2012-06-04 22:31:44 +02:00
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/*
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* Copyright 2012 The Netty Project
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*
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* The Netty Project licenses this file to you under the Apache License,
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* version 2.0 (the "License"); you may not use this file except in compliance
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* with the License. You may obtain a copy of the License at:
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*
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* http://www.apache.org/licenses/LICENSE-2.0
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*
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* Unless required by applicable law or agreed to in writing, software
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* distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
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* WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
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* License for the specific language governing permissions and limitations
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* under the License.
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*/
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2013-02-11 12:08:18 +01:00
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package io.netty.util;
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2012-05-18 07:30:42 +02:00
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import java.util.concurrent.ConcurrentHashMap;
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import java.util.concurrent.ConcurrentMap;
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2012-12-21 08:16:00 +01:00
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/**
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2013-02-11 12:08:18 +01:00
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* A special {@link Error} which is used to signal some state or request by throwing it.
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* {@link Signal} has an empty stack trace and has no cause to save the instantiation overhead.
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2012-12-21 08:16:00 +01:00
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*/
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2012-05-18 07:30:42 +02:00
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public final class Signal extends Error {
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private static final long serialVersionUID = -221145131122459977L;
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private static final ConcurrentMap<String, Boolean> map =
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new ConcurrentHashMap<String, Boolean>();
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2012-05-24 17:57:10 +02:00
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private final UniqueName uname;
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2012-05-18 07:30:42 +02:00
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2012-12-21 08:16:00 +01:00
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/**
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* Create a new instance
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*
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* @param name the name under which it is registered
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*/
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2012-05-18 07:30:42 +02:00
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public Signal(String name) {
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super(name);
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2012-05-24 17:57:10 +02:00
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uname = new UniqueName(map, name);
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2012-05-18 07:30:42 +02:00
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}
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2012-12-21 08:16:00 +01:00
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/**
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* Check if the given {@link Signal} is the same as this instance. If not an {@link IllegalStateException} will
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* be thrown.
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*/
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2012-05-18 07:30:42 +02:00
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public void expect(Signal signal) {
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if (this != signal) {
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throw new IllegalStateException("unexpected signal: " + signal);
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}
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}
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@Override
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public Throwable initCause(Throwable cause) {
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return this;
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}
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@Override
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public Throwable fillInStackTrace() {
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return this;
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}
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@Override
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public String toString() {
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return uname.name();
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}
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}
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