io.netty.channel.kqueue.KQueue Maven / Gradle / Ivy
/*
* Copyright 2016 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.channel.kqueue;
import io.netty.channel.unix.FileDescriptor;
import io.netty.util.internal.SystemPropertyUtil;
import io.netty.util.internal.UnstableApi;
/**
* If KQueue is available the JNI resources will be loaded when this class loads.
*/
@UnstableApi
public final class KQueue {
private static final Throwable UNAVAILABILITY_CAUSE;
static {
Throwable cause = null;
if (SystemPropertyUtil.getBoolean("io.netty.transport.noNative", false)) {
cause = new UnsupportedOperationException(
"Native transport was explicit disabled with -Dio.netty.transport.noNative=true");
} else {
FileDescriptor kqueueFd = null;
try {
kqueueFd = Native.newKQueue();
} catch (Throwable t) {
cause = t;
} finally {
if (kqueueFd != null) {
try {
kqueueFd.close();
} catch (Exception ignore) {
// ignore
}
}
}
}
UNAVAILABILITY_CAUSE = cause;
}
/**
* Returns {@code true} if and only if the {@code
* netty-transport-native-kqueue} is available.
*/
public static boolean isAvailable() {
return UNAVAILABILITY_CAUSE == null;
}
/**
* Ensure that {@code netty-transport-native-kqueue} is
* available.
*
* @throws UnsatisfiedLinkError if unavailable
*/
public static void ensureAvailability() {
if (UNAVAILABILITY_CAUSE != null) {
throw (Error) new UnsatisfiedLinkError(
"failed to load the required native library").initCause(UNAVAILABILITY_CAUSE);
}
}
/**
* Returns the cause of unavailability of {@code
* netty-transport-native-kqueue}.
*
* @return the cause if unavailable. {@code null} if available.
*/
public static Throwable unavailabilityCause() {
return UNAVAILABILITY_CAUSE;
}
private KQueue() {
}
}