Mapping up arrow to repeat command on DBX

Hi
Anyone can help me how to map Up Arrow key to repeat commands when debugging using DBX on Solaris?
Thanks

This is a frequently asked question that I always thought
was unsupported until today.
# black magic to set arrow keys bindings
# (thanks to Andrey Petrusenko for help)
bind ^[[=prefix-1
bind ^[[A=up-history
bind ^[[B=down-history
bind ^[[D=backward-char
bind ^[[C=forward-char
# clear screen on Ctrl-L
bind -m ^L='/usr/bin/clear^J'

Similar Messages

Repeat command in illustrator

Hello,
Is there a repeat command like the one you find in office (control+Y).
My problem is that I have a bunch of objects in a page, each one is 100 pixels height, I want to change each one to 95.
Any suggestions?
By the way, is there any format painter like you have in office? The brush simbol.
Thanks in advance!

See this script: http://js4ai.blogspot.com/2012/01/set-all-things.html

Implementing a "repeat command" function

I'm working on a text editor, with much the same functionality as vi. I'm kinda stuck on the "repeat last command" feature. My thought was to get the most recent undoable edit, and then call a redo on it, but that doesn't seem to be working. Any ideas?

I'm implementing undo/redo as outlined in this page
http://java.sun.com/docs/books/tutorial/uiswing/components/generaltext.html
which basically consists of...
1) create a new instance of UndoManager (defined in javax.swing.undo)
2) register the document object of the text area as an UndoableEditListener
3) implement undo and redo actions that extend AbstractAction (I copied these from the above page)
4) call the UndoManager's undo and redo methods from the undo and redo actions.
My idea for repeat was to call the UndoManager's editToBeUndone() method (the most recent edit) and call the redo() method of the UndoableEdit object that it returns. However, the editToBeUndone() method is protected, so I created a class that extends UndoManager and overrode the editToBeUndone() method as follows.
public UndoableEdit editToBeUndone(){
return super.editToBeRedone();
This could be wrong, but I'm pretty sure I've done something similar before.
The other thing that could be a problem is the redo() method of the UndoableEdit class. In the API, it reads "Re-apply the edit, assuming that it has been undone." I don't really know what it means by, "assuming that it has been undone." Is there somewhere I can find a more detailed description? It doesn't throw a CannotRedoException.
What is an undoable edit and not undoable are (presumably) defined in javax.swing.undo also.
Thanks for your reply,
jt

Repeat command or action like the F4 command in Excel

In Excel there is a way to repeat the same command previously performed by pressing the F4 key. This makes thing like adding a new rows or columns and changing characteristics much easier. Is this option available in Numbers 2009? I have not been able to find it in Numbers 2008. It seems like a very easy option to have because the command is stored in memory in order to be able to undo and redo the command.
My apologies for referencing such an inferior product class as Microsoft when discussing Apple programs but Excel is probably Microsoft's best program, has been around for a while, and Numbers is still a baby. Although, Numbers is much more idealistic in many respects which is great, especially considering its age.
I want to find out if this issue has been addressed before I send feedback to Apple.
ThankU Much,
DarrellSY

Fay Valli wrote:
I too have been looking for this shortcut, disappointed it is not available. Also searing for the F2 command in Excel, which allows you to edit the cell to enter text without having to double click on it using a mouse.
Also not available.
If it's important, make a feature request.
In Numbers, go to the Numbers menu, choose Provide Numbers Feedback. Submit your request. If enough users make the request to catch the development team's attention, you may see the feature (or something similar) added (but not before the next full edition).
Regards,
Barry

How can I map remote presses to keyboard commands WITOUT using LIRC?

