/**
* 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.OutputStreamWriter;
import java.io.Writer;
import java.util.ArrayList;
import java.util.Arrays;
import java.util.List;
import java.util.Map;
import java.util.TreeMap;
import org.apache.hadoop.hbase.HBaseAdmin;
import org.apache.hadoop.hbase.HBaseConfiguration;
import org.apache.hadoop.hbase.HConnection;
import org.apache.hadoop.hbase.HConnectionManager;
import org.apache.hadoop.hbase.HConstants;
import org.apache.hadoop.hbase.HScannerInterface;
import org.apache.hadoop.hbase.HStoreKey;
import org.apache.hadoop.hbase.HTable;
import org.apache.hadoop.hbase.HTableDescriptor;
import org.apache.hadoop.hbase.Shell;
import org.apache.hadoop.hbase.filter.RowFilterInterface;
import org.apache.hadoop.hbase.filter.StopRowFilter;
import org.apache.hadoop.hbase.filter.WhileMatchRowFilter;
import org.apache.hadoop.hbase.hql.generated.HQLParser;
import org.apache.hadoop.hbase.util.Writables;
import org.apache.hadoop.io.Text;
/**
* Selects values from tables.
*/
public class SelectCommand extends BasicCommand {
private Text tableName;
private Text rowKey = new Text("");
private Text stopRow = new Text("");
private List<String> columns;
private long timestamp;
private int limit;
// Count of versions to return.
private int version;
private boolean countFunction = false;
private boolean whereClause = false;
private static final String[] HEADER_ROW_CELL = new String[] { "Row", "Cell" };
private static final String[] HEADER_COLUMN_CELL = new String[] { "Column", "Cell" };
private static final String[] HEADER = new String[] { "Row", "Column", "Cell" };
private static final String ASTERISK = "*";
private final TableFormatter formatter;
// Not instantiable
@SuppressWarnings("unused")
private SelectCommand() {
this(null, null);
}
public SelectCommand(final Writer o, final TableFormatter f) {
super(o);
this.formatter = f;
}
public ReturnMsg execute(final HBaseConfiguration conf) {
if (tableName.equals("") || rowKey == null || columns.size() == 0) {
return new ReturnMsg(0, "Syntax error : Please check 'Select' syntax.");
}
try {
HConnection conn = HConnectionManager.getConnection(conf);
if (!conn.tableExists(tableName) && !isMetaTable()) {
return new ReturnMsg(0, "'" + tableName + "'" + TABLE_NOT_FOUND);
}
HTable table = new HTable(conf, tableName);
HBaseAdmin admin = new HBaseAdmin(conf);
int count = 0;
if (whereClause) {
if (countFunction) {
count = 1;
} else {
count = compoundWherePrint(table, admin);
}
} else {
count = scanPrint(table, admin);
}
return new ReturnMsg(1, Integer.toString(count) + " row(s) in set.");
} catch (IOException e) {
String[] msg = e.getMessage().split("[,]");
return new ReturnMsg(0, msg[0]);
}
}
private boolean isMetaTable() {
return (tableName.equals(HConstants.ROOT_TABLE_NAME) || tableName
.equals(HConstants.META_TABLE_NAME)) ? true : false;
}
private int compoundWherePrint(HTable table, HBaseAdmin admin) {
int count = 0;
try {
if (version != 0) {
// A number of versions has been specified.
byte[][] result = null;
ParsedColumns parsedColumns = getColumns(admin, false);
boolean multiple = parsedColumns.isMultiple() || version > 1;
for (Text column : parsedColumns.getColumns()) {
if (count == 0) {
formatter.header(multiple ? HEADER_COLUMN_CELL : null);
}
if (timestamp != 0) {
result = table.get(rowKey, column, timestamp, version);
} else {
result = table.get(rowKey, column, version);
}
for (int ii = 0; result != null && ii < result.length; ii++) {
if (multiple) {
formatter.row(new String[] { column.toString(),
toString(column, result[ii]) });
} else {
formatter.row(new String[] { toString(column, result[ii]) });
}
count++;
}
}
} else {
for (Map.Entry<Text, byte[]> e : table.getRow(rowKey).entrySet()) {
if (count == 0) {
formatter.header(isMultiple() ? HEADER_COLUMN_CELL : null);
}
Text key = e.getKey();
String keyStr = key.toString();
if (!columns.contains(ASTERISK) && !columns.contains(keyStr)) {
continue;
}
String cellData = toString(key, e.getValue());
if (isMultiple()) {
formatter.row(new String[] { key.toString(), cellData });
} else {
formatter.row(new String[] { cellData });
}
count++;
}
}
if (count == 0 && Shell.HTML_OPTION != null) {
formatter.header(isMultiple() ? HEADER_COLUMN_CELL : null);
}
formatter.footer();
} catch (IOException e) {
e.printStackTrace();
}
return 1;
}
private String toString(final Text columnName, final byte[] cell)
throws IOException {
String result = null;
if (columnName.equals(HConstants.COL_REGIONINFO)
|| columnName.equals(HConstants.COL_SPLITA)
|| columnName.equals(HConstants.COL_SPLITA)) {
result = Writables.getHRegionInfoOrNull(cell).toString();
} else if (columnName.equals(HConstants.COL_STARTCODE)) {
result = Long.toString(Writables.bytesToLong(cell));
} else {
result = Writables.bytesToString(cell);
}
return result;
}
/**
* Data structure with columns to use scanning and whether or not the scan
* could return more than one column.
