org.infinispan.counter.impl.function.FunctionHelper Maven / Gradle / Ivy
package org.infinispan.counter.impl.function;
import static org.infinispan.counter.impl.entries.CounterValue.newCounterValue;
import org.infinispan.counter.api.CounterState;
import org.infinispan.counter.api.CounterType;
import org.infinispan.counter.impl.entries.CounterValue;
import org.infinispan.functional.impl.CounterConfigurationMetaParam;
import org.infinispan.functional.EntryView;
/**
* A helper with the function logic.
*
* It avoids duplicate code between the functions and the create-functions.
*
* @author Pedro Ruivo
* @since 9.2
*/
final class FunctionHelper {
private FunctionHelper() {
}
/**
* Performs a compare-and-swap and return the previous value.
*
* The compare-and-swap is successful if the return value is equals to the {@code expected}.
*
* @return the previous value or {@link CounterState#UPPER_BOUND_REACHED}/{@link CounterState#LOWER_BOUND_REACHED} if
* it reaches the boundaries of a bounded counter.
*/
static Object compareAndSwap(EntryView.ReadWriteEntryView entry,
CounterValue value, CounterConfigurationMetaParam metadata, long expected, long update) {
long retVal = value.getValue();
if (expected == retVal) {
if (metadata.get().type() == CounterType.BOUNDED_STRONG) {
if (update < metadata.get().lowerBound()) {
return CounterState.LOWER_BOUND_REACHED;
} else if (update > metadata.get().upperBound()) {
return CounterState.UPPER_BOUND_REACHED;
}
}
entry.set(CounterValue.newCounterValue(update, CounterState.VALID), metadata);
return retVal;
} else {
return retVal;
}
}
static CounterValue add(EntryView.ReadWriteEntryView entry,
CounterValue value, CounterConfigurationMetaParam metadata, long delta) {
if (delta == 0) {
return value;
}
if (metadata.get().type() == CounterType.BOUNDED_STRONG) {
if (delta > 0) {
return addAndCheckUpperBound(entry, value, metadata, delta);
} else {
return addAndCheckLowerBound(entry, value, metadata, delta);
}
} else {
return addUnbounded(entry, value, metadata, delta);
}
}
private static CounterValue addAndCheckUpperBound(EntryView.ReadWriteEntryView entry,
CounterValue value, CounterConfigurationMetaParam metadata, long delta) {
if (value.getState() == CounterState.UPPER_BOUND_REACHED) {
return value;
}
CounterValue newValue;
long upperBound = metadata.get().upperBound();
try {
long addedValue = Math.addExact(value.getValue(), delta);
if (addedValue > upperBound) {
newValue = newCounterValue(upperBound, CounterState.UPPER_BOUND_REACHED);
} else {
newValue = newCounterValue(addedValue, CounterState.VALID);
}
} catch (ArithmeticException e) {
//overflow!
newValue = newCounterValue(Long.MAX_VALUE, CounterState.UPPER_BOUND_REACHED);
}
entry.set(newValue, metadata);
return newValue;
}
private static CounterValue addAndCheckLowerBound(EntryView.ReadWriteEntryView entry,
CounterValue value, CounterConfigurationMetaParam metadata, long delta) {
if (value.getState() == CounterState.LOWER_BOUND_REACHED) {
return value;
}
CounterValue newValue;
long lowerBound = metadata.get().lowerBound();
try {
long addedValue = Math.addExact(value.getValue(), delta);
if (addedValue < lowerBound) {
newValue = newCounterValue(lowerBound, CounterState.LOWER_BOUND_REACHED);
} else {
newValue = newCounterValue(addedValue, CounterState.VALID);
}
} catch (ArithmeticException e) {
//overflow!
newValue = newCounterValue(Long.MIN_VALUE, CounterState.LOWER_BOUND_REACHED);
}
entry.set(newValue, metadata);
return newValue;
}
private static CounterValue addUnbounded(EntryView.ReadWriteEntryView entry, CounterValue value,
CounterConfigurationMetaParam metadata, long delta) {
if (noChange(value.getValue(), delta)) {
return value;
}
CounterValue newValue;
try {
newValue = newCounterValue(Math.addExact(value.getValue(), delta));
} catch (ArithmeticException e) {
//overflow!
newValue = newCounterValue(delta > 0 ? Long.MAX_VALUE : Long.MIN_VALUE);
}
entry.set(newValue, metadata);
return newValue;
}
private static boolean noChange(long currentValue, long delta) {
return (currentValue == Long.MAX_VALUE && delta > 0) ||
(currentValue == Long.MIN_VALUE && delta < 0);
}
}