   * @param title the title of the widget
+   * @param valueSupplier the supplier for values
+   * @return a widget to display data
+   */
+  SuppliedValueWidget<bool>& AddBoolean(const wpi::Twine& title,
+                                        std::function<bool()> supplier);
+
+  /**
+   * Adds a widget to this container. The widget will display the data provided
+   * by the value supplier. Changes made on the dashboard will not propagate to
+   * the widget object, and will be overridden by values from the value
+   * supplier.
+   *
+   * @param title the title of the widget
+   * @param valueSupplier the supplier for values
+   * @return a widget to display data
+   */
+  SuppliedValueWidget<std::vector<std::string>>& AddStringArray(
+      const wpi::Twine& title,
+      std::function<std::vector<std::string>()> supplier);
+
+  /**
+   * Adds a widget to this container. The widget will display the data provided
+   * by the value supplier. Changes made on the dashboard will not propagate to
+   * the widget object, and will be overridden by values from the value
+   * supplier.
+   *
+   * @param title the title of the widget
+   * @param valueSupplier the supplier for values
+   * @return a widget to display data
+   */
+  SuppliedValueWidget<std::vector<double>>& AddNumberArray(
+      const wpi::Twine& title, std::function<std::vector<double>()> supplier);
+
+  /**
+   * Adds a widget to this container. The widget will display the data provided
+   * by the value supplier. Changes made on the dashboard will not propagate to
+   * the widget object, and will be overridden by values from the value
+   * supplier.
+   *
+   * @param title the title of the widget
+   * @param valueSupplier the supplier for values
+   * @return a widget to display data
+   */
+  SuppliedValueWidget<std::vector<int>>& AddBooleanArray(
+      const wpi::Twine& title, std::function<std::vector<int>()> supplier);
+
+  /**
+   * Adds a widget to this container. The widget will display the data provided
+   * by the value supplier. Changes made on the dashboard will not propagate to
+   * the widget object, and will be overridden by values from the value
+   * supplier.
+   *
+   * @param title the title of the widget
+   * @param valueSupplier the supplier for values
+   * @return a widget to display data
+   */
+  SuppliedValueWidget<wpi::StringRef>& AddRaw(
+      const wpi::Twine& title, std::function<wpi::StringRef()> supplier);
+
   /**
    * Adds a widget to this container to display a simple piece of data.
    *

wpilibc/src/main/native/include/frc/shuffleboard/SuppliedValueWidget.h

@@ -0,0 +1,48 @@
+/*----------------------------------------------------------------------------*/
+/* Copyright (c) 2019 FIRST. 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 <functional>
+#include <memory>
+
+#include <networktables/NetworkTable.h>
+#include <networktables/NetworkTableEntry.h>
+#include <wpi/Twine.h>
+
+#include "frc/shuffleboard/ShuffleboardComponent.h"
+#include "frc/shuffleboard/ShuffleboardComponent.inc"
+#include "frc/shuffleboard/ShuffleboardComponentBase.h"
+#include "frc/shuffleboard/ShuffleboardContainer.h"
+#include "frc/shuffleboard/ShuffleboardWidget.h"
+
+namespace frc {
+template <typename T>
+class SuppliedValueWidget : public ShuffleboardWidget<SuppliedValueWidget<T> > {
+ public:
+  SuppliedValueWidget(ShuffleboardContainer& parent, const wpi::Twine& title,
+                      std::function<T()> supplier,
+                      std::function<void(nt::NetworkTableEntry, T)> setter)
+      : ShuffleboardValue(title),
+        ShuffleboardWidget<SuppliedValueWidget<T> >(parent, title),
+        m_supplier(supplier),
+        m_setter(setter) {}
+
+  void BuildInto(std::shared_ptr<nt::NetworkTable> parentTable,
+                 std::shared_ptr<nt::NetworkTable> metaTable) override {
+    this->BuildMetadata(metaTable);
+    metaTable->GetEntry("Controllable").SetBoolean(false);
+
+    auto entry = parentTable->GetEntry(this->GetTitle());
+    m_setter(entry, m_supplier());
+  }
+
+ private:
+  std::function<T()> m_supplier;
+  std::function<void(nt::NetworkTableEntry, T)> m_setter;
+};
+}  // namespace frc

