[wpilib] Tunable Values API

wpilibj/src/main/java/edu/wpi/first/wpilibj/TunableValues.java

@@ -0,0 +1,208 @@
+// Copyright (c) FIRST and other WPILib contributors.
+// Open Source Software; you can modify and/or share it under the terms of
+// the WPILib BSD license file in the root directory of this project.
+
+package edu.wpi.first.wpilibj;
+
+import java.util.HashMap;
+
+import edu.wpi.first.networktables.BooleanEntry;
+import edu.wpi.first.networktables.DoubleEntry;
+import edu.wpi.first.networktables.IntegerEntry;
+import edu.wpi.first.networktables.NetworkTableInstance;
+
+/**
+ * An api for creating NT tunable values.
+ * Bools, Ints and Doubles are supported.
+ *
+ * @see TunableValues#getDouble(String, double) TunableValues.getDouble()
+ * @see TunableValues#getInteger(String, int) TunableValues.getInteger()
+ * @see TunableValues#getBoolean(String, boolean) TunableValues.getBoolean()
+ */
+public class TunableValues {
+    private static final String pathPrefix = "/Tunables/";
+
+    private static final HashMap<String, TunableDouble> doubleTunables = new HashMap<>();
+    private static final HashMap<String, TunableInteger> intTunables = new HashMap<>();
+    private static final HashMap<String, TunableBoolean> boolTunables = new HashMap<>();
+
+    /**
+     * An object representing a tunable double value.
+     *
+     * @see TunableValues#getDouble(String, double) Creating a tunable double
+     */
+    public static class TunableDouble implements Cloneable {
+        private final DoubleEntry entry;
+        private final double defaultValue;
+
+        private TunableDouble(String path, double defaultValue) {
+            this.entry = NetworkTableInstance
+                .getDefault()
+                .getDoubleTopic(pathPrefix + path)
+                .getEntry(defaultValue);
+            entry.setDefault(defaultValue);
+            this.defaultValue = defaultValue;
+        }
+
+        private TunableDouble(DoubleEntry entry, double defaultValue) {
+            this.entry = entry;
+            this.defaultValue = defaultValue;
+        }
+
+        /**
+         * Get the value of the tunable, returns the default value a value is not present.
+         *
+         * @return The value of the tunable
+         */
+        public double value() {
+            return entry.get(defaultValue);
+        }
+
+        @Override
+        public TunableDouble clone() {
+            return new TunableDouble(entry, defaultValue);
+        }
+    }
+
+    /**
+     * Get a tunable double value.
+     *
+     * <p>Tunable values are cached, so calling this method with the same path will return the same object
+     * and not create a new one (throwing out the new default value if it was different).
+     *
+     * @param path The path to the tunable value (it will be prefixed with "/Tunables/")
+     * @param defaultValue The default value of the tunable
+     * @return The tunable value object
+     *
+     * @see TunableDouble#value() How to get a value from the object
+     */
+    public static TunableDouble getDouble(String path, double defaultValue) {
+        if (doubleTunables.containsKey(path)) {
+            return doubleTunables.get(path);
+        } else {
+            TunableDouble newTunable = new TunableDouble(path, defaultValue);
+            doubleTunables.put(path, newTunable);
+            return newTunable;
+        }
+    }
+
+    /**
+     * An object representing a tunable integer value.
+     *
+     * @see TunableValues#getInteger(String, int) Creating a tunable integer
+     */
+    public static class TunableInteger implements Cloneable {
+        private final IntegerEntry entry;
+        private final int defaultValue;
+
+        private TunableInteger(String path, int defaultValue) {
+            this.entry = NetworkTableInstance
+                .getDefault()
+                .getIntegerTopic(pathPrefix + path)
+                .getEntry(defaultValue);
+            entry.setDefault(defaultValue);
+            this.defaultValue = defaultValue;
+        }
+
+        private TunableInteger(IntegerEntry entry, int defaultValue) {
+            this.entry = entry;
+            this.defaultValue = defaultValue;
+        }
+
+        /**
+         * Get the value of the tunable, returns the default value a value is not present.
+         *
+         * @return The value of the tunable
+         */
+        public int value() {
+            return (int) Math.min(Math.max(entry.get(defaultValue), Integer.MIN_VALUE), Integer.MAX_VALUE);
+        }
+
+        @Override
+        public TunableInteger clone() {
+            return new TunableInteger(entry, defaultValue);
+        }
+    }
+
+    /**
+     * Get a tunable integer value.
+     *
+     * <p>Tunable values are cached, so calling this method with the same path will return the same object
+     * and not create a new one (throwing out the new default value if it was different).
+     *
+     * @param path The path to the tunable value (it will be prefixed with "/Tunables/")
+     * @param defaultValue The default value of the tunable
+     * @return The tunable value object
+     *
+     * @see TunableInteger#value() How to get a value from the object
+     */
+    public static TunableInteger getInteger(String path, int defaultValue) {
+        if (intTunables.containsKey(path)) {
+            return intTunables.get(path);
+        } else {
+            TunableInteger newTunable = new TunableInteger(path, defaultValue);
+            intTunables.put(path, newTunable);
+            return newTunable;
+        }
+    }
+
+    /**
+     * An object representing a tunable boolean value.
+     *
+     * @see TunableValues#getBoolean(String, boolean) Creating a tunable boolean
+     */
+    public static class TunableBoolean implements Cloneable {
+        private final BooleanEntry entry;
+        private final boolean defaultValue;
+
+        private TunableBoolean(String path, boolean defaultValue) {
+            this.entry = NetworkTableInstance
+                .getDefault()
+                .getBooleanTopic(pathPrefix + path)
+                .getEntry(defaultValue);
+            entry.setDefault(defaultValue);
+            this.defaultValue = defaultValue;
+        }
+
+        private TunableBoolean(BooleanEntry entry, boolean defaultValue) {
+            this.entry = entry;
+            this.defaultValue = defaultValue;
+        }
+
+        /**
+         * Get the value of the tunable, returns the default value if a value is not present.
+         *
+         * @return The value of the tunable
+         */
+        public boolean value() {
+            return entry.get(defaultValue);
+        }
+
+        @Override
+        public TunableBoolean clone() {
+            return new TunableBoolean(entry, defaultValue);
+        }
+    }
+
+    /**
+     * Get a tunable boolean value.
+     *
+     * <p>Tunable values are cached, so calling this method with the same path will return the same object
+     * and not create a new one (throwing out the new default value if it was different).
+     *
+     * @param path The path to the tunable value (it will be prefixed with "/Tunables/")
+     * @param defaultValue The default value of the tunable
+     * @return The tunable value object
+     *
+     * @see TunableBoolean#value() How to get a value from the object
+     */
+    public static TunableBoolean getBoolean(String path, boolean defaultValue) {
+        if (boolTunables.containsKey(path)) {
+            return boolTunables.get(path);
+        } else {
+            TunableBoolean newTunable = new TunableBoolean(path, defaultValue);
+            boolTunables.put(path, newTunable);
+            return newTunable;
+        }
+    }
+}