For those who find it useful, here is my final code:
In the same package as CacheFactory, a file jcs.default with the default values
is expected. (Using the same property names as regularly specified in JCS
cache.ccf file)
import java.io.IOException;
import java.io.InputStream;
import java.util.Properties;
import org.apache.jcs.JCS;
import org.apache.jcs.access.exception.CacheException;
import org.apache.jcs.engine.CompositeCacheAttributes;
import org.apache.jcs.engine.ElementAttributes;
import org.apache.jcs.config.PropertySetter;
public class CacheFactory {
private static final String DEFAULT_VALUES_SETTINGS_FILE =
"jcs.default";
private static Properties defaultProperties = new Properties();
private static String defaultsFile = null;
private CacheFactory() {
}
/**
* An auxiliary method to create JCS caches.
* This method looks for the file jcs.properties in the same package as
the
* provided Class. The cache is created by using the region cache and
* element attributes specified in the jcs.properties file.
*
* Note that region names are global. Region names must not contain "/"
or "."
* If you ask two times for the same region, you will get a different
JCS object
* but they act over the same region, therefore elements in the cache
are accesible
* to both.
*
* The key and elements to be inserted in the cache MUST be
Serializable. This is
* expected by JCS because it can cache elements to disk or provide
them to a remote
* agent, even if the cache is just defined as in-memory cache.
*
* @param clazz - A clazz used to specify the location of the
jcs.properties file
* @param region - The region name
* @return a JCS cache object with access to the specified region
*/
public static JCS createCache(Class clazz, String region) {
if( defaultProperties.isEmpty() ) {
String pkg = CacheFactory.class.getPackage().getName();
pkg = pkg.replace(".", "/");
defaultsFile = "/" + pkg + "/" +
DEFAULT_VALUES_SETTINGS_FILE;
JCS.setConfigFilename( defaultsFile );
try {
defaultProperties.load(
CacheFactory.class.getResourceAsStream(DEFAULT_VALUES_SETTINGS_FILE ));
} catch (IOException ioe) {
throw new RuntimeException("Unable to find
resource ", ioe );
}
}
Properties props = new Properties();
CompositeCacheAttributes cca = new CompositeCacheAttributes();
ElementAttributes eca = new ElementAttributes();
try {
// First apply the default values from jcs.default
PropertySetter.setProperties(cca, defaultProperties,
"jcs.default.cacheattributes.");
PropertySetter.setProperties(eca, defaultProperties,
"jcs.default.elementattributes.");
// Now apply the values from a specific jcs.propeties
file
InputStream is =
clazz.getResourceAsStream("jcs.properties");
if( is != null ) {
props.load( is );
PropertySetter.setProperties(cca,props,
"jcs.region." + region + ".cacheattributes.");
PropertySetter.setProperties(eca,props,
"jcs.region." + region + ".elementattributes.");
}
} catch (IOException ioe) {
throw new RuntimeException("Unable to read
jcs.properties from package " + clazz.getPackage().getName() , ioe);
}
JCS resp = null;
try {
resp = JCS.getInstance(region, cca);
resp.setDefaultElementAttributes(eca);
} catch (CacheException e) {
throw new RuntimeException("Unable to set initialize
JCS cache for region name [" +
region +"]",e);
}
return resp;
}
}
-----Original Message-----
From: Niall Gallagher [mailto:[EMAIL PROTECTED]
Sent: Friday, May 02, 2008 7:38 AM
To: JCS Users List
Subject: RE: Using JCS from many libraries
Thanks for sharing that Jorge- might come in useful!
On Thu, 2008-05-01 at 18:27 -0400, Jorge Medina wrote:
> Never mind. I solved my problem.
>
> JCS.setDefaultElementAttributes(IElementAttributes) does the trick.
>
> Now I specify global cache defaults in the properties file jcs.default, that
> resides in the same place as my CacheFactory.
>
> The cache attributes and default element attributes can be specified now in
> independent jcs.properties files living in the same package -path- of the
> class doing the caching.
