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/*
* Licensed to the Apache Software Foundation (ASF) under one or more
* contributor license agreements. See the NOTICE file distributed with
* this work for additional information regarding copyright ownership.
* The ASF licenses this file to You under the Apache License, Version 2.0
* (the "License"); you may not use this file except in compliance with
* the License. You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
package org.apache.activemq.artemis.utils;
import java.util.concurrent.atomic.AtomicIntegerFieldUpdater;
import java.util.concurrent.atomic.AtomicLongFieldUpdater;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
import java.lang.invoke.MethodHandles;
public class SizeAwareMetric {
public interface AddCallback {
void add(int delta, boolean sizeOnly);
}
private static final Logger logger = LoggerFactory.getLogger(MethodHandles.lookup().lookupClass());
private static final int PENDING_FREE = 0, FREE = 1, PENDING_OVER_SIZE = 2, OVER_SIZE = 3, PENDING_OVER_ELEMENTS = 4, OVER_ELEMENTS = 5, NOT_USED = -1;
private static final AtomicLongFieldUpdater elementsUpdater = AtomicLongFieldUpdater.newUpdater(SizeAwareMetric.class, "elements");
private volatile long elements;
private static final AtomicLongFieldUpdater sizeUpdater = AtomicLongFieldUpdater.newUpdater(SizeAwareMetric.class, "size");
private volatile long size;
private static final AtomicIntegerFieldUpdater flagUpdater = AtomicIntegerFieldUpdater.newUpdater(SizeAwareMetric.class, "flag");
private volatile int flag = NOT_USED;
private long maxElements;
private long lowerMarkElements;
private long maxSize;
private long lowerMarkSize;
private boolean sizeEnabled = false;
private boolean elementsEnabled = false;
private AddCallback onSizeCallback;
private Runnable overCallback;
private Runnable underCallback;
/** To be used in a case where we just measure elements */
public SizeAwareMetric() {
this.sizeEnabled = false;
this.elementsEnabled = false;
}
public SizeAwareMetric(long maxSize, long lowerMarkSize, long maxElements, long lowerMarkElements) {
if (lowerMarkSize > maxSize) {
throw new IllegalArgumentException("lowerMark must be <= maxSize");
}
if (lowerMarkElements > maxElements) {
throw new IllegalArgumentException("lowerMarkElements must be <= maxElements");
}
this.maxElements = maxElements;
this.lowerMarkElements = lowerMarkElements;
this.maxSize = maxSize;
this.lowerMarkSize = lowerMarkSize;
this.sizeEnabled = maxSize >= 0;
this.elementsEnabled = maxElements >= 0;
}
public boolean isOver() {
return flag > FREE; // equivalent to flag != FREE && flag != NOT_USED;
}
public boolean isOverSize() {
return flag == OVER_SIZE;
}
public boolean isOverElements() {
return flag == OVER_ELEMENTS;
}
public long getSize() {
return size;
}
public boolean isElementsEnabled() {
return elementsEnabled;
}
public SizeAwareMetric setElementsEnabled(boolean elementsEnabled) {
this.elementsEnabled = elementsEnabled;
return this;
}
public long getElements() {
return elements;
}
public boolean isSizeEnabled() {
return sizeEnabled;
}
public SizeAwareMetric setSizeEnabled(boolean sizeEnabled) {
this.sizeEnabled = sizeEnabled;
return this;
}
public SizeAwareMetric setOnSizeCallback(AddCallback onSize) {
this.onSizeCallback = onSize;
return this;
}
public SizeAwareMetric setOverCallback(Runnable over) {
this.overCallback = over;
return this;
}
public SizeAwareMetric setUnderCallback(Runnable under) {
this.underCallback = under;
return this;
}
protected void over() {
if (overCallback != null) {
try {
overCallback.run();
} catch (Throwable e) {
logger.warn(e.getMessage(), e);
}
}
}
protected void under() {
if (underCallback != null) {
try {
underCallback.run();
} catch (Throwable e) {
logger.warn(e.getMessage(), e);
}
}
}
private boolean changeFlag(int expected, int newValue) {
return flagUpdater.compareAndSet(this, expected, newValue);
}
public final long addSize(final int delta) {
return addSize(delta, false);
}
public final long addSize(final int delta, final boolean sizeOnly) {
if (delta == 0) {
if (logger.isDebugEnabled()) {
logger.debug("SizeAwareMetric ignored with size 0", new Exception("trace"));
}
return sizeUpdater.get(this);
}
changeFlag(NOT_USED, FREE);
if (onSizeCallback != null) {
try {
onSizeCallback.add(delta, sizeOnly);
} catch (Throwable e) {
logger.warn(e.getMessage(), e);
}
}
long currentSize = sizeUpdater.addAndGet(this, delta);
long currentElements;
if (sizeOnly) {
currentElements = elementsUpdater.get(this);
} else if (delta > 0) {
currentElements = elementsUpdater.incrementAndGet(this);
} else {
currentElements = elementsUpdater.decrementAndGet(this);
}
if (delta > 0) {
checkOver(currentElements, currentSize);
} else { // (delta < 0)
checkUnder(currentElements, currentSize);
}
return currentSize;
}
public void setMax(long maxSize, long lowerMarkSize, long maxElements, long lowerMarkElements) {
this.maxSize = maxSize;
this.lowerMarkSize = lowerMarkSize;
this.maxElements = maxElements;
this.lowerMarkElements = lowerMarkElements;
long currentSize = sizeUpdater.get(this);
long currentElements = elementsUpdater.get(this);
checkOver(currentElements, currentSize);
checkUnder(currentElements, currentSize);
}
private void checkUnder(long currentElements, long currentSize) {
if (sizeEnabled) {
if (currentSize <= lowerMarkSize && changeFlag(OVER_SIZE, PENDING_FREE)) {
// checking if we need to switch from OVER_SIZE to OVER_ELEMENTS, to avoid calling under needless
if (!(elementsEnabled && currentElements >= maxElements && changeFlag(PENDING_FREE, OVER_ELEMENTS))) {
try {
under();
} finally {
changeFlag(PENDING_FREE, FREE);
}
}
return; // we must return now as we already checked for the elements portion
}
}
if (elementsEnabled) {
if (currentElements <= lowerMarkElements && changeFlag(OVER_ELEMENTS, PENDING_FREE)) {
// checking if we need to switch from OVER_ELEMENTS to OVER_SIZE, to avoid calling under needless
if (!(sizeEnabled && currentSize >= maxSize && changeFlag(PENDING_FREE, OVER_SIZE))) {
// this is checking the other side from size (elements).
// on this case we are just switching sides and we should not fire under();
try {
under();
} finally {
changeFlag(PENDING_FREE, FREE);
}
}
return; // this return here is moot I know. I am keeping it here for consistence with the size portion
// and in case eventually further checks are added on this method, this needs to be reviewed.
}
}
}
private void checkOver(long currentElements, long currentSize) {
if (sizeEnabled) {
if (currentSize >= maxSize && changeFlag(FREE, PENDING_OVER_SIZE)) {
try {
over();
} finally {
changeFlag(PENDING_OVER_SIZE, OVER_SIZE);
}
}
}
if (elementsEnabled && currentElements >= 0) {
if (currentElements >= maxElements && changeFlag(FREE, PENDING_OVER_ELEMENTS)) {
try {
over();
} finally {
changeFlag(PENDING_OVER_ELEMENTS, OVER_ELEMENTS);
}
}
}
}
@Override
public String toString() {
return "SizeAwareMetric{" + "elements=" + elements + ", size=" + size + '}';
}
}
