001/**
002 * Licensed to the Apache Software Foundation (ASF) under one
003 * or more contributor license agreements.  See the NOTICE file
004 * distributed with this work for additional information
005 * regarding copyright ownership.  The ASF licenses this file
006 * to you under the Apache License, Version 2.0 (the
007 * "License"); you may not use this file except in compliance
008 * with the License.  You may obtain a copy of the License at
009 *
010 *     http://www.apache.org/licenses/LICENSE-2.0
011 *
012 * Unless required by applicable law or agreed to in writing, software
013 * distributed under the License is distributed on an "AS IS" BASIS,
014 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
015 * See the License for the specific language governing permissions and
016 * limitations under the License.
017 */
018
019package org.apache.hadoop.security.token;
020
021import java.util.Collection;
022
023import org.apache.hadoop.classification.InterfaceAudience;
024import org.apache.hadoop.classification.InterfaceStability;
025import org.apache.hadoop.io.Text;
026
027/**
028 * Select token of type T from tokens for use with named service
029 * 
030 * @param <T>
031 *          T extends TokenIdentifier
032 */
033@InterfaceAudience.Public
034@InterfaceStability.Evolving
035public interface TokenSelector<T extends TokenIdentifier> {
036  Token<T> selectToken(Text service,
037      Collection<Token<? extends TokenIdentifier>> tokens);
038}