Title: Configuration
<a name="Configuration-ShortOverview"></a>
# Short Overview

<a name="Configuration-ConfigurationProperties"></a>
## Configuration Properties

*  _openejb.home_ - OpenEJB home (installation) directory path. All relative paths are resolved against the property unless openejb.base is set. Unless set, the value is assigned to the _user.dir_ Java property.
*  _openejb.base_ - OpenEJB base directory path. If set, the directory pointed by the property is searched for resources before openejb.home.
*  _openejb.configuration_ - OpenEJB configuration file path.
*  _openejb.loader_ - OpenEJB loader that's responsible for loading EJBs. There are 3 different loader types:  
**  _tomcat-webapp_ - set it when inside of Tomcat scoped at just the webapp, aka. [Collapsed EAR](collapsed-ear.html)
**  _tomcat_ - set it when inside of Tomcat scoped for all webapps to share
**  _system_ (also: bootstrap)
**  _embedded_ (also: noload)
*  _openejb.configurator_ (default: _org.openejb.alt.config.ConfigurationFactory_ ) - a class that builds org.openejb.alt.assembler.classic.OpenEjbConfiguration object; implements the org.openejb.alt.assembler.classic.OpenEjbConfigurationFactory interface
*  _openejb.descriptors.output_ - possible values: true|false - When set OpenEJB saves deployment descriptors - ejb-jar.xml and openejb-jar.xml

<a name="Configuration-ConfigurationFile"></a>
## Configuration File

Show a config file with the elements hyperlinked.

    <?xml version="1.0"?>
    <openejb>
      <Container id="Default CMP Container" ctype="CMP_ENTITY">
        Global_TX_Database	c:/my/app/conf/postgresql.cmp_global_database.xml
        Local_TX_Database	c:/my/app/conf/postgresql.cmp_local_database.xml
      </Container>
      <Connector id="Default JDBC Database">
        JdbcDriver org.postgresql.Driver
        JdbcUrl jdbc:postgresql://localhost/mydb
        UserName username
        Password password
      </Connector>
      <SecurityService id="Default Security Service"/>
      <TransactionService id="Default Transaction Manager"/>
      <Deployments jar="c:/my/app/employee.jar"/>
      <Deployments dir="beans/" />
    </openejb>

    
#  Basic Layout
    
Basically, openejb.base is the source for 100% of all configuration
information and third party config files (log4j, castor, instantdb,
whatever).  This includes finding where the, possibly many, <Deployment>
entries in the openejb.conf point.  The openejb.home is where the code
loading OpenEJB will look for all the OpenEJB libraries.  Usually
openejb.base is not explicitly set and defaults to the value of
openejb.home, so many people are used to only dealing with openejb.home.

The point of having and openejb.base and openejb.home was basically to
allow several independently configured instances of OpenEJB running on a
system (perhaps embedded in Swing apps, in Tomcat, running as a standalone
Server, or even in Groovy as Mr. Strachan did!) but without the need to
copy all the OpenEJB system libraries everywhere.
    
  *openejb.home*
    * can be set explicitly via a system property.
    * if not set it default's to user.dir, which is the current working
  directory.

  *openejb.base*
    * can be set explicitly via a system property.
    * If not set it default's to openejb.home.

  *openejb.configuration*
    * can be set to explicitly point to the file containing your
  configuration.
    * If set to a relative path, we first look in user.dir/your-conf-file,
  then in openejb.base/your-conf-file
    * If not set we check in openejb.base/conf/openejb.conf
    * If no conf file is found, we create one in
  openejb.base/conf/openejb.conf


  *relative paths in openejb.conf*
    * Deployment entries are resolved relative to openejb.base.
    * Containers use openejb.base to resolve their own config files.  For
  example, Castor JDO to loads the database.xml and all other files from the
  openejb.base directory.
    * Resource adapters that are embedded usually have config files of their
  own and are also loaded from the openeb.base.

  *log files*
    * The log4.configuration file is resolved relative to openejb.base.
    * The properties in the config file that point to files are also resolved
  relative to openejb.base.

  *OpenEJB libraries*
    * The jars in the lib and dist directories under openejb.home are added
to the classpath.
    
## Summary
    
A summary of the above in a different notation:

    openejb.home = user.dir (can be set explicitly)
    openejb.base = openejb.home (can be set explicitly)
    openejb.conf = openejb.base/conf/openejb.conf (can be set explicitly)
    logging.conf = openejb.base/conf/logging.conf (can be set explicitly)
    deployments  = paths listed in openejb.conf (relative paths resolved from openejb.base)
    Classpath includes openejb.home/lib and openejb.home/dist

## Example layout
    
In this one the openejb.home and openejb.base are set, everything else is
defaulted.  The openejb.conf file as been updated to point to the ejb jars
by name (abc-ejbs.jar and xyz-ejbs.jar).
    
An example layout:

    /usr/local/openejb  (openejb.home)
    /usr/local/openejb/lib	(in classpath)
    /usr/local/openejb/dist (in classpath)
    /home/jsmith/foo_app  (openejb.base)
    /home/jsmith/foo_app/conf/openejb.conf
    /home/jsmith/foo_app/conf/logging.conf
    /home/jsmith/foo_app/abc-ejbs.jar (Deployment entry in openejb.conf)
    /home/jsmith/foo_app/xyz-ejbs.jar (Deployment entry in openejb.conf)
    /home/jsmith/foo_app/logs/  

    
## Another Example layout
    
In this example openejb.home and openejb.base are setup as well as the
explicit paths for the openejb and log4j configuration files.
    
An example layout:

    /usr/local/openejb  (openejb.home)
    /usr/local/openejb/lib	(in classpath)
    /usr/local/openejb/dist (in classpath)
    /home/jsmith/foo_app  (openejb.base)
    /home/jsmith/foo_app/openejb.xml  (openejb.configuration)
    /home/jsmith/foo_app/abc-ejbs.jar (Deployment entry in openejb.xml)
    /home/jsmith/foo_app/xyz-ejbs.jar (Deployment entry in openejb.xml)
    /home/jsmith/foo_app/log4j.conf  (log4j.configuration)
    /home/jsmith/foo_app/mylogs/  (logging dir as defined in log4j.conf)