Hi, i'm tearing my hair out here, and I'm really starting from scratch here now I guess.
I have a media centre USB remote, that I would like to map (using evdev, as I gather you can do that now) each button press to a single letter on the keyboard, so that when I press the Play button on my remote, it's as though I typed the letter P on the keyboard.
I've been told not to use LIRC as it's now possible to do this within Xorg, but I have literally no clue how to do this, and the internet has not been helpful so far. I'll start off by giving you the output of ir-keytable. The remote I want to control is on RC1, and I can't get rid of the device on RC0, as that's my tuner card, unfortuantly:
Found /sys/class/rc/rc0/ (/dev/input/event10) with:
Driver saa716x, table rc-tbs-nec
Supported protocols: NEC RC-5 RC-6 JVC SONY LIRC other
Enabled protocols:
Name: saa716x IR (TurboSight TBS 6284)
bus: 1, vendor/product: 6284:0001, version: 0x0001
Repeat delay = 500 ms, repeat period = 125 ms
Found /sys/class/rc/rc1/ (/dev/input/event14) with:
Driver mceusb, table rc-rc6-mce
Supported protocols: NEC RC-5 RC-6 JVC SONY LIRC other
Enabled protocols: NEC RC-5 RC-6 JVC SONY LIRC other
Name: Media Center Ed. eHome Infrared
bus: 3, vendor/product: 0471:0815, version: 0x0000
Repeat delay = 500 ms, repeat period = 125 ms
Please help! I've been tearing my hair out here...
Last edited by bergqvistjl (2013-04-06 14:04:33)

Trilby wrote:
Where did you here you could do this with just xlib? Have you verified this with xev?
EDIT: I'm not claiming it can't be done with xlib - I hope it can, as if it can be I'll start tinkering with this too. I'm just curious whether this was a good source and whether xev receives the events.
Well look at ir-keytable....
Anyway first off, I want to either disable the current device that's at rc0, or move it away so that my usb remote goes onto rc0, can anyone help?

The voice repeating commands is too fast

The voice that repeats the commands on Apple tv is too fast and hard to understand.

Can you send the router config and the debug isdn q931 debugs ?
This sounds like you have a dial peer destination pattern that may be a close enough match for the incoming digits.

How can I map last of the repeating records into a single record?

I have a following input schema, I need to take only one of the <Student> records and map that to a single record in output. Doesn't matter if the first, second or last one of the records get mapped, I only need one in the output. Any idea how can
this be accomplished?
Input:
<Students>
<Student id="1">
<Name>
A
</Name>
<Roll>
1
</Roll>
</Student>
<Student id="2">
<Name>
A
</Name>
<Roll>
1
</Roll>
</Student>
<Student id="3">
<Name>
A
</Name>
<Roll>
1
</Roll>
</Student>
</Students>
Expected Output:
<Candidate>
<Student>
<Name>
A
</Name>
</Student>
</Candidate>

Sounds rather complex for something that could be done very simple in custom XSLT like this:
<?xml version="1.0" encoding="utf-16"?>
<xsl:stylesheet version="1.0" xmlns:xsl="http://www.w3.org/1999/XSL/Transform">
<xsl:template match="Students">
<Candidate>
<Student>
<Name>
<xsl:value-of select="Student/Name" />
</Name>
</Student>
</Candidate>
</xsl:template>
</xsl:stylesheet>
Morten la Cour

Regarding Mapping of fields for Repeated Segments in an IDoc

Hello Experts,
We have an Orders IDoc with segment E1EDK02 with Occurence 0..10.
In this segment there are two fields QUALF & BELNR.
We want to map a value (Yes or No) to 2 target fields based on the incoming values of QUALF & BELNR .
Now the problem is that for the first occurence of segment E1EDK02 the mapping is working fine.
But for the subsequent occurences of the segment wrong value is mapped to the target field.
The context of both QUALF & BELNR is set to E1EDK02.
Please help!
Thanks in advance,
Suraj

Hello Suraj,
The Source structure is of IDOC Orders05
ORDERS05                     1..1
           IDOC                    1..1
              Segment1
              Segment2
              E1EDK02          1..10
                    QUALF       0..1
                    BELNR       0..1
              Segmentn
Target Structure
MT_ORDERDATA             1..1
             TargetField1        0..1
             TargetField2        0..1
              ORDERITEM         0..unbounded

Message mapping of sort and repeated

Dear all,
I am new to SAP XI. I have a scenario where my Input message and out put message will be like this:
Input Messgae:                                                    Output Message:
Emp_DT                                                               EmpOut_DT
Info - Element - 1-infinity                                     EmpInfo           1-1
Department ID 1-1                                                Manager      1-1
Details 1-1                                                           Department      1-Infinity
EMpNO 1-1                                                            NoofEmployee 1-1
Manager 1-1                                                          Department   1-infinity
Ihave to map by following rules:
1. Sort output message by taking inputmessage Details- Manager
2. Have to count totla no of employee of respective manager
3. have to check how many department under that manager.
Thanks in advance.

