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| Java Plug-in and Global Environment |
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| EKhalil |
 Posted: Thu May 06, 2004 4:13 am Post subject: Java Plug-in and Global Environment |
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Voyager
Joined: 29 Apr 2003
Posts: 99
Location: Boston, MA
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Hey,
Could someone please provide some input …
The Java Plug-in - MQInquiryNode (developed in-house) inquires on queues or other MQObjects' attributes and stores the values it retrieves in the Environment.Variables tree.
The Flow/s - MQInquiryNode is used in the Exception Handling sub flow, which is wired off the input node catch terminal.
Scenario - The message flow receives an MRM message which is too long/short for the message format specified in the statement:
CREATE LASTCHILD OF Environment.Variables.MRM_Record DOMAIN 'MRM' PARSE (bitstream(InputBody), 785, 500, 'DPDEFT807O001', 'HubReplyMessage', 'CWF').
When later attempting to reference a field within this record, a parser error is thrown indicating buffer underrun/overflow, which sends the message down the exception handling path. The first compute node in the exception handling path inserts several fields into the Environment.Variables tree, then a later trace node produces a trace of the Environment.Variables tree, including Environment.Variables.MRM_Record. Depending on the length of the message, the trace contains either the whole message (if the incoming test message was too long) or a truncated one (if too short).
Now the message is passed to the plug-in. In the plug-in, an error occurs while invoking the propagate method and the trace node following the plug-in produces a trace, which stops at Environment.Variables.MRM_Record.
The Question - How is the in-house node different from the primitives that it can not deal with the message being present in the Environment??? What exactly happens to the Environment when the CREATE/PARSE fails? I can see the overlaying MRM format in the trace, but the left over bytes are not visible. Are they in the Environment? |
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| Sandman |
| Posted: Thu May 13, 2004 12:14 pm Post subject: |
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Centurion
Joined: 16 Oct 2001
Posts: 134
Location: Lincoln, RI
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Anyone?  |
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| jefflowrey |
| Posted: Thu May 13, 2004 12:41 pm Post subject: |
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Grand Poobah
Joined: 16 Oct 2002
Posts: 19981
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I think the answer to
| Quote: |
| How is the in-house node different from the primitives that it can not deal with the message being present in the Environment??? |
is that it's an in-house node, rather than an IBM developed node.
Other than that... 
_________________
I am *not* the model of the modern major general. |
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| Sandman |
| Posted: Thu May 13, 2004 12:46 pm Post subject: |
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Centurion
Joined: 16 Oct 2001
Posts: 134
Location: Lincoln, RI
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| But we even tried commenting out the code that adds items to the Environment and simply pass the message and all its parts through unchanged. Still same problem. |
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| jefflowrey |
| Posted: Thu May 13, 2004 1:05 pm Post subject: |
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Grand Poobah
Joined: 16 Oct 2002
Posts: 19981
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Can we see the code?
_________________
I am *not* the model of the modern major general. |
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| Sandman |
| Posted: Mon May 17, 2004 7:12 am Post subject: |
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Centurion
Joined: 16 Oct 2001
Posts: 134
Location: Lincoln, RI
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Sure. Let's start w/ this. If you'd like to see more, let me know.
Thank you!
Here's the MQInquiryNode:
| Code: |
package com.XXXXX.wmqi.plugins;
import java.util.Hashtable;
import com.XXXXX.wmq.MQManagedObjectInquiry;
import com.ibm.broker.plugin.MbElement;
import com.ibm.broker.plugin.MbException;
import com.ibm.broker.plugin.MbInputTerminal;
import com.ibm.broker.plugin.MbMessage;
import com.ibm.broker.plugin.MbMessageAssembly;
import com.ibm.broker.plugin.MbNodeInterface;
/**
* @author a4654
*
* This plugin class will query any MQ managed object and return the
* attributes in the global environment.
*/
public class MQInquiryNode extends XXXXXMbNode implements MbNodeInterface {
private static final String nodeName = "MQInquiryNode";
private final String VARIABLE_ELEMENT_NAME_TAG = "Variables";
private String objectType = "Queue";
private String objectTypeID = null;
private String objectName = null;
private String selectorFileName = "selectors.properties";
private MQManagedObjectInquiry mqMOI = null;
/**
* @see java.lang.Object#Object()
*/
public MQInquiryNode() throws Exception {
createInputTerminal("in");
createOutputTerminal("out");
createOutputTerminal("failure");
}
/**
* Method getNodeName declares the name of this node to the broker.
* @return String
*/
public static String getNodeName() {
return nodeName;
}
/**
* Method getObjectName.
* @return String
*/
public String getObjectName() {
return objectName;
}
/**
* Method setObjectName.
* @param attr
*/
public void setObjectName(String attr) {
objectName = attr;
logMessage(LOG_INFORMATIONAL_MSG, "Object Name set to " + attr, "setObjectName");
}
/**
* Method getSelectorFileName.
* @return String
*/
public String getSelectorFileName() {
return selectorFileName;
}
/**
* Method setSelectorFileName.
