[playframework#621] Destroy the datasource when needed

In PROD mode, the datasource should be destroyed on application stop.
In DEV mode, it should be destroyed before a new one is created.

Also, for JNDI datasources, a new property "db.destroyMethod" is added
to let decide if the application should destroy the datasource or not,
and how (By default, the datasource is not destroyed).

framework/src/play/db/DB.java

@@ -1,11 +1,13 @@
 package play.db;
 
+import java.lang.reflect.Method;
 import java.sql.Connection;
 import java.sql.ResultSet;
 import java.sql.SQLException;
 import javax.sql.DataSource;
 import play.db.jpa.JPA;
 import play.exceptions.DatabaseException;
+import play.Logger;
 
 /**
  * Database connection utilities.
@@ -17,6 +19,11 @@ public class DB {
      */
     public static DataSource datasource = null;
 
+    /**
+     * The method used to destroy the datasource
+     */
+    public static String destroyMethod = "";
+
     /**
      * Close the connection opened for the current thread.
      */
@@ -84,4 +91,22 @@ public static ResultSet executeQuery(String SQL) {
             throw new DatabaseException(ex.getMessage(), ex);
         }
     }
+
+    /**
+     * Destroy the datasource
+     */
+    public static void destroy() {
+        try {
+            if (DB.datasource != null && DB.destroyMethod != null && !DB.destroyMethod.equals("")) {
+                Method close = DB.datasource.getClass().getMethod(DB.destroyMethod, new Class[] {});
+                if (close != null) {
+                    close.invoke(DB.datasource, new Object[] {});
+                    DB.datasource = null;
+                    Logger.info("Datasource destroyed");
+                }
+            }
+        } catch (Throwable t) {
+             Logger.error("Couldn't destroy the datasource", t);
+        }
+    }
 }

framework/src/play/db/DBPlugin.java

@@ -58,6 +58,10 @@ public void onApplicationStart() {
 
                 Properties p = Play.configuration;
 
+                if (DB.datasource != null) {
+                    DB.destroy();
+                }
+
                 if (p.getProperty("db", "").startsWith("java:")) {
 
                     Context ctx = new InitialContext();
@@ -117,6 +121,8 @@ public void onApplicationStart() {
 
                 }
 
+                DB.destroyMethod = p.getProperty("db.destroyMethod", "");
+
             } catch (Exception e) {
                 DB.datasource = null;
                 Logger.error(e, "Cannot connected to the database : %s", e.getMessage());
@@ -128,6 +134,12 @@ public void onApplicationStart() {
         }
     }
 
+    public void onApplicationStop() {
+        if (Play.mode.isProd()) {
+            DB.destroy();
+        }
+    }
+
     @Override
     public String getStatus() {
         StringWriter sw = new StringWriter();
@@ -192,6 +204,11 @@ private static boolean changed() {
             if (DB.datasource == null) {
                 return true;
             }
+        } else {
+            // Internal pool is c3p0, we should call the close() method to destroy it.
+            check(p, "internal pool", "db.destroyMethod");
+
+            p.put("db.destroyMethod", "close");
         }
 
         Matcher m = new jregex.Pattern("^mysql:(({user}[\\w]+)(:({pwd}[^@]+))?@)?({name}[\\w]+)$").matcher(p.getProperty("db", ""));
@@ -229,6 +246,11 @@ private static boolean changed() {
                 return true;
             }
         }
+
+        if (!p.getProperty("db.destroyMethod", "").equals(DB.destroyMethod)) {
+            return true;
+        }
+
         return false;
     }
 

resources/application-skel/conf/application.conf

@@ -95,6 +95,11 @@ date.format=yyyy-MM-dd
 #
 # If you want to reuse an existing Datasource from your application server, use:
 # db=java:/comp/env/jdbc/myDatasource
+#
+# When using an existing Datasource, it's sometimes needed to destroy it when
+# the application is stopped. Depending on the datasource, you can define a
+# generic "destroy" method :
+# db.destroyMethod=close
 
 # JPA Configuration (Hibernate)
 # ~~~~~