Background:
I have a requirement that messages displayed to the user must vary both by language and by company division. Thus, I can't use out of the box resource bundles, so I'm essentially writing my own version of resource bundles using PropertiesConfiguration files.
In addition, I have a requirement that messages must be modifiable dynamically in production w/o doing restarts.
I'm loading up three different iterations of property files:
-basename_division.properties
-basename_2CharLanguageCode.properties
-basename.properties
These files exist in the classpath. This code is going into a tag library to be used by multiple portlets in a Portal.
I construct the possible .properties files, and then try to load each of them via the following:
PropertiesConfiguration configurationProperties;
try {
configurationProperties = new PropertiesConfiguration(propertyFileName);
configurationProperties.setReloadingStrategy(new FileChangedReloadingStrategy());
} catch (ConfigurationException e) {
/* This is ok -- it just means that the specific configuration file doesn't
exist right now, which will often be true. */
return(null);
}
If it did successfully locate a file, it saves the created PropertiesConfiguration into a hashmap for reuse, and then tries to find the key. (Unlike regular resource bundles, if it doesn't find the key, it then tries to find the more general file to see if the key exists in that file -- so that only override exceptions need to be put into language/division specific property files.)
The Problem:
If a file did not exist the first time it was checked, it throws the expected exception. However, if at a later time a file is then later dropped into the classpath and this code is then re-run, the exception is still thrown. Restarting the portal obviously clears the problem, but that's not useful to me -- I need to be able to allow them to drop new messages in place for language/companyDivision overrides w/o a restart. And I'm not that interested in creating blank files for all possible divisions, since there are quite a few divisions.
I'm assuming this is a classLoader issue, in that it determines that the file did not exist in the classpath the first time, and caches that result when trying to reload the same file. I'm not interested in doing anything too fancy w/ the classLoader. (I'd be the only one who would be able to understand/maintain that code.) The specific environment is WebSphere Portal.
Any ways around this or am I stuck?
My guess is that I am not sure if Apache's FileChangedReloadingStrategy also reports the events of ENTRY_CREATE on a file system directory.
If you're using Java 7, I propose to try the following. Simply, implement a new ReloadingStrategy using Java 7 WatchService. In this way, every time either a file is changed in your target directories or a new property file is placed there, you poll for the event and able to add the properties to your application.
If not on Java 7, maybe using a library such as JNotify would be a better solution to get the event of a new entry in a directory. But again, you need to implement the ReloadingStrategy.
UPDATE for Java 6:
PropertiesConfiguration configurationProperties;
try {
configurationProperties = new PropertiesConfiguration(propertyFileName);
configurationProperties.setReloadingStrategy(new FileChangedReloadingStrategy());
} catch (ConfigurationException e) {
JNotify.addWatch(propertyFileDirectory, JNotify.FILE_CREATED, false, new FileCreatedListener());
}
where
class FileCreatedListener implements JNotifyListener {
// other methods
public void fileCreated(int watchId, String rootPath, String fileName) {
configurationProperties = new PropertiesConfiguration(rootPath + "/" + fileName);
configurationProperties.setReloadingStrategy(new FileChangedReloadingStrategy());
// or any other business with configurationProperties
}
}
Related
I have a requirement of implementing a Watch Service on a folder. This is straight forward approach of using Java7's watch service. I have successfully done it, I am able to capture events whenever a file is created/updated/deleted on the folder where I have been watching. The problem here is it is not applicable for contents of sub folders and it is clearly written in the documentation. My requirement is to watch over contents of sub folder as well. This is not possible using the above approach unless I write a loop over all the sub folders manually and listen to each and every folder, this I think leads to some memory leak if not programmed well. Hence I am going with what spring suggested in the newer release explained here This is very clear approach which I have seen for WatchService. The problem here is this will listen to only ENTRY_CREATE events i.e., only the events where we have created the file and this can be at any level. This is not working when I change the file or delete the file. How should we go ahead in this case.
public static void watchFolderTree(String pathStr)
throws Exception
{
long waitTime = 10000;
WatchServiceDirectoryScanner scanner = new WatchServiceDirectoryScanner(pathStr);
scanner.start();
List<File> changedFiles = null;
while(true)
{
changedFiles = scanner.listFiles(new File(pathStr));
if(changedFiles.size() > 0)
{
System.out.println("There is a file ");
}
Thread.sleep(waitTime);
}
}
References :
Monitor subfolders with a Java watch service
JAVA 7 watch service
I need to create a log file in application directory. Currently I'm using hard-coded absolute path, like
public class Transformer
{
static String LOG_DIR = "ABSOLUTE_PATH_TO_THE_APPLICATION_DIRECTORY";
File log = new File(log_DIR, "log");
}
If someone else have my code, he will has to go the source code, change the LOG_DIR and then recompile. I just know a little about GNU make. My question is, how can I create a "installer" that works like:
./config
make install
and what's the standard/better way of achieving this?
