Java example source code file (ResourceLeakDetector.java)
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The ResourceLeakDetector.java Java example source code
/*
* Copyright 2013 The Netty Project
*
* The Netty Project 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 io.netty.util;
import io.netty.util.internal.MathUtil;
import io.netty.util.internal.PlatformDependent;
import io.netty.util.internal.SystemPropertyUtil;
import io.netty.util.internal.logging.InternalLogger;
import io.netty.util.internal.logging.InternalLoggerFactory;
import java.lang.ref.PhantomReference;
import java.lang.ref.ReferenceQueue;
import java.util.ArrayDeque;
import java.util.Deque;
import java.util.EnumSet;
import java.util.concurrent.ConcurrentMap;
import java.util.concurrent.atomic.AtomicBoolean;
import static io.netty.util.internal.StringUtil.EMPTY_STRING;
import static io.netty.util.internal.StringUtil.NEWLINE;
import static io.netty.util.internal.StringUtil.simpleClassName;
public class ResourceLeakDetector<T> {
private static final String PROP_LEVEL_OLD = "io.netty.leakDetectionLevel";
private static final String PROP_LEVEL = "io.netty.leakDetection.level";
private static final Level DEFAULT_LEVEL = Level.SIMPLE;
private static final String PROP_MAX_RECORDS = "io.netty.leakDetection.maxRecords";
private static final int DEFAULT_MAX_RECORDS = 4;
private static final int MAX_RECORDS;
/**
* Represents the level of resource leak detection.
*/
public enum Level {
/**
* Disables resource leak detection.
*/
DISABLED,
/**
* Enables simplistic sampling resource leak detection which reports there is a leak or not,
* at the cost of small overhead (default).
*/
SIMPLE,
/**
* Enables advanced sampling resource leak detection which reports where the leaked object was accessed
* recently at the cost of high overhead.
*/
ADVANCED,
/**
* Enables paranoid resource leak detection which reports where the leaked object was accessed recently,
* at the cost of the highest possible overhead (for testing purposes only).
*/
PARANOID
}
private static Level level;
private static final InternalLogger logger = InternalLoggerFactory.getInstance(ResourceLeakDetector.class);
static {
final boolean disabled;
if (SystemPropertyUtil.get("io.netty.noResourceLeakDetection") != null) {
disabled = SystemPropertyUtil.getBoolean("io.netty.noResourceLeakDetection", false);
logger.debug("-Dio.netty.noResourceLeakDetection: {}", disabled);
logger.warn(
"-Dio.netty.noResourceLeakDetection is deprecated. Use '-D{}={}' instead.",
PROP_LEVEL, DEFAULT_LEVEL.name().toLowerCase());
} else {
disabled = false;
}
Level defaultLevel = disabled? Level.DISABLED : DEFAULT_LEVEL;
// First read old property name
String levelStr = SystemPropertyUtil.get(PROP_LEVEL_OLD, defaultLevel.name()).trim().toUpperCase();
// If new property name is present, use it
levelStr = SystemPropertyUtil.get(PROP_LEVEL, levelStr).trim().toUpperCase();
Level level = DEFAULT_LEVEL;
for (Level l: EnumSet.allOf(Level.class)) {
if (levelStr.equals(l.name()) || levelStr.equals(String.valueOf(l.ordinal()))) {
level = l;
}
}
MAX_RECORDS = SystemPropertyUtil.getInt(PROP_MAX_RECORDS, DEFAULT_MAX_RECORDS);
ResourceLeakDetector.level = level;
if (logger.isDebugEnabled()) {
logger.debug("-D{}: {}", PROP_LEVEL, level.name().toLowerCase());
logger.debug("-D{}: {}", PROP_MAX_RECORDS, MAX_RECORDS);
}
}
// Should be power of two.
private static final int DEFAULT_SAMPLING_INTERVAL = 128;
/**
* @deprecated Use {@link #setLevel(Level)} instead.
*/
@Deprecated
public static void setEnabled(boolean enabled) {
setLevel(enabled? Level.SIMPLE : Level.DISABLED);
}
/**
* Returns {@code true} if resource leak detection is enabled.
*/
public static boolean isEnabled() {
return getLevel().ordinal() > Level.DISABLED.ordinal();
}
/**
* Sets the resource leak detection level.
*/
public static void setLevel(Level level) {
if (level == null) {
throw new NullPointerException("level");
}
ResourceLeakDetector.level = level;
}
/**
* Returns the current resource leak detection level.
*/
public static Level getLevel() {
return level;
}
/** the linked list of active resources */
private final DefaultResourceLeak head = new DefaultResourceLeak(null);
private final DefaultResourceLeak tail = new DefaultResourceLeak(null);
private final ReferenceQueue<Object> refQueue = new ReferenceQueue