Also, check out the SDN Wiki's. There are a good number of examples out there.
[Help with mapping|http://wiki.sdn.sap.com/wiki/display/XI/GraphicalMapping-Standard+functions|Wiki link to help with mapping]
[Step by Step guides to PI Scenarios|http://wiki.sdn.sap.com/wiki/display/XI/Step-by-Step+Guides|SDN Wiki link for Step by Step guides to PI Scenarios]

Map keyboard arrows to shortcuts

Hi guys,
I type with all ten fingers so I'm using Alt + h(j,k,l) shortcuts in Vim in insert mode to move cursor and it's very cool I would like to remap arrow keys in X (Gnome) to use this shortcuts in all X applications
So if I press Alt+K it should work as Up arrow and so on ...
Thank you for your reply.

I have verified this and agree it is a bug. A bug report has been filed.

Requirement is to run CMD.EXE under the Local System Account. So that we can map a network drive to be used by a windows service, which will be created by command: - net use z: \\servername\sharedfolder /persistent:yes

Environment:
OS: Windows 7 32/64 bit, Windows 2008 Server 64
bit/ Windows 2012 Server 64 bit
Priority:
- Critical
Requirement: - Since
the Windows Service is running under the Local System Account, we would like to emulate this same behaviour.
Basically, we would like to run CMD.EXE under the Local System Account. So that we can map a network drive to be used by a service using following
command
net use z: \\servername\sharedfolder /persistent:yes.
Already Attempt:
We tried to launch the CMD.exe using the DOS Task Scheduler AT command. Here’s a sample command:
AT 10:36 /interactive cmd.exe
But I received a warning that “due
to security enhancements, this task will run at the time excepted but not interactively.”
It turns out that this approach will work for XP, 2000 and Server 2003 but due to session isolation
Interactive services no longer work on Windows 7, Windows Server 2008 and above.
2. We
tried to create a secondary Windows Service via the Service Control (sc.exe) which merely launches CMD.exe.
<Drive>:\sc create RunCMDAsLSA binpath= "cmd" type=own type=interact <Drive>:\sc
start RunCMDAsLSA
In this case the service fails to start and results it the following error message:
FAILED 1053: The service did not respond to the start or control request in a timely fashion.
3. One
suggestion, we found to launch CMD.exe via a Scheduled Task, but
it is not giving any option to launch CMD.exe in interactive mode; so that I can map network drive using net command.
4. I read an article, which
demonstrates the use of PSTools from SysInternals. I launched the command line and executed following command
psexec -i -s cmd.exe
PSTools worked fine, but It seems that in scope of Sysinternals Software License
Terms. You may not "use the software for commercial software hosting services."
Application will deploy on client, which will be like commercial,
so we are not able to use PSTools.
Kindly assist us for achieving the requirement. We have tried all the ways, but nothing is working for us. Kindly suggest.
I will be really thankful.

Hi Sir,
Nothing worked from above for us. You can see our remarks on posted query.
That’s why, we posted on forum.
And there will not be any vulnerability, because, if we will use "net
use ..."
in network domain; definitely,
we will provide username and password of mapped drive system.
And, that system, itself is given by client; so that, there must not be any vulnerability; they are ready to provide user name and password.
We need a way; by which we can complete the requirement. Kindly assist.
Regards,
S. P. Singh

