The following comment has been added to this issue:
Author: David Jencks
Created: Mon, 6 Oct 2003 6:51 PM
Body:
I've spent some time looking at the ConnectionManager part of this code, and
I'm not very happy with it. I'm having a very hard time understanding how the
classes fit together and where any of the actual work occurs.
Two architectural decisions I disagree with are:
1. number of ConnectionManager instances. I think it makes most sense to have
a ConnectionManager for each deployed ManagedConnectionFactory.
2. structure of interceptor stack for a ConnectionManager implementation. If I
understand the design correctly, the interceptor class called Partition, and
has multiple children. Each interceptor is responsible for deciding which
child to delegate to. While this is a very powerful class model or
meta-pattern, I don't think it is appropriate here. IMO a ConnectionManager
for a single ManagedConnectionFactory/ConnectionFactory should have a single
stack of interceptors each of which can perform inverse operations for getting
and returning a connection. If an interceptor cannot finish the request, it
delegates to the single next interceptor, without knowing what it is.
If I've misunderstood your design, please let me know.
I'm going to attach the preliminary implementation of interceptors I've been
working on. My implementation is extremely incomplete (for instance it lacks a
pooling interceptor) but does include some transaction management and
illustrates my idea for an interceptor implementation.
On another front, I think it is a good idea to deploy the ResourceAdapter and
ManagedConnectionFactory as mbeans so their properties are directly accessible
via jmx.
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View the issue:
http://jira.codehaus.org/secure/ViewIssue.jspa?key=GERONIMO-97
Here is an overview of the issue:
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Key: GERONIMO-97
Summary: JCA - Connection Management
Type: New Feature
Status: Assigned
Priority: Major
Time Spent: Unknown
Remaining: Unknown
Project: Apache Geronimo
Components:
core
Assignee: David Jencks
Reporter: Gianny DAMOUR
Created: Thu, 2 Oct 2003 5:10 AM
Updated: Mon, 6 Oct 2003 6:34 PM
Description:
This is the final proposal for the Connection Management section of the JCA
specifications. It is a "clean" version of GERONIMO-90 + a minimalist deployer
which allows to test such an implementation within a running server.
When I write "clean", it is evident that some works still need to be done,
however based on the size of the code-base - 30 classes - it should be great to
reflect seriously on this proposal.
The content by package is:
*********************************************************
org.apache.geronimo.connector.connection:
*********************************************************
The ConnectionManager spi interface has been implemented and delegates the
allocation of connection handles to a pool of ManagedConnection. By now, the
ConnectionManager is really simple: it delegates directly to the pool. However,
one needs to hook-in the Transaction and Security services in the
allocateConnection method.
*********************************************************
org.apache.geronimo.connector.connection.partition:
*********************************************************
The specifications do not define how connection pooling should be implemented.
However, some non-prescriptive guidelines have been provided. One of them is to
partition this pool. This is basically what I have decided to implement: The
pool is partition on a per-ManagedConnectionFactory basis. By now, it is
further partitioned on an idle, active, factory, destroy basis. The general
idea of this design is to define distinct set of behaviors depending on the
kind of partition.
Examples:
The factory partition is in charge of creating/allocating new connection
handles. When its allocateConnection method is called, it decides if a new
ManagedConnection should be created or if an existing one can be re-used.
The XA partition (to be implemented) is in charge of creating/allocating new
transacted connection handles. When its allocateConnection is called, it
enlists the ManagedConnection with our TM and then gets a connection handle
from this enlisted ManagedConnection.
Inter-partition events can be propagated via an AWT like event model. This
mechanism is used for example by the factory partition: It monitors the idle
and destroy partitions in order to decide how to serve a new allocation
request. More accurately, if a ManagedConnection is added to the idle
partition, then a permit to try a matchManagedConnection is added. If a
ManagedConnection is added to the destroy partition, then a permit to create a
new ManagedConnection is added.
*********************************************************
org.apache.geronimo.connector.connection.recycler:
*********************************************************
Partitions may be recycled. For instance, if a ManagedConnection seats idle too
long time, then this ManagedConnection may be eligible for recycling (destroy
in the case of idle ManagedConnection).
*********************************************************
org.apache.geronimo.connector.connection.logging:
*********************************************************
The inner workings of ManagedConnectionFactory and ManagedConnection can be
tracked via a PrintWriter. LoggerFactory defines the contract to obtain a
PrintWriter factory backed by various output streams.
*********************************************************
org.apache.geronimo.connector.deploy:
*********************************************************
A minimalist deployer for the outbound-resourceadapter nodes is implemented.
Gianny
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