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/*
* Copyright (C) 2016, Google Inc. and others
*
* This program and the accompanying materials are made available under the
* terms of the Eclipse Distribution License v. 1.0 which is available at
* https://www.eclipse.org/org/documents/edl-v10.php.
*
* SPDX-License-Identifier: BSD-3-Clause
*/
package org.eclipse.jgit.util.time;
import static java.util.concurrent.TimeUnit.MICROSECONDS;
import static java.util.concurrent.TimeUnit.MILLISECONDS;
import java.sql.Timestamp;
import java.time.Duration;
import java.time.Instant;
import java.util.Date;
import java.util.Iterator;
import java.util.concurrent.TimeUnit;
import java.util.concurrent.TimeoutException;
/**
* A timestamp generated by
* {@link org.eclipse.jgit.util.time.MonotonicClock#propose()}.
* <p>
* ProposedTimestamp implements AutoCloseable so that implementations can
* release resources associated with obtaining certainty about time elapsing.
* For example the constructing MonotonicClock may start network IO with peers
* when creating the ProposedTimestamp, and {@link #close()} can ensure those
* network resources are released in a timely fashion.
*
* @since 4.6
*/
public abstract class ProposedTimestamp implements AutoCloseable {
/**
* Wait for several timestamps.
*
* @param times
* timestamps to wait on.
* @param maxWait
* how long to wait for the timestamps.
* @throws java.lang.InterruptedException
* current thread was interrupted before the waiting process
* completed normally.
* @throws java.util.concurrent.TimeoutException
* the timeout was reached without the proposed timestamp become
* certainly in the past.
*/
public static void blockUntil(Iterable<ProposedTimestamp> times,
Duration maxWait) throws TimeoutException, InterruptedException {
Iterator<ProposedTimestamp> itr = times.iterator();
if (!itr.hasNext()) {
return;
}
long now = System.currentTimeMillis();
long deadline = now + maxWait.toMillis();
for (;;) {
long w = deadline - now;
if (w < 0) {
throw new TimeoutException();
}
itr.next().blockUntil(Duration.ofMillis(w));
if (itr.hasNext()) {
now = System.currentTimeMillis();
} else {
break;
}
}
}
/**
* Read the timestamp as {@code unit} since the epoch.
* <p>
* The timestamp value for a specific {@code ProposedTimestamp} object never
* changes, and can be read before {@link #blockUntil(Duration)}.
*
* @param unit
* what unit to return the timestamp in. The timestamp will be
* rounded if the unit is bigger than the clock's granularity.
* @return {@code unit} since the epoch.
*/
public abstract long read(TimeUnit unit);
/**
* Wait for this proposed timestamp to be certainly in the recent past.
* <p>
* This method forces the caller to wait up to {@code timeout} for
* {@code this} to pass sufficiently into the past such that the creating
* {@link org.eclipse.jgit.util.time.MonotonicClock} instance will not
* create an earlier timestamp.
*
* @param maxWait
* how long the implementation may block the caller.
* @throws java.lang.InterruptedException
* current thread was interrupted before the waiting process
* completed normally.
* @throws java.util.concurrent.TimeoutException
* the timeout was reached without the proposed timestamp
* becoming certainly in the past.
*/
public abstract void blockUntil(Duration maxWait)
throws InterruptedException, TimeoutException;
/**
* Get milliseconds since epoch; {@code read(MILLISECONDS}).
*
* @return milliseconds since epoch; {@code read(MILLISECONDS}).
*/
public long millis() {
return read(MILLISECONDS);
}
/**
* Get microseconds since epoch; {@code read(MICROSECONDS}).
*
* @return microseconds since epoch; {@code read(MICROSECONDS}).
*/
public long micros() {
return read(MICROSECONDS);
}
/**
* Get time since epoch, with up to microsecond resolution.
*
* @return time since epoch, with up to microsecond resolution.
*/
public Instant instant() {
long usec = micros();
long secs = usec / 1000000L;
long nanos = (usec % 1000000L) * 1000L;
return Instant.ofEpochSecond(secs, nanos);
}
/**
* Get time since epoch, with up to microsecond resolution.
*
* @return time since epoch, with up to microsecond resolution.
*
* @deprecated Use instant() instead
*/
@Deprecated(since = "7.2")
public Timestamp timestamp() {
return Timestamp.from(instant());
}
/**
* Get time since epoch, with up to millisecond resolution.
*
* @return time since epoch, with up to millisecond resolution.
*
* @deprecated Use instant() instead
*/
@Deprecated(since = "7.2")
public Date date() {
return new Date(millis());
}
/**
* {@inheritDoc}
* <p>
* Release resources allocated by this timestamp.
*/
@Override
public void close() {
// Do nothing by default.
}
@Override
public String toString() {
return instant().toString();
}
}
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