io.netty.util.AttributeKey Maven / Gradle / Ivy

Go to download

Show more of this group Show more artifacts with this name
Show all versions of wildfly-client-all

This artifact provides a single jar that contains all classes required to use remote Jakarta Enterprise Beans and Jakarta Messaging, including all dependencies. It is intended for use by those not using maven, maven users should just import the Jakarta Enterprise Beans and Jakarta Messaging 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).

There is a newer version: 35.0.0.Beta1

Show newest version

/*
 * 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;

import static io.netty.util.internal.ObjectUtil.checkNotNull;

/**
 * Key which can be used to access {@link Attribute} out of the {@link AttributeMap}. Be aware that it is not be
 * possible to have multiple keys with the same name.
 *
 *
 * @param    the type of the {@link Attribute} which can be accessed via this {@link AttributeKey}.
 */
@SuppressWarnings({ "UnusedDeclaration", "deprecation" }) // 'T' is used only at compile time
public final class AttributeKey extends UniqueName {

    @SuppressWarnings("rawtypes")
    private static final ConcurrentMap names = PlatformDependent.newConcurrentHashMap();

    /**
     * Creates a new {@link AttributeKey} with the specified {@param name} or return the already existing
     * {@link AttributeKey} for the given name.
     */
    @SuppressWarnings("unchecked")
    public static  AttributeKey valueOf(String name) {
        checkNotNull(name, "name");
        AttributeKey option = names.get(name);
        if (option == null) {
            option = new AttributeKey(name);
            AttributeKey old = names.putIfAbsent(name, option);
            if (old != null) {
                option = old;
            }
        }
        return option;
    }

    /**
     * Returns {@code true} if a {@link AttributeKey} exists for the given {@code name}.
     */
    public static boolean exists(String name) {
        checkNotNull(name, "name");
        return names.containsKey(name);
    }

    /**
     * Creates a new {@link AttributeKey} for the given {@param name} or fail with an
     * {@link IllegalArgumentException} if a {@link AttributeKey} for the given {@param name} exists.
     */
    @SuppressWarnings("unchecked")
    public static  AttributeKey newInstance(String name) {
        checkNotNull(name, "name");
        AttributeKey option = new AttributeKey(name);
        AttributeKey old = names.putIfAbsent(name, option);
        if (old != null) {
            throw new IllegalArgumentException(String.format("'%s' is already in use", name));
        }
        return option;
    }

    /**
     * @deprecated Use {@link #valueOf(String)} instead.
     */
    @Deprecated
    public AttributeKey(String name) {
        super(name);
    }
}