[epilogue] Add an annotation-based logging framework for Java programs (#6584)

epilogue-runtime/src/test/java/edu/wpi/first/epilogue/logging/ClassSpecificLoggerTest.java

@@ -0,0 +1,44 @@
+// 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.epilogue.logging;
+
+import static org.junit.jupiter.api.Assertions.assertEquals;
+
+import edu.wpi.first.epilogue.Logged;
+import java.util.List;
+import org.junit.jupiter.api.Test;
+
+class ClassSpecificLoggerTest {
+  @Logged
+  record Point2d(double x, double y, int dim) {
+    static class Logger extends ClassSpecificLogger<Point2d> {
+      Logger() {
+        super(Point2d.class);
+      }
+
+      @Override
+      protected void update(DataLogger dataLogger, Point2d object) {
+        dataLogger.log("x", object.x);
+        dataLogger.log("y", object.y);
+        dataLogger.log("dim", object.dim);
+      }
+    }
+  }
+
+  @Test
+  void testReadPrivate() {
+    var point = new Point2d(1, 4, 2);
+    var logger = new Point2d.Logger();
+    var dataLog = new TestLogger();
+    logger.update(dataLog.getSubLogger("Point"), point);
+
+    assertEquals(
+        List.of(
+            new TestLogger.LogEntry<>("Point/x", 1.0),
+            new TestLogger.LogEntry<>("Point/y", 4.0),
+            new TestLogger.LogEntry<>("Point/dim", 2)),
+        dataLog.getEntries());
+  }
+}

epilogue-runtime/src/test/java/edu/wpi/first/epilogue/logging/LazyLoggerTest.java

@@ -0,0 +1,56 @@
+// 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.epilogue.logging;
+
+import static org.junit.jupiter.api.Assertions.assertEquals;
+import static org.junit.jupiter.api.Assertions.assertSame;
+
+import java.util.List;
+import org.junit.jupiter.api.Test;
+
+class LazyLoggerTest {
+  @Test
+  void lazyOfLazyReturnsSelf() {
+    var lazy = new LazyLogger(new NullLogger());
+    assertSame(lazy, lazy.lazy());
+  }
+
+  @Test
+  void lazyInt() {
+    var logger = new TestLogger();
+    var lazy = new LazyLogger(logger);
+
+    {
+      // First time logging to "int" should go through
+      lazy.log("int", 0);
+      assertEquals(List.of(new TestLogger.LogEntry<>("int", 0)), logger.getEntries());
+    }
+
+    {
+      // Logging the current value shouldn't go through
+      lazy.log("int", 0);
+      assertEquals(List.of(new TestLogger.LogEntry<>("int", 0)), logger.getEntries());
+    }
+
+    {
+      // Logging a new value should go through
+      lazy.log("int", 1);
+      assertEquals(
+          List.of(new TestLogger.LogEntry<>("int", 0), new TestLogger.LogEntry<>("int", 1)),
+          logger.getEntries());
+    }
+
+    {
+      // Logging a previous value should go through
+      lazy.log("int", 0);
+      assertEquals(
+          List.of(
+              new TestLogger.LogEntry<>("int", 0),
+              new TestLogger.LogEntry<>("int", 1),
+              new TestLogger.LogEntry<>("int", 0)),
+          logger.getEntries());
+    }
+  }
+}

epilogue-runtime/src/test/java/edu/wpi/first/epilogue/logging/TestLogger.java

@@ -0,0 +1,109 @@
+// 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.epilogue.logging;
+
+import edu.wpi.first.util.struct.Struct;
+import edu.wpi.first.util.struct.StructBuffer;
+import java.util.ArrayList;
+import java.util.HashMap;
+import java.util.List;
+import java.util.Map;
+
+@SuppressWarnings("PMD.TestClassWithoutTestCases") // This is not a test class!
+public class TestLogger implements DataLogger {
+  public record LogEntry<T>(String identifier, T value) {}
+
+  private final Map<String, SubLogger> m_subLoggers = new HashMap<>();
+
+  private final List<LogEntry<?>> m_entries = new ArrayList<>();
+
+  public List<LogEntry<?>> getEntries() {
+    return m_entries;
+  }
+
+  @Override
+  public DataLogger getSubLogger(String path) {
+    return m_subLoggers.computeIfAbsent(path, k -> new SubLogger(k, this));
+  }
+
+  @Override
+  public void log(String identifier, int value) {
+    m_entries.add(new LogEntry<>(identifier, value));
+  }
+
+  @Override
+  public void log(String identifier, long value) {
+    m_entries.add(new LogEntry<>(identifier, value));
+  }
+
+  @Override
+  public void log(String identifier, float value) {
+    m_entries.add(new LogEntry<>(identifier, value));
+  }
+
+  @Override
+  public void log(String identifier, double value) {
+    m_entries.add(new LogEntry<>(identifier, value));
+  }
+
+  @Override
+  public void log(String identifier, boolean value) {
+    m_entries.add(new LogEntry<>(identifier, value));
+  }
+
+  @Override
+  public void log(String identifier, byte[] value) {
+    m_entries.add(new LogEntry<>(identifier, value));
+  }
+
+  @Override
+  public void log(String identifier, int[] value) {
+    m_entries.add(new LogEntry<>(identifier, value));
+  }
+
+  @Override
+  public void log(String identifier, long[] value) {
+    m_entries.add(new LogEntry<>(identifier, value));
+  }
+
+  @Override
+  public void log(String identifier, float[] value) {
+    m_entries.add(new LogEntry<>(identifier, value));
+  }
+
+  @Override
+  public void log(String identifier, double[] value) {
+    m_entries.add(new LogEntry<>(identifier, value));
+  }
+
+  @Override
+  public void log(String identifier, boolean[] value) {
+    m_entries.add(new LogEntry<>(identifier, value));
+  }
+
+  @Override
+  public void log(String identifier, String value) {
+    m_entries.add(new LogEntry<>(identifier, value));
+  }
+
+  @Override
+  public void log(String identifier, String[] value) {
+    m_entries.add(new LogEntry<>(identifier, value));
+  }
+
+  @Override
+  public <S> void log(String identifier, S value, Struct<S> struct) {
+    var serialized = StructBuffer.create(struct).write(value).array();
+
+    m_entries.add(new LogEntry<>(identifier, serialized));
+  }
+
+  @Override
+  public <S> void log(String identifier, S[] value, Struct<S> struct) {
+    var serialized = StructBuffer.create(struct).writeArray(value).array();
+
+    m_entries.add(new LogEntry<>(identifier, serialized));
+  }
+}