Currently I have:
String path = Transformer.class.getProtectionDomain().getCodeSource().getLocation().getPath()
Best way to load application settings
With 2, I think I can use a shell script to generate a .properties file.
update
Sorry about the confusing "log file", but I actually mean a regular file, it just happen to containing some sort of log information.
You could define the "app.logs.dir" property on application start and refer to it in the log4j configuration:
main(String[] args) {
...
final String appRootDir = /* Detect app location. */;
System.setProperty("app.logs.dir", appRootDir);
// Now we can use the logger.
...
}
And in "log4j.properties":
log4j.appender.filelog.file=${app.logs.dir}/myapp.log
UPDATE
Option #1, the getProtectionDomain() one, might not work depending on the JVM's SecurityManager settings so the best way probably is option #2 - your installer script should store the application installation location in the application configuration file.
And to keep the number of component references low you can read the configuration file into System properties just like I showed above.
File log = new File(System.getProperty("app.logs.dir"), "log");
Is there any method to create a file in java that cannot be deleted.
I have googled it and found processes involving the cmd.
However, I require a pure "java" way that can be done on any platform.
Thanks in advance.
Thank you for your help.
I finally got it right.
I used the following code to deny access to user
public static void main() throws IOException
{
Path file = Paths.get("c:/b.txt");
AclFileAttributeView aclAttr = Files.getFileAttributeView(file, AclFileAttributeView.class);
//System.out.println();
UserPrincipalLookupService upls = file.getFileSystem().getUserPrincipalLookupService();
UserPrincipal user = upls.lookupPrincipalByName(System.getProperty("user.name"));
AclEntry.Builder builder = AclEntry.newBuilder();
builder.setPermissions(EnumSet.of(AclEntryPermission.APPEND_DATA, AclEntryPermission.DELETE, AclEntryPermission.DELETE_CHILD, AclEntryPermission.EXECUTE, AclEntryPermission.READ_ACL, AclEntryPermission.READ_ATTRIBUTES, AclEntryPermission.READ_DATA, AclEntryPermission.READ_NAMED_ATTRS, AclEntryPermission.SYNCHRONIZE, AclEntryPermission.WRITE_ACL, AclEntryPermission.WRITE_ATTRIBUTES, AclEntryPermission.WRITE_DATA, AclEntryPermission.WRITE_NAMED_ATTRS, AclEntryPermission.WRITE_OWNER));
builder.setPrincipal(user);
builder.setType(AclEntryType.DENY);
aclAttr.setAcl(Collections.singletonList(builder.build()));
}
Try the method setPosixFilePermissions() and set the permissions to read only for all the classes of users. Refer this - http://docs.oracle.com/javase/7/docs/api/java/nio/file/Files.html#setPosixFilePermissions%28java.nio.file.Path,%20java.util.Set%29
If you want to create a file that can't be accidentally overwritten, then look at the various answers to this: How do i programmatically change file permissions?
If you want to create a file that the current program cannot delete at all (but a privileged one could), it might be possible by setting permissions appropriately on the parent directory, or possibly using SELinux Mandatory Access Control cleverness.
If you want to create a truly undeleteable file, then you are out of luck. I am not aware of any operating system that supports creation of files that can never be deleted. It would be an "anti-feature".
I would also agree with #Teifi's comment. Create a file that cannot ever be deleted on the user's machine is not acceptable ... unless done by, or with the authorization of the system's administrators. I would call any software that did that "malicious" too.
I'm attempting to provide a StreamingResponse for files stored under Lifts resources/toserve directory, in order to authorize access for different users.
I can access an image for example with:
localhost:8080/classpath/images/test.jpg
But when I try and actually read the file using scala I keep getting file not found exceptions:
val file = new java.io.FileInputStream("/classpath/images/test.jpg")
Is there a specific method to reading files located on classpath?