>
>
> import org.apache.jcs.JCS;
> import org.apache.jcs.access.exception.CacheException;
> import org.apache.jcs.engine.CompositeCacheAttributes;
> import org.apache.jcs.engine.ElementAttributes;
> import org.apache.jcs.config.PropertySetter;
>
> public class CacheFactory {
>
>
> private CacheFactory() {
>
> }
>
> public static JCS createCache(Class clazz, String region) {
> String pkg = CacheFactory.class.getPackage().getName();
> pkg = pkg.replace(".", "/");
> String file = "/" + pkg + "/jcs.default";
>
>
> Properties props = new Properties();
> CompositeCacheAttributes cca = new CompositeCacheAttributes();
> ElementAttributes eca = new ElementAttributes();
>
> try {
> props.load( clazz.getResourceAsStream("jcs.properties")
> );
> PropertySetter.setProperties(cca,props, "jcs.region." +
> region + ".cacheattributes.");
> PropertySetter.setProperties(eca,props, "jcs.region." +
> region + ".elementattributes.");
> } catch (IOException ioe) {
> throw new RuntimeException("Unable to read
> jcs.properties from package " + clazz.getPackage().getName() , ioe);
> }
> JCS resp = null;
> try {
>
> JCS.setConfigFilename( file );
> resp = JCS.getInstance(region, cca);
> resp.setDefaultElementAttributes(eca);
> } catch (CacheException e) {
> throw new RuntimeException("Unable to set initialize
> JCS cache for region name [" +
> region +"]",e);
> }
> return resp;
> }
> }
>
> -----Original Message-----
> From: Jorge Medina [mailto:[EMAIL PROTECTED]
> Sent: Thursday, May 01, 2008 6:04 PM
> To: JCS Users List
> Subject: RE: Using JCS from many libraries
>
>
> In other words, is there any way to configure the default element attributes
> for a region programmatically?
>
> -Jorge
>
> -----Original Message-----
> From: Jorge Medina [mailto:[EMAIL PROTECTED]
> Sent: Thursday, May 01, 2008 5:54 PM
> To: jcs-users@jakarta.apache.org
> Subject: Using JCS from many libraries
>
> Hi,
> Here is what I have run into:
>
> A group in the company has created a java library, component1.jar,
> which extensively uses JCS and bundles cache.ccf within the jar file. It has
> been unit tested and it works fine.
> A second group develops another java library, component2.jar, which
> also uses JCS and bundles cache.ccf within the jar file. It has been unit
> tested and it works fine.
>
> An application requires to use component1.jar and component2.jar but
> now there are two cache.ccf and only one is being loaded.
> The regions used by the second component are created with the default
> cache and element attributes found in the first cache.ccf. Only the first
> call to JCS.setConfigFilename( file ) has effect.
>
> Extracting cache.ccf from the jars and creating a single file is not a
> viable solution if JCS is used in many more components or subsystems. For
> example, another application may make use of component2.jar and
> component5.jar ...besides, there is no way to guarantee that anyone knows all
> places where JCS is used - and loaded from the same class loader .
>
> What have you do to go around this? Has anybody have had the same
> problem?
>
> I have tried to create a CacheFactory but the JCS class allows to
> specify the cache attributes on the getInstance( regionName, ICacheAtributes)
> method, but it does not allow to specify the default element attributes for
> this region. The default elements attributes are applied but from the first
> config file.( jcs.properties file in my code)
>
> Any help is appreciated.
>
> -Jorge
>
>
> import java.io.IOException;
> import java.util.Properties;
>
> import org.apache.jcs.JCS;
> import org.apache.jcs.access.exception.CacheException;
> import org.apache.jcs.engine.CompositeCacheAttributes;
> import org.apache.jcs.engine.ElementAttributes;
> import org.apache.jcs.config.PropertySetter;
>
> public class CacheFactory {
>
>
> private CacheFactory() {
>
> }
>
> // clazz is used to find the the location of jcs.properties (instead of
> /cache.ccf ) for the region.
> // Each developer would use a class in their own package. (for
> practical purposes, the class caching the objects )
>
> public static JCS createCache(Class clazz, String region) {
> String pkg = clazz.getPackage().getName();
> pkg = pkg.replace(".", "/");
> String file = "/" + pkg + "/jcs.properties";
>
> Properties props = new Properties();
> CompositeCacheAttributes cca = new CompositeCacheAttributes();
> ElementAttributes eca = new ElementAttributes();
>
> try {
> props.load( clazz.getResourceAsStream("jcs.properties")
> );
> PropertySetter.setProperties(cca,props, "jcs.region." +
> region + ".cacheattributes.");
> PropertySetter.setProperties(eca,props, "jcs.region." +
> region + ".elementattributes.");
> } catch (IOException e1) {
> }
> JCS resp = null;
> try {
> JCS.setConfigFilename( file );
> resp = JCS.getInstance(region, cca); // ← No way to
> specify default element attributes for this cache
> } catch (CacheException e) {
> throw new RuntimeException("Unable to set initialize
> JCS cache for region name [" +
> region +"]",e);
> }
> return resp;
> }
> }
>
>
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