deprecate old executor usage; allow for specifying your own

lock-api/src/main/java/com/palantir/lock/client/LockRefresher.java

@@ -29,7 +29,7 @@
 import com.palantir.lock.v2.LockToken;
 import com.palantir.lock.v2.TimelockService;
 
-public class LockRefresher implements AutoCloseable {
+public class LockRefresher {
 
     private final Logger log = LoggerFactory.getLogger(LockRefresher.class);
 
@@ -76,9 +76,4 @@ public void registerLock(LockToken token) {
     public void unregisterLocks(Collection<LockToken> tokens) {
         tokensToRefresh.removeAll(tokens);
     }
-
-    @Override
-    public void close() throws Exception {
-        executor.shutdown();
-    }
 }

lock-api/src/main/java/com/palantir/lock/client/LockRefreshingTimelockService.java

@@ -16,10 +16,12 @@
 
 package com.palantir.lock.client;
 
+import java.util.Optional;
 import java.util.Set;
 import java.util.concurrent.Executors;
 import java.util.concurrent.ScheduledExecutorService;
 
+import com.google.common.annotations.VisibleForTesting;
 import com.google.common.util.concurrent.ThreadFactoryBuilder;
 import com.palantir.lock.v2.LockImmutableTimestampRequest;
 import com.palantir.lock.v2.LockImmutableTimestampResponse;
@@ -39,19 +41,47 @@ public class LockRefreshingTimelockService implements AutoCloseable, TimelockSer
 
     private final TimelockService delegate;
     private final LockRefresher lockRefresher;
-
+    private final Optional<ScheduledExecutorService> managedExecutor;
+
+    /**
+     * @deprecated Use {@link #create(TimelockService, ScheduledExecutorService)} instead.
+     *
+     * @param timelockService The {@link TimelockService} to wrap
+     * @return A {@link TimelockService} that automatically refreshes locks
+     */
+    @Deprecated
     public static LockRefreshingTimelockService createDefault(TimelockService timelockService) {
         ScheduledExecutorService executor = Executors.newSingleThreadScheduledExecutor(new ThreadFactoryBuilder()
                 .setNameFormat(LockRefreshingTimelockService.class.getSimpleName() + "-%d")
                 .setDaemon(true)
                 .build());
         LockRefresher lockRefresher = new LockRefresher(executor, timelockService, REFRESH_INTERVAL_MILLIS);
-        return new LockRefreshingTimelockService(timelockService, lockRefresher);
+        return new LockRefreshingTimelockService(timelockService, lockRefresher, executor);
+    }
+
+    /**
+     * Creates a {@link TimelockService} that uses the specified executor to regularly refresh
+     * locks that have been taken out.
+     *
+     * @param timelockService The {@link TimelockService} proxy to wrap
+     * @param executor An executor service whose lifecycle is managed by the consumer of this method
+     * @return The {@link TimelockService} that automatically refreshes locks
+     */
+    public static LockRefreshingTimelockService create(
+            TimelockService timelockService,
+            ScheduledExecutorService executor) {
+        LockRefresher lockRefresher = new LockRefresher(executor, timelockService, REFRESH_INTERVAL_MILLIS);
+        return new LockRefreshingTimelockService(timelockService, lockRefresher, null);
     }
 
-    public LockRefreshingTimelockService(TimelockService delegate, LockRefresher lockRefresher) {
+    @VisibleForTesting
+    LockRefreshingTimelockService(
+            TimelockService delegate,
+            LockRefresher lockRefresher,
+            ScheduledExecutorService executor) {
         this.delegate = delegate;
         this.lockRefresher = lockRefresher;
+        this.managedExecutor = Optional.ofNullable(executor);
     }
 
     @Override
@@ -108,6 +138,6 @@ public long currentTimeMillis() {
 
     @Override
     public void close() throws Exception {
-        lockRefresher.close();
+        managedExecutor.ifPresent(ScheduledExecutorService::shutdown);
     }
 }

lock-api/src/test/java/com/palantir/lock/client/LockRefreshingTimelockServiceTest.java

@@ -52,7 +52,7 @@ public class LockRefreshingTimelockServiceTest {
 
     private final LockRefresher refresher = mock(LockRefresher.class);
     private final TimelockService delegate = mock(TimelockService.class);
-    private final TimelockService timelock = new LockRefreshingTimelockService(delegate, refresher);
+    private final TimelockService timelock = new LockRefreshingTimelockService(delegate, refresher, null);
 
     private static final long TIMEOUT = 10_000;