HBase tutorial to get started

1. HBase Programming
Mani
mmaniga@yahoo.co.uk

2. CreateTable
public static int VERSION = 5;
public static void createTable(byte[] tableName,
byte[][] families,
int numVersions) throws IOException {
HBaseConfiguration hbaseConfig = new HBaseConfiguration();
HBaseAdmin hbaseAdmin = new HBaseAdmin(hbaseConfig);
HTableDescriptor htableDesc = new HTableDescriptor(tableName);
for (byte[] family : families) {
HColumnDescriptor hColumnDescriptor = new HColumnDescriptor(family,
numVersions, HColumnDescriptor.DEFAULT_COMPRESSION,
HColumnDescriptor.DEFAULT_IN_MEMORY,
HColumnDescriptor.DEFAULT_BLOCKCACHE,
HColumnDescriptor.DEFAULT_TTL,
HColumnDescriptor.DEFAULT_BLOOMFILTER);
htableDesc.addFamily(hColumnDescriptor);
}
hbaseAdmin.createTable(htableDesc);
}

3. Table Exists & Get Table Name
public static boolean tableExist(byte[] tableName) throws IOException {
HBaseConfiguration hbaseConfig = new HBaseConfiguration();
HBaseAdmin hbaseAdmin = new HBaseAdmin(hbaseConfig);
return hbaseAdmin.tableExists(tableName);
}
public static List<String> getTableNames() throws IOException {
HBaseConfiguration hbaseConfig = new HBaseConfiguration();
HBaseAdmin hbaseAdmin = new HBaseAdmin(hbaseConfig);
List<String> tables = new ArrayList<String>();
for (HTableDescriptor htableDesc : hbaseAdmin.listTables()) {
printTableDescriptors(htableDesc);
tables.add(htableDesc.getNameAsString());
}
return tables;
}
public static void printTableDescriptors(HTableDescriptor descriptor) {
System.out.println("Table name " + descriptor.getNameAsString());
for (HColumnDescriptor columnDescriptor : descriptor.getColumnFamilies()) {
System.out.println(columnDescriptor.getNameAsString());
System.out.println(columnDescriptor.getMaxVersions());
System.out.println(columnDescriptor.getMinVersions());
}
}

4. Insert Record
public static void insertRecord(HTable htable, byte[] columnFamily,
boolean createColumnFamily,
HashMap<String, HashMap<String, String>> creditLogMaps) throws IOException {
String rowKey;// record key
HashMap<String, String> columnData;
if (!columnFamilyExist(htable, columnFamily)) {
if (!createColumnFamily)
return;
else
createColumnFamily(htable, columnFamily, VERSION);
}
for (Map.Entry<String, HashMap<String, String>> creditLogMap :
creditLogMaps.entrySet()) {
rowKey = creditLogMap.getKey();
columnData = creditLogMap.getValue();
Put put = new Put(rowKey.getBytes());
for (Map.Entry<String, String> kv : columnData.entrySet()) {
put.add(columnFamily, kv.getKey().getBytes(), kv.getValue()
.getBytes());
}
htable.put(put);
System.out.println("Record inserted");
}
}

5. Create Column Family
public static void createColumnFamily(HTable htable,
byte[] columnFamily,
int numVersions) throws IOException {
disableTable(htable.getTableName());
while (isTableEnabled(htable.getTableName()));// wait untill table is
disabled
HBaseConfiguration hbaseConfig = new HBaseConfiguration();
HBaseAdmin hbaseAdmin = new HBaseAdmin(hbaseConfig);
HColumnDescriptor hColumnDescriptor = new HColumnDescriptor(
columnFamily, numVersions,
HColumnDescriptor.DEFAULT_COMPRESSION,
HColumnDescriptor.DEFAULT_IN_MEMORY,
HColumnDescriptor.DEFAULT_BLOCKCACHE,
HColumnDescriptor.DEFAULT_TTL,
HColumnDescriptor.DEFAULT_BLOOMFILTER);
hbaseAdmin.addColumn(htable.getTableName(), hColumnDescriptor);
enableTable(htable.getTableName());
}

6. Get Column Family
public static List<String> getColumnFamilies(HTable htable) throws IOException {
List<String> columnFamilies = new ArrayList<String>();
for (HColumnDescriptor columnDesc :
htable.getTableDescriptor().getColumnFamilies()) {
columnFamilies.add(columnDesc.getNameAsString());
}
return columnFamilies;
}
public static boolean columnFamilyExist(HTable htable, byte[] columnFamily)
throws IOException {
boolean hasColumn = false;
if (htable.getTableDescriptor().getFamily(columnFamily) != null) {
hasColumn = true;
}
return hasColumn;
}
public static boolean isTableEnabled(byte[] tableName) throws IOException {
HBaseConfiguration hbaseConfig = new HBaseConfiguration();
HBaseAdmin hbaseAdmin = new HBaseAdmin(hbaseConfig);
System.out.println("Table enabled " + hbaseAdmin.isTableEnabled(tableName));
return hbaseAdmin.isTableEnabled(tableName);
}