* @param attr
*/
public void setSelectorFileName(String attr) {
selectorFileName = attr;
logMessage(LOG_INFORMATIONAL_MSG, "Selector File Name set to " + attr, "setSelectorFileName");
}
/**
* Method getObjectType.
* @return String
*/
public String getObjectType() {
return objectType;
}
/**
* Method setObjectType.
* @param attr
* @throws Exception
*/
public void setObjectType(String attr) throws MbException {
if (getObjectType().equalsIgnoreCase("Queue")) {
setObjectTypeID(MQManagedObjectInquiry.QUEUE_OBJECT_TYPE);
}
else if (getObjectType().equalsIgnoreCase("QueueManager")) {
setObjectTypeID(MQManagedObjectInquiry.QUEUEMANAGER_OBJECT_TYPE);
}
else if (getObjectType().equalsIgnoreCase("Process")) {
setObjectTypeID(MQManagedObjectInquiry.PROCESS_OBJECT_TYPE);
}
else if (getObjectType().equalsIgnoreCase("NameList")) {
setObjectTypeID(MQManagedObjectInquiry.NAME_LIST_OBJECT_TYPE);
}
else {
throw getMbUserException("The object type " + attr + " is not a valid type.", "setObjectType");
}
objectType = attr;
logMessage(LOG_INFORMATIONAL_MSG, "Object Type set to " + attr, "setObjectType");
}
/**
* Method setObjectTypeID.
* @param objectTypeID
*/
private void setObjectTypeID(String objectTypeID) {
this.objectTypeID = objectTypeID;
logMessage(LOG_INFORMATIONAL_MSG, "Object Type ID set to " + objectTypeID, "setObjectTypeID");
}
/**
* Method getObjectTypeID.
* @return String
*/
private String getObjectTypeID() {
return objectTypeID;
}
/**
* Method getMQMOInquiry.
* @return MQManagedObjectInquiry
* @throws Exception
*/
private synchronized MQManagedObjectInquiry getMQMOInquiry() throws Exception {
if (null == mqMOI) {
mqMOI = new MQManagedObjectInquiry(getSelectorFileName(), getBroker().getQueueManagerName());
}
return mqMOI;
}
/**
* Method onDelete.
*/
public void onDelete() {
if (null != mqMOI) {
mqMOI.cleanUp();
mqMOI = null;
}
}
/**
* @see com.ibm.broker.plugin.MbNodeInterface#evaluate(MbMessageAssembly, MbInputTerminal)
*/
public void evaluate(MbMessageAssembly assembly, MbInputTerminal inputTerm) throws MbException {
Hashtable attributes = null;
try {
logMessage(LOG_INFORMATIONAL_MSG, "Starting evaluate function", "evaluate");
if (getObjectTypeID().equalsIgnoreCase(MQManagedObjectInquiry.QUEUE_OBJECT_TYPE)) {
if (null == objectName || objectName.trim().length() < 1) {
setObjectName(getQueueNameFromMessage(assembly.getMessage()));
}
}
attributes = getMQMOInquiry().getObjectAttributes(getObjectTypeID(), getObjectName());
logMessage(LOG_INFORMATIONAL_MSG, "MQ Managed Object attributes successfully retrieved", "evaluate");
MbMessage env = new MbMessage(assembly.getGlobalEnvironment());
loadElements(attributes, getElement(env.getRootElement(), VARIABLE_ELEMENT_NAME_TAG, MbElement.TYPE_NAME));
logMessage(LOG_INFORMATIONAL_MSG, "Environment successfully loaded", "evaluate");
getOutputTerminal("out").propagate(
new MbMessageAssembly(assembly, assembly.getLocalEnvironment(), env, assembly.getExceptionList(), assembly.getMessage()));
logMessage(LOG_INFORMATIONAL_MSG, "Output message successfully propogated to out terminal - exiting node now", "evaluate");
}
catch (Exception e) {
logMessage(LOG_ERROR_MSG, e.toString(), "evaluate");
if (getOutputTerminal("failure").isAttached()) {
getOutputTerminal("failure").propagate(assembly);
}
}
catch (Throwable t) {
logMessage(LOG_ERROR_MSG, "The following fatal error occurred: " + t.toString(), "evaluate");
throw getMbUserException("The following fatal error occurred: " + t.toString(), "evaluate");
}
}
/**
* Method getQueueNameFromMessage.
* @param msg The message portion of the assembly passed to the evaluate function.
* @return String
* @throws MbException
*/
protected String getQueueNameFromMessage(MbMessage msg) throws Exception {
String queueName = null;
try {
queueName = (String) msg.getRootElement().getFirstElementByPath("/MQMD/SourceQueue").getValue();
}
catch (Exception e) {
throw new Exception("Error retrieving queue name from message: " + e.toString());
}
return queueName;
}
}
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And here's the XXXXXMBNode:
| Code: |
package com.XXXXX.wmqi.plugins;
import java.util.Enumeration;
import java.util.Hashtable;
import com.ibm.broker.plugin.MbElement;
import com.ibm.broker.plugin.MbException;
import com.ibm.broker.plugin.MbInputTerminal;
import com.ibm.broker.plugin.MbMessage;
import com.ibm.broker.plugin.MbMessageAssembly;
import com.ibm.broker.plugin.MbNode;
import com.ibm.broker.plugin.MbNodeInterface;
import com.ibm.broker.plugin.MbService;
import com.ibm.broker.plugin.MbUserException;
/**
* @author a4654
*
* This is the base class for all plugins created by XXXXX.
