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.tajo.cli.tsql.commands; import jline.console.completer.ArgumentCompleter; import jline.console.completer.NullCompleter; import jline.console.completer.StringsCompleter; import org.apache.commons.lang.CharUtils; import org.apache.commons.lang.StringEscapeUtils; import org.apache.tajo.TajoConstants; import org.apache.tajo.catalog.Column; import org.apache.tajo.catalog.TableDesc; import org.apache.tajo.catalog.partition.PartitionMethodDesc; import org.apache.tajo.catalog.proto.CatalogProtos.IndexDescProto; import org.apache.tajo.catalog.proto.CatalogProtos.SortSpecProto; import org.apache.tajo.cli.tsql.TajoCli; import org.apache.tajo.exception.TajoException; import org.apache.tajo.schema.IdentifierUtil; import org.apache.tajo.util.FileUtil; import org.apache.tajo.util.StringUtils; import java.util.List; import java.util.Map; public class DescTableCommand extends TajoShellCommand { public DescTableCommand(TajoCli.TajoCliContext context) { super(context); } @Override public String getCommand() { return "\\d"; } @Override public void invoke(String[] cmd) throws TajoException { if (cmd.length >= 2) { StringBuilder tableNameMaker = new StringBuilder(); for (int i = 1; i < cmd.length; i++) { if (i != 1) { tableNameMaker.append(" "); } tableNameMaker.append(cmd[i]); } String tableName = tableNameMaker.toString().replace("\"", ""); TableDesc desc = client.getTableDesc(tableName); if (desc == null) { context.getError().println("Did not find any relation named \"" + tableName + "\""); } else { context.getOutput().println(toFormattedString(desc)); // If there exists any indexes for the table, print index information if (client.hasIndexes(tableName)) { StringBuilder sb = new StringBuilder(); sb.append("Indexes:\n"); for (IndexDescProto index : client.getIndexes(tableName)) { sb.append("\"").append(index.getIndexName()).append("\" "); sb.append(index.getIndexMethod()).append(" ("); for (SortSpecProto key : index.getKeySortSpecsList()) { sb.append(IdentifierUtil.extractSimpleName(key.getColumn().getName())); sb.append(key.getAscending() ? " ASC" : " DESC"); sb.append(key.getNullFirst() ? " NULLS FIRST, " : " NULLS LAST, "); } sb.delete(sb.length() - 2, sb.length() - 1).append(")\n"); } context.getOutput().println(sb.toString()); } } } else if (cmd.length == 1) { List<String> tableList = client.getTableList(null); if (tableList.size() == 0) { context.getError().println("No Relation Found"); } for (String table : tableList) { context.getOutput().println(table); } } else { throw new IllegalArgumentException(); } } @Override public String getUsage() { return "[table_name]"; } @Override public String getDescription() { return "show table description"; } protected String toFormattedString(TableDesc desc) { StringBuilder sb = new StringBuilder(); sb.append("\ntable name: ").append(desc.getName()).append("\n"); sb.append("table uri: ").append(desc.getUri()).append("\n"); sb.append("store type: ").append(desc.getMeta().getDataFormat()).append("\n"); if (desc.getStats() != null) { long row = desc.getStats().getNumRows(); String rowText = row == TajoConstants.UNKNOWN_ROW_NUMBER ? "unknown" : row + ""; sb.append("number of rows: ").append(rowText).append("\n"); sb.append("volume: ").append(FileUtil.humanReadableByteCount(desc.getStats().getNumBytes(), true)) .append("\n"); } sb.append("Options:\n"); for (Map.Entry<String, String> entry : desc.getMeta().toMap().entrySet()) { /* * Checks whether the character is ASCII 7 bit printable. * For example, a printable unicode '\u007c' become the character |. * * Control-chars : ctrl-a(\u0001), tab(\u0009) .. * Printable-chars : '|'(\u007c), ','(\u002c) .. * */ String value = entry.getValue(); String unescaped = StringEscapeUtils.unescapeJava(value); if (unescaped.length() == 1 && CharUtils.isAsciiPrintable(unescaped.charAt(0))) { value = unescaped; } sb.append("\t").append("'").append(entry.getKey()).append("'").append("=").append("'").append(value) .append("'").append("\n"); } sb.append("\n"); sb.append("schema: \n"); for (int i = 0; i < desc.getSchema().size(); i++) { Column col = desc.getSchema().getColumn(i); sb.append(col.getSimpleName()).append("\t").append(col.getTypeDesc()); sb.append("\n"); } sb.append("\n"); if (desc.getPartitionMethod() != null) { PartitionMethodDesc partition = desc.getPartitionMethod(); sb.append("Partitions: \n"); sb.append("type:").append(partition.getPartitionType().name()).append("\n"); sb.append("columns:").append(":"); sb.append(StringUtils.join(partition.getExpressionSchema().toArray())); } return sb.toString(); } @Override public ArgumentCompleter getArgumentCompleter() { return new ArgumentCompleter(new StringsCompleter(getCommand()), new TableNameCompleter(), NullCompleter.INSTANCE); } }