Datanucleus Level 2 Cache in app engine

Level 2 cache is disabled by default in Datanucleus, 

to enable it you've gotta 

• download the cache plugin here
• place it in your applications lib directory
• edit your persistence.xml and add
• <property name="datanucleus.cache.level2" value="true">
<property name="datanucleus.cache.level2.type" value="soft">

  after
  
<property name="datanucleus.ConnectionURL" value="appengine"/>

Additional configuration options are available here.


App engines memcache implements JCache(javax.cache) interface, but i get a serialization error when attempting to save a object.

Beginning Grails on Google AppEngine

Just a quick writeup on Grails+Gorm-JPA+GAE

What you will need:

• http://grails.org/
• http://code.google.com/appengine/
• http://grails.org/plugin/app-engine
• http://grails.org/plugin/gorm-jpa

At the time of this writeup i'm using

• Grails 1.1.1
• GAE 1.2.5
• appengine plugin 0.8.5
• gorm-jpa plugin 0.5

Things to note:

• App engine uses Datanucleus to enhance Domain classes, on Windows there is a character limit on the command line see here one way i found around this problem is to end Domain classes with XXXDomain. e.g. UserDomain.groovy and update %APPENGINE_HOME%/config/user/ant-macros.xml
  from
‹fileset dir="@{war}/WEB-INF/classes" includes="**/*.class"›
  to
‹fileset dir="@{war}/WEB-INF/classes" includes="**/*Domain.class"›
  
• To use google's datatypes in Domains, you have to add the annotation
  @Enumerated
e.g.
@Enumerated
Text longText;
• Also when bootstrapping do NOT populate the FIRST google datatype in a Domain class,
  this causes the datatype NOT to be mapped.
• To simplify saving Text datatypes, you can override the default getters and setters on the Domain class like so:
void setLongText(String text){
longText = new Text(text);
}

String getLongText(){
return longText?.getValue();
}