Source code
package org.apache.kafka.common.utils;
import java.time.Duration;
import java.util.concurrent.ExecutionException;
import java.util.concurrent.Future;
import java.util.concurrent.TimeUnit;
import java.util.concurrent.TimeoutException;
import java.util.function.Supplier;
/**
* An interface abstracting the clock to use in unit testing classes that make use of clock time.
*
* Implementations of this class should be thread-safe.
*/
public interface Time {
Time SYSTEM = SystemTime.getSystemTime();
/**
* Returns the current time in milliseconds.
*/
long milliseconds();
/**
* Returns the value returned by `nanoseconds` converted into milliseconds.
*/
default long hiResClockMs() {
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return TimeUnit.NANOSECONDS.toMillis(nanoseconds());
}
/**
* Returns the current value of the running JVM's high-resolution time source, in nanoseconds.
*
* <p>This method can only be used to measure elapsed time and is
* not related to any other notion of system or wall-clock time.
* The value returned represents nanoseconds since some fixed but
* arbitrary <i>origin</i> time (perhaps in the future, so values
* may be negative). The same origin is used by all invocations of
* this method in an instance of a Java virtual machine; other
* virtual machine instances are likely to use a different origin.
*/
long nanoseconds();
/**
* Sleep for the given number of milliseconds
*/
void sleep(long ms);
/**
* Wait for a condition using the monitor of a given object. This avoids the implicit
* dependence on system time when calling {@link Object#wait()}.
*
* @param obj The object that will be waited with {@link Object#wait()}. Note that it is the responsibility
* of the caller to call notify on this object when the condition is satisfied.
* @param condition The condition we are awaiting
* @param deadlineMs The deadline timestamp at which to raise a timeout error
*
* @throws org.apache.kafka.common.errors.TimeoutException if the timeout expires before the condition is satisfied
*/
default void waitObject(Object obj, Supplier<Boolean> condition, long deadlineMs) throws InterruptedException {
synchronized (obj) {
while (true) {
if (condition.get())
return;
long currentTimeMs = milliseconds();
if (currentTimeMs >= deadlineMs)
throw new org.apache.kafka.common.errors.TimeoutException("Condition not satisfied before deadline");
obj.wait(deadlineMs - currentTimeMs);
}
}
}
/**
* Get a timer which is bound to this time instance and expires after the given timeout
*/
default Timer timer(long timeoutMs) {
return new Timer(this, timeoutMs);
}
/**
* Get a timer which is bound to this time instance and expires after the given timeout
*/
default Timer timer(Duration timeout) {
return timer(timeout.toMillis());
}
/**
* Wait for a future to complete, or time out.
*
* @param future The future to wait for.
* @param deadlineNs The time in the future, in monotonic nanoseconds, to time out.
* @return The result of the future.
* @param <T> The type of the future.
*/
default <T> T waitForFuture(
Future<T> future,
long deadlineNs
) throws TimeoutException, InterruptedException, ExecutionException {
TimeoutException timeoutException = null;
while (true) {
long nowNs = nanoseconds();
if (deadlineNs <= nowNs) {
throw (timeoutException == null) ? new TimeoutException() : timeoutException;
}
long deltaNs = deadlineNs - nowNs;
try {
return future.get(deltaNs, TimeUnit.NANOSECONDS);
} catch (TimeoutException t) {
timeoutException = t;
}
}
}
}