*/
public abstract class XXXXXMbNode extends MbNode {
public final int LOG_INFORMATIONAL_MSG = 1;
public final int LOG_WARNING_MSG = 2;
public final int LOG_ERROR_MSG = 3;
private final String ELEMENT_PATH_DELIMITER_TAG = "./";
private boolean debug = false;
/**
* @see java.lang.Object#Object()
*/
public XXXXXMbNode() throws MbException {
super();
}
/**
* The setDebug method sets whether informational messages are logged or not.
* @param attr "<b>True</b>" if informational messages are wanted or "<b>False</b>"
* if informational messages are not wanted.
*/
public void setDebug(String attr) {
setDebug(Boolean.getBoolean(attr));
}
/**
* @param attr
*/
protected void setDebug(boolean attr) {
debug = attr;
}
/**
* @return
*/
public String getDebug() {
return String.valueOf(debug);
}
/**
* The isDebug returns a boolean indicating whether informational messages are logged or not.
* @return boolean
*/
public boolean isDebug() {
return debug;
}
/**
* The logMessage method will log an informational, warning or error message based
* on the <i>msgType</i> provided.
* <ul>
* <li>Informational Message Code = 4360</li>
* <li>Warning Message Code = 4361</li>
* <li>Error Message Code = 4362</li>
* </ul>
* @param msgType Available types are:
* <ul>
* <li>LOG_INFORMATIONAL_MSG</li>
* <li>LOG_WARNING_MSG</li>
* <li>LOG_ERROR_MSG</li>
* </ul>
* @param msgText Message to be displayed in the log.
* @param functionName Name of the function in which the message was logged
*/
public void logMessage(int msgType, String msgText, String functionName) {
try {
switch (msgType) {
case LOG_INFORMATIONAL_MSG :
if (isDebug()) {
MbService.logInformation(
getClass().getName(),
functionName,
"WMQIv210",
"4360",
msgText,
new String[] { msgText });
}
break;
case LOG_WARNING_MSG :
MbService.logWarning(
getClass().getName(),
functionName,
"WMQIv210",
"4361",
msgText,
new String[] { msgText });
break;
case LOG_ERROR_MSG :
MbService.logError(
getClass().getName(),
functionName,
"WMQIv210",
"4362",
msgText,
new String[] { msgText });
break;
}
}
catch (Exception e) {
}
}
/**
* The getMbUserException returns a MbUserException with error code of 4362.
* @param errorText Text describing the error
* @param functionName Name of the function from which the error was thrown
* @return MbUserException
*/
public MbUserException getMbUserException(String errorText, String functionName) {
return new MbUserException(
getClass().getName(),
functionName,
"WMQIv210",
"4362",
errorText,
new String[] { errorText });
}
/**
* Method loadEnvironment.
* @param elements Hashtable containing all the elements to be loaded into the
* parent element <i>parentElement</>
* @param parentElement The element into which elements in <i>elements</i> will be added.
* @throws MbException
*/
protected void loadElements(Hashtable elements, MbElement parentElement) throws Exception {
String elementToAddName;
MbElement newElement;
Object elementObjectToAdd;
try {
Enumeration elementNames = elements.keys();
while (elementNames.hasMoreElements()) {
elementToAddName = (String)elementNames.nextElement();
elementObjectToAdd = elements.get(elementToAddName);
if (elementObjectToAdd.getClass().getName().indexOf("Hashtable") >= 0) {
loadElements((Hashtable)elementObjectToAdd, getElement(parentElement, elementToAddName, MbElement.TYPE_NAME));
}
else {
newElement = getElement(parentElement, elementToAddName, MbElement.TYPE_VALUE);
newElement.setValue(elements.get(elementToAddName));
}
}
}
catch (Exception e) {
throw new Exception("Error loading attributes into the environment: " + e.toString());
}
}
/**
* This method will return the first element in the <i>parentElement</i>
* with the name <i>elementName</i>. If the element named <i>elementName</i>
* is not found it will be created and returned.
* @param parentElement The parent of the element being retrieved or added
* @param elementName The name of the element being retrieved or added
* @param elementType The type of the element being added
* @return MbElement
* @throws MbException
*/
protected MbElement getElement(MbElement parentElement, String elementName, int elementType)
throws MbException {
MbElement element =
parentElement.getFirstElementByPath(ELEMENT_PATH_DELIMITER_TAG + elementName);
if (null == element) {
element = parentElement.createElementAsLastChild(elementType);
element.setName(elementName);
}
return element;
}
}
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| Sandman |
| Posted: Thu May 20, 2004 7:13 am Post subject: |
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Centurion
Joined: 16 Oct 2001
Posts: 134
Location: Lincoln, RI
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