Thanks in advance, much appreciated :)
To read resources from the toserve-directory you need to do a call like
LiftRules.getResource("/toserve/images/test.jpg")
If you try to use 'classpath' instead of 'toserve' you will receive an empty box.
By default, Lift uses two different path-prefixes to locate resources either programmatically within the server or through a link-element from HTML. For the former, you will use the 'toserve'-prefix, for the latter the 'classpath'-prefix.
This behavior is specified in the objects net.liftweb.http.LiftRules and net.liftweb.http.ResourceServer. In particular, you can there specify (i.e. replace) the path to the resources. The relevant code is:
/** (from net.liftweb.http.ResourceServer)
* The base package for serving resources. This way, resource names can't be spoofed
*/
var baseResourceLocation = "toserve"
You might also want to look at the following method in LiftRules, which allows you to redefine the name used to serve resources through the server:
/** (from net.liftweb.http.LiftRules)
* The path to handle served resources
*/
#volatile var resourceServerPath = "classpath"
If you wish to use the same prefix to refer both to resources you can use either (or both) of these settings to achieve your purpose.
Have you tried:
LiftRules.getResource("/classpath/images/test.jpg")
That should return a java.net.URL to the item you are looking for.
This may also have more information on what you are looking to do: http://exploring.liftweb.net/master/index-9.html#lst:streaming-download
I apologize if this is a duplicate, I couldn't find anything describing exactly what I wanted. I'm building a webapp that has a number of different properties that need to change depending on the environment in addition to a number of .properties configuration files that need to change as well. Right now I have a global enum (DEVELOPMENT, STAGING, and PRODUCTION) that is used to determine which string constants are used in the application and then I utilize a bunch of comments in the configuration files to switch between database servers, etc. There has got to be a better way to do this...I'd ideally like to be able to make one change in one file (A large block comment would be fine...) to adjust these configurations. I saw this post where the answer is to utilize JNDI which I really like, but it would seem as though I would need to call that from a servlet that starts up or a bean that gets initialized on start in order to use it for my log4j or JDBC configuration files.
Does anybody have any strategies for dealing with this?
Thanks!
I'm not sure if this strategy will apply to your situation, but in the past I've successfully used our build tool (ant in that case) to build different war files depending on the profile. So you would have multiple log4j configuration files in your source tree, and then delete the ones you don't want from the final build depending on the profile that was used to build it.
Traceability becomes slightly hard (i.e. difficult sometimes to figure out which one was used to build it), but it's a very clean solution, from your code perspective, since it's all done in your build script.
We store all our default configuration values in a single XML file. During deployment we apply an XML patch (RFC-5261) with values specific to the environment.
https://www.rfc-editor.org/rfc/rfc5261
http://xmlpatch.sourceforge.net/
I am going to assume that your properties files are made up of 95% name=value pairs that are identical across all your deployment environments and 5% of name=value pairs that change from one deployment environment to another.
If this assumption is correct, then you could try something like the following pseudocode.
void generateRuntimeConfigFiles(int deploymentMode)
{
String[] searchAndReplacePairs;
if (deploymentMode == Constants.PRODUCTION) {
searchAndReplacePairs = ...
} else if (deploymentMode == Constants.STAGING) {
searchAndReplacePairs = ...
} else { // Constants.DEVELOPMENT
searchAndReplacePairs = ...
}
String[] filePairs = new String[] {
"log4j-template.properties", "log4j.properties",
"jdbc-template.properties", "jdbc.properties",
"foo-template.xml", "foo.xml",
...
};
for (int i = 0; i < filePairs.length; i += 2) {
String inFile = filePairs[i + 0];
String ouFile = filePairs[i + 1];
searchAndReplaceInFile(inFile, outFile,
searchAndReplacePairs);
}
}
Your application calls generateRuntimeConfigFiles() before initialising anything else that might rely on properties/XML files.
Now the only problem you have to deal with is how to store and retrieve different settings for searchAndReplacePairs. Perhaps you could obtain them from files with names such as production.properties, staging.properties and development.properties.
If the above approach is appealing to you, then email me for the source code of searchAndReplaceInFile() to save you having to re-invent the wheel. You can find my email address from the "info" box in my Stackoverflow profile.
I suggest using Apache Commons Configuration. It provides all the plumbing for dealing with different configurations depending on your environment.
http://commons.apache.org/configuration