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sviolet.thistle.util.common.CloseableUtils Maven / Gradle / Ivy
/*
* Copyright (C) 2015-2018 S.Violet
*
* Licensed 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.
*
* Project GitHub: https://github.com/shepherdviolet/thistle
* Email: [email protected]
*/
package sviolet.thistle.util.common;
import sviolet.thistle.entity.common.Destroyable;
import java.io.Closeable;
import java.lang.reflect.Field;
import java.lang.reflect.Method;
import java.nio.ByteBuffer;
import java.nio.MappedByteBuffer;
import java.security.AccessController;
import java.security.PrivilegedAction;
/**
* Closeable工具
*
* @author S.Violet
*/
public class CloseableUtils {
public static void closeQuiet(Closeable closeable) {
if (closeable == null) {
return;
}
try {
closeable.close();
} catch (Exception ignore) {
}
}
public static void closeQuiet(Destroyable destroyable) {
if (destroyable == null) {
return;
}
try {
destroyable.onDestroy();
} catch (Exception ignore) {
}
}
public static void closeIfCloseable(Object obj){
if (obj == null) {
return;
}
try {
if (obj instanceof Closeable){
((Closeable) obj).close();
} else if (obj instanceof Destroyable) {
((Destroyable) obj).onDestroy();
}
} catch (Exception ignore){
}
}
/* **********************************************************************************************************
* MappedByteBuffer:注意事项
* MappedByteBuffer在一些运行时环境中(例如HOTSPOT), 会占用内存并占用文件句柄, 导致文件无法读写删除, 直到对象被GC.
* 且没有常规办法可以回收资源. ANDROID中不存在此问题.
* isMappedByteBufferCanClean方法可以判断当前运行环境是否能手动回收MappedByteBuffer, 无法手动回收的运行时环境建
* 议不要随便使用MappedByteBuffer, 改用传统的IO.
* cleanMappedByteBuffer方法可以手动回收MappedByteBuffer.
*
* MappedByteBuffer是通过下列方法获得的:
* FileInputStream inputStream = new FileInputStream(file);
* FileChannel channel = inputStream.getChannel();
* MappedByteBuffer byteBuffer = channel.map(FileChannel.MapMode.READ_ONLY, 0, file.length());
*/
/**
* 判断当前运行环境是否能手动回收MappedByteBuffer, 无法手动回收的运行时建议不要随便使用MappedByteBuffer, 建议用传统的IO.
* 注意, 安卓平台中, MappedByteBuffer不支持手动回收, 但是不回收也不存在文件句柄占用问题, 可以用MappedByteBuffer.
*
* @return true:支持手动回收MappedByteBuffer
*/
public static boolean isMappedByteBufferCanClean(){
return MAPPED_BYTE_BUFFER_UNMAP.isMappedByteBufferCanClean();
}
/**
* 手动回收MappedByteBuffer.
*
* @return true:回收成功
*/
public static boolean cleanMappedByteBuffer(ByteBuffer byteBuffer) {
return MAPPED_BYTE_BUFFER_UNMAP.cleanMappedByteBuffer(byteBuffer);
}
private static final MappedByteBufferUnmap MAPPED_BYTE_BUFFER_UNMAP;
static {
if (PlatformUtils.PLATFORM == PlatformUtils.Platform.DALVIK ||
PlatformUtils.RUNTIME_VERSION == null){
//1. Android : 安卓平台中, MappedByteBuffer不支持手动回收, 但是不回收也不存在文件句柄占用问题, 可以用MappedByteBuffer
//2. 未知版本 : 不支持手动回收, 不建议使用MappedByteBuffer
MAPPED_BYTE_BUFFER_UNMAP = new UnsupportedMappedByteBufferUnmap();
} else if (PlatformUtils.RUNTIME_VERSION.startsWith("1.")) {
//JDK8- : MappedByteBuffer需要被手动回收, 会有句柄未释放问题
MAPPED_BYTE_BUFFER_UNMAP = new Jdk8MappedByteBufferUnmap();
} else {
//JDK9+ : MappedByteBuffer需要被手动回收, 会有句柄未释放问题
MAPPED_BYTE_BUFFER_UNMAP = new Jdk9MappedByteBufferUnmap();
}
}
private interface MappedByteBufferUnmap {
boolean isMappedByteBufferCanClean();
boolean cleanMappedByteBuffer(ByteBuffer byteBuffer);
}
private static class UnsupportedMappedByteBufferUnmap implements MappedByteBufferUnmap {
@Override
public boolean isMappedByteBufferCanClean() {
return false;
}
@Override
public boolean cleanMappedByteBuffer(ByteBuffer byteBuffer) {
return false;
}
}
private static class Jdk8MappedByteBufferUnmap implements MappedByteBufferUnmap {
private volatile int isMappedByteBufferCanClean = -1;
private Class directByteBufferClass;
private Method directByteBufferCleanerMethod;
private Method cleanerCleanMethod;
@Override
public boolean isMappedByteBufferCanClean() {
if (isMappedByteBufferCanClean >= 0){
