ZK AJAX Framework Introduction
I am in the process of working with and researching ZK as an AJAX framework to integrate into Java Web Development that I do. So far, AJAX looks really amazing, and is fully integrated into the J2EE framework. It is an event driven framework that has the option of hooking directly into existing JSP, or entirely writing ZK event handlers to do the processing. There is no wonder that ZK won the Project of the Month Source Forge award.
RMI Pitfalls and Problems
In this post, I plan on laying out multiple common problems with RMI, that a developer can run into. I hope that this will be a concise guide to fixing the common RMI problems that beginners run into. As I come up with more, I will edit this post, rather than creating a new one. I will then post a comment on this entry; if you are subscribed to the comments (RSS feed), you will get notification when there is an update.
Also, if you are having some sort of RMI trouble, post a comment, and I will let you know if I know the solution. I may also add the solution directly to this post, if it happens to actually be an RMI related issue.
EJB3 @RolesAllowed, annotation type not applicable to this kind of declaration
I'm just learning EJB3, and I'm stumbling here and there. When developing an EJB object, I had a problem where the compiler was giving me an error that says "annotation type not applicable to this kind of declaration". It was on a line like the following...
@RolesAllowed({"admin", "entryclerk"})
Obviously this is normal to use on a method. Unfortunately, I had it defined on not just any method, but the constructor method of my Java class. It took me awhile to figure out why it was happening, so I thought would spare others a bit of grief.
Safe Shrinking of ext3 LVM volumes
When shrinking your LVM volumes, it is important to do it safely. I will show you how I like to do that here.
Intel WIFI 5300 AGN Unknown error 132
See comments for latest updates
Recently I started having problems with my Intel Corporation PRO/Wireless 5300 AGN card. It simply quit working after I did a kernel upgrade. It was giving errors like "Unknown error 132", and "deauthenticated (Reason: 9)". The hardware switch did not seem to affect it, and the errors were the same whether I had the switch on, or off; so I'm assuming it had to do with the hardware not being initialized properly when the module loaded.
Gentoo Portage Python Update issues
I have been having some gentoo portage problems due to my system being out of sync. When I finally updated a month or two later, it simply wasn't working. I was getting an error like the following...
Performing Global Updates: /usr/portage/profiles/updates/3Q-2009 (Could take a couple of minutes if you have a lot of binary packages.) .='update pass' *='binary update' #='/var/db update' @='/var/db move' s='/var/db SLOT move' %='binary move' S='binary SLOT move' p='update /etc/portage/package.*' ...................................................... Performing Global Updates: /usr/portage/profiles/updates/4Q-2009 (Could take a couple of minutes if you have a lot of binary packages.) .='update pass' *='binary update' #='/var/db update' @='/var/db move' s='/var/db SLOT move' %='binary move' S='binary SLOT move' p='update /etc/portage/package.*' .................. Traceback (most recent call last): File "/usr/bin/emerge", line 40, in <module> retval = emerge_main() File "/usr/lib64/portage/pym/_emerge/main.py", line 1328, in emerge_main return action_sync(settings, trees, mtimedb, myopts, myaction) File "/usr/lib64/portage/pym/_emerge/actions.py", line 2173, in action_sync if portage._global_updates(trees, mtimedb["updates"]): File "/usr/lib64/portage/pym/portage/__init__.py", line 8572, in _global_updates moves = bindb.move_ent(update_cmd) File "/usr/lib64/portage/pym/portage/dbapi/bintree.py", line 273, in move_ent mytbz2.recompose_mem(portage.xpak.xpak_mem(mydata)) File "/usr/lib64/portage/pym/portage/xpak.py", line 106, in xpak_mem indexglob=indexglob+encodeint(len(x))+x+encodeint(datapos)+encodeint(mydatasize) UnicodeDecodeError: 'ascii' codec can't decode byte 0xb0 in position 49: ordinal not in range(128)
XSL Break or Wrap String on Word Boundary
I've searched all over the Internet for this, and was unable to find anything reasonable. I found an example somewhere, of how to break a string at a specific location, but it breaks whether there is a word there or not. So, either you have to re-compose the XML elements without a space, and hope every system you interact with does the same thing as you, or re-compose them with a space, and a word may then be broken up in the end result.