*/
class ParsedColumns {
private final List<Text> cols;
private final boolean isMultiple;
ParsedColumns(final List<Text> columns) {
this(columns, true);
}
ParsedColumns(final List<Text> columns, final boolean isMultiple) {
this.cols = columns;
this.isMultiple = isMultiple;
}
public List<Text> getColumns() {
return this.cols;
}
public boolean isMultiple() {
return this.isMultiple;
}
}
private int scanPrint(HTable table, HBaseAdmin admin) {
int count = 0;
HScannerInterface scan = null;
try {
ParsedColumns parsedColumns = getColumns(admin, true);
Text[] cols = parsedColumns.getColumns().toArray(new Text[] {});
if (timestamp == 0) {
scan = table.obtainScanner(cols, rowKey);
} else {
scan = table.obtainScanner(cols, rowKey, timestamp);
}
if (this.stopRow.toString().length() > 0) {
RowFilterInterface filter = new WhileMatchRowFilter(new StopRowFilter(
stopRow));
scan = table.obtainScanner(cols, rowKey, filter);
}
HStoreKey key = new HStoreKey();
TreeMap<Text, byte[]> results = new TreeMap<Text, byte[]>();
// If only one column in query, then don't print out the column.
while (scan.next(key, results) && checkLimit(count)) {
if (count == 0 && !countFunction) {
formatter.header((parsedColumns.isMultiple()) ? HEADER : HEADER_ROW_CELL);
}
Text r = key.getRow();
if (!countFunction) {
for (Text columnKey : results.keySet()) {
String cellData = toString(columnKey, results.get(columnKey));
if (parsedColumns.isMultiple()) {
formatter.row(new String[] { r.toString(), columnKey.toString(),
cellData });
} else {
// Don't print out the column since only one specified in query.
formatter.row(new String[] { r.toString(), cellData });
}
if (limit > 0 && count >= limit) {
break;
}
}
}
count++;
// Clear results else subsequent results polluted w/ previous finds.
results.clear();
}
if (count == 0 && Shell.HTML_OPTION != null && !countFunction) {
formatter.header((parsedColumns.isMultiple()) ? HEADER : HEADER_ROW_CELL);
}
formatter.footer();
scan.close();
} catch (IOException e) {
e.printStackTrace();
}
return count;
}
/**
* Make sense of the supplied list of columns.
*
* @param admin Admin to use.
* @return Interpretation of supplied list of columns.
*/
public ParsedColumns getColumns(final HBaseAdmin admin, final boolean scanning) {
ParsedColumns result = null;
try {
if (columns.contains(ASTERISK)) {
if (tableName.equals(HConstants.ROOT_TABLE_NAME)
|| tableName.equals(HConstants.META_TABLE_NAME)) {
result = new ParsedColumns(Arrays.asList(HConstants.COLUMN_FAMILY_ARRAY));
} else {
HTableDescriptor[] tables = admin.listTables();
for (int i = 0; i < tables.length; i++) {
if (tables[i].getName().equals(tableName)) {
result = new ParsedColumns(new ArrayList<Text>(tables[i].families()
.keySet()));
break;
}
}
}
} else {
List<Text> tmpList = new ArrayList<Text>();
for (int i = 0; i < columns.size(); i++) {
Text column = null;
// Add '$' to column name if we are scanning. Scanners support
// regex column names. Adding '$', the column becomes a
// regex that does an explicit match on the supplied column name.
// Otherwise, if the specified column is a column family, then
// default behavior is to fetch all columns that have a matching
// column family.
column = (columns.get(i).contains(":")) ? new Text(columns.get(i)
+ (scanning ? "$" : "")) : new Text(columns.get(i) + ":"
+ (scanning ? "$" : ""));
tmpList.add(column);
}
result = new ParsedColumns(tmpList, tmpList.size() > 1);
}
} catch (IOException e) {
e.printStackTrace();
}
return result;
}
/*
* @return True if query contains multiple columns.
*/
private boolean isMultiple() {
return this.columns.size() > 1 || this.columns.contains(ASTERISK);
}
private boolean checkLimit(int count) {
return (this.limit == 0) ? true : (this.limit > count) ? true : false;
}
public void setTable(String table) {
this.tableName = new Text(table);
}
public void setLimit(int limit) {
this.limit = limit;
}
public void setWhere(boolean isWhereClause) {
if (isWhereClause)
this.whereClause = true;
}
public void setTimestamp(String timestamp) {
this.timestamp = Long.parseLong(timestamp);
}
public void setColumns(List<String> columns) {
this.columns = columns;
}
public void setRowKey(String rowKey) {
if (rowKey == null)
this.rowKey = null;
else
this.rowKey = new Text(rowKey);
}
public void setCountFunction(boolean countFunction) {
this.countFunction = countFunction;
}
public void setStopRow(String stopRow) {
this.stopRow = new Text(stopRow);
}
/**
* @param version Set maximum versions for this selection
*/
public void setVersion(int version) {
this.version = version;
}
public static void main(String[] args) throws Exception {
Writer out = new OutputStreamWriter(System.out, "UTF-8");
HBaseConfiguration c = new HBaseConfiguration();
// For debugging
TableFormatterFactory tff = new TableFormatterFactory(out, c);
HQLParser parser = new HQLParser("select * from 'x' where row='x';", out, tff.get());
Command cmd = parser.terminatedCommand();
ReturnMsg rm = cmd.execute(c);
out.write(rm == null ? "" : rm.toString());
out.flush();
}
}