Java tutorial
/** * Licensed to the Apache Software Foundation (ASF) under one * or more contributor license agreements. See the NOTICE file * distributed with this work for additional information * regarding copyright ownership. The ASF licenses this file * to you 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 org.apache.storm.common; import org.apache.commons.lang.StringUtils; import org.apache.commons.math3.util.Pair; import org.apache.hadoop.security.Credentials; import org.slf4j.Logger; import org.slf4j.LoggerFactory; import javax.xml.bind.DatatypeConverter; import java.io.ByteArrayInputStream; import java.io.ObjectInputStream; import java.util.Collection; import java.util.HashSet; import java.util.Map; import java.util.Set; /** * Utility class for getting credential for Hadoop. */ final class HadoopCredentialUtil { private static final Logger LOG = LoggerFactory.getLogger(HadoopCredentialUtil.class); private HadoopCredentialUtil() { } static Set<Pair<String, Credentials>> getCredential(CredentialKeyProvider provider, Map<String, String> credentials, Collection<String> configKeys) { Set<Pair<String, Credentials>> res = new HashSet<>(); if (!configKeys.isEmpty()) { for (String configKey : configKeys) { Credentials cred = doGetCredentials(provider, credentials, configKey); if (cred != null) { res.add(new Pair(configKey, cred)); } } } else { Credentials cred = doGetCredentials(provider, credentials, StringUtils.EMPTY); if (cred != null) { res.add(new Pair(StringUtils.EMPTY, cred)); } } return res; } private static Credentials doGetCredentials(CredentialKeyProvider provider, Map<String, String> credentials, String configKey) { Credentials credential = null; String credentialKey = provider.getCredentialKey(configKey); if (credentials != null && credentials.containsKey(credentialKey)) { try { byte[] credBytes = DatatypeConverter.parseBase64Binary(credentialKey); ObjectInputStream in = new ObjectInputStream(new ByteArrayInputStream(credBytes)); credential = new Credentials(); credential.readFields(in); } catch (Exception e) { LOG.error("Could not obtain credentials from credentials map.", e); } } return credential; } }