Blocking and non-blocking workflows

How to specify a workflow to be blocking and non-blocking?
Regards,
Miguel

When registering the custom workflow from Application Server Control (Enterprise Manager Web Site), you will see an option to specify whether the workflow is blocking:
Application Server Control > Content > Custom Workflows
Register Workflow
* Name
Description
* Launch Event
* Cancel Event
Blocking
Approvers Required

Similar Messages

Both blocking and non-blocking io

I'm wondering if this scenario is possible with the new nio classes:
I have a caching server. Clients connect to the server and occasionally send requests for objects. I'd like to use the nio non-blocking APIs to detect that there is a read pending on a socket. However, once I detect this, I'd like to go into a blocking loop to process the request. After this done, I'd like to go back into non-blocking mode and wait for another request.
It seems like this should be possible but the (woefully lacking) documentation isn't clear. Neither is the source code, apparently.
I've got a test case working but I was hoping someone could validate for me that this is support behavior. It's done by waiting for the isReadable() key then calling socket.keyFor(selector).cancel(); and then socket.configureBlocking(true); The reads are then done in blocking mode until the request is done and then the socket is registered with the selector again.
Thanks for any help on this.

I have to ask why you would want to mix blocking and non-blocking I/O.
The only reason you would (IMHO) want to use non-blocking I/O is in a highly concurrent system, to increase the maximum load a system can handle.
The main reason you would want to use blocking I/O rather than non-blocking I/O would be to minimise the latency for a single request.
Unfortunately, the two don't seem to mix together very well... by switching a thread to blocking, you decrease the latency for a single request, but increase latency for the other requests due to reduced resources available. Similarly, by switching to blocking, you are requiring a dedicated thread for that request, so limiting the number of concurrent requests that can be serviced.
That is, it seems to me that using both blocking and non-blocking I/O introduces the weaknesses of both into the system, without gaining much of the benefits of either.
The above aside, the method you gave looks like it would work as you expect, depending on what you are doing with thread creation/delegation. Did your test case work as expected?

SQL Developer blocking vs non-blocking

Hi,
Is there a way in SQL Developer 3.0 to have a non-blocking SQL call? In Oracle Forms we can choose between blocking and non-blocking SQL Net connections to the database. Does SQL Developer have the same capability? If so where exactly are those options hidden in the preferences menus?
Annoyed,
ScottK
Edited by: ScottK on Jun 1, 2011 11:20 AM

Hi ScottK,
SQLDeveloper locks access to individual connections when they are in use, if you want to simulate
some aspects of non blocking behaviour you can use other connections.
The following features might help:
Use a different connection name back to the same schema in your database - it will be treated as an independent connection and 'blocking' on this connection will not affect your other connections.
This can be achieved temporarily in the worksheet by:
ctrl shift n
which creates a worksheet with new connection independent of your existing worksheet connection
though connected to the same schema and database.
-Turloch
SQLDeveloper team

UTL_TCP (blocking or non-blocking sockets mode)

Hi for All,
Please, someone knows if the UTL_TCP using blocking or non-blocking sockets mode? I did a search but can not find this information.
Regards,

Blocking only occurs when you attempt to read from the socket and there's no data to read. (in which case, the time out setting applies if specified)
This is however not that robust in my experience. UTL_TCP provides a peek method (returns byte size of socket buffer) that tells you whether or not there is data for that socket. This enables you to verify that you read on that socket will not be a blocking call.
I prefer using this method, as dealing with a timeout approach results in run-time behaviour issues (either a call waiting too long, or a call timing out too quickly).

Reg Price block and Qty block in MM Invoice docs Tolerence Keys adjustment

Hi Friends,
Related to MM Invoice documents gets blocked with Price block and Qty block,based on this FI doc also gets blocked with Payment block indicator"R".As per Std SAP we can remove these blocks thru MRBR. Right now my users are asking not required to remove these blocks with MRBR Tcode.
So i checked the Tolerence Limits defined for the co code and Tolerence keys.
As per my understanding Tolerence Keys "PP-Price variance", "DQ-Exceed amount: quantity variance" need to adjust with upper llimits and Lower Limits.
here i can see Upper and Lower check limit Tolerance limit 5.00% for Tolerence Key "PP-Price variance"
Tolerence limit 0.01% for Tolerence key "DQ-Exceed amount: quantity :quantity variance
Instead of changing the Tolerence Limits can i select the DO NOT CHECK Radio button for the bothe Price and Qty block.
If i selected the DO NOT check button what will happen,how it works.
How i can maintain the Tolerence keys,is there any other Tolerence keys also need to maintain.
Please suggest me with your valuable inputs.
Brgds,
RK
Edited by: RK.SAP on Nov 17, 2010 7:02 AM

hi,
If you do not want to check the Invoice for tolerance keys like quantity variance and price varaince then tick on don't check .In this case system will not block any invoice and invoice will post Automatically without any error.
Please check other tolerance keys in SPRO: OMR6
One more blocking is defined in the vendor master also under payment transactions accounting screen.There you are defining the tolerance group for Invoice Verification.
Regards,
Amit

