driver: add basic 'cancel' implementation

src/main/java/org/dcache/nearline/cta/CtaNearlineStorage.java

@@ -16,11 +16,13 @@ import java.net.InetSocketAddress;
 import java.net.URI;
 import java.net.UnknownHostException;
 import java.time.Instant;
+import java.util.Iterator;
 import java.util.Map;
 import java.util.Objects;
 import java.util.Set;
 import java.util.UUID;
 
+import java.util.concurrent.CancellationException;
 import java.util.concurrent.ConcurrentHashMap;
 import java.util.concurrent.ConcurrentMap;
 import java.util.concurrent.ExecutionException;
@@ -307,6 +309,16 @@ public class CtaNearlineStorage implements NearlineStorage {
      */
     @Override
     public void cancel(UUID uuid) {
+        // FIXME: we need to cancel the requests in CTA.
+        var requestIterator =  pendingRequests.entrySet().iterator();
+        while (requestIterator.hasNext()) {
+            var r = requestIterator.next().getValue().getRequest();
+            if (r.getId().equals(uuid)) {
+                r.failed(new CancellationException("Canceled by dCache"));
+                // no other matches expected.
+                break;
+            }
+        }
     }
 
     /**

src/test/java/org/dcache/nearline/cta/CtaNearlineStorageTest.java

@@ -416,6 +416,24 @@ public class CtaNearlineStorageTest {
         assertEquals("pending request count not zero", 0, driver.getPendingRequestsCount());
     }
 
+    @Test
+    public void testCencelOfPendingRequest() {
+
+        var request = mockedStageRequest();
+        driver = new CtaNearlineStorage("foo", "bar");
+        driver.configure(drvConfig);
+        driver.start();
+
+        driver.stage(Set.of(request));
+
+        cta.waitToReply();
+
+        driver.cancel(request.getId());
+        assertEquals("unexpected pending request queue size", 0, driver.getPendingRequestsCount());
+
+    }
+
+
     void waitToComplete() {
         try {
             waitForComplete.get(1, TimeUnit.SECONDS);