From f2554d0f6380f0c67ff4afb6c8e77d8af9545bea Mon Sep 17 00:00:00 2001
From: Nick Burch <nick.burch@quanticate.com>
Date: Thu, 4 Feb 2010 14:35:49 +0000
Subject: [PATCH] Allow lazy loading of beans from the ApplicationContext if
 requested

git-svn-id: https://svn.alfresco.com/repos/alfresco-enterprise/alfresco/HEAD/root@18453 c4b6b30b-aa2e-2d43-bbcb-ca4b014f7261
---
 .../util/ApplicationContextHelper.java        | 29 +++++++-
 .../LazyClassPathXmlApplicationContext.java   | 67 +++++++++++++++++++
 2 files changed, 94 insertions(+), 2 deletions(-)
 create mode 100644 source/java/org/alfresco/util/LazyClassPathXmlApplicationContext.java

diff --git a/source/java/org/alfresco/util/ApplicationContextHelper.java b/source/java/org/alfresco/util/ApplicationContextHelper.java
index 4aded2c80d..12052fb47e 100644
--- a/source/java/org/alfresco/util/ApplicationContextHelper.java
+++ b/source/java/org/alfresco/util/ApplicationContextHelper.java
@@ -39,6 +39,7 @@ public class ApplicationContextHelper
 {
     private static ClassPathXmlApplicationContext instance;
     private static String[] usedConfiguration;
+    private static boolean useLazyLoading = false;
     
     /** location of required configuration files */
     public static final String[] CONFIG_LOCATIONS = new String[] { "classpath:alfresco/application-context.xml" };
@@ -79,8 +80,13 @@ public class ApplicationContextHelper
         }
         // The config has changed so close the current context (if any)
         closeApplicationContext();
-        
-        instance = new ClassPathXmlApplicationContext(configLocations);            
+       
+        if(useLazyLoading) {
+           instance = new LazyClassPathXmlApplicationContext(configLocations);
+        } else {
+           instance = new ClassPathXmlApplicationContext(configLocations);
+        }
+                    
         usedConfiguration = configLocations;
         
         return instance;
@@ -102,6 +108,25 @@ public class ApplicationContextHelper
         usedConfiguration = null;
     }
     
+    /**
+     * Should the Spring beans be initilised in a lazy manner, or
+     *  all in one go?
+     * Normally lazy loading/intialising shouldn't be used when
+     *  running with the full context, but it may be appropriate
+     *  to reduce startup times when using a small, cut down context.
+     */
+    public static void setUseLazyLoading(boolean lazyLoading) {
+       useLazyLoading = lazyLoading;
+    }
+    /**
+     * Will the Spring beans be initilised in a lazy manner, or
+     *  all in one go? The default it to load everything in one
+     *  go, as spring normally does.
+     */
+    public static boolean isUsingLazyLoading() {
+       return useLazyLoading;
+    }
+    
     public static void main(String ... args)
     {
         ClassPathXmlApplicationContext ctx = (ClassPathXmlApplicationContext) getApplicationContext();
diff --git a/source/java/org/alfresco/util/LazyClassPathXmlApplicationContext.java b/source/java/org/alfresco/util/LazyClassPathXmlApplicationContext.java
new file mode 100644
index 0000000000..97128f16a4
--- /dev/null
+++ b/source/java/org/alfresco/util/LazyClassPathXmlApplicationContext.java
@@ -0,0 +1,67 @@
+/*
+ * Copyright (C) 2005-2007 Alfresco Software Limited.
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License
+ * as published by the Free Software Foundation; either version 2
+ * of the License, or (at your option) any later version.
+
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
+
+ * As a special exception to the terms and conditions of version 2.0 of 
+ * the GPL, you may redistribute this Program in connection with Free/Libre 
+ * and Open Source Software ("FLOSS") applications as described in Alfresco's 
+ * FLOSS exception.  You should have recieved a copy of the text describing 
+ * the FLOSS exception, and it is also available here: 
+ * http://www.alfresco.com/legal/licensing"
+ */
+package org.alfresco.util;
+
+import org.springframework.beans.BeansException;
+import org.springframework.beans.factory.xml.BeanDefinitionParserDelegate;
+import org.springframework.beans.factory.xml.DefaultBeanDefinitionDocumentReader;
+import org.springframework.beans.factory.xml.XmlBeanDefinitionReader;
+import org.springframework.beans.factory.xml.XmlReaderContext;
+import org.springframework.context.support.ClassPathXmlApplicationContext;
+import org.w3c.dom.Element;
+
+/**
+ * A wrapper around {@link ClassPathXmlApplicationContext} which forces
+ *  all beans to be loaded lazily.
+ * You shouldn't do this in production, but it can be handy with
+ *  unit tests, as it allows a quicker startup when you don't touch
+ *  much of the application.
+ *  
+ * @author Nick Burch
+ */
+public class LazyClassPathXmlApplicationContext extends
+      ClassPathXmlApplicationContext {
+   
+   public LazyClassPathXmlApplicationContext(String[] configLocations)
+         throws BeansException {
+      super(configLocations);
+   }
+
+   protected void initBeanDefinitionReader(XmlBeanDefinitionReader reader) {
+      super.initBeanDefinitionReader(reader);
+      
+      reader.setDocumentReaderClass(AlwaysLazyInitBeanDefinitionDocumentReader.class);
+   }
+
+   protected static class AlwaysLazyInitBeanDefinitionDocumentReader extends DefaultBeanDefinitionDocumentReader {
+      @Override
+      protected BeanDefinitionParserDelegate createHelper(
+            XmlReaderContext readerContext, Element root) {
+         BeanDefinitionParserDelegate helper = super.createHelper(readerContext, root);
+         helper.getDefaults().setLazyInit("true");
+         return helper;
+      }
+   }
+}