Bob,
Thank you for taking the time to help out - unfortunately the security
restriction kicks in:
java.security.AccessControlException: access denied (java.io.FilePermission
velocity.log write)
at
java.security.AccessControlContext.checkPermission(AccessControlContext.java:323)
at
java.security.AccessController.checkPermission(AccessController.java:546)
at java.lang.SecurityManager.checkPermission(SecurityManager.java:532)
at
com.google.appengine.tools.development.DevAppServerFactory$CustomSecurityManager.checkPermission(DevAppServerFactory.java:166)
at java.lang.SecurityManager.checkWrite(SecurityManager.java:962)
at java.io.FileOutputStream.<init>(FileOutputStream.java:169)
at java.io.FileOutputStream.<init>(FileOutputStream.java:102)
at org.apache.log4j.FileAppender.setFile(FileAppender.java:290)
at
org.apache.log4j.RollingFileAppender.setFile(RollingFileAppender.java:194)
at org.apache.log4j.FileAppender.<init>(FileAppender.java:109)
at
org.apache.log4j.RollingFileAppender.<init>(RollingFileAppender.java:72)
at
org.apache.velocity.runtime.log.Log4JLogChute.initAppender(Log4JLogChute.java:118)
at
org.apache.velocity.runtime.log.Log4JLogChute.init(Log4JLogChute.java:85)
at
org.apache.velocity.runtime.log.LogManager.createLogChute(LogManager.java:157)
at
org.apache.velocity.runtime.log.LogManager.updateLog(LogManager.java:255)
at
org.apache.velocity.runtime.RuntimeInstance.initializeLog(RuntimeInstance.java:795)
at
org.apache.velocity.runtime.RuntimeInstance.init(RuntimeInstance.java:250)
at
org.apache.velocity.runtime.RuntimeInstance.requireInitialization(RuntimeInstance.java:290)
at
org.apache.velocity.runtime.RuntimeInstance.getLoaderNameForResource(RuntimeInstance.java:1462)
at
org.apache.velocity.runtime.RuntimeSingleton.getLoaderNameForResource(RuntimeSingleton.java:380)
at org.apache.velocity.app.Velocity.resourceExists(Velocity.java:423)
On Dec 26, 2010, at 5:39 PM, Bob Schellink wrote:
> Hi Tim,
>
> Velocity has a way to check if a template/resource exists through this static
> method[1]:
>
> Velocity.resourceExists(name);
>
> I'm not sure how efficient this check is though as it might touch the file
> system. You could ask on
> the Velocity mailing list just to make sure. If it does touch the file system
> it should be easy to
> cache it in your app through some utility class:
>
> VelocityUtils {
> private static Map<String, Integer> CACHE = new ConcurrentHashMap();
>
> public boolean resourceExists(String name) {
> int val = CACHE.get(name);
> if (val == 1) {
> return true;
> } else if (val == 0) {
> return false;
> } else {
> if(Velocity.resourceExists(name)) {
> CACHE.put(name, 1);
> } else {
> CACHE.put(name, 0);
> }
> }
> }
>
> or something along those lines.
>
> Id you are using GAE you should probably use 2.3.0-M1 which provides a
> workaround[2] for a GAE bug
> which breaks Page automapping.
>
> Hope this helps
>
> Kind regards
>
> Bob
>
> [1]:
> http://velocity.apache.org/engine/releases/velocity-1.7/apidocs/org/apache/velocity/app/Velocity.html#resourceExists(java.lang.String)
> [2]:
> http://click.apache.org/docs/extras-api/org/apache/click/extras/gae/GoogleAppEngineListener.html
> (See the Limitations section in the Javadoc)
>
>
> On 27/12/2010 10:34, Tim Christensen wrote:
>> I am building a web application using Click on the Google App Engine. One of
>> the 'features' I would
>> like to have is the ability to try setting a template -- if it is available.
>> Like the Click example
>> we have a BasePage > BorderPage (with a template of border.htm) and our Page
>> classes extend BorderPage.
>>
>> One of those Page classes is BrandPage -- for some consumer brands. The
>> BrandPage will have some
>> common methods - search for products matching this brand for example - think
>> ecommerce.
>> Additionally, there is a brand.htm file for the BrandPage.
>>
>> However, I would like some brands, not all, to have a template available to
>> parse - we would like to
>> build out some custom .htm pages to parse in the brand.htm. For example we
>> may have three brands ,
>> A, B, C and A.htm, C.htm but not a B.htm in a directory say ... /brand/A.htm
>>
>> Normally in the BrandPage I would put something like this:
>>
>> public String getTemplate()
>> {
>> return A.htm (or C.htm, or even B.htm)
>> }
>>
>> From the example above, while A.htm or C.htm exist, B.htm does not.
>>
>> How this would have happened is that when the BrandPage was requested, with
>> a brand id for example,
>> the database search would return the brand (and product etc...). I would
>> then 'dynamically' set the
>> getTemplate() return to [Normalized Brand Name].htm
>>
>> My question is this -- how can I test to see if B.htm exists before I even
>> set the getTemplate
>> return value? My focus has been using something utility-wise in Click - am I
>> missing a simple way to
>> do this? Wrap a try catch somewhere? As you would expect, I currently get the
>> org.apache.velocity.exception.ResourceNotFoundException -- but I cannot
>> catch it in the Page in
>> order to do something else.
>>
>> I also want it to be a quick process. I have pondered using File to look in
>> a specific directory
>> ("/brand/file.htm"). My biggest concerns are: 1. Speed for this 'function',
>> 2. Google App Engine
>> restrictions - would looking at a file in the /war cause an issue, and
>> finally if Click has
>> something I missed as a convenience for this idea. Solving this gives us
>> tremendous flexibility on
>> the presentation and is a critical feature to our application. I am also
>> concerned that the way I am
>> thinking about this is flawed so any alternative design pattern suggestions
>> are welcome.
>>
>> Thank you for a great framework - I have tried nearly all of them and Click
>> nailed it.
>>
>
-------------------------------------------------
Tim Christensen
Director Media & Technology
Vann's Inc.
406-203-4656
http://www.vanns.com
Follow me on Twitter: http://twitter.com/tim_christensen
[email protected]
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