MdbInstanceFactory

java.lang.Object
- org.apache.openejb.core.mdb.MdbInstanceFactory

```
public class MdbInstanceFactory
extends java.lang.Object
```
A MdbInstanceFactory creates instances of message driven beans for a single instance. This class differs from other instance managers in OpenEJB as it doesn't do pooling and it creates instances for only a single EJB deployment.
The MdbContainer assumes that the resouce adapter is pooling message endpoints so a second level of pooling in the container would be inefficient. This is true of all known resouce adapters in opensource (ActiveMQ), so if this is a poor assumption for your resource adapter, contact the OpenEJB developers.
This class can optionally limit the number of bean instances and therefore the message endpoints available to the resource adapter.

Constructor Summary

Constructors
Constructor and Description
`MdbInstanceFactory(BeanContext beanContext, SecurityService securityService, int instanceLimit)` Creates a MdbInstanceFactory for a single specific deployment.

Method Summary

All Methods Instance Methods Concrete Methods
Modifier and Type	Method and Description
`java.lang.Object`	`createInstance(boolean ignoreInstanceCount)` Creates a new mdb instance preforming all necessary lifecycle callbacks
`void`	`freeInstance(Instance instance, boolean ignoredInstanceCount)` Frees an instance no longer needed by the resource adapter.
`int`	`getInstanceCount()` Gets the current number of created instances.
`int`	`getInstanceLimit()` Gets the maximal number of instances that can exist at any time.
`java.lang.Object`	`recreateInstance(java.lang.Object bean)` Recreates a bean instance that has thrown a system exception.

Methods inherited from class java.lang.Object
clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

- Constructor Detail
  - MdbInstanceFactory
```
public MdbInstanceFactory(BeanContext beanContext,
                          SecurityService securityService,
                          int instanceLimit)
                   throws OpenEJBException
```
    Creates a MdbInstanceFactory for a single specific deployment.
    
    Parameters:
    
    beanContext - the deployment for which instances will be created
    
    securityService - the transaction manager for this container system
    
    instanceLimit - the maximal number of instances or <= 0 if unlimited
    
    Throws:
    
    OpenEJBException
- Method Detail
  - getInstanceLimit
```
public int getInstanceLimit()
```
    Gets the maximal number of instances that can exist at any time.
    
    Returns:
    
    the maximum number of instances or <= 0 if unlimitied
  - getInstanceCount
```
public int getInstanceCount()
```
    Gets the current number of created instances.
    
    Returns:
    
    the current number of instances created
  - createInstance
```
public java.lang.Object createInstance(boolean ignoreInstanceCount)
                                throws UnavailableException
```
    Creates a new mdb instance preforming all necessary lifecycle callbacks
    
    Parameters:
    
    ignoreInstanceCount -
    
    Returns:
    
    a new message driven bean instance
    
    Throws:
    
    UnavailableException - if the instance limit has been exceeded or if an exception occurs while creating the bean instance
  - freeInstance
```
public void freeInstance(Instance instance,
                         boolean ignoredInstanceCount)
```
    Frees an instance no longer needed by the resource adapter. This method makes all the necessary lifecycle callbacks and decrements the instance count. This method should not be used to disposed of beans that have thrown a system exception. Instead the discardInstance method should be called.
    
    Parameters:
    
    instance - the bean instance to free
    
    ignoredInstanceCount -
  - recreateInstance
```
public java.lang.Object recreateInstance(java.lang.Object bean)
                                  throws UnavailableException
```
    Recreates a bean instance that has thrown a system exception. As required by the EJB specification, lifecycle callbacks are not invoked. To normally free a bean instance call the freeInstance method.
    
    Parameters:
    
    bean - the bean instance to discard
    
    Returns:
    
    the new replacement bean instance
    
    Throws:
    
    UnavailableException

Class MdbInstanceFactory

Constructor Summary

Method Summary

Methods inherited from class java.lang.Object

Constructor Detail

MdbInstanceFactory

Method Detail

getInstanceLimit

getInstanceCount

createInstance

freeInstance

recreateInstance