narrow down the interface for extension purposes

git-svn-id: https://svn.apache.org/repos/asf/tomcat/trunk@766912 13f79535-47bb-0310-9956-ffa450edef68

diff --git a/modules/jdbc-pool/java/org/apache/tomcat/jdbc/pool/FairBlockingQueue.java b/modules/jdbc-pool/java/org/apache/tomcat/jdbc/pool/FairBlockingQueue.java
index 67f83e5..db5a0b3 100644 (file)
--- a/modules/jdbc-pool/java/org/apache/tomcat/jdbc/pool/FairBlockingQueue.java
+++ b/modules/jdbc-pool/java/org/apache/tomcat/jdbc/pool/FairBlockingQueue.java
@@ -17,6 +17,7 @@
 package org.apache.tomcat.jdbc.pool;
 
 import java.util.Collection;
+import java.util.Deque;
 import java.util.Iterator;
 import java.util.LinkedList;
 import java.util.NoSuchElementException;
@@ -39,7 +40,7 @@ import java.util.concurrent.locks.ReentrantLock;
 public class FairBlockingQueue<E> implements BlockingQueue<E> {
     ReentrantLock lock = new ReentrantLock(false);
 
-    LinkedList<E> items = null;
+    Deque<E> items = null;
 
     LinkedList<ExchangeCountDownLatch<E>> waiters = null;