Exact Aggregation and Delivery - Real-Time Analytics - page 363

Next the expiration time and the retention time are defined. The TimeUnit
class is an often overlooked Java core class that is part of the
java.util.concurrent package. It provides convenient conversions to
and from different time units. In this case, the base time format is:
long expirationMillis = -1;
public Aggregate expire( long time,TimeUnit unit) {
expirationMillis =
TimeUnit. MILLISECONDS .convert(time, unit);
return this ;
}
public long expire( long time) {
return expirationMillis == -1 ?
-1 : expirationMillis*(time/expirationMillis);
}
long resolutionMillis = 1000;
TimeUnit unit = TimeUnit. SECONDS ;
public Aggregate resolution( long time,TimeUnit unit)
{
resolutionMillis =
TimeUnit. MILLISECONDS .convert(time, unit);
this .unit = unit;
return this ;
}
The quantization functions can take in a millisecond timestamp and return
an appropriately quantized version. Using the formatting strings from the
preceding code, it can also return a time key that is suitable for use in
key-value storage systems:
public TimeUnit quantizeUnit() { return unit; }
public long quantize( long time) {
return resolutionMillis*(resolutionMillis/time);
}
public long quantize( long time,TimeUnit unit) {
return quantize(
TimeUnit. MILLISECONDS .convert(time, unit));
}
public String quantizeString( long time) {