io.netty.util.Signal Maven / Gradle / Ivy
/*
* Copyright 2012 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.PlatformDependent;
import java.util.concurrent.ConcurrentMap;
/**
* A special {@link Error} which is used to signal some state or request by throwing it.
* {@link Signal} has an empty stack trace and has no cause to save the instantiation overhead.
*/
public final class Signal extends Error {
private static final long serialVersionUID = -221145131122459977L;
private static final ConcurrentMap map = PlatformDependent.newConcurrentHashMap();
private final UniqueName uname;
/**
* Create a new instance
*
* @param name the name under which it is registered
*/
public Signal(String name) {
super(name);
uname = new UniqueName(map, name);
}
/**
* Check if the given {@link Signal} is the same as this instance. If not an {@link IllegalStateException} will
* be thrown.
*/
public void expect(Signal signal) {
if (this != signal) {
throw new IllegalStateException("unexpected signal: " + signal);
}
}
@Override
public Throwable initCause(Throwable cause) {
return this;
}
@Override
public Throwable fillInStackTrace() {
return this;
}
@Override
public String toString() {
return uname.name();
}
}