io.undertow.util.AttachmentKey Maven / Gradle / Ivy
Go to download
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).
/*
* JBoss, Home of Professional Open Source.
* Copyright 2014 Red Hat, Inc., and individual contributors
* as indicated by the @author tags.
*
* Licensed 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.undertow.util;
/**
* @author Stuart Douglas
*/
/**
* An immutable, type-safe object attachment key. Such a key has no value outside of its object identity.
*
* @param the attachment type
*/
public abstract class AttachmentKey {
AttachmentKey() {
}
/**
* Cast the value to the type of this attachment key.
*
* @param value the value
* @return the cast value
*/
public abstract T cast(Object value);
/**
* Construct a new simple attachment key.
*
* @param valueClass the value class
* @param the attachment type
* @return the new instance
*/
public static AttachmentKey create(final Class valueClass) {
return new SimpleAttachmentKey(valueClass);
}
/**
* Construct a new list attachment key.
*
* @param valueClass the list value class
* @param the list value type
* @return the new instance
*/
@SuppressWarnings("unchecked")
public static AttachmentKey> createList(final Class valueClass) {
return new ListAttachmentKey(valueClass);
}
}
class ListAttachmentKey extends AttachmentKey> {
private final Class valueClass;
ListAttachmentKey(final Class valueClass) {
this.valueClass = valueClass;
}
@SuppressWarnings({"unchecked"})
public AttachmentList cast(final Object value) {
if (value == null) {
return null;
}
AttachmentList list = (AttachmentList) value;
final Class listValueClass = list.getValueClass();
if (listValueClass != valueClass) {
throw new ClassCastException();
}
return (AttachmentList) list;
}
Class getValueClass() {
return valueClass;
}
}