From 8d12edf752913738aa7ebd05851131472980f141 Mon Sep 17 00:00:00 2001
From: wenshao <szujobs@hotmail.com>
Date: Tue, 23 Oct 2012 10:08:37 +0800
Subject: [PATCH] smart select lock fair or unfair

---
 .../druid/pool/DruidAbstractDataSource.java   | 22 ++++++++++++++++++-
 .../alibaba/druid/pool/DruidDataSource.java   |  6 +----
 2 files changed, 22 insertions(+), 6 deletions(-)

diff --git a/src/main/java/com/alibaba/druid/pool/DruidAbstractDataSource.java b/src/main/java/com/alibaba/druid/pool/DruidAbstractDataSource.java
index b0a5c1f47f..d1523683f8 100644
--- a/src/main/java/com/alibaba/druid/pool/DruidAbstractDataSource.java
+++ b/src/main/java/com/alibaba/druid/pool/DruidAbstractDataSource.java
@@ -38,6 +38,7 @@ import java.util.Properties;
 import java.util.Set;
 import java.util.concurrent.CopyOnWriteArrayList;
 import java.util.concurrent.atomic.AtomicLong;
+import java.util.concurrent.locks.Condition;
 import java.util.concurrent.locks.ReentrantLock;
 import java.util.logging.Logger;
 
@@ -220,13 +221,18 @@ public abstract class DruidAbstractDataSource extends WrapperAdapter implements
 
     protected boolean                                  useOracleImplicitCache                    = true;
 
-    protected final ReentrantLock                      lock;
+    protected ReentrantLock                            lock;
+    protected Condition                                notEmpty;
+    protected Condition                                empty;
 
     protected AtomicLong                               createCount                               = new AtomicLong();
     protected AtomicLong                               destroyCount                              = new AtomicLong();
 
     public DruidAbstractDataSource(boolean lockFair){
         lock = new ReentrantLock(lockFair);
+
+        notEmpty = lock.newCondition();
+        empty = lock.newCondition();
     }
 
     public boolean isOracle() {
@@ -788,6 +794,20 @@ public abstract class DruidAbstractDataSource extends WrapperAdapter implements
             return;
         }
 
+        if (maxWaitMillis > 0 && !this.inited) {
+            final ReentrantLock lock = this.lock;
+            lock.lock();
+            try {
+                if ((!this.inited) && (!lock.isFair())) {
+                    this.lock = new ReentrantLock(true);
+                    this.notEmpty = this.lock.newCondition();
+                    this.empty = this.lock.newCondition();
+                }
+            } finally {
+                lock.unlock();
+            }
+        }
+
         if (inited) {
             LOG.error("maxWait changed : " + this.maxWait + " -> " + maxWaitMillis);
         }
diff --git a/src/main/java/com/alibaba/druid/pool/DruidDataSource.java b/src/main/java/com/alibaba/druid/pool/DruidDataSource.java
index 6303b05897..0f06d961e4 100644
--- a/src/main/java/com/alibaba/druid/pool/DruidDataSource.java
+++ b/src/main/java/com/alibaba/druid/pool/DruidDataSource.java
@@ -32,7 +32,6 @@ import java.util.ServiceLoader;
 import java.util.concurrent.CountDownLatch;
 import java.util.concurrent.TimeUnit;
 import java.util.concurrent.atomic.AtomicLong;
-import java.util.concurrent.locks.Condition;
 import java.util.concurrent.locks.Lock;
 
 import javax.management.JMException;
@@ -83,9 +82,6 @@ public class DruidDataSource extends DruidAbstractDataSource implements DruidDat
 
     private static final long                serialVersionUID        = 1L;
 
-    private final Condition                  notEmpty                = lock.newCondition();
-    private final Condition                  empty                   = lock.newCondition();
-
     // stats
     private long                             connectCount            = 0L;
     private long                             closeCount              = 0L;
@@ -127,7 +123,7 @@ public class DruidDataSource extends DruidAbstractDataSource implements DruidDat
     private JdbcDataSourceStat               dataSourceStat;
 
     public DruidDataSource(){
-        this(true);
+        this(false);
     }
 
     public DruidDataSource(boolean fairLock){