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.accumulo.shell.commands; import java.io.IOException; import java.util.Iterator; import java.util.Map; import java.util.TreeMap; import org.apache.accumulo.core.client.AccumuloException; import org.apache.accumulo.core.client.AccumuloSecurityException; import org.apache.accumulo.core.client.NamespaceNotFoundException; import org.apache.accumulo.core.client.impl.Tables; import org.apache.accumulo.shell.Shell; import org.apache.accumulo.shell.Shell.Command; import org.apache.commons.cli.CommandLine; import org.apache.commons.cli.Option; import org.apache.commons.cli.Options; import org.apache.commons.collections.MapUtils; import com.google.common.collect.Iterators; import com.google.common.collect.Maps; public class TablesCommand extends Command { static final String NAME_AND_ID_FORMAT = "%-20s => %9s%n"; private Option tableIdOption; private Option sortByTableIdOption; private Option disablePaginationOpt; @SuppressWarnings("unchecked") @Override public int execute(final String fullCommand, final CommandLine cl, final Shell shellState) throws AccumuloException, AccumuloSecurityException, IOException, NamespaceNotFoundException { final String namespace = cl.hasOption(OptUtil.namespaceOpt().getOpt()) ? OptUtil.getNamespaceOpt(cl, shellState) : null; Map<String, String> tables = shellState.getConnector().tableOperations().tableIdMap(); // filter only specified namespace tables = Maps.filterKeys(tables, tableName -> namespace == null || Tables.qualify(tableName).getFirst().equals(namespace)); final boolean sortByTableId = cl.hasOption(sortByTableIdOption.getOpt()); tables = new TreeMap<String, String>((sortByTableId ? MapUtils.invertMap(tables) : tables)); Iterator<String> it = Iterators.transform(tables.entrySet().iterator(), entry -> { String tableName = String.valueOf(sortByTableId ? entry.getValue() : entry.getKey()); String tableId = String.valueOf(sortByTableId ? entry.getKey() : entry.getValue()); if (namespace != null) tableName = Tables.qualify(tableName).getSecond(); if (cl.hasOption(tableIdOption.getOpt())) return String.format(NAME_AND_ID_FORMAT, tableName, tableId); else return tableName; }); shellState.printLines(it, !cl.hasOption(disablePaginationOpt.getOpt())); return 0; } @Override public String description() { return "displays a list of all existing tables"; } @Override public Options getOptions() { final Options o = new Options(); tableIdOption = new Option("l", "list-ids", false, "display internal table ids along with the table name"); o.addOption(tableIdOption); sortByTableIdOption = new Option("s", "sort-ids", false, "with -l: sort output by table ids"); o.addOption(sortByTableIdOption); disablePaginationOpt = new Option("np", "no-pagination", false, "disable pagination of output"); o.addOption(disablePaginationOpt); o.addOption(OptUtil.namespaceOpt("name of namespace to list only its tables")); return o; } @Override public int numArgs() { return 0; } }