Strange Errors from Import Server on Schema-based maps for repeating nodes

I have already posted one thread about this, but perhaps some more in-depth information is required:
We have uploaded our schema into the console, and have mapped the following multi-node file to it:
CUSTOMER <repeating node>
MDM_CUST (new Customer number returned)
CUSTOMER(mapped back from XI for RECORD MATCHING)
CREATE_DATE (text field)
CONTACT<repeating node>
    CONTACT_NO (RECORD MATCHING : NON-QUALIFIER)
    CONTACT_SAP_NO (QUALIFIER)
     [NOTE: There are other qualifers for CONTACT, but only this one
qualifier is being returned and is the only field that would and should be updated.
The other fields should be left alone. However, it appears to overwrite EVERYthing
with NULL other than these two fields. The CONTACT_NO is the sole qualifer on
the table. It is a calculated field that equals the Auto-ID that is also produced on
the table - but obviously not mapped.]
PARTNER<repeating node>
    CUSTOMER_NO (RECORD MATCHING : NON-QUALIFER)
    PARTNER_FUNC (NON-QUALIFIER - Code given to lookup from PARTNER_FUNCTION table which has Code and Desc)
    PARTNER_NO     (NON-QUALIFIER)
    DEFAULT_PARTNER_FLAG (QUALIFIER)
<CLOSE CUSTOMER NODE>
In the Customer main table, all records are matched on CUSTOMER. The CONTACT_NO non-qualifer is matched to the CONTACT qualified lookup table directly since it is the only available non-qualifier. For the PARTNER table, the three qualifiers are mapped and then a compound field is created to map to the PARTNER table entry.
We have the Configurations set at:
Default Multi-Valued Update: Replace
Default Qualified Update: Replace
Default Matching Qualifiers: None
Our record matching is: Create / Update(ALL MAPPED FIELDS) / Update(ALL MAPPED FIELDS)
When the map is reused, the repeating nodes are all recognized, be it one node or many. However, when the map is reused, it does not automatically map the values for many of the Partner fields (nor the compound field) though the fields are correctly mapped.
Also, when we attempt to use Import Server to automate the mapping, we use the mdis.ini set to
Automap Unmapped Value=True
Unmapped Value Handling=Add
Always Use Unmapped Value Handling=False
We get a very strange error saying that :
[code]Encountered a pre-SP4 map. The map needs to be upgraded to SP4.
Solution: Please, Launch the Import Manager GUI using the same source file and simply save the map.[code]
Could it be that our MDM 5.5 SP4 is not compatible with schemas generated with XI v.7 SP9?
All of our MDM is 5.5 SP4. It makes no sense that we would get THIS kind of error. Also, I am questioning our combination of these and other configurations since it doesn't always seem to do what it should

Hi Donald,
this sounds good so far. Just a short hint: you've set "Default Qualified Update: Replace". This explains why Import server "appears to overwrite EVERYthing
with NULL other than these two fields.". The reason is the replace. A replace means that the old values are completely deleted and only the new incoming ones are stored. I'd suggest to use any of the Update possibilities.
Note: the definitions you set in in the record matching step are mainly for the new records in the main table! Records in qualified look ups are handled differently! If you open your map in Import Manager, switch to tab "Map Fields/Values". Select a field that is your non qualifier. Right-Click on it and choose "Set qualified update" from the context menu. Now you can define which qualifiers can be used for the qualified look up matching. And you can define as well what should happen with new and/or existing records.
Regarding the value mapping: do you use keymapping? Or do you use simple values only? Do you save the map everytime you add a new value mapping?
Regarding the issue "Encountered a pre-SP4 map. The map needs to be upgraded to SP4. Solution: Please, Launch the Import Manager GUI using the same source file and simply save the map". This sounds very likely like a bug in MDIS and should be reported to SAP!
Hope that helps
Michael

Problem with up-arrow on a long command line

I often use the "terminal" window to open up a connection (via ssh) to linux and unix boxes.
While I'm logged into the remote computer and I try to edit a previous command, I notice that my
display gets all fouled up if the command that I'm trying edit is very long. I'm unable to do the
usual unix tricks of up-arrowing to the command and then backspacing through it to perform my edits. Often my only recourse is to retype the entire command which is a pain and prone to error.
I'm using bash as my Mac shell and tcsh on the remote machines.
Has anybody experienced this? Any hints?

It's a visual-only problem with Terminal.app.
Other than the cosmetic effect, you will find that the editing works as you expect - you might just have to be psychic with regards to telling how far to backspace and where/when to make your edits.
The problem has been there for a long time. You might have better luck setting the terminal to a different emulation (Terminal -> Preferences -> Declare terminal as:) to see if one of the other emulations work for you, or use a different terminal application such as iTerm

Can't figure out where "up arrow" command on Mac for keyboard shortcuts.

