private boolean eventuallyGetMaxKeyInDB(final FDate key, final boolean force) {
// not updating highest allowed key, since this already happened during key adjustment
final FDate newMaxKeyInDB = getAdjustKeyProvider().getHighestAllowedKey();
if (newMaxKeyInDB != null) {
if (newMaxKeyInDB.isAfter(maxKeyInDB)) {
maxKeyInDB = newMaxKeyInDB;
return true;
} else {
return false;
}
}
// fallback to normal procedure if curHighWaterMark is not provided by provider
if (maxKeyInDB == null || force) {
final V maxValue = readNewestValueFromDB(maxKey());
if (maxValue != null) {
final FDate maxValueKey = extractKey(key, maxValue);
if (maxKeyInDB == null || maxValueKey.compareTo(maxKeyInDB) <= -1) {
maxKeyInDB = maxValueKey;
getValuesMap().put(maxValueKey, maxValue);
return true;
}
}
}
return false;
}
private V eventuallyGetMinValue(final FDate key, final boolean newMinKey) {
// if key < minKey; use value for minKey
if (minKeyInDB != null) {
final boolean afterMinKey = !newMinKey && key.compareTo(minKey) >= 0;
if (afterMinKey && key.compareTo(minKeyInDB) <= 0 && containsKey(minKey)) {
// via readNewestValueTo
return query().withFuture().getValue(minKey);
}
if (key.compareTo(minKeyInDB) <= 0 && containsKey(minKeyInDB)) {
// via searchInFurtherValues
return query().withFuture().getValue(minKeyInDB);
}
}
return (V) null;
}
private boolean eventuallyGetMinKeyInDB(final FDate key, final boolean force) {
if (minKeyInDB == null || force) {
final V minValue = readNewestValueFromDB(minKey());
if (minValue != null) {
final FDate minValueKey = extractKey(key, minValue);
// min key must be kept intact if all values have been loaded from a later key
if (minKeyInDB == null || minValueKey.compareTo(minKeyInDB) <= -1) {
minKeyInDB = minValueKey;
getValuesMap().put(minValueKey, minValue);
return true;
}
}
}
return false;
}
private boolean eventuallyLoadFurtherValues(
final String source,
final FDate key,
final FDate adjustedKey,
final boolean newMinKey,
final boolean forced) {
if (forced || shouldLoadFurtherValues(key, newMinKey)) {
final FDate keyForReadAllValues;
if (newMinKey
&& minKeyInDBFromLoadFurtherValues != null
&& key.isBefore(minKeyInDBFromLoadFurtherValues)) {
// performance optimization for first load
keyForReadAllValues = FDates.min(minKeyInDB, FDates.max(minKeyInDB, adjustedKey));
} else {
keyForReadAllValues = FDates.max(minKeyInDB, adjustedKey);
}
furtherValues.clear();
lastValuesFromFurtherValues.clear();
furtherValues.addAll(readAllValuesAscendingFrom(keyForReadAllValues));
if (!furtherValues.isEmpty()) {
assertFurtherValuesSorting(key);
}
return true;
}
return false;
}
private boolean updateMinKey(final FDate key) {
if (minKey == null || key.compareTo(minKey) <= -1) {
minKey = key;
return true;
} else {
return false;
}
}
private boolean updateMaxKey(final FDate key) {
if (maxKey == null || key.compareTo(maxKey) >= 1) {
maxKey = key;
return true;
} else {
return false;
}
}
private boolean shouldLoadFurtherValues(final FDate key, final boolean newMinKey) {
if (furtherValues.isEmpty()) {
final V tail = lastValuesFromFurtherValues.getTail();
if (tail == null) {
return true;
}
final V head = lastValuesFromFurtherValues.getHead();
final FDate tailKey = extractKey(key, tail);
final FDate headKey = extractKey(key, head);
final boolean isEndReachedAnyway =
tailKey.equals(maxKeyInDB)
&& key.isBeforeOrEqualTo(maxKeyInDB)
&& headKey.isBeforeOrEqualTo(key);
return !isEndReachedAnyway;
}
final boolean keyIsBeforeMinKeyFromLoadFurtherValues =
newMinKey && key.isBefore(minKeyInDBFromLoadFurtherValues);
if (keyIsBeforeMinKeyFromLoadFurtherValues) {
return true;
}
final boolean newMinKeyFromDBMayFindNewValues =
isMinKeyInDBFromLoadFurtherValues() && key.compareTo(minKeyInDB) <= -1 && newMinKey;
if (newMinKeyFromDBMayFindNewValues) {
return true;
}
return false;
}
private boolean isPotentiallyAlreadyEvicted(final FDate key, final V value) {
final boolean isEvictedBeforeCurrentFurtherValues =
(value == null || extractKey(key, value).isAfter(key))
&& (key.isAfter(minKeyInDB) || key.isAfter(minKeyInDBFromLoadFurtherValues));
if (isEvictedBeforeCurrentFurtherValues) {
return true;
}
final boolean mightBeEvictedAfterFurtherValues = value != null && furtherValues.isEmpty();
if (mightBeEvictedAfterFurtherValues) {
final FDate valueKey = extractKey(key, value);
final boolean isEvictedAfterCurrentFurtherValues =
valueKey.isBefore(key) && valueKey.isBeforeOrEqualTo(maxKeyInDB);
if (isEvictedAfterCurrentFurtherValues) {
return true;
}
}
return false;
}
private void assertFurtherValuesSorting(final FDate key) {
final FDate firstKey = extractKey(key, furtherValues.getHead());
