This document provides code examples for performing common HBase operations like creating and managing tables, inserting and retrieving records, and scanning data. It includes methods for creating tables, adding and dropping column families, inserting and deleting records, getting single records and scanning multiple records. Filtering scans by column values is also demonstrated through the use of a custom filter class.

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