7. Enable, Disable & Drop Table
public static void enableTable(byte[] tableName) throws IOException {
HBaseConfiguration hbaseConfig = new HBaseConfiguration();
HBaseAdmin hbaseAdmin = new HBaseAdmin(hbaseConfig);
hbaseAdmin.enableTable(tableName);
}
public static void disableTable(byte[] tableName) throws IOException {
HBaseConfiguration hbaseConfig = new HBaseConfiguration();
HBaseAdmin hbaseAdmin = new HBaseAdmin(hbaseConfig);
hbaseAdmin.disableTable(tableName);
System.out.println("Table " + new String(tableName) + " disabled");
}
public static void dropTable(byte[] tableName) throws IOException {
HBaseConfiguration hbaseConfig = new HBaseConfiguration();
HBaseAdmin hbaseAdmin = new HBaseAdmin(hbaseConfig);
hbaseAdmin.deleteTable(tableName);
System.out.println("Table " + new String(tableName) + " deleted");
}

8. Get Table, Get & Delete Record
public static HTable getTable(byte[] tableName) throws IOException {
HBaseConfiguration hbaseConfig = new HBaseConfiguration();
HBaseAdmin hbaseAdmin = new HBaseAdmin(hbaseConfig);
return new HTable(hbaseConfig, tableName);
}
public static void deleteRecord(HTable hTable, String rowKey)
throws IOException {
Delete delete = new Delete(rowKey.getBytes());
hTable.delete(delete);
System.out.println("Record " + rowKey + " deleted ");
}
public static PResultSet getRecord(HTable hTable, String rowKey,
String family) throws IOException {
Get get = new Get(rowKey.getBytes());
get.addFamily(family.getBytes());
PResultSet resultSet = new PResultSet(hTable, get);
return resultSet;
}

9. Scan Records
• public static void scanRecords(byte[] startKey, HTable hTable)
• throws IOException {
• Scan scan = new Scan(startKey);
• ResultScanner resultScanner = hTable.getScanner(scan);
• System.out.println("#########Scan result ################");
• for (Result result : resultScanner) {
• System.out.println(">key is " + new String(result.getRow()));
• for (KeyValue kv : result.raw()) {
• System.out.println(new String(kv.getFamily()) + ":"
• + new String(kv.getQualifier()) + " = "
• + new String(kv.getValue()));
• }
• }
• System.out.println("--------Scan result ends here-------------------");
• }

10. Scan Records by Filter
public static void scanRecords(byte[] startKey, HTable hTable, TestFilter testFilter)
throws IOException {
Scan scan = new Scan(startKey);
scan.setFilter(testFilter.getFilters());
ResultScanner resultScanner = hTable.getScanner(scan);
System.out.println("#########filter scan result ################");
for (Result result : resultScanner) {
System.out.println(">key is " + new String(result.getRow()));
for (KeyValue kv : result.raw()) {
System.out.println(new String(kv.getFamily()) + ":"
+ new String(kv.getQualifier()) + " = "
+ new String(kv.getValue()));
}
}
System.out.println("--------Scan result ends here-------------------");
}

11. Filter Object
class FilterObject {
String columnFamilyName;
String columnName;
String value;
CompareOp compareOp;
public FilterObject(String columnFamilyName, String columnName,
String value, CompareOp compareOp) {
this.columnFamilyName = columnFamilyName;
this.columnName = columnName;
this.value = value;
this.compareOp = compareOp;
}
}

12. Filter Class
class TestFilter {
private List<FilterObject> filterObjects;
private FilterList filterList;
public TestFilter() {
filterObjects = new ArrayList<FilterObject>();
filterList = new FilterList();
}
public void addFilterObject(FilterObject ft) {
filterObjects.add(ft);
}
public FilterList getFilters() {
for (FilterObject filterObject : filterObjects) {
filterList.addFilter(new SingleColumnValueFilter(
filterObject.columnFamilyName.getBytes(),
filterObject.columnName.getBytes(), filterObject.compareOp,
filterObject.value.getBytes()));
}
return filterList;
}
}

