Cache Usage with Error Handling

cache-sample-2.bal

cache:Error? result = cache.put("key1", "value1");
if (result is cache:Error) {
    // implement what to do, if any error happen when inserting 
    // item to the cache
}
any|cache:Error result = cache.get("key1");
if (result is cache:Error) {
    // implement what to do, if any error happen when retrieving
    // item from the cache
}
string value = <string>result;
cache:Error? result = check cache.invalidate("key1");
if (result is cache:Error) {
    // implement what to do, if any error happen when discarding
    // item from the cache
}
cache:Error? result = check cache.invalidateAll();
if (result is cache:Error) {
    // implement what to do, if any error happen when discarding
    // item from the cache
}
boolean hasKey = cache.hasKey("key1");
string[] keys = cache.keys();
int size = cache.size();
int capacity = cache.capacity();