You guys helped me fix the presets in LR, but now I have to go and do each image by hand. When I go to "photo" in the library module, then to "develop settings," and then to "reset," it shows a keyboard shortcut of an up arrow, the apple command and R. I have never figured out where that stupid arrow is on my MAC keyboard. I would appreciate your help with this one also. I have several thousand photos to get thru. Many thanks for your willingness to share your expertise!!!!
Dodie

Thank you so much for your time and patience! I am a middle aged woman who doesn't love computers. You have saved me a LOT of time.
dodie

Feedback on use of incubator command pattern

Hi,
We are currently prototyping some different solutions using coherence incubator (namely command pattern) and are looking for some feedback as to the viability and potential improvements to the solution.
h3. Summary of Prototype
The prototype does the following (i have a nice sequence diagram for this but don't see a way to attach it :():
+ client (e.g. through coherence extend) calls local api to save a "message" for a particular account (e.g. Account id = 1234). This calls namedcache.put and inserts an entry into the cache.
+ BackingMapListener is configured for the cache into which the client indirectly inserts. In the prototype this is a spring bean that extends AbstractMultiplexingBackingMapListener - which is fully "loaded" with all the required dependencies for the processing of the message (services, etc.).
+ The listener then registers a new context (using ContextManager) using a "grouping" id based on the sequence/ordering requirements. For example, say that each message against an account needs to be processed in order. The context would get instantiated with name = "1234", so that subsequent requests for account 1234 will get queued against the context with the same name whilst the previous request(s) are still processing. Messages for other accounts would register a different context name so they will get simultaneously processed.
NB: The functionality of this listener can be paralleled to the sample in CommandPatternExample for one submission. I am not entirely clear where command submissions typically "tie-in" but I am planning to kick them off from a backingmaplistener. I briefly explored using the 'com.oracle.coherence.common.events.dispatching.listeners.DelegatingBackingMapListener' to dispatch the commands but not entirely how this would tie in. As I understand it the delegating backingmaplistener is used within the 'liveobjects' context and dispatches entries that implement the LifecycleAwareEntry but not sure how we would create "custom-contexts" as we require (i.e. the identifier is not for the key of the cache entry but rather a subset of that -e.g. account id versus account message id).
+ A command is then created to process the account message, which is comprised of
- the Account which needs processed (the value of the backing map listener contains the Account itself)
- Any components that are required during processing (services, daos, etc - service might itself be injected with daos, etc.)
+ The newly instantiated command is then then submitted to the CommandSubmitter for the appropriate contextIdentifer (the one returned by 1234 in our example).
From some basic tests, the prototype is behaving as I desire - i.e. it queues and "synchronizes" the commands for the same context and also simultaneously processes commands assigned to different contexts asynchronously. That's great.
However, there are a number of things I am exploring for the actual implementation. I believe most of these are typical concerns so I wonder if Oracle or anyone can provide some feedback from past experience/proposed recommendations:
h3. Questions
h4. 1. Grid/server-side Business Logic Deployment
One of the things that has occurred to us is that ideally we would like to store the business processing logic (i.e. the heart of the processing within the command) either inside the grid or within a coherence node (i.e. made available through the classpath of the node startup).
In our case we have a few different "processing models", but ideally the processor/command will simply determine the appropriate control flow (i.e. within the command - or maybe the appropriate lifecycle if we end up using that) and associated business logic off the attributes of the object to be processed. I am not sure if our use case is typical, but to be clear we have a fair bit of business logic to be performed within the 'command', each in separate modules. In implementation, most modules will be interacting with the grid for lookups, etc. but ideally that will be abstracted from the Processor/Command which will only know that it is using an 'accountService' - for e.g.
Currently the business logic is "loaded" into the listener and "passed on" to the command through composition. Ideally we ant the command would be light-weight and the various "processing models" would either:
a) be deployed to each node and somehow "available" to the command during execution. Would need to work out how this would be come available to the execution environment; perhaps each 'Context' would wrap the processing details. However, even this is a bit too granular as likely a processing model will apply to many contexts.
b) Perhaps the business logic/processing components are deployed to the cache itself. Then within the command attributes on the object would be consulted to determine which processing model to "apply" and a simple lookup could return the appropriate control flow/processor(s).
c) Perhpaps the different logic/flow is embedded in a different "lifecycle" for the event processing and the appropriate lifecycle is detected by the listener and appropirately applied. Even with such a model we'd still like the various processing for each phase to be maintained in the server if possible.