Set Posting block and Purchasing block automatically upon vendor creation

Hi.
I have a requirement to automatically set the purchasing block and posting block to 'X' upon creation of vendor master. I have seen a user exit to do this but then I can't seem to find a way to set the SPERM field to 'X'.
Please help. THanks.

Transaction FIBF start the event manager.
on menu: environment->info system (P/S) and then execute: it will be displayed all possible events.
between event 1410 and 1460, you will find all events about vendor.
click on documentation, it will tell you when the event is reached and what you can do.
After you have choose an event, you must create a function module, copying it from the sample function module of the event.
Once you have created your own funcion module, you should go to:
FIBF->SETTINGS->P/S MODULES.
This part of customization is not very clear to me, i've never done by myself. Anyway, here you associate at the businness event the function module you have created.
Sorry for not beeing exaustive, hope anyway could be help you.
Regards
Andrea

Problem in Execute query on non-database block and database block together

Hi All,
In my form,i have
1. First block is Non-database block with one non-database item.
2. Second and third blocks are database blocks.
Now the problem is that i want to perform execute-query for all the blocks.
If the cursor is on the non-database item of 1st block and i clicks on the "Enter-query" then i am getting message " This function can not be performed here".
If i click on the item of the database block and then clicks on the "Enter-query" and then "execute-query" it's working fine.
But i don't want to do in this way.
My cursor will be on the First block only and then it should perform execute-query.
I am using this non-database item to copy value of this item to the item of the database block item.
I think i make you understand about my problem.
I am using forms 10g on Window xp.
Please help me.

Hi!
Simply create a enter-query trigger on the non-database-block:
begin
go_block ( 'database_block' );
enter_query;
end;If your search criteria is in the non-database-item in the first block,
you actually do not need the enter_query build-in.
Just create a execute-query trigger on the first block like:
begin
go_block ( 'database_block' );
execute_query;
go_item ( :System.trigger_item );
end;And in a pre-query trigger on the database-block copy the
value of your seach item into the item you want to search for.
Regards

OCCI and non-blocking

I'd like to use the OCCI interface in a non-blocking mode. Does anyone have any experience with this? Looks like I need to use a combo of OCI and OCCI calls to set the OCI_HTYPE_SERVER handle with the OCI_ATTR_NONBLOCKING MODE. However, my stmt->executeQuery() method seems to be throwing an exceptions, which I would have though would have been the OCI_STILL_EXECUTING error, but it's not. The exeception is an "ORA-32103 error from OCI call". If I continue to do another stmt->executeQuery(), I eventually get an access exception.
Anyone have any code snippets using OCCI in non-blocking mode?

I use threads. ACE/TAO to be precise.
I have singleton class that manages the Oracle environment and connection as well as being a statement
factory.
Just have a thread perform your stmt->executeXXX() method and you will not need to worry about non-blocking.
That's how I do it and it works well.

Chaining WritableByteChannels and non-blocking I/O?

