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How do I move source code to a another package/group ID?

The trick here is changing the package name in multiple places. It is easiest to let Eclipse handle most of it (via Refactor->Rename).

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<dependencySet>
   <outputFileNameMapping>${artifact.artifactId}-${artifact.baseVersion}${dashClassifier?}.${artifact.extension}</outputFileNameMapping>
   <unpack>false</unpack>
   <useTransitiveDependencies>false</useTransitiveDependencies>
   <outputDirectory>bundles/aspire</outputDirectory>
   <includes>
     <include>com.newgroupid:*</include>
   </includes>
 </dependencySet>

JUNIT returns "Class Not Found" error

Things to try:

• Run a "Project/Clean..." command (within Eclipse) on your project.
• Right-click on your component project and do "Configure Build Path...", then go to the "Order and Export" task and make any dependent projects are moved to the top, before the Java System Libraries.

Error When Checking Out A Maven Project From Subversion

(within Eclipse)

The error is:

...

Check out the Subversion Console and the Maven Console for more details.

IE may try and turn our XML files into feeds

Try to avoid using metadata tags which start with "<rss" or "<feed", e.g., <feederLabel>.

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IE may then report that the XML file can not be parsed as an RSS feed (or some such error).

How do I solve class loading errors when running my third party code in OSGI?

When running under just the component test bench, everything worked fine, but when running under the application test bench, a third-party JAR is unable to locate its own properties file.

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// Reset the classloader for this thread to prevent issues finding the ROME properties file
// and classes
if (!Thread.currentThread().getContextClassLoader().equals(SyndFeedInput.class.getClassLoader())) {
	System.out.println("Setting ClassLoader");
    Thread.currentThread().setContextClassLoader(SyndFeedInput.class.getClassLoader());
} else {
     System.out.println("!!! ClassLoader equal");
}

How to load a class from an external JAR file

You need to create a classloader containing the current classloader and the JAR file you wish to use. Try the following code:

...

// Add the jars in to the classloader for this thread
if (_queueClassLoader != null) {
	debug("Adding jars to classloader");
	Thread.currentThread().setContextClassLoader(_queueClassLoader);
}

Why am I getting an infinite loop when reading my component's configuration?

I ran into a subtle infinite loop, which I'd like to share with you.

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And so, it started all of the components, which meant that it started another copy of itself! (When it then went again to /config/components/component, got the top-level components again, and then started another copy if itself again, etc. etc.)

The Moral of the story:

When accessing your configuration elements with XPATH, do not use a leading "/". If you do, you will access the configuration of the system manager all the way at the top.

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Note there is no need to prefix it with "config", since we are already "inside" the config node.

Don't Create Your Stage Inside of Another Maven Project

This will create unnecessary and destructive <parent> tags inside your stage's pom.xml file. If you discover these, just delete the entire <parent> tag.

It is best to use the archetype to create the stage directly inside your Eclipse project.

Why do my bundles sometimes get a timestamp when I use "mvn assembly:assembly"

Under certain circumstances, the bundles copied to the output directoy are named with a timestamp:

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<dependencySet>
       <outputFileNameMapping>${artifact.artifactId}-${artifact.baseVersion}.${artifact.extension}</outputFileNameMapping>
       <unpack>false</unpack>
       <useTransitiveDependencies>false</useTransitiveDependencies>
       <outputDirectory>bundles/aspire</outputDirectory>
       <includes>
             <include>com.searchtechnologies:*</include>
       </includes>
 </dependencySet>

How do I abort / terminate a job?

Call job.terminate(). This will set a flag which causes the job to be terminated once the current stage completes. See Terminating Jobs for more details.

Strange class issues when running bundles

I got a stange class loadeder issue when loading a component

...

Again, this was a missing import. I cleaned up the pom and added javax.xml.namespace to the <Import-Package>

One error not caused by the pom:

ERROR: Unable to start system bundle. (java.lang.ClassCastException: com.sun.org.apache.xerces.internal.dom.CommentImpl cannot be cast to org.w3c.dom.Element)
java.lang.ClassCastException: com.sun.org.apache.xerces.internal.dom.CommentImpl cannot be cast to org.w3c.dom.Element
       at com.searchtechnologies.aspire.distributed.discovery.DiscoveryManager.initialize(DiscoveryManager.java:106)
       at com.searchtechnologies.aspire.distributed.DistributedCommunicationsManager.initialize(DistributedCommunicationsManager.java:137)
       at com.searchtechnologies.aspire.application.AspireApplicationImpl.doAdditionalInitialization(AspireApplicationImpl.java:69)

...

The only solution at the moment is to remove the comment.

Calling Components from other Components

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• Open up the JAR files for both bundles with WINRAR and check the directories to ensure that the one which is supposed to have the com.searchtechnologies.cpatools.Logger file does have it (the called) and that the one which is not supposed to have it (the caller), in fact does not have it.
• Also open up the JAR files and check the MANIFEST file to see if the imports from the <Import-Package> and <Export-Package> elements are correctly copied into the MANIFEST file.

Pom File Dependencies

When creating components, you'll often need to reference other Aspire components or third-party JAR files. In order to do this, you'll end up with one or more dependencies in the pom file, similar to this:

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In versions 0.3 and earlier, you need to ensure that a dependent bundle is loaded first by ensuring the file appears first in you <bundles> tag. Again, third-party JAR files must be included in your component (as a compile-time dependency).

Enabling JMX Console to investigate memory issues with Felix

If you experience memory issues or JVM core dumps you can enable JMX on Felix and then connect using JConsole.

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Restart Aspire and then use JConsole to connect to port 9999.

Aspire and permgen memory issues

The permgen is where the JVM keeps the actual classes (not the instances, just the "boiler plates"), including fields, method names, etc.

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Pipeline manager thread pool and queue are full, but all processing is stuck

In some rare cases, an error in the configuration of pipeline managers and branches can cause a deadlock. To prevent that, be sure that you are not branching sub-jobs to the same pipeline manager doing the branching.

Incorrect

Pipeline Manager A: XMLSubjobExtractor -> PrintToFile

Where XMLSubjobExtractor branch is configured to send jobs to Pipeline Manager A. This will almost certainly cause a deadlock.

Correct

Pipeline Manager A (parent jobs): XMLSubjobExtractor

...

Notice that the same may happen wherever you have a branch configuration. So be careful when setting the destination of your branches.

Parsing Errors

org.xml.sax.SAXParseException: Content is not allowed in prolog.

This error is caused by the presence of a byte-order mark (BOM) at the start of your XML file. You can see the BOM using "od -c <filename>". You can remove the BOM simply by copying and pasting the entire file contents to a new file in a text editor since the BOM does not get copied to the clipboard.