return isMappedByteBufferCanClean == 0;
}
return AccessController.doPrivileged(new PrivilegedAction() {
@Override
public Boolean run() {
try {
//cleaner method
directByteBufferClass = Class.forName("java.nio.DirectByteBuffer");
directByteBufferCleanerMethod = directByteBufferClass.getDeclaredMethod("cleaner");
if (!"sun.misc.Cleaner".equals(directByteBufferCleanerMethod.getReturnType().getName())){
throw new Exception("Return type of method cleaner is not sun.misc.Cleaner");
}
directByteBufferCleanerMethod.setAccessible(true);
//clean method
Class cleanerClass = Class.forName("sun.misc.Cleaner");
cleanerCleanMethod = cleanerClass.getDeclaredMethod("clean");
cleanerCleanMethod.setAccessible(true);
isMappedByteBufferCanClean = 0;
return true;
} catch (Throwable t) {
System.out.println("WARNING: This jre environment can not clean MappedByteBuffer manually (jdk8- 1), isMappedByteBufferCanClean = false, error: " + t.getMessage());
t.printStackTrace();
isMappedByteBufferCanClean = 1;
return false;
}
}
});
}
@Override
public boolean cleanMappedByteBuffer(final ByteBuffer byteBuffer) {
if (byteBuffer instanceof MappedByteBuffer && isMappedByteBufferCanClean()){
return AccessController.doPrivileged(new PrivilegedAction() {
@Override
public Boolean run() {
try {
if (!directByteBufferClass.isAssignableFrom(byteBuffer.getClass())){
return false;
}
cleanerCleanMethod.invoke(directByteBufferCleanerMethod.invoke(byteBuffer));
return true;
} catch (Throwable t) {
System.out.println("WARNING:This jre environment can not clean MappedByteBuffer manually (jdk8- 2), isMappedByteBufferCanClean = false, error: " + t.getMessage());
isMappedByteBufferCanClean = 1;
return false;
}
}
});
}
return false;
}
}
private static class Jdk9MappedByteBufferUnmap implements MappedByteBufferUnmap {
private volatile int isMappedByteBufferCanClean = -1;
private Object unsafeInstance;
private Method unsafeInvokeCleanerMethod;
@Override
public boolean isMappedByteBufferCanClean() {
if (isMappedByteBufferCanClean >= 0){
return isMappedByteBufferCanClean == 0;
}
return AccessController.doPrivileged(new PrivilegedAction() {
@Override
public Boolean run() {
try {
Class unsafeClass;
try {
unsafeClass = Class.forName("sun.misc.Unsafe");
} catch(Throwable t) {
// 现在(JDK11) jdk.internal.misc.Unsafe里没有invokeCleaner方法, 但是哪天sun.misc.Unsafe被删除的时候,
// jdk.internal.misc.Unsafe里会不会就有invokeCleaner了呢?
unsafeClass = Class.forName("jdk.internal.misc.Unsafe");
}
//unsafe instance
Field unsafeTheUnsafeField = unsafeClass.getDeclaredField("theUnsafe");
unsafeTheUnsafeField.setAccessible(true);
unsafeInstance = unsafeTheUnsafeField.get(null);
//invokeCleaner method
unsafeInvokeCleanerMethod = unsafeClass.getMethod("invokeCleaner", ByteBuffer.class);
unsafeInvokeCleanerMethod.setAccessible(true);
isMappedByteBufferCanClean = 0;
return true;
} catch (Throwable t) {
System.out.println("WARNING: This jre environment can not clean MappedByteBuffer manually (jdk9+ 1), isMappedByteBufferCanClean = false, error: " + t.getMessage());
t.printStackTrace();
isMappedByteBufferCanClean = 1;
return false;
}
}
});
}
@Override
public boolean cleanMappedByteBuffer(final ByteBuffer byteBuffer) {
if (byteBuffer instanceof MappedByteBuffer && byteBuffer.isDirect() && isMappedByteBufferCanClean()){
return AccessController.doPrivileged(new PrivilegedAction() {
@Override
public Boolean run() {
try {
unsafeInvokeCleanerMethod.invoke(unsafeInstance, byteBuffer);
return true;
} catch (IllegalArgumentException e) {
//byteBuffer本身无法被清理, 不是环境不支持
return false;
} catch (Throwable t) {
System.out.println("WARNING:This jre environment can not clean MappedByteBuffer manually (jdk8- 2), isMappedByteBufferCanClean = false, error: " + t.getMessage());
isMappedByteBufferCanClean = 1;
return false;
}
}
});
}
return false;
}
}
}
