--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/src/fschmidt/util/locks/TimedReadWriteLocker.java	Sun Oct 05 17:24:15 2025 -0600
@@ -0,0 +1,154 @@
+/*
+Copyright (c) 2008  Franklin Schmidt <fschmidt@gmail.com>
+
+Permission is hereby granted, free of charge, to any person obtaining a copy
+of this software and associated documentation files (the "Software"), to deal
+in the Software without restriction, including without limitation the rights
+to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+copies of the Software, and to permit persons to whom the Software is
+furnished to do so, subject to the following conditions:
+
+The above copyright notice and this permission notice shall be included in
+all copies or substantial portions of the Software.
+
+THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
+THE SOFTWARE.
+*/
+
+package fschmidt.util.locks;
+
+import java.util.Map;
+import java.util.HashMap;
+import java.util.concurrent.TimeUnit;
+import java.util.concurrent.locks.Lock;
+import java.util.concurrent.locks.ReadWriteLock;
+import java.util.concurrent.locks.ReentrantReadWriteLock;
+
+
+public final class TimedReadWriteLocker<T> implements ReadWriteLocker<T> {
+
+	private static class Tracker {
+		final ReentrantReadWriteLock lock0 = new ReentrantReadWriteLock();
+		final ReadWriteLock lock = new TimedReadWriteLock(lock0);
+		int waiters = 0;
+	}
+
+	private final Map<T,Tracker> map = new HashMap<T,Tracker>();
+
+	private Tracker getTracker(T obj) {
+		Tracker t = map.get(obj);
+		if( t==null ) {
+			t = new Tracker();
+			map.put(obj,t);
+		}
+		return t;
+	}
+
+	private Tracker getTrackerForWait(T obj) {
+		synchronized(map) {
+			Tracker t = getTracker(obj);
+			t.waiters++;
+			return t;
+		}
+	}
+
+	private void afterWait(Tracker t) {
+		synchronized(map) {
+			t.waiters--;
+		}
+	}
+
+	private void maybeRemove(T obj,Tracker t) {
+		if( t.waiters==0 && !t.lock0.isWriteLocked() && t.lock0.getReadLockCount()==0 ) {
+			map.remove(obj);
+		}
+	}
+
+	private final Locker<T> writeLocker = new Locker<T>() {
+
+		public void lock(T obj) {
+			Tracker t = getTrackerForWait(obj);
+			try {
+				t.lock.writeLock().lock();
+			} finally {
+				afterWait(t);
+			}
+		}
+	
+		public boolean tryLock(T obj) {
+			synchronized(map) {
+				return getTracker(obj).lock.writeLock().tryLock();
+			}
+		}
+	
+		public boolean tryLock(T obj,long time,TimeUnit unit)
+			throws InterruptedException
+		{
+			Tracker t = getTrackerForWait(obj);
+			try {
+				return t.lock.writeLock().tryLock(time,unit);
+			} finally {
+				afterWait(t);
+			}
+		}
+	
+		public void unlock(T obj) {
+			synchronized(map) {
+				Tracker t = map.get(obj);
+				t.lock.writeLock().unlock();
+				maybeRemove(obj,t);
+			}
+		}
+	};
+
+	private final Locker<T> readLocker = new Locker<T>() {
+
+		public void lock(T obj) {
+			Tracker t = getTrackerForWait(obj);
+			try {
+				t.lock.readLock().lock();
+			} finally {
+				afterWait(t);
+			}
+		}
+	
+		public boolean tryLock(T obj) {
+			synchronized(map) {
+				return getTracker(obj).lock.readLock().tryLock();
+			}
+		}
+
+		public boolean tryLock(T obj,long time,TimeUnit unit)
+			throws InterruptedException
+		{
+			Tracker t = getTrackerForWait(obj);
+			try {
+				return t.lock.readLock().tryLock(time,unit);
+			} finally {
+				afterWait(t);
+			}
+		}
+	
+		public void unlock(T obj) {
+			synchronized(map) {
+				Tracker t = map.get(obj);
+				t.lock.readLock().unlock();
+				maybeRemove(obj,t);
+			}
+		}
+	};
+
+	public Locker<T> readLocker() {
+		return readLocker;
+	}
+
+	public Locker<T> writeLocker() {
+		return writeLocker;
+	}
+
+}