Java-574 New SemaphoresOut constructor accepting int which caller can define number of allowed permits.

Author: breinero-zz

src/main/com/mongodb/DBPortPool.java

@@ -145,8 +145,13 @@ public static class NoMoreConnection extends MongoInternalException {
 
     public static class SemaphoresOut extends NoMoreConnection {
         private static final long serialVersionUID = -4415279469780082174L;
+        private static final String message = "Concurrent requests for database connection have exceeded limit";
         SemaphoresOut(){
-            super( "Out of semaphores to get db connection" );
+            super( message );
+        }
+        
+        SemaphoresOut(int numPermits){
+            super( message + " of " + numPermits);
         }
     }
 
@@ -189,7 +194,7 @@ protected int pick( int recommended, boolean couldCreate ){
     public DBPort get() {
         DBPort port = null;
         if ( ! _waitingSem.tryAcquire() )
-            throw new SemaphoresOut();
+            throw new SemaphoresOut(_waitingSem.availablePermits() );
 
         try {
             port = get( _options.maxWaitTime );