wpilibc/src/test/native/cpp/shuffleboard/SuppliedValueWidgetTest.cpp

@@ -0,0 +1,107 @@
+/*----------------------------------------------------------------------------*/
+/* Copyright (c) 2018-2019 FIRST. 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.                                                               */
+/*----------------------------------------------------------------------------*/
+
+#include <networktables/NetworkTableEntry.h>
+#include <networktables/NetworkTableInstance.h>
+
+#include "frc/shuffleboard/ShuffleboardInstance.h"
+#include "frc/shuffleboard/ShuffleboardTab.h"
+#include "gtest/gtest.h"
+
+using namespace frc;
+
+class SuppliedValueWidgetTest : public testing::Test {
+  void SetUp() override {
+    m_ntInstance = nt::NetworkTableInstance::Create();
+    m_instance = std::make_unique<detail::ShuffleboardInstance>(m_ntInstance);
+    m_tab = &(m_instance->GetTab("Tab"));
+  }
+
+ protected:
+  nt::NetworkTableInstance m_ntInstance;
+  ShuffleboardTab* m_tab;
+  std::unique_ptr<detail::ShuffleboardInstance> m_instance;
+};
+
+TEST_F(SuppliedValueWidgetTest, AddString) {
+  std::string str = "foo";
+  m_tab->AddString("String", [&str]() { return str; });
+  auto entry = m_ntInstance.GetEntry("/Shuffleboard/Tab/String");
+
+  m_instance->Update();
+  EXPECT_EQ("foo", entry.GetValue()->GetString());
+}
+
+TEST_F(SuppliedValueWidgetTest, AddNumber) {
+  int num = 0;
+  m_tab->AddNumber("Num", [&num]() { return ++num; });
+  auto entry = m_ntInstance.GetEntry("/Shuffleboard/Tab/Num");
+
+  m_instance->Update();
+  EXPECT_FLOAT_EQ(1.0, entry.GetValue()->GetDouble());
+}
+
+TEST_F(SuppliedValueWidgetTest, AddBoolean) {
+  bool value = true;
+  m_tab->AddBoolean("Bool", [&value]() { return value; });
+  auto entry = m_ntInstance.GetEntry("/Shuffleboard/Tab/Bool");
+
+  m_instance->Update();
+  EXPECT_EQ(true, entry.GetValue()->GetBoolean());
+}
+
+TEST_F(SuppliedValueWidgetTest, AddStringArray) {
+  std::vector<std::string> strings = {"foo", "bar"};
+  m_tab->AddStringArray("Strings", [&strings]() { return strings; });
+  auto entry = m_ntInstance.GetEntry("/Shuffleboard/Tab/Strings");
+
+  m_instance->Update();
+  auto actual = entry.GetValue()->GetStringArray();
+
+  EXPECT_EQ(strings.size(), actual.size());
+  for (size_t i = 0; i < strings.size(); i++) {
+    EXPECT_EQ(strings[i], actual[i]);
+  }
+}
+
+TEST_F(SuppliedValueWidgetTest, AddNumberArray) {
+  std::vector<double> nums = {0, 1, 2, 3};
+  m_tab->AddNumberArray("Numbers", [&nums]() { return nums; });
+  auto entry = m_ntInstance.GetEntry("/Shuffleboard/Tab/Numbers");
+
+  m_instance->Update();
+  auto actual = entry.GetValue()->GetDoubleArray();
+
+  EXPECT_EQ(nums.size(), actual.size());
+  for (size_t i = 0; i < nums.size(); i++) {
+    EXPECT_FLOAT_EQ(nums[i], actual[i]);
+  }
+}
+
+TEST_F(SuppliedValueWidgetTest, AddBooleanArray) {
+  std::vector<int> bools = {true, false};
+  m_tab->AddBooleanArray("Booleans", [&bools]() { return bools; });
+  auto entry = m_ntInstance.GetEntry("/Shuffleboard/Tab/Booleans");
+
+  m_instance->Update();
+  auto actual = entry.GetValue()->GetBooleanArray();
+
+  EXPECT_EQ(bools.size(), actual.size());
+  for (size_t i = 0; i < bools.size(); i++) {
+    EXPECT_FLOAT_EQ(bools[i], actual[i]);
+  }
+}
+
+TEST_F(SuppliedValueWidgetTest, AddRaw) {
+  wpi::StringRef bytes = "\1\2\3";
+  m_tab->AddRaw("Raw", [&bytes]() { return bytes; });
+  auto entry = m_ntInstance.GetEntry("/Shuffleboard/Tab/Raw");
+
+  m_instance->Update();
+  auto actual = entry.GetValue()->GetRaw();
+  EXPECT_EQ(bytes, actual);
+}

