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package sun.jvm.hotspot.utilities;

import sun.jvm.hotspot.memory.*;
import sun.jvm.hotspot.oops.*;

This class wraps a user's chosen HeapVisitor with the functionality that a chosen "thunk" is called periodically during the heap traversal. This allows a progress bar to be displayed during long heap scans.
/** This class wraps a user's chosen HeapVisitor with the functionality that a chosen "thunk" is called periodically during the heap traversal. This allows a progress bar to be displayed during long heap scans. */
public class ProgressiveHeapVisitor implements HeapVisitor { private HeapVisitor userHeapVisitor; private HeapProgressThunk thunk; private long usedSize; private long visitedSize; private double lastNotificationFraction; private static double MINIMUM_NOTIFICATION_FRACTION = 0.01; public ProgressiveHeapVisitor(HeapVisitor userHeapVisitor, HeapProgressThunk thunk) { this.userHeapVisitor = userHeapVisitor; this.thunk = thunk; } public void prologue(long usedSize) { this.usedSize = usedSize; visitedSize = 0; userHeapVisitor.prologue(usedSize); thunk.heapIterationFractionUpdate(0.0); } public boolean doObj(Oop obj) { userHeapVisitor.doObj(obj); visitedSize += obj.getObjectSize(); double curFrac = (double) visitedSize / (double) usedSize; if (curFrac > lastNotificationFraction + MINIMUM_NOTIFICATION_FRACTION) { thunk.heapIterationFractionUpdate(curFrac); lastNotificationFraction = curFrac; } return false; } public void epilogue() { userHeapVisitor.epilogue(); thunk.heapIterationComplete(); } }