/**
* Copyright 2007 The Apache Software Foundation
*
* 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.hadoop.hbase.hql;
import java.io.IOException;
import java.io.Writer;
import org.apache.hadoop.hbase.HBaseConfiguration;
import org.apache.hadoop.hbase.HColumnDescriptor;
import org.apache.hadoop.hbase.HConnection;
import org.apache.hadoop.hbase.HConnectionManager;
import org.apache.hadoop.hbase.HTableDescriptor;
import org.apache.hadoop.io.Text;
/**
* Prints information about tables.
*/
public class DescCommand extends BasicCommand {
private static final String[] HEADER = new String[] { "Column Family Descriptor" };
private Text tableName;
private final TableFormatter formatter;
// Not instantiable
@SuppressWarnings("unused")
private DescCommand() {
this(null, null);
}
public DescCommand(final Writer o, final TableFormatter f) {
super(o);
this.formatter = f;
}
public ReturnMsg execute(final HBaseConfiguration conf) {
if (tableName == null)
return new ReturnMsg(0, "Syntax error : Please check 'Describe' syntax.");
try {
HConnection conn = HConnectionManager.getConnection(conf);
if (!conn.tableExists(tableName)) {
return new ReturnMsg(0, "Table not found.");
}
HTableDescriptor[] tables = conn.listTables();
HColumnDescriptor[] columns = null;
for (int i = 0; i < tables.length; i++) {
if (tables[i].getName().equals(tableName)) {
columns = tables[i].getFamilies().values().toArray(
new HColumnDescriptor[] {});
break;
}
}
formatter.header(HEADER);
// Do a toString on the HColumnDescriptors
String[] columnStrs = new String[columns.length];
for (int i = 0; i < columns.length; i++) {
String tmp = columns[i].toString();
// Strip the curly-brackets if present.
if (tmp.length() > 2 && tmp.startsWith("{") && tmp.endsWith("}")) {
tmp = tmp.substring(1, tmp.length() - 1);
}
columnStrs[i] = tmp;
formatter.row(new String[] { columnStrs[i] });
}
formatter.footer();
return new ReturnMsg(1, columns.length + " columnfamily(s) in set.");
} catch (IOException e) {
return new ReturnMsg(0, "error msg : " + e.toString());
}
}
public void setArgument(String table) {
this.tableName = new Text(table);
}
}