Message:
The following issue has been closed.
Resolver: Kenneth Tam
Date: Tue, 5 Oct 2004 2:29 PM
Providing an 'onFinish' event is problematic, for several different reasons:
- A control is just a JavaBean, that can have one or more references to it.
The full lifecycle of the bean (like any other Java object) is determined by
the lifetime of one or more references to the object. The only time you know
you are 'finished' with the control is when all references are released;
however, relying upon a final notification when the last reference is released
has all the same issues that relying upon java.lang.Object.finalize() has.
- The number of controls that may be in-memory at any point in time is not
constrained or managed... but generally speaking you do want to manage the
number of active connections to an EIS resource. The common approach is to use
pooling and to have clients only obtain/release connections for short periods
of time. The pool mgr will generally hold and recycle connections if they are
expensive to obtain or release. The Controls runtime does not (and should
not) provide the mechanisms for resource pooling; it's intent is to provide a
facade pattern for resource access, not a system-level mechanism for resource
management.
- The ResourceManager onAcquire/onRelease LifeCycle events are provided for
precisely the purpose described in this bug scenario. A control will get an
onAcquire event when any of its methods are invoked (excluding property
accessors) and will receive the onRelease event at an appropriate endpoint
defined by the container in which the control is executing (end of current
request, transaction, ...). A control should *never* hold onto external
resources (connections/sessions in pools, etc) outside the scope of these
ResourceManager events.
Just to be complete, the onCreate event exists for a very specific purpose. It
enables a Control author to write code that would normally be placed in a
constructor, but in the context of a control implementation guarantees that the
control is fully initialized (ex. nested controls or contextual services are
init'ed); whereas code running in the impl class constructor would precede this
initialization.
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View the issue:
http://issues.apache.org/jira/browse/BEEHIVE-4
Here is an overview of the issue:
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Key: BEEHIVE-4
Summary: ControlBeanContext.LifeCycle does not have OnFinish() callback
Type: Improvement
Status: Closed
Priority: Major
Resolution: FIXED
Project: Beehive
Components:
Controls
Fix Fors:
TBD
Assignee: Kyle Marvin
Reporter: suryanarayanan nagarajan
Created: Sun, 12 Sep 2004 11:09 PM
Updated: Tue, 5 Oct 2004 2:29 PM
Description:
ControlBeanContext.LifeCycle has only OnCreate() method. OnFinish() callback is
important to release all resources used to connect to EIS.
A typical use case would be one where connections to EIS need to be persisted
across resource scopes but connection objects cannot be serialized. Connections
would be acquired in OnCreate() through a factory and the same connectio would
be got in every OnAcquire() call. These connections can be released only when
the ControlBeanContext goes out of scope.
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