Has anyone else done something like this and/or are there any thoughts about deploying the business logic to the grid this way? I see advantages/disadvantages with the different solutions, and some of them seem better for upgrades. For example if you upgrade the processing logic whilst requests are still coming in (clearly you would attempt to avoid this) and it is embedded into each node, what would happen if one node has been upgraded and a request comes to that node. Say one of the business logic modules performs a query against the cache which needs to consult another node (e.g. assuming you're using partitioned data) and that node has not received the upgrade and there's a conflict. In that regard perhaps deploying the different processing logic to a replicated cache makes more sense because once updated it should get pushed immediately to all nodes?
Are these known concerns? I'm new to grid-side processing concepts so just correct me if there's an obvious issue with tis.
h4. 2. Cleanup/Management of contexts
One thing I noticed on my prototype is that the context's that I create don't really go away. We are envisioning creating Many context per day (let's just say a few hundred million to be safe)
so ...
a) how do people normally remove the contexts? Does the command framework sort this out behind the scenes? I can see the 'stop' method on the CommandExecutor removing the context, but from a quick follow-through the only scenario which seems to potentially call this is if the context version number has changed. Is there some way to change the version when we submit additional commands to the same context?
b) Is there an issue with creating this many Contexts? As per earlier mention, to reduce overhead ideally the context will not be too heavy but any thoughts on our intended usage? We could use something like a hashing scheme to "bucket" the requests to contexts to reduce the total number of Contexts if required but this is not ideal.
h4. 3. Creation of new Command Every time.
In our scenario, each command needs to act upon a given object (e.g. one account). As I see it, this requires us to create a new Command for each message, because I do not see a way to 'pass in' the object to the execute method. Setting it to the context does not work either because we need to queue a few requests to each given context; I played with wrapping the object with GenericContext and setting the value but in reality we're submitting the commands whilst others are currently being processed so I don't see how this could work.
Any thoughts on this? Do you agree we'll have to create a new command for every message to be processed? We'll likely have millions of Commands per day so this will make a difference for us (although if we eliminate the logic from q#1 or the dependencies are singletons it's not a big deal)
h4. 4. Concurrency guarantees with the commandpattern
I also want to confirm my understanding of concurrency controls around the command pattern. Unlike an entry processor which controls updates to the entry upon which it was invoked, the command pattern only guarantees concurrency against processing occuring within the context of the currently operating command. Commands submitted to the same context will be processed synchronously but any entries which may have had a listener which spawned the command submission are in no way guarded. This latter point is pretty obvious I believe since there's no real link but I just want to make sure my assumptions are correct.
NB: in the scenario I am describing we do NOT need to update the original cache entry into which the account message was submitted. Instead other caches will be updated with results from additional processing logic so this is not that much of an issue for us.
h4. 5. Confirmation of concerns with "straight" entry processor
If we were to use a "straight" entry processor (versus command pattern which uses entry processor) which gets kicked off from a threadpool on a backing map listener (for example on insert or update), is it true that if a node were to go down, we would have issues with failover? NB: The reason we would kick off the entry processor from a threadpool would be to "simulate" asynchronous processing. As I see it, if we kicked off a thread on the listener and returned back to the client, nothing would "re-submit" the request if a node goes down. Is that correct?
ALTERNATIVELY, As I understand it, with an entry processor invoked from a client, it is the client coherence jar that receives the exception when a node goes down mid-process and the coherence jar takes care of "re-sending" the request to another node. So - if the threadpool is managed by the client and the client kicks off an invoke in one of the threads - then I believe the client WILL re-submit the entry processor requests if the node goes down - through the coherence jar/extend - not sure on the details but my point is that the client application does not have to provide any code for the "failover" but the coherence client jar performs this.
h4. 6. Lifecycle
I have not explored the "lifecycle" functionality available within the incubator - but as I understand it the main thing it could offer is that if we have many phases of the processing (as we do in most our use cases) - that the processing can be managed with the different lifecycles. NB: To be clear I am referring to 'live objects' with their own series of processing steps - not 100% if Lifecycle directly relates to 'live objects'. If a node goes down and is in the midst of processing 200,000 commands - the entire processing doesn't need to start over.. each request will need to go back to the previous completed phase of the lifecycle but may well avoid duplicated processing. All processing will need to be idempotent regardless, but lifecycles could avoid re-processing that was already complete.
Is this correct?
Other benefits?
(e.g. configurable processing logic as alluded to in Q#1).
Thanks very much
Edited by: 822486 on 21-Dec-2010 16:23
Edited by: 822486 on 21-Dec-2010 16:59

