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 * individual contributors.                                                   *
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 * This is free software; you can redistribute it and/or modify it            *
 * under the terms of the GNU Lesser General Public License as                *
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 * 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.                            *
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 * You should have received a copy of the GNU Lesser General Public           *
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 ******************************************************************************/
package org.gatein.pc.api.invocation.resolver;

import java.util.Set;

/**
 * An attribute resolver.
 *
 * @author <a href="mailto:julien@jboss.org">Julien Viet</a>
 * @version $Revision: 7228 $
 */
public interface AttributeResolver<K, V>
{
   /**
    * Returns the set of keys of the attributes bound in that resolver.
    *
    * @return a set of keys
    */
   Set<K> getKeys();

   /**
    * Return an attribute from this resolver.
    *
    * @param attrKey
    * @return the attribute value or null if it is not found
    * @throws IllegalArgumentException if the attribute key is not valid
    */
   V getAttribute(K attrKey) throws IllegalArgumentException;

   /**
    * Update an attribute value on this resolve. If the attribute value is null the resolver must treat the operation as
    * a removal of the attribute.
    *
    * @param attrKey
    * @param attrValue the attribute value
    * @throws IllegalArgumentException if the attribute key is not valid
    */
   void setAttribute(K attrKey, V attrValue) throws IllegalArgumentException;
}
