io.netty.util.Signal Maven / Gradle / Ivy
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This artifact provides a single jar that contains all classes required to use remote EJB and JMS, including
all dependencies. It is intended for use by those not using maven, maven users should just import the EJB and
JMS BOM's instead (shaded JAR's cause lots of problems with maven, as it is very easy to inadvertently end up
with different versions on classes on the class path).
/*
* 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:
*
* https://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;
/**
* 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 implements Constant {
private static final long serialVersionUID = -221145131122459977L;
private static final ConstantPool pool = new ConstantPool() {
@Override
protected Signal newConstant(int id, String name) {
return new Signal(id, name);
}
};
/**
* Returns the {@link Signal} of the specified name.
*/
public static Signal valueOf(String name) {
return pool.valueOf(name);
}
/**
* Shortcut of {@link #valueOf(String) valueOf(firstNameComponent.getName() + "#" + secondNameComponent)}.
*/
public static Signal valueOf(Class firstNameComponent, String secondNameComponent) {
return pool.valueOf(firstNameComponent, secondNameComponent);
}
private final SignalConstant constant;
/**
* Creates a new {@link Signal} with the specified {@code name}.
*/
private Signal(int id, String name) {
constant = new SignalConstant(id, 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);
}
}
// Suppress a warning since the method doesn't need synchronization
@Override
public Throwable initCause(Throwable cause) {
return this;
}
// Suppress a warning since the method doesn't need synchronization
@Override
public Throwable fillInStackTrace() {
return this;
}
@Override
public int id() {
return constant.id();
}
@Override
public String name() {
return constant.name();
}
@Override
public boolean equals(Object obj) {
return this == obj;
}
@Override
public int hashCode() {
return System.identityHashCode(this);
}
@Override
public int compareTo(Signal other) {
if (this == other) {
return 0;
}
return constant.compareTo(other.constant);
}
@Override
public String toString() {
return name();
}
private static final class SignalConstant extends AbstractConstant {
SignalConstant(int id, String name) {
super(id, name);
}
}
}