wpilibj/src/main/java/edu/wpi/first/wpilibj/shuffleboard/ContainerHelper.java

@@ -1,5 +1,5 @@
 /*----------------------------------------------------------------------------*/
-/* Copyright (c) 2018 FIRST. All Rights Reserved.                             */
+/* Copyright (c) 2018-2019 FIRST. 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.                                                               */
@@ -15,6 +15,10 @@ import java.util.Map;
 import java.util.NoSuchElementException;
 import java.util.Objects;
 import java.util.Set;
+import java.util.function.BiConsumer;
+import java.util.function.BooleanSupplier;
+import java.util.function.DoubleSupplier;
+import java.util.function.Supplier;
 
 import edu.wpi.first.networktables.NetworkTableEntry;
 import edu.wpi.first.wpilibj.Sendable;
@@ -22,6 +26,7 @@ import edu.wpi.first.wpilibj.Sendable;
 /**
  * A helper class for Shuffleboard containers to handle common child operations.
  */
+@SuppressWarnings("PMD.TooManyMethods")
 final class ContainerHelper {
   private final ShuffleboardContainer m_container;
   private final Set<String> m_usedTitles = new HashSet<>();
@@ -79,6 +84,55 @@ final class ContainerHelper {
     return widget;
   }
 
+  SuppliedValueWidget<String> addString(String title, Supplier<String> valueSupplier) {
+    precheck(title, valueSupplier);
+    return addSupplied(title, valueSupplier, NetworkTableEntry::setString);
+  }
+
+  SuppliedValueWidget<Double> addNumber(String title, DoubleSupplier valueSupplier) {
+    precheck(title, valueSupplier);
+    return addSupplied(title, valueSupplier::getAsDouble, NetworkTableEntry::setDouble);
+  }
+
+  SuppliedValueWidget<Boolean> addBoolean(String title, BooleanSupplier valueSupplier) {
+    precheck(title, valueSupplier);
+    return addSupplied(title, valueSupplier::getAsBoolean, NetworkTableEntry::setBoolean);
+  }
+
+  SuppliedValueWidget<String[]> addStringArray(String title, Supplier<String[]> valueSupplier) {
+    precheck(title, valueSupplier);
+    return addSupplied(title, valueSupplier, NetworkTableEntry::setStringArray);
+  }
+
+  SuppliedValueWidget<double[]> addDoubleArray(String title, Supplier<double[]> valueSupplier) {
+    precheck(title, valueSupplier);
+    return addSupplied(title, valueSupplier, NetworkTableEntry::setDoubleArray);
+  }
+
+  SuppliedValueWidget<boolean[]> addBooleanArray(String title, Supplier<boolean[]> valueSupplier) {
+    precheck(title, valueSupplier);
+    return addSupplied(title, valueSupplier, NetworkTableEntry::setBooleanArray);
+  }
+
+  SuppliedValueWidget<byte[]> addRaw(String title, Supplier<byte[]> valueSupplier) {
+    precheck(title, valueSupplier);
+    return addSupplied(title, valueSupplier, NetworkTableEntry::setRaw);
+  }
+
+  private void precheck(String title, Object valueSupplier) {
+    Objects.requireNonNull(title, "Title cannot be null");
+    Objects.requireNonNull(valueSupplier, "Value supplier cannot be null");
+    checkTitle(title);
+  }
+
+  private <T> SuppliedValueWidget<T> addSupplied(String title,
+                                                 Supplier<T> supplier,
+                                                 BiConsumer<NetworkTableEntry, T> setter) {
+    SuppliedValueWidget<T> widget = new SuppliedValueWidget<>(m_container, title, supplier, setter);
+    m_components.add(widget);
+    return widget;
+  }
+
   private static void checkNtType(Object data) {
     if (!NetworkTableEntry.isValidDataType(data)) {
       throw new IllegalArgumentException(