Hello all,
Suppose I want to implement a data transformation algorithm that works in chunks of say 4 bytes.
The algorithm would hook into existing I/O paradigms for writing and reading data.
Ignoring the transformation algorithm for now (it is actually irrelevant for my question), let's just I need to buffer data in 4-byte chunks.
Since I want to make as little assumptions as possible about the decorated channel, BufferingWritableByteChannel needs to work channels in blocking and in non-blocking mode.
When the decorated channel is in non-blocking mode, BuffereingWritableByteChannel may behave as in non-blocking mode itself, which is fine by me.
However the problem is with the residual bytes: they do not get written until the close() method is called.
I have implemented the close() method to be blocking (the while loop with the ugly yield() calls), so even when the decorated channel is in non-blocking mode everything will get written properly.
However, writing potentially blocking calls (busy loops) in close() methods seems like a bad idea...
So the question is:
Is there a better way of doing this?
Can I avoid having to write busy loops?
package nio;
import java.io.IOException;
import java.nio.ByteBuffer;
import java.nio.channels.WritableByteChannel;
import static nio.ChannelUtils.*;
public class BufferingWritableByteChannel implements WritableByteChannel {
private final WritableByteChannel decoratedChannel;
private final ByteBuffer buffer = ByteBuffer.allocate(4);
private boolean buffering = true;
public BufferingWritableByteChannel(WritableByteChannel decoratedChannel) {
    this.decoratedChannel = decoratedChannel;
public synchronized void close() throws IOException {
    if (buffering) {
      buffer.flip();
    writeBlockingly(decoratedChannel, buffer);
    buffer.clear();
    decoratedChannel.close();
public synchronized boolean isOpen() {
    return decoratedChannel.isOpen();
public synchronized int write(ByteBuffer input) throws IOException {
    int bytesWritten = 0;
    if (!buffering) {
      decoratedChannel.write(buffer);
      if (buffer.hasRemaining()) { // May happen when decorated channel in non-blocking mode
        return bytesWritten;
      buffer.clear();
      buffering = true;
    while (input.hasRemaining()) {
      bytesWritten += putAsMuchAsPossible(input, buffer);
      if (!buffer.hasRemaining()) {
        buffer.flip();
        decoratedChannel.write(buffer);
        if (buffer.hasRemaining()) { // May happen when decorated channel in non-blocking mode
          buffering = false;
          return bytesWritten;
        buffer.clear();
    return bytesWritten;
package nio;
import java.io.IOException;
import java.nio.BufferOverflowException;
import java.nio.ByteBuffer;
import java.nio.channels.WritableByteChannel;
public class ChannelUtils {
private ChannelUtils() {
   * Blockingly writes data to a channel, even if the channel is in non-blocking mode.
public static final int writeBlockingly(WritableByteChannel channel, ByteBuffer buffer) throws IOException {
    int bytesWritten = 0;
    boolean yield = false;
    while (buffer.hasRemaining()) {
      bytesWritten += channel.write(buffer);
      if (yield)
        Thread.yield();
      else
        yield = true;
    return bytesWritten;
   * Puts as much bytes as possible from an input buffer into an output buffer, avoiding {@link BufferOverflowException}.
public static final int putAsMuchAsPossible(ByteBuffer input, ByteBuffer output) {
    int bytesWritten = Math.min(input.remaining(), output.remaining());
    ByteBuffer inputSlice = input.slice();
    inputSlice.limit(inputSlice.position() + bytesWritten);
    output.put(inputSlice);
    input.position(input.position() + bytesWritten);
    return bytesWritten;
}

Hello all,
Suppose I want to implement a data transformation algorithm that works in chunks of say 4 bytes.
The algorithm would hook into existing I/O paradigms for writing and reading data.
Ignoring the transformation algorithm for now (it is actually irrelevant for my question), let's just I need to buffer data in 4-byte chunks.
Since I want to make as little assumptions as possible about the decorated channel, BufferingWritableByteChannel needs to work channels in blocking and in non-blocking mode.
When the decorated channel is in non-blocking mode, BuffereingWritableByteChannel may behave as in non-blocking mode itself, which is fine by me.
However the problem is with the residual bytes: they do not get written until the close() method is called.
I have implemented the close() method to be blocking (the while loop with the ugly yield() calls), so even when the decorated channel is in non-blocking mode everything will get written properly.
However, writing potentially blocking calls (busy loops) in close() methods seems like a bad idea...
So the question is:
Is there a better way of doing this?
Can I avoid having to write busy loops?
package nio;
import java.io.IOException;
import java.nio.ByteBuffer;
import java.nio.channels.WritableByteChannel;
import static nio.ChannelUtils.*;
public class BufferingWritableByteChannel implements WritableByteChannel {
private final WritableByteChannel decoratedChannel;
private final ByteBuffer buffer = ByteBuffer.allocate(4);
private boolean buffering = true;
public BufferingWritableByteChannel(WritableByteChannel decoratedChannel) {
    this.decoratedChannel = decoratedChannel;
public synchronized void close() throws IOException {
    if (buffering) {
      buffer.flip();
    writeBlockingly(decoratedChannel, buffer);
    buffer.clear();
    decoratedChannel.close();
public synchronized boolean isOpen() {
    return decoratedChannel.isOpen();
public synchronized int write(ByteBuffer input) throws IOException {
    int bytesWritten = 0;
    if (!buffering) {
      decoratedChannel.write(buffer);
      if (buffer.hasRemaining()) { // May happen when decorated channel in non-blocking mode
        return bytesWritten;
      buffer.clear();
      buffering = true;
    while (input.hasRemaining()) {
      bytesWritten += putAsMuchAsPossible(input, buffer);
      if (!buffer.hasRemaining()) {
        buffer.flip();
        decoratedChannel.write(buffer);
        if (buffer.hasRemaining()) { // May happen when decorated channel in non-blocking mode
          buffering = false;
          return bytesWritten;
        buffer.clear();
    return bytesWritten;
package nio;
import java.io.IOException;
import java.nio.BufferOverflowException;
import java.nio.ByteBuffer;
import java.nio.channels.WritableByteChannel;
public class ChannelUtils {
private ChannelUtils() {
   * Blockingly writes data to a channel, even if the channel is in non-blocking mode.
public static final int writeBlockingly(WritableByteChannel channel, ByteBuffer buffer) throws IOException {
    int bytesWritten = 0;
    boolean yield = false;
    while (buffer.hasRemaining()) {
      bytesWritten += channel.write(buffer);
      if (yield)
        Thread.yield();
      else
        yield = true;
    return bytesWritten;
   * Puts as much bytes as possible from an input buffer into an output buffer, avoiding {@link BufferOverflowException}.
public static final int putAsMuchAsPossible(ByteBuffer input, ByteBuffer output) {
    int bytesWritten = Math.min(input.remaining(), output.remaining());
    ByteBuffer inputSlice = input.slice();
    inputSlice.limit(inputSlice.position() + bytesWritten);
    output.put(inputSlice);
    input.position(input.position() + bytesWritten);
    return bytesWritten;
}

