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 eagle.service.security.hdfs.resolver; import eagle.service.alert.resolver.AttributeResolvable; import eagle.service.alert.resolver.AttributeResolveException; import eagle.service.alert.resolver.BadAttributeResolveRequestException; import eagle.service.alert.resolver.GenericAttributeResolveRequest; import org.apache.commons.lang3.StringUtils; import org.slf4j.Logger; import org.slf4j.LoggerFactory; import java.util.ArrayList; import java.util.Arrays; import java.util.List; import java.util.regex.Pattern; public class HDFSCommandResolver implements AttributeResolvable<GenericAttributeResolveRequest, String> { private final static Logger LOG = LoggerFactory.getLogger(HDFSCommandResolver.class); private final static String[] cmdStrs = { "open", "create", "append", "delete", "listfileinfo", "rename", "mkdirs", "listStatus", "setReplication", "setOwner", "setPermission", "setTimes", "setXAttr", "removeXAttr", "getXAttrs", "contentSummary", "createEncryptionZone", "checkAccess" }; private final static String HDFS_CMD_RESOLVE_FORMAT_HINT = String.format("hdfs command must be in {%s}", StringUtils.join(cmdStrs, ",")); private final static List<String> commands = Arrays.asList(cmdStrs); public List<String> resolve(GenericAttributeResolveRequest request) throws AttributeResolveException { String query = request.getQuery().trim(); List<String> res = new ArrayList<>(); for (String cmd : commands) { Pattern pattern = Pattern.compile("^" + query, Pattern.CASE_INSENSITIVE); if (pattern.matcher(cmd).find()) { res.add(cmd); } } if (res.size() == 0) { return commands; } return res; } @Override public void validateRequest(GenericAttributeResolveRequest request) throws BadAttributeResolveRequestException { String query = request.getQuery(); boolean matched = Pattern.matches("[a-zA-Z]+", query); if (query == null || !matched) { throw new BadAttributeResolveRequestException(HDFS_CMD_RESOLVE_FORMAT_HINT); } } @Override public Class<GenericAttributeResolveRequest> getRequestClass() { return GenericAttributeResolveRequest.class; } }