wpilibj/src/main/java/edu/wpi/first/wpilibj/shuffleboard/ShuffleboardContainer.java

@@ -1,5 +1,5 @@
 /*----------------------------------------------------------------------------*/
-/* Copyright (c) 2018 FIRST. All Rights Reserved.                             */
+/* Copyright (c) 2018-2019 FIRST. 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.                                                               */
@@ -9,6 +9,9 @@ package edu.wpi.first.wpilibj.shuffleboard;
 
 import java.util.List;
 import java.util.NoSuchElementException;
+import java.util.function.BooleanSupplier;
+import java.util.function.DoubleSupplier;
+import java.util.function.Supplier;
 
 import edu.wpi.cscore.VideoSource;
 import edu.wpi.first.wpilibj.Sendable;
@@ -16,6 +19,7 @@ import edu.wpi.first.wpilibj.Sendable;
 /**
  * Common interface for objects that can contain shuffleboard components.
  */
+@SuppressWarnings("PMD.TooManyMethods")
 public interface ShuffleboardContainer extends ShuffleboardValue {
 
   /**
@@ -80,8 +84,8 @@ public interface ShuffleboardContainer extends ShuffleboardValue {
   /**
    * Adds a widget to this container to display the given video stream.
    *
-   * @param title    the title of the widget
-   * @param video    the video stream to display
+   * @param title the title of the widget
+   * @param video the video stream to display
    * @return a widget to display the sendable data
    * @throws IllegalArgumentException if a widget already exists in this container with the given
    *                                  title
@@ -124,6 +128,104 @@ public interface ShuffleboardContainer extends ShuffleboardValue {
    */
   SimpleWidget add(String title, Object defaultValue) throws IllegalArgumentException;
 
