BatchingProgressMonitor.java
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package org.eclipse.jgit.lib;
import java.util.concurrent.Future;
import java.util.concurrent.TimeUnit;
import org.eclipse.jgit.lib.internal.WorkQueue;
/**
* ProgressMonitor that batches update events.
*/
public abstract class BatchingProgressMonitor implements ProgressMonitor {
private long delayStartTime;
private TimeUnit delayStartUnit = TimeUnit.MILLISECONDS;
private Task task;
/**
* Set an optional delay before the first output.
*
* @param time
* how long to wait before output. If 0 output begins on the
* first {@link #update(int)} call.
* @param unit
* time unit of {@code time}.
*/
public void setDelayStart(long time, TimeUnit unit) {
delayStartTime = time;
delayStartUnit = unit;
}
/** {@inheritDoc} */
@Override
public void start(int totalTasks) {
// Ignore the number of tasks.
}
/** {@inheritDoc} */
@Override
public void beginTask(String title, int work) {
endTask();
task = new Task(title, work);
if (delayStartTime != 0)
task.delay(delayStartTime, delayStartUnit);
}
/** {@inheritDoc} */
@Override
public void update(int completed) {
if (task != null)
task.update(this, completed);
}
/** {@inheritDoc} */
@Override
public void endTask() {
if (task != null) {
task.end(this);
task = null;
}
}
/** {@inheritDoc} */
@Override
public boolean isCancelled() {
return false;
}
/**
* Update the progress monitor if the total work isn't known,
*
* @param taskName
* name of the task.
* @param workCurr
* number of units already completed.
*/
protected abstract void onUpdate(String taskName, int workCurr);
/**
* Finish the progress monitor when the total wasn't known in advance.
*
* @param taskName
* name of the task.
* @param workCurr
* total number of units processed.
*/
protected abstract void onEndTask(String taskName, int workCurr);
/**
* Update the progress monitor when the total is known in advance.
*
* @param taskName
* name of the task.
* @param workCurr
* number of units already completed.
* @param workTotal
* estimated number of units to process.
* @param percentDone
* {@code workCurr * 100 / workTotal}.
*/
protected abstract void onUpdate(String taskName, int workCurr,
int workTotal, int percentDone);
/**
* Finish the progress monitor when the total is known in advance.
*
* @param taskName
* name of the task.
* @param workCurr
* total number of units processed.
* @param workTotal
* estimated number of units to process.
* @param percentDone
* {@code workCurr * 100 / workTotal}.
*/
protected abstract void onEndTask(String taskName, int workCurr,
int workTotal, int percentDone);
private static class Task implements Runnable {
/** Title of the current task. */
private final String taskName;
/** Number of work units, or {@link ProgressMonitor#UNKNOWN}. */
private final int totalWork;
/** True when timer expires and output should occur on next update. */
private volatile boolean display;
/** Scheduled timer, supporting cancellation if task ends early. */
private Future<?> timerFuture;
/** True if the task has displayed anything. */
private boolean output;
/** Number of work units already completed. */
private int lastWork;
/** Percentage of {@link #totalWork} that is done. */
private int lastPercent;
Task(String taskName, int totalWork) {
this.taskName = taskName;
this.totalWork = totalWork;
this.display = true;
}
void delay(long time, TimeUnit unit) {
display = false;
timerFuture = WorkQueue.getExecutor().schedule(this, time, unit);
}
@Override
public void run() {
display = true;
}
void update(BatchingProgressMonitor pm, int completed) {
lastWork += completed;
if (totalWork == UNKNOWN) {
// Only display once per second, as the alarm fires.
if (display) {
pm.onUpdate(taskName, lastWork);
output = true;
restartTimer();
}
} else {
// Display once per second or when 1% is done.
int currPercent = lastWork * 100 / totalWork;
if (display) {
pm.onUpdate(taskName, lastWork, totalWork, currPercent);
output = true;
restartTimer();
lastPercent = currPercent;
} else if (currPercent != lastPercent) {
pm.onUpdate(taskName, lastWork, totalWork, currPercent);
output = true;
lastPercent = currPercent;
}
}
}
private void restartTimer() {
display = false;
timerFuture = WorkQueue.getExecutor().schedule(this, 1,
TimeUnit.SECONDS);
}
void end(BatchingProgressMonitor pm) {
if (output) {
if (totalWork == UNKNOWN) {
pm.onEndTask(taskName, lastWork);
} else {
int pDone = lastWork * 100 / totalWork;
pm.onEndTask(taskName, lastWork, totalWork, pDone);
}
}
if (timerFuture != null)
timerFuture.cancel(false /* no interrupt */);
}
}
}