13. ResultSet
class PResultSet {
private String tableName;
private String columnFamily;
private HashMap<String, String> resutlMap;
private Result rs;
public PResultSet(HTable hTable, Get get) throws IOException {
this.rs = hTable.get(get);
this.tableName = hTable.getTableDescriptor().getNameAsString();
this.columnFamily = hTable.getTableDescriptor().getColumnFamilies()
.toString();
this.resutlMap = new HashMap<String, String>();
}
public String getTableName() {
return tableName;
}
public void setTableName(String tableName) {
this.tableName = tableName;
}
Cont…

14. ResultSet cont….
public String getColumnFamily() {
return columnFamily;
}
public void setColumnFamily(String columnFamily) {
this.columnFamily = columnFamily;
}
public HashMap<String, String> getResutlMap() {
return resutlMap;
}
public void setResutlMap(HashMap<String, String> resutlMap) {
this.resutlMap = resutlMap;
}
public String toString() {
System.out.println("TableName :" + getTableName());
System.out.println("ColumnFamily : " + getColumnFamily());
System.out.println("No Of Rows : " + rs.size());
for (KeyValue kv : rs.raw()) {
resutlMap.put(Bytes.toString(kv.getQualifier()),
Bytes.toString(kv.getValue()));
}
return resutlMap.toString();
}
}

15. Testing Code – Create Functions
Create Table Testing:
String tableName = "TrainingDB";
String familyName = "CreditLog";
byte[] tableNameBytes = tableName.getBytes();
byte[] familyBytes = familyName.getBytes();
byte[][] columnFamilyByteArray = new byte[][] { familyBytes };
if (tableExist(tableNameBytes)) {
System.out.println("Table exist");
disableTable(tableNameBytes);
dropTable(tableNameBytes);
}
createTable(tableNameBytes, columnFamilyByteArray, 5);
HTable hTable = getTable(tableNameBytes);
System.out.println("Successfully created");
System.out.println("Column exist : "
+ columnFamilyExist(hTable, familyBytes));

16. Testing Code – Put
HashMap<String, HashMap<String, String>> creditLogMaps
= new HashMap<String, HashMap<String, String>>();
HashMap<String, String> creditLogMap = new HashMap<String, String>();
creditLogMap.put("Name", "Karthik");
creditLogMap.put("Age", "36");
creditLogMap.put("Rating", "Good");
creditLogMap.put("Limit", "404$");
String rowKey = "1753-4343-4322-5423";
creditLogMaps.put(rowKey, creditLogMap);
creditLogMap = new HashMap<String, String>();
creditLogMap.put("Name", "Manik");
creditLogMap.put("Age", "36");
creditLogMap.put("Rating", "Average");
creditLogMap.put("Limit", "-2$");
String rowKey2 = "5557-4343-4322-5422";
creditLogMaps.put(rowKey2, creditLogMap);
insertRecord(hTable, familyBytes, false, creditLogMaps);

17. Testing Code - Put
HashMap<String, String> transLogMap = new HashMap<String, String>();
transLogMap.put("Date", "23-NOV-2011");
transLogMap.put("Amount", "$30");
transLogMap.put("Balance", "$450");
transLogMap.put("Bank", "Barclays");
HashMap<String, HashMap<String, String>> transLogMaps
= new HashMap<String, HashMap<String, String>>();
transLogMaps.put(rowKey, transLogMap);
insertRecord(hTable, "TransLog".getBytes(), true, transLogMaps);

18. Testing Code – List Tables
System.out.println("Tables in HBase");
for (String name : getTableNames()) {
System.out.println("# " + name);
System.out.println("Table columns");
HTable table = getTable(name.getBytes());
for (String columnName : getColumnFamilies(table)) {
System.out.println("- " + columnName);
}
}

19. Testing Code – Get & Scan Records
System.out.println(getRecord(hTable, rowKey, familyName).toString());
System.out.println(getRecord(hTable, rowKey, "TransLog").toString());
scanRecords(rowKey.getBytes(), hTable);
FilterObject filterObject = new FilterObject(familyName, "Age", "36",
CompareOp.EQUAL);
FilterObject filterObject2 = new FilterObject(familyName, "Limit",
"-2$", CompareOp.EQUAL);
TestFilter testFilter = new TestFilter();
testFilter.addFilterObject(filterObject);
testFilter.addFilterObject(filterObject2);
scanRecords(rowKey.getBytes(), hTable, testFilter);
deleteRecord(hTable, rowKey);
System.out.println("After delete");
scanRecords(rowKey.getBytes(), hTable);

20. Happy Coding
– Mani
– mmaniga@yahoo.co.uk