+  /**
+   * Adds a widget to this container. The widget will display the data provided by the value
+   * supplier. Changes made on the dashboard will not propagate to the widget object, and will be
+   * overridden by values from the value supplier.
+   *
+   * @param title the title of the widget
+   * @param valueSupplier the supplier for values
+   * @return a widget to display data
+   * @throws IllegalArgumentException if a widget already exists in this container with the given
+   *                                  title
+   */
+  SuppliedValueWidget<String> addString(String title, Supplier<String> valueSupplier)
+      throws IllegalArgumentException;
+
+  /**
+   * Adds a widget to this container. The widget will display the data provided by the value
+   * supplier. Changes made on the dashboard will not propagate to the widget object, and will be
+   * overridden by values from the value supplier.
+   *
+   * @param title the title of the widget
+   * @param valueSupplier the supplier for values
+   * @return a widget to display data
+   * @throws IllegalArgumentException if a widget already exists in this container with the given
+   *                                  title
+   */
+  SuppliedValueWidget<Double> addNumber(String title, DoubleSupplier valueSupplier)
+      throws IllegalArgumentException;
+
+  /**
+   * Adds a widget to this container. The widget will display the data provided by the value
+   * supplier. Changes made on the dashboard will not propagate to the widget object, and will be
+   * overridden by values from the value supplier.
+   *
+   * @param title the title of the widget
+   * @param valueSupplier the supplier for values
+   * @return a widget to display data
+   * @throws IllegalArgumentException if a widget already exists in this container with the given
+   *                                  title
+   */
+  SuppliedValueWidget<Boolean> addBoolean(String title, BooleanSupplier valueSupplier)
+      throws IllegalArgumentException;
+
+  /**
+   * Adds a widget to this container. The widget will display the data provided by the value
+   * supplier. Changes made on the dashboard will not propagate to the widget object, and will be
+   * overridden by values from the value supplier.
+   *
+   * @param title the title of the widget
+   * @param valueSupplier the supplier for values
+   * @return a widget to display data
+   * @throws IllegalArgumentException if a widget already exists in this container with the given
+   *                                  title
+   */
+  SuppliedValueWidget<String[]> addStringArray(String title, Supplier<String[]> valueSupplier)
+      throws IllegalArgumentException;
+
+  /**
+   * Adds a widget to this container. The widget will display the data provided by the value
+   * supplier. Changes made on the dashboard will not propagate to the widget object, and will be
+   * overridden by values from the value supplier.
+   *
+   * @param title the title of the widget
+   * @param valueSupplier the supplier for values
+   * @return a widget to display data
+   * @throws IllegalArgumentException if a widget already exists in this container with the given
+   *                                  title
+   */
+  SuppliedValueWidget<double[]> addDoubleArray(String title, Supplier<double[]> valueSupplier)
+      throws IllegalArgumentException;
+
+  /**
+   * Adds a widget to this container. The widget will display the data provided by the value
+   * supplier. Changes made on the dashboard will not propagate to the widget object, and will be
+   * overridden by values from the value supplier.
+   *
+   * @param title the title of the widget
+   * @param valueSupplier the supplier for values
+   * @return a widget to display data
+   * @throws IllegalArgumentException if a widget already exists in this container with the given
+   *                                  title
+   */
+  SuppliedValueWidget<boolean[]> addBooleanArray(String title, Supplier<boolean[]> valueSupplier)
+      throws IllegalArgumentException;
+
+  /**
+   * Adds a widget to this container. The widget will display the data provided by the value
+   * supplier. Changes made on the dashboard will not propagate to the widget object, and will be
+   * overridden by values from the value supplier.
+   *
+   * @param title the title of the widget
+   * @param valueSupplier the supplier for values
+   * @return a widget to display data
+   * @throws IllegalArgumentException if a widget already exists in this container with the given
+   *                                  title
+   */
+  SuppliedValueWidget<byte[]> addRaw(String title, Supplier<byte[]> valueSupplier)
+      throws IllegalArgumentException;
+
   /**
    * Adds a widget to this container to display a simple piece of data. Unlike
    * {@link #add(String, Object)}, the value in the widget will be saved on the robot and will be

wpilibj/src/main/java/edu/wpi/first/wpilibj/shuffleboard/ShuffleboardLayout.java

@@ -1,5 +1,5 @@
 /*----------------------------------------------------------------------------*/
-/* Copyright (c) 2018 FIRST. All Rights Reserved.                             */
+/* Copyright (c) 2018-2019 FIRST. 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.                                                               */
@@ -10,6 +10,9 @@ package edu.wpi.first.wpilibj.shuffleboard;
 import java.util.List;
 import java.util.NoSuchElementException;
 import java.util.Objects;
+import java.util.function.BooleanSupplier;
+import java.util.function.DoubleSupplier;
+import java.util.function.Supplier;
 
 import edu.wpi.first.networktables.NetworkTable;
 import edu.wpi.first.wpilibj.Sendable;
@@ -17,6 +20,7 @@ import edu.wpi.first.wpilibj.Sendable;
 /**
  * A layout in a Shuffleboard tab. Layouts can contain widgets and other layouts.
  */
+@SuppressWarnings("PMD.TooManyMethods")
 public class ShuffleboardLayout extends ShuffleboardComponent<ShuffleboardLayout>
     implements ShuffleboardContainer {
   private final ContainerHelper m_helper = new ContainerHelper(this);
@@ -55,6 +59,55 @@ public class ShuffleboardLayout extends ShuffleboardComponent<ShuffleboardLayout
     return m_helper.add(title, defaultValue);
   }
 
