Memcached incr and decr commands are used to increment or decrement the numeric value of an existing key. If the key is not found, then it returns NOT_FOUND. If the key is not numeric, then it returns CLIENT_ERROR cannot increment or decrement non-numeric value. Otherwise, ERROR is returned.
Syntax – incr
The basic syntax of Memcached incr command is as shown below −
incr key increment_value
Example
In this example, we use visitors as key and set 10 initially into it, thereafter we increment the visitors by 5.
set visitors 0 900 2 10 STORED get visitors VALUE visitors 0 2 10 END incr visitors 5 15 get visitors VALUE visitors 0 2 15 END
Syntax – decr
The basic syntax of Memcached decr command is as shown below
decr key decrement_value
Example
set visitors 0 900 2 10 STORED get visitors VALUE visitors 0 2 10 END decr visitors 5 5 get visitors VALUE visitors 0 1 5 END
Incr/Decr Using Java Application
To increment or decrement data in a Memcached server, you need to use Memcached incr or decr methods respectively.
Example
import net.spy.memcached.MemcachedClient;
public class MemcachedJava {
public static void main(String[] args) {
// Connecting to Memcached server on localhost
MemcachedClient mcc = new MemcachedClient(new
InetSocketAddress("127.0.0.1", 11211));
System.out.println("Connection to server sucessfully");
System.out.println("set status:"+mcc.set("count", 900, "5").isDone());
// Get value from cache
System.out.println("Get from Cache:"+mcc.get("count"));
// now increase the stored value
System.out.println("Increment value:"+mcc.incr("count", 2));
// now decrease the stored value
System.out.println("Decrement value:"+mcc.decr("count", 1));
// now get the final stored value
System.out.println("Get from Cache:"+mcc.get("count"));
}
}
Output
On compiling and executing the program, you get to see the following output −
Connection to server successfully set status:true Get from Cache:5 Increment value:7 Decrement value:6 Get from Cache:6