Channel reference in the ClosedChannel (#88)

Author: Blef666

channel-ops/src/test/java/com/softwaremill/jox/ops/SourceOpsCollectTest.java

@@ -7,6 +7,7 @@
 import org.junit.jupiter.api.Test;
 
 import static org.junit.jupiter.api.Assertions.assertEquals;
+import static org.junit.jupiter.api.Assertions.assertInstanceOf;
 
 public class SourceOpsCollectTest {
     @Test
@@ -26,7 +27,7 @@ void testMapOverSource() throws Exception {
             assertEquals(10, s.receive());
             assertEquals(20, s.receive());
             assertEquals(30, s.receive());
-            assertEquals(new ChannelDone(), s.receiveOrClosed());
+            assertInstanceOf(ChannelDone.class, s.receiveOrClosed());
             return null;
         });
     }
@@ -52,7 +53,7 @@ void testCollectOverSource() throws Exception {
 
             assertEquals(20, s.receive());
             assertEquals(40, s.receive());
-            assertEquals(new ChannelDone(), s.receiveOrClosed());
+            assertInstanceOf(ChannelDone.class, s.receiveOrClosed());
             return null;
         });
     }
@@ -71,7 +72,7 @@ void testCollectOverSourceStressTest() throws Exception {
                 Source<Integer> s = SourceOps.forSource(scope, c).collect(x -> x * 10).toSource();
 
                 assertEquals(10, s.receive());
-                assertEquals(new ChannelDone(), s.receiveOrClosed());
+                assertInstanceOf(ChannelDone.class, s.receiveOrClosed());
                 return null;
             });
         }
@@ -94,7 +95,7 @@ void testCollectOverSourceUsingForSyntax() throws Exception {
             assertEquals(2, s.receive());
             assertEquals(4, s.receive());
             assertEquals(6, s.receive());
-            assertEquals(new ChannelDone(), s.receiveOrClosed());
+            assertInstanceOf(ChannelDone.class, s.receiveOrClosed());
             return null;
         });
     }

channels/src/main/java/com/softwaremill/jox/Channel.java

@@ -706,7 +706,7 @@ public void done() {
 
     @Override
     public Object doneOrClosed() {
-        return closeOrClosed(new ChannelDone());
+        return closeOrClosed(new ChannelDone(this));
     }
 
     @Override
@@ -722,7 +722,7 @@ public void error(Throwable reason) {
 
     @Override
     public Object errorOrClosed(Throwable reason) {
-        return closeOrClosed(new ChannelError(reason));
+        return closeOrClosed(new ChannelError(reason, this));
     }
 
     private Object closeOrClosed(ChannelClosed channelClosed) {

channels/src/main/java/com/softwaremill/jox/ChannelClosed.java

@@ -5,4 +5,5 @@
  */
 public sealed interface ChannelClosed permits ChannelDone, ChannelError {
     ChannelClosedException toException();
+    Channel<?> channel();
 }

channels/src/main/java/com/softwaremill/jox/ChannelDone.java

@@ -1,6 +1,6 @@
 package com.softwaremill.jox;
 
-public record ChannelDone() implements ChannelClosed {
+public record ChannelDone(Channel<?> channel) implements ChannelClosed {
     @Override
     public ChannelClosedException toException() {
         return new ChannelDoneException();

channels/src/main/java/com/softwaremill/jox/ChannelError.java

@@ -1,6 +1,6 @@
 package com.softwaremill.jox;
 
-public record ChannelError(Throwable cause) implements ChannelClosed {
+public record ChannelError(Throwable cause, Channel<?> channel) implements ChannelClosed {
     @Override
     public ChannelClosedException toException() {
         return new ChannelErrorException(cause);

channels/src/main/java/com/softwaremill/jox/Select.java

@@ -48,7 +48,8 @@ public class Select {
      * <p>
      * If no clauses are given, throws {@link ChannelDoneException}.
      *
-     * @param clauses The clauses, from which one will be selected. Not {@code null}.
+     * @param clauses The clauses, from which one will be selected. Array must not be empty or {@code null} and
+     *                can't contain {@code null} values.
      * @return The value returned by the selected clause.
      * @throws ChannelClosedException When any of the channels is closed (done or in error).
      */
@@ -72,16 +73,21 @@ public static <U> U select(SelectClause<? extends U>... clauses) throws Interrup
      * <p>
      * If no clauses are given, returns {@link ChannelDone}.
      *
-     * @param clauses The clauses, from which one will be selected. Not {@code null}.
+     * @param clauses The clauses, from which one will be selected. Array must not be empty or {@code null} and
+     *                can't contain {@code null} values.
      * @return Either the value returned by the selected clause, or {@link ChannelClosed}, when any of the channels
      * is closed (done or in error).
      */
     @SafeVarargs
     public static <U> Object selectOrClosed(SelectClause<? extends U>... clauses) throws InterruptedException {
         while (true) {
-            if (clauses.length == 0) {
+            if (clauses == null || clauses.length == 0) {
                 // no clauses given
-                return new ChannelDone();
+                throw new IllegalArgumentException("No clauses given");
+            }
+            if (Arrays.stream(clauses).anyMatch(Objects::isNull)){
+                // null clauses given
+                throw new IllegalArgumentException("Null clauses are not supported");
             }
 
             var r = doSelectOrClosed(clauses);

channels/src/test/java/com/softwaremill/jox/ChannelClosedTest.java

@@ -3,28 +3,29 @@
 import org.junit.jupiter.api.Test;
 
 import java.util.concurrent.ExecutionException;
-import java.util.concurrent.Future;
-import java.util.concurrent.Semaphore;
 