+  @Override
+  public SuppliedValueWidget<String> addString(String title,
+                                               Supplier<String> valueSupplier)
+      throws IllegalArgumentException {
+    return m_helper.addString(title, valueSupplier);
+  }
+
+  @Override
+  public SuppliedValueWidget<Double> addNumber(String title,
+                                               DoubleSupplier valueSupplier)
+      throws IllegalArgumentException {
+    return m_helper.addNumber(title, valueSupplier);
+  }
+
+  @Override
+  public SuppliedValueWidget<Boolean> addBoolean(String title,
+                                                 BooleanSupplier valueSupplier)
+      throws IllegalArgumentException {
+    return m_helper.addBoolean(title, valueSupplier);
+  }
+
+  @Override
+  public SuppliedValueWidget<String[]> addStringArray(String title,
+                                                      Supplier<String[]> valueSupplier)
+      throws IllegalArgumentException {
+    return m_helper.addStringArray(title, valueSupplier);
+  }
+
+  @Override
+  public SuppliedValueWidget<double[]> addDoubleArray(String title,
+                                                      Supplier<double[]> valueSupplier)
+      throws IllegalArgumentException {
+    return m_helper.addDoubleArray(title, valueSupplier);
+  }
+
+  @Override
+  public SuppliedValueWidget<boolean[]> addBooleanArray(String title,
+                                                        Supplier<boolean[]> valueSupplier)
+      throws IllegalArgumentException {
+    return m_helper.addBooleanArray(title, valueSupplier);
+  }
+
+  @Override
+  public SuppliedValueWidget<byte[]> addRaw(String title,
+                                            Supplier<byte[]> valueSupplier)
+      throws IllegalArgumentException {
+    return m_helper.addRaw(title, valueSupplier);
+  }
+
   @Override
   public void buildInto(NetworkTable parentTable, NetworkTable metaTable) {
     buildMetadata(metaTable);

wpilibj/src/main/java/edu/wpi/first/wpilibj/shuffleboard/ShuffleboardTab.java

@@ -1,5 +1,5 @@
 /*----------------------------------------------------------------------------*/
-/* Copyright (c) 2018 FIRST. All Rights Reserved.                             */
+/* Copyright (c) 2018-2019 FIRST. 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.                                                               */
@@ -9,6 +9,9 @@ package edu.wpi.first.wpilibj.shuffleboard;
 
 import java.util.List;
 import java.util.NoSuchElementException;
+import java.util.function.BooleanSupplier;
+import java.util.function.DoubleSupplier;
+import java.util.function.Supplier;
 
 import edu.wpi.first.networktables.NetworkTable;
 import edu.wpi.first.wpilibj.Sendable;
@@ -19,6 +22,7 @@ import edu.wpi.first.wpilibj.Sendable;
  * can also be added to layouts with {@link #getLayout(String, String)}; layouts can be nested
  * arbitrarily deep (note that too many levels may make deeper components unusable).
  */
+@SuppressWarnings("PMD.TooManyMethods")
 public final class ShuffleboardTab implements ShuffleboardContainer {
   private final ContainerHelper m_helper = new ContainerHelper(this);
   private final ShuffleboardRoot m_root;
@@ -68,6 +72,55 @@ public final class ShuffleboardTab implements ShuffleboardContainer {
     return m_helper.add(title, defaultValue);
   }
 