if (firstKey.compareTo(key) <= -1) {
/*
* readAllValuesAscendingFrom loads all data, thus we set the min key very deep so that later queries are
* skipped if they are before minKey
*/
minKey = minKey();
}
if (minKeyInDB == null || firstKey.compareTo(minKey) <= -1) {
minKeyInDB = firstKey;
}
minKeyInDBFromLoadFurtherValues = FDates.min(minKeyInDBFromLoadFurtherValues, firstKey);
final FDate lastKey = extractKey(key, furtherValues.getTail());
if (maxKeyInDB == null || lastKey.compareTo(maxKeyInDB) <= -1) {
maxKeyInDB = FDates.max(maxKeyInDB, lastKey);
}
maxKeyInDBFromLoadFurtherValues = FDates.max(maxKeyInDBFromLoadFurtherValues, lastKey);
if (furtherValues.size() > 1) {
Assertions.checkState(
firstKey.compareTo(lastKey) <= 0,
"Not ascending sorted! At firstKey [%s] and lastKey [%s]",
firstKey,
lastKey);
}
}
private V loadFromCacheBeforeLoadFurtherValues(
final FDate key, final boolean newMaxKey, final boolean newMinKey) {
final V value = eventuallyGetMinValue(key, newMinKey);
if (value != null) {
return value;
}
// maybe use max value
if (maxKeyInDB != null && key.compareTo(maxKeyInDB) >= 0 && containsKey(maxKeyInDB)) {
return query().withFuture().getValue(maxKeyInDB);
}
return (V) null;
}
/**
* These checks may only be called after furtherValues were searched and eventuelly the list has
* been reloaded.
*/
private V tryLoadFromCacheAfterLoadFurtherValues(
final FDate key, final boolean newMaxKey, final FDate previousMaxKey) {
// maybe minKey in db did not change even though the minKey in the cache changed
// after reloading of furtherValues it is ok to search this again instead of doing another query
// for the newest value
if (furtherValuesLoaded) {
final V value = eventuallyGetMinValue(key, false);
if (value != null) {
return value;
}
}
// with maxKey
if (newMaxKey
&& previousMaxKey != null
&& containsKey(previousMaxKey)
&& key.isAfterOrEqualTo(maxKeyInDB)) {
// use the last maxKey
// because this one is behind it and not a new one
// thus working if the db does not have further values
return query().withFuture().getValue(previousMaxKey);
}
return (V) null;
}
/**
* when this does not match, then getLatestValue will be used automatically anyway to go further
* back in time
*/
private FDate determineEaliestStartOfLoadFurtherValues(final FDate key) {
// 1 day is fine for most cases
return key.addMilliseconds(-cacheMissCounter.getOptimalReadBackStepMillis());
}
private V searchInFurtherValues(final FDate key) {
// Take the first matching value from the sorted list
// Search for the newest value
V prevValue = (V) null;
FDate prevKey = null;
if (!lastValuesFromFurtherValues.isEmpty()) {
// though maybe use the last one for smaller increments than the data itself is loaded
for (final V lastValueFromFurtherValues : lastValuesFromFurtherValues) {
final FDate keyLastValueFromFurtherValues = extractKey(key, lastValueFromFurtherValues);
if (keyLastValueFromFurtherValues.isBeforeOrEqualTo(key)) {
prevValue = lastValueFromFurtherValues;
prevKey = keyLastValueFromFurtherValues;
} else {
// only go to further values if it might be possible that those are useable
return prevValue;
}
}
}
final FDate earliestStartOfLoadFurtherValues = determineEaliestStartOfLoadFurtherValues(key);
while (furtherValues.size() > 0) {
final V newValue = furtherValues.getHead();
final FDate newValueKey = extractKey(key, newValue);
final int compare = key.compareTo(newValueKey);
if (compare < 0) {
// key < newValueKey
// run over the key we wanted
break;
} else if (compare == 0) {
// key == newValueKey
// This is the value we searched for! It will later be added with the db key to the cache.
pushLastValueFromFurtherValues();
return newValue;
} else {
// key > newValueKey
// put this value into the cache; gaps do not get filled here, so that the max size of the
// cache does not get reached prematurely
put(newValueKey, newValue, prevKey, prevValue);
pushLastValueFromFurtherValues();
// continue with the next one
prevValue = newValue;
prevKey = newValueKey;
if (furtherValues.isEmpty()
&& newValueKey.isBefore(maxKeyInDB)
&& key.isBefore(maxKeyInDB)
&& maxKeyInDBFromLoadFurtherValues.isBefore(maxKeyInDB)) {
final FDate timeForLoadFurtherValues =
FDates.max(newValueKey, earliestStartOfLoadFurtherValues);
Assertions.checkState(
eventuallyLoadFurtherValues(
"searchInFurtherValues", newValueKey, timeForLoadFurtherValues, false, true));
if (!furtherValues.isEmpty()) {
pushLastValueFromFurtherValues();
if (!timeForLoadFurtherValues.equals(newValue)) {
// do not distort prev/next lookup when using earlisetStartOfLoadFurtherValues, thus
// reset those
prevValue = null;
prevKey = null;
}
}
}
}
}
return prevValue;
}
