implemente a pure logger

effect/src/main/java/com/github/tonivade/purefun/effect/util/PureLog.java

@@ -0,0 +1,89 @@
+package com.github.tonivade.purefun.effect.util;
+
+import java.lang.StackWalker.Option;
+import java.lang.StackWalker.StackFrame;
+import java.util.Queue;
+import java.util.logging.Level;
+import java.util.logging.LogRecord;
+import java.util.logging.Logger;
+
+import com.github.tonivade.purefun.core.Producer;
+import com.github.tonivade.purefun.core.Unit;
+import com.github.tonivade.purefun.effect.RIO;
+
+public interface PureLog {
+
+  <R extends PureLog> PureLog.Service<R> logger(StackFrame frame);
+
+  static <R extends PureLog> RIO<R, Unit> debug(Producer<String> message) {
+    var frame = getFrame();
+    return RIO.accessM(env -> env.<R>logger(frame).debug(message));
+  }
+
+  static <R extends PureLog> RIO<R, Unit> info(Producer<String> message) {
+    var frame = getFrame();
+    return RIO.accessM(env -> env.<R>logger(frame).info(message));
+  }
+
+  static <R extends PureLog> RIO<R, Unit> warn(Producer<String> message) {
+    var frame = getFrame();
+    return RIO.accessM(env -> env.<R>logger(frame).warn(message));
+  }
+
+  static <R extends PureLog> RIO<R,Unit> error(Producer<String> message) {
+    var frame = getFrame();
+    return RIO.accessM(env -> env.<R>logger(frame).error(message));
+  }
+
+  interface Service<R extends PureLog> {
+
+    default RIO<R, Unit> debug(Producer<String> message) {
+      return log(Level.FINE, message);
+    }
+
+    default RIO<R, Unit> info(Producer<String> message) {
+      return log(Level.INFO, message);
+    }
+
+    default RIO<R, Unit> warn(Producer<String> message) {
+      return log(Level.WARNING, message);
+    }
+
+    default RIO<R, Unit> error(Producer<String> message) {
+      return log(Level.SEVERE, message);
+    }
+
+    RIO<R, Unit> log(Level level, Producer<String> message);
+  }
+
+  static PureLog javaUtilLogging() {
+    return new PureLog() {
+      @Override
+      public <R extends PureLog> Service<R> logger(StackFrame frame) {
+        return (level, message) -> {
+          var logger = Logger.getLogger(frame.getClassName());
+          return RIO.exec(() -> logger.logp(level, frame.getClassName(), frame.getMethodName(), message.get()));
+        };
+      }
+    };
+  }
+
+  static PureLog test(final Queue<LogRecord> traces) {
+    return new PureLog() {
+      @Override
+      public <R extends PureLog> Service<R> logger(StackFrame frame) {
+        return (level, message) -> RIO.exec(() -> {
+          var log = new LogRecord(level, message.get());
+          log.setSourceClassName(frame.getClassName());
+          log.setSourceMethodName(frame.getMethodName());
+          traces.add(log);
+        });
+      }
+    };
+  }
+
+  private static StackFrame getFrame() {
+    var walker = StackWalker.getInstance(Option.RETAIN_CLASS_REFERENCE);
+    return walker.walk(frames -> frames.skip(2).findFirst().orElseThrow());
+  }
+}

effect/src/test/java/com/github/tonivade/purefun/effect/RIOTest.java

@@ -11,6 +11,7 @@
 import static com.github.tonivade.purefun.effect.RIO.sleep;
 import static com.github.tonivade.purefun.effect.RIO.task;
 import static com.github.tonivade.purefun.effect.RIOOf.toRIO;
+import static com.github.tonivade.purefun.effect.util.PureLog.info;
 import static java.util.concurrent.ThreadLocalRandom.current;
 import static org.junit.jupiter.api.Assertions.assertEquals;
 import static org.junit.jupiter.api.Assertions.assertTrue;
@@ -36,6 +37,7 @@
 import com.github.tonivade.purefun.core.Producer;
 import com.github.tonivade.purefun.core.Unit;
 import com.github.tonivade.purefun.data.Sequence;
+import com.github.tonivade.purefun.effect.util.PureLog;
 import com.github.tonivade.purefun.instances.RIOInstances;
 import com.github.tonivade.purefun.type.Either;
 import com.github.tonivade.purefun.type.Try;
@@ -171,22 +173,22 @@ public void traverse() {
 
   @Test
   void raceA() {
-    RIO<Void, Either<Integer, String>> race = race(
-        RIO.<Void>sleep(Duration.ofMillis(10)).map(x -> 10),
-        RIO.<Void>sleep(Duration.ofMillis(100)).map(x -> "b"));
+    RIO<PureLog, Either<Integer, String>> race = race(
+        RIO.<PureLog>sleep(Duration.ofMillis(10)).andThen(info(() -> "done A")).map(x -> 10),
+        RIO.<PureLog>sleep(Duration.ofMillis(100)).andThen(info(() -> "done B")).map(x -> "b"));
 
-    Try<Either<Integer, String>> orElseThrow = race.safeRunSync(null);
+    Try<Either<Integer, String>> orElseThrow = race.safeRunSync(PureLog.javaUtilLogging());
 
     assertEquals(Try.success(Either.left(10)), orElseThrow);
   }
 
   @Test
   void raceB() {
-    RIO<Void, Either<Integer, String>> race = race(
-        RIO.<Void>sleep(Duration.ofMillis(100)).map(x -> 10),
-        RIO.<Void>sleep(Duration.ofMillis(10)).map(x -> "b"));
+    RIO<PureLog, Either<Integer, String>> race = race(
+        RIO.<PureLog>sleep(Duration.ofMillis(100)).andThen(info(() -> "done A")).map(x -> 10),
+        RIO.<PureLog>sleep(Duration.ofMillis(10)).andThen(info(() -> "done B")).map(x -> "b"));
 
-    Try<Either<Integer, String>> orElseThrow = race.safeRunSync(null);
+    Try<Either<Integer, String>> orElseThrow = race.safeRunSync(PureLog.javaUtilLogging());
 
     assertEquals(Try.success(Either.right("b")), orElseThrow);
   }

effect/src/test/java/com/github/tonivade/purefun/effect/util/PureLogTest.java

@@ -0,0 +1,26 @@
+package com.github.tonivade.purefun.effect.util;
+
+import static org.junit.jupiter.api.Assertions.*;
+
+import java.util.LinkedList;
+import java.util.Queue;
+import java.util.logging.Level;
+import java.util.logging.LogRecord;
+
+import org.junit.jupiter.api.Test;
+
+class PureLogTest {
+
+  @Test
+  void test() {
+    Queue<LogRecord> traces = new LinkedList<>();
+
+    PureLog.info(() -> "this is a test").safeRunSync(PureLog.test(traces));
+
+    LogRecord logRecord = traces.poll();
+    assertEquals("this is a test", logRecord.getMessage());
+    assertEquals(Level.INFO, logRecord.getLevel());
+    assertEquals(PureLogTest.class.getName(), logRecord.getSourceClassName());
+    assertEquals("test", logRecord.getSourceMethodName());
+  }
+}