+  @Override
+  public SuppliedValueWidget<String> addString(String title,
+                                               Supplier<String> valueSupplier)
+      throws IllegalArgumentException {
+    return m_helper.addString(title, valueSupplier);
+  }
+
+  @Override
+  public SuppliedValueWidget<Double> addNumber(String title,
+                                               DoubleSupplier valueSupplier)
+      throws IllegalArgumentException {
+    return m_helper.addNumber(title, valueSupplier);
+  }
+
+  @Override
+  public SuppliedValueWidget<Boolean> addBoolean(String title,
+                                                 BooleanSupplier valueSupplier)
+      throws IllegalArgumentException {
+    return m_helper.addBoolean(title, valueSupplier);
+  }
+
+  @Override
+  public SuppliedValueWidget<String[]> addStringArray(String title,
+                                                      Supplier<String[]> valueSupplier)
+      throws IllegalArgumentException {
+    return m_helper.addStringArray(title, valueSupplier);
+  }
+
+  @Override
+  public SuppliedValueWidget<double[]> addDoubleArray(String title,
+                                                      Supplier<double[]> valueSupplier)
+      throws IllegalArgumentException {
+    return m_helper.addDoubleArray(title, valueSupplier);
+  }
+
+  @Override
+  public SuppliedValueWidget<boolean[]> addBooleanArray(String title,
+                                                        Supplier<boolean[]> valueSupplier)
+      throws IllegalArgumentException {
+    return m_helper.addBooleanArray(title, valueSupplier);
+  }
+
+  @Override
+  public SuppliedValueWidget<byte[]> addRaw(String title,
+                                            Supplier<byte[]> valueSupplier)
+      throws IllegalArgumentException {
+    return m_helper.addRaw(title, valueSupplier);
+  }
+
   @Override
   public void buildInto(NetworkTable parentTable, NetworkTable metaTable) {
     NetworkTable tabTable = parentTable.getSubTable(m_title);

wpilibj/src/main/java/edu/wpi/first/wpilibj/shuffleboard/SuppliedValueWidget.java

@@ -0,0 +1,50 @@
+/*----------------------------------------------------------------------------*/
+/* Copyright (c) 2019 FIRST. 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.                                                               */
+/*----------------------------------------------------------------------------*/
+
+package edu.wpi.first.wpilibj.shuffleboard;
+
+import java.util.function.BiConsumer;
+import java.util.function.Supplier;
+
+import edu.wpi.first.networktables.NetworkTable;
+import edu.wpi.first.networktables.NetworkTableEntry;
+
+/**
+ * A Shuffleboard widget whose value is provided by user code.
+ *
+ * @param <T> the type of values in the widget
+ */
+public final class SuppliedValueWidget<T> extends ShuffleboardWidget<SuppliedValueWidget<T>> {
+  private final Supplier<T> m_supplier;
+  private final BiConsumer<NetworkTableEntry, T> m_setter;
+
+  /**
+   * Package-private constructor for use by the Shuffleboard API.
+   *
+   * @param parent   the parent container for the widget
+   * @param title    the title of the widget
+   * @param supplier the supplier for values to place in the NetworkTable entry
+   * @param setter   the function for placing values in the NetworkTable entry
+   */
+  SuppliedValueWidget(ShuffleboardContainer parent,
+                      String title,
+                      Supplier<T> supplier,
+                      BiConsumer<NetworkTableEntry, T> setter) {
+    super(parent, title);
+    this.m_supplier = supplier;
+    this.m_setter = setter;
+  }
+
+  @Override
+  public void buildInto(NetworkTable parentTable, NetworkTable metaTable) {
+    buildMetadata(metaTable);
+    metaTable.getEntry("Controllable").setBoolean(false);
+
+    NetworkTableEntry entry = parentTable.getEntry(getTitle());
+    m_setter.accept(entry, m_supplier.get());
+  }
+}

wpilibj/src/test/java/edu/wpi/first/wpilibj/shuffleboard/SuppliedValueWidgetTest.java