Troubles with timeout using java.nio.channels and non-blocking sockets

Hello.
I have a server application that employs java.nio.channels with non-blocking sockets.
The server waits for connections. The client should connect and be first in sending data.
Timeouts are significant! If client exceeds the allowed time to send data, the server should break the connection.
The huge trouble I've discovered that I cannot control the timeout when client connects but remains silent.
My code looks as follows:
<pre>
Selector oSel;
SocketChannel oSockChan;
Socket oSock;
SelectionKey oSelKey;
Iterator<SelectionKey> oItSelKeys;
int iCurrState, iMask, iCount;
iCurrState = INT_SERVER_WORKING;
iMask = SelectionKey.OP_ACCEPT | SelectionKey.OP_CONNECT | SelectionKey.OP_READ | SelectionKey.OP_WRITE;
while ( iCurrState == INT_SERVER_WORKING )
try
*// retrieving next action*
iCount = oSel.select();
if ( iCount > 0 )
oItSelKeys = oSel.selectedKeys().iterator();
while ( oItSelKeys.hasNext() )
oSelKey = oItSelKeys.next();
oItSelKeys.remove();
if ( oSelKey.isValid() )
switch ( oSelKey.readyOps() & iMask ) {
case SelectionKey.OP_ACCEPT :
oSockChan = oSSockChan.accept();
oSockChan.configureBlocking(false);
oSock = oSockChan.socket();
oSock.setKeepAlive(true);
oSockChan.register(oSel,SelectionKey.OP_READ,new MyPacket(oSock.getInetAddress(),oSock.getPort()));
break;
case SelectionKey.OP_READ :
oSelKey.interestOps(0);
((MyPacket) oSelKey.attachment()).inRequest(); *// preparing request*
this.getReader().add(oSelKey); *// sending key to reading thread*
break;
case SelectionKey.OP_WRITE :
oSelKey.interestOps(0);
((MyRequest) oSelKey.attachment()).inResponse(); *// preparing response*
this.getWriter().add(oSelKey); *// sending key to writing thread*
break;
case SelectionKey.OP_CONNECT :
default :
*// nothing to do*
catch ( IOException oExcept )
*// do some actions*
</pre>
Timeouts are easily controlled by reading and writing threads (see OP_READ and OP_WRITE ).
But when a client just connects without consequent data send, the state of this connection remains as OP_ACCEPT. The connection remains open for arbitrarily large time and I cannot control it!
Please help with idea how can I terminate such connections!