Hi User 822486,
When delving into a detailed prototype like the one you have below it's often useful to understand the use cases and business requirements before jumping into a solution. I think it may be best for you to reach out to the Coherence organization within oracle to further discuss these questions in detail so we can better guide you in the different ways to solve problems with Coherence and the incubator. I'll do my best to comment on your prototype and address the questions that you currently have:
NB: The functionality of this listener can be paralleled to the sample in CommandPatternExample for one submission. I am not entirely clear where command submissions typically "tie-in" but I am planning to kick them off from a backingmaplistener. I briefly explored using the 'com.oracle.coherence.common.events.dispatching.listeners.DelegatingBackingMapListener' to dispatch the commands but not entirely how this would tie in. As I understand it the delegating backingmaplistener is used within the 'liveobjects' context and dispatches entries that implement the LifecycleAwareEntry but not sure how we would create "custom-contexts" as we require (i.e. the identifier is not for the key of the cache entry but rather a subset of that -e.g. account id versus account message id).
Command submissions are just that, submissions to the command pattern for execution and they can be triggered from anywhere since they run asynchronously. The DelegatingBackingMapListener and the associated eventing model provides you with the foundations for building an Event Driven Architecture on top of coherence. It's used by both the Push Replication Pattern as well as the Messaging Pattern which you could use as references if you wanted to go down the path of using the eventing model as well. It really comes down to your use case (which I don't have a lot of details on at the moment). An Entry that is a LifecycleAwareEntry can basically take action when it's state is changed (an event occurs). As a completely bogus example you could have a AccountMessageDispatcher object in a cache with a DelegatingBackingMapListener configured and you could submit EntryProcessors to this dispatcher that gives it a set of messages to perform for a set of accounts. The Dispatcher could then every time it's updated submit commands for execution. In essence it's formalizing an approach to responding to events on entries - or server side event driven programming.
h2. Grid/server-side business logic deployment
Have you looked at the processing pattern at all? It's a framework for building compute grids on top of Coherence and may have more plumbing in place for you to achieve what you're looking for. I think it may be best for us to discuss your use case in more detail to understand the pros and cons of each approach before commenting further on a solution for you.
h2. Cleanup and Management of contexts
Contexts are marker interfaces so they can be incredibly lightweight which should allow you to create as many of them as you need. The biggest concern is ensuring that you have enough processing power in your grid to handle the volume of work you want to manage. This should be a simple matter of figuring out your load and sizing your cluster appropriately. The initial design of the command pattern was to have a set of well established contexts that would be used repeatedly. Given that the Command Pattern is primarily an example, you could extend the DefaultContextsManager to have an unregisterContext method.
h2. Creation of new command every time
I'm a little confused by your requirement here. Are you saying that you have a set of pre-defined operations that you want to apply to an account for example incrementAccountBalancyBy1? If so, I don't understand why you couldn't submit the same command instance to a context multiple times. While I wouldn't recommend using statics you could have a CommandFactory that returned the same command each time you call getCommand once it was instantiated once. Usually however we expect that you'll have some additional data unique to each message that the command must execute. This could be handled by having a setter on your command for these properties.
h2. Concurrency Guarantees
The Command Pattern Guaranteees that for a given context commands are processed synchronously in the order they are received. If you have multiple submitters sending commands to the same context, then the order of when the commands are processed will be based on the order in which they arrive at the node where the Context resides. A context is the control point that gives commands their ordering.
h2. Confirmation of concerns with "straight" entry processor
I'm not sure if I follow your question here. EntryProcessors are guaranteed to execute, even in the failure scenario (this is why they're backed up and why they must be idempotent). If you're referring to processing events based on a backing map listener rather than submitting commands, it handles your processing then it's a matter of wether you're asynchronously processing the events or not. If you are synchronously processing things and your node dies while the BML is executing you're right a node failure at that point will result in "nothing happening" and the client will re-try. If however you're asynchronously handling the events from your BML, then you could lose state. This is why we use entries the way we do in the common event layer, we persist state on an entry that we can't lose when a node fails. This allows us to asynchronously process the data after the node has been updated.
h2. Lifecycle
With respect to lifecycle if you're referring to LifeCycleAwareEntry - this is a way of designating that an Entry in the cache can process events when modified/mutated. This may be better discussed by phone or in person.

Mapping up arrow to repeat command on DBX

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