@@ -0,0 +1,119 @@
+/*----------------------------------------------------------------------------*/
+/* Copyright (c) 2019 FIRST. 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.                                                               */
+/*----------------------------------------------------------------------------*/
+
+package edu.wpi.first.wpilibj.shuffleboard;
+
+import java.util.concurrent.atomic.AtomicInteger;
+
+import org.junit.jupiter.api.BeforeEach;
+import org.junit.jupiter.api.Test;
+
+import edu.wpi.first.networktables.NetworkTableEntry;
+import edu.wpi.first.networktables.NetworkTableInstance;
+
+import static org.junit.jupiter.api.Assertions.assertArrayEquals;
+import static org.junit.jupiter.api.Assertions.assertEquals;
+import static org.junit.jupiter.api.Assertions.assertFalse;
+import static org.junit.jupiter.api.Assertions.assertTrue;
+
+class SuppliedValueWidgetTest {
+  private NetworkTableInstance m_ntInstance;
+  private ShuffleboardInstance m_instance;
+
+  @BeforeEach
+  void setup() {
+    m_ntInstance = NetworkTableInstance.create();
+    m_instance = new ShuffleboardInstance(m_ntInstance);
+  }
+
+  @Test
+  void testAddString() {
+    AtomicInteger count = new AtomicInteger(0);
+    m_instance.getTab("Tab")
+        .addString("Title", () -> Integer.toString(count.incrementAndGet()));
+    NetworkTableEntry entry = m_ntInstance.getEntry("/Shuffleboard/Tab/Title");
+
+    m_instance.update();
+    assertEquals("1", entry.getString(null));
+
+    m_instance.update();
+    assertEquals("2", entry.getString(null));
+  }
+
+  @Test
+  void testAddDouble() {
+    AtomicInteger num = new AtomicInteger(0);
+    m_instance.getTab("Tab")
+        .addNumber("Title", num::incrementAndGet);
+    NetworkTableEntry entry = m_ntInstance.getEntry("/Shuffleboard/Tab/Title");
+
+    m_instance.update();
+    assertEquals(1, entry.getDouble(0));
+
+    m_instance.update();
+    assertEquals(2, entry.getDouble(0));
+  }
+
+  @Test
+  void testAddBoolean() {
+    boolean[] bool = {false};
+    m_instance.getTab("Tab")
+        .addBoolean("Title", () -> bool[0] = !bool[0]);
+    NetworkTableEntry entry = m_ntInstance.getEntry("/Shuffleboard/Tab/Title");
+
+    m_instance.update();
+    assertTrue(entry.getBoolean(false));
+
+    m_instance.update();
+    assertFalse(entry.getBoolean(true));
+  }
+
+  @Test
+  void testAddStringArray() {
+    String[] arr = {"foo", "bar"};
+    m_instance.getTab("Tab")
+        .addStringArray("Title", () -> arr);
+    NetworkTableEntry entry = m_ntInstance.getEntry("/Shuffleboard/Tab/Title");
+
+    m_instance.update();
+    assertArrayEquals(arr, entry.getStringArray(new String[0]));
+  }
+
+  @Test
+  void testAddDoubleArray() {
+    double[] arr = {0, 1};
+    m_instance.getTab("Tab")
+        .addDoubleArray("Title", () -> arr);
+    NetworkTableEntry entry = m_ntInstance.getEntry("/Shuffleboard/Tab/Title");
+
+    m_instance.update();
+    assertArrayEquals(arr, entry.getDoubleArray(new double[0]));
+  }
+
+  @Test
+  void testAddBooleanArray() {
+    boolean[] arr = {true, false};
+    m_instance.getTab("Tab")
+        .addBooleanArray("Title", () -> arr);
+    NetworkTableEntry entry = m_ntInstance.getEntry("/Shuffleboard/Tab/Title");
+
+    m_instance.update();
+    assertArrayEquals(arr, entry.getBooleanArray(new boolean[0]));
+  }
+
+  @Test
+  void testAddRawBytes() {
+    byte[] arr = {0, 1, 2, 3};
+    m_instance.getTab("Tab")
+        .addRaw("Title", () -> arr);
+    NetworkTableEntry entry = m_ntInstance.getEntry("/Shuffleboard/Tab/Title");
+
+    m_instance.update();
+    assertArrayEquals(arr, entry.getRaw(new byte[0]));
+  }
+
+}