How to clear methodcacheinterceptor cache

Question

I am developing a web application where I wrote a method, in that method I called a json url and parsing that and store in a pojo class.

I just cache this method using methodcacheinterceptor concept, My xml configuration below:

<bean id="methodCacheInterceptor"
    class="web.app.services.MethodCacheInterceptor">
    <property name="cache">
        <ref local="methodCache" />
    </property>
</bean>

<bean id="methodCache" class="org.springframework.cache.ehcache.EhCacheFactoryBean">
    <property name="cacheManager">
        <ref local="cacheManager" />
    </property>
    <property name="cacheName">
        <value>videoItemsCache</value>
    </property>
</bean>

<bean id="cacheManager"
    class="org.springframework.cache.ehcache.EhCacheManagerFactoryBean">
    <property name="configLocation">
        <value>/WEB-INF/ehcache.xml</value>
    </property>
</bean>

<bean id="methodCachePointCut"
    class="org.springframework.aop.support.RegexpMethodPointcutAdvisor">
    <property name="advice">
        <ref local="methodCacheInterceptor" />
    </property>
    <property name="patterns">
        <list>
            <value>.*web.app.services.ItemCollectionImpl.getCollection</value>
            <value>.*web.app.services.ItemCollectionImpl.buildCollection</value>
        </list>
    </property>
</bean>

I set a time of 20 mins caching & it works perfectly!

All I want is for a particular activity I want to override & clear those cache, For the next time I visit page I want that whole method to be executed and data should not be loaded from cache (I want to clear the cache) for that particular activity.

FYI

CacheManager.getInstance().getCacheNames() - this prints my cachename which I have given in the xml configuration.

I have tried CacheManager.getInstance().clearAll(), removeall methods but it doesn't works!!

Anyone help me here!

Thanks in advance.