程序清单 13-4 带有时间限制的加锁

Author: zhangquanli

src/main/java/chapter_13/code_04/TimedLocking.java

@@ -0,0 +1,33 @@
+package chapter_13.code_04;
+
+import java.util.concurrent.TimeUnit;
+import java.util.concurrent.locks.Lock;
+import java.util.concurrent.locks.ReentrantLock;
+
+/**
+ * 程序清单 13-4 带有时间限制的加锁
+ */
+public class TimedLocking {
+    private Lock lock = new ReentrantLock();
+
+    public boolean trySendOnSharedLine(String message, long timeout, TimeUnit unit)
+            throws InterruptedException {
+        long nanosToLock = unit.toNanos(timeout) - estimatedNanosToSend(message);
+        if (!lock.tryLock(nanosToLock, TimeUnit.NANOSECONDS)) {
+            return false;
+        }
+        try {
+            return sendOnSharedLine(message);
+        } finally {
+            lock.unlock();
+        }
+    }
+
+    private boolean sendOnSharedLine(String message) {
+        return true;
+    }
+
+    long estimatedNanosToSend(String message) {
+        return message.length();
+    }
+}