In my example below, I break a string on a word boundary, outputting to an XML element called "NoteMessage" from the PESC standard. This is dependant on Java, but you could use any language that has a useful lastIndexOf function. In the case of Java, with zero based string index, we need to compensate for the one based string index that XSL has. So, we add one to the result of the lastIndexOf() call.
<!-- Example... java -cp target/dependency/xml-util-0.1.3-SNAPSHOT.jar:/usr/share/xalan/lib/xalan.jar \ org.apache.xalan.xslt.Process -XSL target/classes/xsl/notemessage.xsl \ -PARAM testString "This is a test to break a string into multiple note messages, \ automatically, without programming." --> <xsl:stylesheet version="1.0" xmlns:String="http://xml.apache.org/xalan/java/java.lang.String" xmlns:xsl="http://www.w3.org/1999/XSL/Transform"> <xsl:output indent="${xml.indent}" method="xml" omit-xml-declaration="yes"/> <xsl:param name="testString"/> <xsl:variable name="break-at" select="'76'"/> <xsl:template match="/"> <xsl:call-template name="note-message"> <xsl:with-param name="string" select="$testString"/> </xsl:call-template> </xsl:template> <xsl:template name="note-message"> <xsl:param name="string"/> <xsl:choose> <xsl:when test="string-length($string) <= $break-at"> <xsl:element name="NoteMessage"> <xsl:value-of select="$string"/> </xsl:element> </xsl:when> <xsl:otherwise> <!-- call method to find word boundary index --> <xsl:variable name="truncString" select="String:new(substring($string, 1, $break-at))"/> <xsl:variable name="lastSpaceIndex" select="String:lastIndexOf($truncString, ' ') + 1"/> <xsl:element name="NoteMessage" namespace=""> <xsl:value-of select="substring(string($truncString), 1, $lastSpaceIndex)"/> </xsl:element> <xsl:call-template name="note-message"> <xsl:with-param name="string" select="substring($string, $lastSpaceIndex + 1)"/> </xsl:call-template> </xsl:otherwise> </xsl:choose> </xsl:template> </xsl:stylesheet>
HDA Intel Alsa volume low
I've been having a problem where the volume level of my Dell Studio 17 notebook is just not loud enough when I'm running Linux. I went to windows, to see if the problem was the same there, and I found that the volume in Windows Vista was way higher. So, I booted back into Linux, and started googling.
I quickly found a few places that talked about setting the model to 3stack, and various other options. But, none of that worked for me. So, I decided to search for the problem on my own. I ended up checking out the alsamixer again, from the command line. Last time I checked, I saw that the "Speaker" volume was set to about two thirds, but I had thought that was referring to the volume of the PC Speaker, as on many sound cards, it is actually an option. As it is, that is actually the volume of the external speaker. Once you pump that puppy up to 100% the volume level is good. From there, you can simply adjust the master or PCM volumes as you choose.
Java, Xalan, JAXP, xml transformations from Java String
I racked my head against the wall over and over again for several hours, unable to determine why I was getting a prolog error, when I knew dang well my XML was well formed.
I'm using JAXP, which is detecting and using xalan as my transformation implementation. I'm not sure who's fault it is, but when I create a new StreamSource for my transformation, and I ask it to load the xml-stylesheet from the processing instruction, it simply doesn't work. I keep getting one of two errors, depending on the format of the java String.
The first error I was getting was "javax.xml.transform.TransformerException: Content is not allowed in prolog". The other error I was getting, once I put my xml declaration at the beginning of the string, was "javax.xml.transform.TransformerException: The markup in the document following the root element must be well-formed". Of course, none of these are meaningful in any way. Neither one tells me that I'm not allowed to ask xalan to resolve my xml-stylesheet automatically, while using XML from a Java String object.
MMC/SDHC Card Readers and Gentoo Linux
So, I had a need to use my SDHC card in my Dell Studio 17 (1737) notebook. So, I set out to find out why it wasn't working. I ended up finding out that I needed to load mmc_block and sdhci-pci in order to get it to work. Here's what I did.
