FileDocCategorySizeDatePackage
Counter3.javaAPI DocExample1413Sun Feb 27 14:39:22 GMT 2000tuning. threads

Counter3

public class Counter3 extends Object

Fields Summary
static long[]
vec
Constructors Summary
Methods Summary
public static voidaddAmount(int key, long amount)

    //Use our own threads to make the mapping easier,
    //and to illustrate the technique of customizing threads.
    //For generic Thread objects, could use an unsynchronized 
    //HashMap or other Map,
    //Or use ThreadLocal if JDK 1.2 is available

    //We use the num instance variable of the CounterTest
    //object to determine which array we are going to increment.
    //Sonce each thread is different, here is no conflict.
    //Each thread updates its own counter.
    long[] arr =  vec[((CounterTest) Thread.currentThread()).num];
    arr[key] += amount;
public static synchronized longgetAmount(int key)

    //The current amount must be aggregated across the thread
    //storage arrays. This needs to be synchronized, but
    //does not matter here as I just call it at the end.
    long amount = 0;
    for (int threadnum = vec.length-1; threadnum >= 0 ; threadnum--)
    {
      long[] arr = vec[threadnum];
      if (arr != null)
        amount += arr[key];
    }
    return amount;
public static synchronized voidinitialize(CounterTest t)


       
  
    //For simplicity make just 10 counters per thread
    vec[t.num] = new long[10];