-import static com.softwaremill.jox.TestUtil.*;
+import static com.softwaremill.jox.TestUtil.forkCancelable;
+import static com.softwaremill.jox.TestUtil.scoped;
 import static org.junit.jupiter.api.Assertions.*;
 
 public class ChannelClosedTest {
     @Test
-    void testClosed_noValues_whenError() {
+    void testClosed_noValues_whenError() throws InterruptedException {
         // given
         Channel<Integer> c = new Channel<>();
+        RuntimeException reason = new RuntimeException();
 
         // when
-        c.error(new RuntimeException());
+        c.error(reason);
 
         // then
         assertTrue(c.isClosedForReceive());
         assertTrue(c.isClosedForSend());
+        assertEquals(new ChannelError(reason, c), c.receiveOrClosed());
     }
 
     @Test
-    void testClosed_noValues_whenDone() {
+    void testClosed_noValues_whenDone() throws InterruptedException {
         // given
         Channel<Integer> c = new Channel<>();
 
@@ -34,6 +35,7 @@ void testClosed_noValues_whenDone() {
         // then
         assertTrue(c.isClosedForReceive());
         assertTrue(c.isClosedForSend());
+        assertEquals(new ChannelDone(c), c.receiveOrClosed());
     }
 
     @Test

channels/src/test/java/com/softwaremill/jox/ChannelRendezvousTest.java

@@ -121,10 +121,10 @@ void pendingReceivesShouldGetNotifiedThatChannelIsDone() throws InterruptedExcep
             c.done();
 
             // then
-            assertEquals(new ChannelDone(), f.get());
+            assertEquals(new ChannelDone(c), f.get());
 
             // should be rejected immediately
-            assertEquals(new ChannelDone(), c.receiveOrClosed());
+            assertEquals(new ChannelDone(c), c.receiveOrClosed());
         });
     }
 

channels/src/test/java/com/softwaremill/jox/SelectReceiveTest.java

@@ -10,6 +10,7 @@
 import static com.softwaremill.jox.Select.selectOrClosed;
 import static com.softwaremill.jox.TestUtil.*;
 import static org.junit.jupiter.api.Assertions.assertEquals;
+import static org.junit.jupiter.api.Assertions.assertThrows;
 
 public class SelectReceiveTest {
     @Test
@@ -139,7 +140,7 @@ void testSelectWhenDone() throws InterruptedException {
         Object received = selectOrClosed(ch1.receiveClause(), ch2.receiveClause());
 
         // then
-        assertEquals(new ChannelDone(), received);
+        assertEquals(new ChannelDone(ch1), received);
     }
 
     @TestWithCapacities
@@ -219,12 +220,24 @@ void testBufferExpandedWhenSelecting() throws InterruptedException {
     }
 
     @Test
-    void testSelectFromNone() throws InterruptedException {
-        assertEquals(new ChannelDone(), selectOrClosed());
+    void testSelectFromNone() {
+        assertThrows(IllegalArgumentException.class, Select::selectOrClosed);
     }
 
     @Test
-    public void testSelect_immediate_withError() throws InterruptedException {
+    void testSelectFromNullableList() throws InterruptedException {
+        // given
+        Channel<String> ch1 = new Channel<>(1);
+        Channel<String> ch2 = new Channel<>(1);
+        ch1.send("v");
+
+        // when
+        assertThrows(IllegalArgumentException.class,
+                () -> select(ch1.receiveClause(), null, ch2.receiveClause()));
+    }
+
+    @Test
+    void testSelect_immediate_withError() throws InterruptedException {
         // given
         Channel<String> ch1 = new Channel<>(2);
         ch1.send("x");
@@ -237,6 +250,6 @@ public void testSelect_immediate_withError() throws InterruptedException {
         var result = selectOrClosed(ch1.receiveClause(), ch2.receiveClause());
 
         // then
-        assertEquals(new ChannelError(e), result);
+        assertEquals(new ChannelError(e, ch2), result);
     }
 }

channels/src/test/java/com/softwaremill/jox/SelectSendTest.java

@@ -107,7 +107,7 @@ public void testSelectWhenDone() throws InterruptedException {
         Object received = selectOrClosed(ch1.sendClause("v1"), ch2.sendClause("v2"));
 
         // then
-        assertEquals(new ChannelDone(), received);
+        assertEquals(new ChannelDone(ch2), received);
     }
 
     @TestWithCapacities