org.jboss.as.server.deployment.AttachmentKey Maven / Gradle / Ivy
/*
* JBoss, Home of Professional Open Source.
* Copyright 2012, Red Hat, Inc., and individual contributors
* as indicated by the @author tags. See the copyright.txt file in the
* distribution for a full listing of individual contributors.
*
* This is free software; you can redistribute it and/or modify it
* under the terms of the GNU Lesser General Public License as
* published by the Free Software Foundation; either version 2.1 of
* the License, or (at your option) any later version.
*
* This software is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
* Lesser General Public License for more details.
*
* You should have received a copy of the GNU Lesser General Public
* License along with this software; if not, write to the Free
* Software Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA
* 02110-1301 USA, or see the FSF site: http://www.fsf.org.
*/
package org.jboss.as.server.deployment;
/**
* 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
*/
@SuppressWarnings("unchecked")
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;
}
}