KeyGenerator

[amjad1210]

Hi,

I'm moving over from Spring cache to Jetcache but can't seem to figure out the best way to specify a global key generator.

In spring cache this was achieved by the code below:

    @Bean
    @Override
    public KeyGenerator keyGenerator() {
        return (o, method, params) -> {
            StringBuilder sb = new StringBuilder();
            sb.append(method.getDeclaringClass().getSimpleName());
            sb.append("_");
            sb.append(method.getName());
            for (Object param : params) {
                sb.append("_");
                sb.append(param.toString());
            }
            return sb.toString();
        };
    }

The reason i need this is because i have some subclasses which need to have a different cache name hence the usage of method.getDeclaringClass().getSimpleName().

Can you maybe tell me what the easiest way to achieve this in Jetcache would be?

Thanks

[areyouok]

I do not understand.

If you use @Cached annotation and do not specified the key attribute, simply say the final key is cacheName+keyConvertor.convert(methodArguments).

The cacheName is specified by name attribute. A default name is used if you do not give one. The default name include all information of class and method :

    @Override
    public String generateCacheName(Method method) {
        String cacheName = cacheNameMap.get(method);

        if (cacheName == null) {
            final StringBuilder sb = new StringBuilder();

            String className = method.getDeclaringClass().getName();
            sb.append(ClassUtil.getShortClassName(removeHiddenPackage(hiddenPackages, className)));
            sb.append('.');
            sb.append(method.getName());
            sb.append('(');

            for(Class<?> c : method.getParameterTypes()){
                getDescriptor(sb, c , hiddenPackages);
            }

            sb.append(')');

            String str = sb.toString();
            cacheNameMap.put(method, str);
            return str;
        } else {
            return cacheName;
        }
    }

[areyouok]

If you have 2 beans implements same method in same interface, and want to seperate them in different Cache, you can add @Cached annotation on the concrete method with different name attribute.

[amjad1210]

This is exactly what i needed. Could you possibly tell me which class in Jetcache the generateCacheName is declared inside? I think the issue i have is related to method.getDeclaringClass().getName() as the superclass methods i'm annotating are creating the key using the superclass name instead of the subclass.

public abstract class SuperClass {

    @Cache
    public void test() {
        System.out.println("Hello world");
    }

}

public class Subclass extends SuperClass {
}

When calling the method test from Subclass i'm expecting the cache name to be Subclass.test() but instead it's SuperClass.test().

[areyouok]

The method is passed to the org.aopalliance.intercept.MethodInterceptor(which is JetCacheInterceptor in jetcache) instance by Spring AOP. If you annotate on an abstract class, the method may be SubClass.test(). If you annotate on an interface, the method may be IntfaceClass.test().

However, you can seperate Cache explicitly using these code:

public abstract class SuperClass {
    public void test() {
        System.out.println("Hello world");
    }
}

public class Subclass1 extends SuperClass {
    @Cache(name="c1")
    public void test() {
        super.test();
    }
}

public class Subclass2 extends SuperClass {
    @Cache(name="c2")
    public void test() {
        super.test();
    }
}

Annotations with same area and name will point to same Cache instance.

[amjad1210]

Hey @areyouok thank you for all the help. The issue is I didn't want to resort to the solution you posted above as i'd have to write boiler plate code for multiple sub classes. Would there be a way to achieve my solution in a more efficient way such as letting the abstract class @Cache annotation figure out the key using the subclass name?

[areyouok]

I think you need fork jetcache and modify these methods or class:

• JetCacheInterceptor.invoke (add invocation.getThis() to CacheInvokeContext)
• CacheInvokeContext
• CacheContext.createCacheInvokeContext
• CacheContext.createCacheByCachedConfig

[amjad1210]

I've created #47 to solve this problem. It now takes the target class which the method was executed from as the className value.

[areyouok]

I had implement it on master branch. You can build it youself or use 2.5.0-SNAPSHOT:

    <repositories>
        <repository>
            <id>sonatype-nexus-snapshots</id>
            <name>Sonatype Nexus Snapshots</name>
            <url>https://oss.sonatype.org/content/repositories/snapshots</url>
            <releases>
                <enabled>false</enabled>
            </releases>
            <snapshots>
                <enabled>true</enabled>
            </snapshots>
        </repository>
    </repositories>

To supply you own NameGenerator, use this if you are using spring boot：

    @Bean
    public SpringConfigProvider springConfigProvider() {
        return new SpringConfigProvider(){
                public CacheNameGenerator createCacheNameGenerator(String[] hiddenPackages) {
                    return new YourCacheNameGenerator(........){.......};
                }
        }
    }

Without spring boot, invoke globalCacheConfig.setConfigProvider when you construct globalCacheConfig.

If no problem occurs I will release 2.5.0 in next few days.

[amjad1210]

Hi @areyouok thank you very much! I'll give this a test and get back with any issues!

[amjad1210]

@areyouok I've tested the changes and it's working as expected. I've also created #51 as i want to reuse most of the DefaultCacheGenerator functionality and need access to the fields. Other than that everything is perfect! Thank you.

For anyone with the same issue here's a full example with @areyouok solution.

    @Bean
    public SpringConfigProvider springConfigProvider() {
        return new SpringConfigProvider() {
            public CacheNameGenerator createCacheNameGenerator(String[] hiddenPackages) {
                return new RedisCacheNameGenerator(hiddenPackages);
            }
        };
    }

public class RedisCacheNameGenerator extends DefaultCacheNameGenerator {

    public RedisCacheNameGenerator(String[] hiddenPackages) {
        super(hiddenPackages);
    }

    @Override
    public String generateCacheName(Method method, Object targetObject) {
        String cacheName = cacheNameMap.get(method);

        if (cacheName == null) {
            final StringBuilder sb = new StringBuilder();

            String className = targetObject.getClass().getName();
            sb.append(ClassUtil.getShortClassName(removeHiddenPackage(hiddenPackages, className)));
            sb.append('.');
            sb.append(method.getName());
            sb.append('(');

            for(Class<?> c : method.getParameterTypes()){
                getDescriptor(sb, c , hiddenPackages);
            }

            sb.append(')');

            String str = sb.toString();
            cacheNameMap.put(method, str);
            return str;
        }

        return cacheName;
    }

}

[areyouok]

PR 51 is merged and 2.5.0 is released.
See https://github.com/alibaba/jetcache/releases/tag/v2.5.0