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.yarn.security;
020
021import java.util.Collection;
022
023import org.apache.commons.logging.Log;
024import org.apache.commons.logging.LogFactory;
025import org.apache.hadoop.classification.InterfaceAudience.Public;
026import org.apache.hadoop.classification.InterfaceStability.Stable;
027import org.apache.hadoop.io.Text;
028import org.apache.hadoop.security.token.Token;
029import org.apache.hadoop.security.token.TokenIdentifier;
030import org.apache.hadoop.security.token.TokenSelector;
031
032@Public
033@Stable
034public class ContainerTokenSelector implements
035    TokenSelector<ContainerTokenIdentifier> {
036
037  private static final Log LOG = LogFactory
038      .getLog(ContainerTokenSelector.class);
039
040  @SuppressWarnings("unchecked")
041  @Override
042  public Token<ContainerTokenIdentifier> selectToken(Text service,
043      Collection<Token<? extends TokenIdentifier>> tokens) {
044    if (service == null) {
045      return null;
046    }
047    for (Token<? extends TokenIdentifier> token : tokens) {
048      if (LOG.isDebugEnabled()) {
049        LOG.info("Looking for service: " + service + ". Current token is "
050            + token);
051      }
052      if (ContainerTokenIdentifier.KIND.equals(token.getKind()) && 
053          service.equals(token.getService())) {
054        return (Token<ContainerTokenIdentifier>) token;
055      }
056    }
057    return null;
058  }
059
060}