How can I process the keys that weren't selected at the bottom of the loop? Should I use the method keys() ?Yes. Form a new set from keys() and removeAll(selectedKeys()). Do that before you process selectedKeys().
And the second moment: as I understood a single key may contain several operations simultaneously? Thus I should use several if's (but not if/else 'cause it's the equivalent of switch ... case ).If there is anything unclear about 'your switch statement is invalid. You need an if/else chain' I fail to see what it is. Try reading it again. And if several ifs were really the equivalent of "switch ... case", there wouldn't be a problem in the first place. They're not, and there is.

Release Invoice Price Block and Quantity Block

Hi,
How can I release the Invoice Price and Quantity block at the same time? I need to create a Step in a work flow to release all blocks of a two-way match block invoice.
I've already tried to have a BDC for transaction MRBR but it is not working.
Can anyone help?

Hi Simi,
This type of behaviour is documented in SAP note 394370:
"A document generated with MIRO was blocked for payment.You cancel the
payment block from the vendor line item in the FI follow-up
document.Transaction MRBR then displays the invoice document
nevertheless. Why?
The invoice document itself cannot be changed by changes to the
follow-up documents; this is not programmed.Transaction MRBR therefore
continues to display the document as blocked. If this document is
released from an MM point of view, the FI follow-up document remains
released.Thus the damage caused is restricted to unnecessary work by the
user.
SAP recommends that you only use the release transactions for releasing
invoices."
MRBR generates its list of blocked invoices from table RBKP_BLOCKED and is the
only transaction which deletes entries from this table thats why when your report
calls FB02 to remove the payent block MRBR will still show the invoice as blocked.
You could code in a pop up message in your report that prevents the user from
deleting the payment block and to advise using MRBR instead to delete the block.
Hope this helps,
Adam.

Page up and page down to go to next block and previous block

hii all
I want to incorporate a functionality which when the user clicks the page up button the cursor should navigate to the previous block and if i press the page down button the cursor should navigate to the next block
are there any triggersto do this ??
plzz help
thanks
mandar

hii
thanks for ur response
i have written the code told my james
i have two blokcs master and details
i press the page down key to navigate to the details block from the master block..
after writing the code and executng the form when i press page down key
the message appears that at last block but the cursor still remains in that block only how do i make the cursor to next block ??
plzz help
mandar

Max-width Ignored on fo:block and fo:block-container

I am writing an XSLT template using XSL-FO and I have an fo:block for which I want to limit the width. I set the property max-width to "3in" on the block, and that did nothing. Then I put the block into an fo:block-container and set the max-width property of it to "3in", and this was also ignored.
Is this a bug in the rendering engine or am I doing something wrong?
The block is in an fo:static-content.
Thanks,
Kurz

I'm not exactly sure I get what you intention is, but here are a few things to consider maybe.
max width will not make the image expand, just keep it from being any wider than the max width.
images by default display as in line. To make a width property work reliably, you will need to set it to block:
div#secondaries ol.secondary li div.item-img img {
display: block;
width: 100%;
image width as set above will be affected by its containers. (If you meant to limit the width of the image rather than to resize it, the same thing should still be true of a max-width on the image, though cross-browser support will be unreliable.)
The relevant container for the case above is:
div#secondaries ol.secondary li {
font-size: 1.1em;
width: 30%;
margin-top: 0em;
margin-bottom: 1.5em;
margin-left: 0em;
So do you really mean it to be 30% or did you mean 100%.

FileInputStream.read() and non-blocking file i/o

According to the API, FileInputStream.read() is :
public native int read() throws IOException
Reads a byte of data from this input stream. This method blocks if no input is yet available.
Returns:
the next byte of data, or -1 if the end of the file is reached.In what instances does the read() blocks? Is there a danger that the call to read() would block forever?

thanks martian!
is the ff code right enough to prevent i/o blocking?
FileInputStream fis = new FileInputStream(src);
FileOutputStream fos = new FileOutputStream(sPersistorFolder+src.getName());
if(fis.available() > 0) {
    int c = -1;
    while((c=fis.read()) != -1) {
      fos.write(c);
fis.close();
fos.close();

Co-relation between oracle blocks and OS blocks ??

how is the database data-block co-related withe the OS data-block ??

Akshay, 
 
Ca va, merci. ;-) 
In the doc above, we can read "Each operating system has a block size. Oracle requests data in multiples of Oracle data blocks, not operating system blocks.". 
 
Anyway, you can search into Oracle doc, and find DB_BLOCK_SIZE Initialization Parameter : If a database's block size is different from the operating system block size, make the database block size a multiple of the operating system's block size. 
 
Nicolas.

Blocking and non-blocking workflows

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