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CloudGraph(tm) is a suite of Service Data Object (SDO) 2.1 services designed for relational and big-table style "cloud" databases, such as HBase and others.
/**
* CloudGraph Community Edition (CE) License
*
* This is a community release of CloudGraph, a dual-license suite of
* Service Data Object (SDO) 2.1 services designed for relational and
* big-table style "cloud" databases, such as HBase and others.
* This particular copy of the software is released under the
* version 2 of the GNU General Public License. CloudGraph was developed by
* TerraMeta Software, Inc.
*
* Copyright (c) 2013, TerraMeta Software, Inc. All rights reserved.
*
* General License information can be found below.
*
* This distribution may include materials developed by third
* parties. For license and attribution notices for these
* materials, please refer to the documentation that accompanies
* this distribution (see the "Licenses for Third-Party Components"
* appendix) or view the online documentation at
*
* Acts as a container for one or more {@link RowReader} elements
* and encapsulates the HBase client Get
* operations for use in read operations across one or more graph rows.
*
*
* @see org.cloudgraph.hbase.io.RowReader
* @author Scott Cinnamond
* @since 0.5.1
*/
public class GraphTableReader extends GraphTable
implements TableReader
{
private static Log log = LogFactory.getLog(GraphTableReader.class);
private Connection connection;
private Table table;
/** maps data object UUIDs strings and row key strings to row readers */
private Map rowReaderMap = new HashMap();
private DistributedOperation distributedOperation;
public GraphTableReader(TableConfig table,
DistributedOperation distributedOperation) {
super(table);
this.distributedOperation = distributedOperation;
}
/**
*
* Returns the qualified table name associated with this reader.
* @return the qualified table name associated with this reader.
*/
public String getTableName() {
return this.getTableConfig().getQualifiedName();
}
@Override
public Table getTable() {
if (this.connection == null) {
try {
this.connection = HBaseConnectionManager.instance().getConnection();
TableName tableName = TableName.valueOf(tableConfig.getQualifiedName());
// Note: calling tableExists() using the admin HBase API is expensive and is
// showing up on CPU profiling results. Just call get table and catch :(
// Unfortunately at least on windows client, below get operation does not throw
// anything and continues on.
if (!this.connection.tableExists(tableName)) {
HBaseConnectionManager.instance().createTable(this.connection, tableName);
this.table = this.connection.getTable(tableName);
}
else {
try {
this.table = this.connection.getTable(tableName);
}
catch (TableNotFoundException | NamespaceNotFoundException e) {
HBaseConnectionManager.instance().createTable(this.connection, tableName);
this.table = this.connection.getTable(tableName);
}
}
} catch (IOException e) {
throw new OperationException(e);
}
}
return this.table;
}
/**
* Returns whether there is an active HBase table pooled connection
* for this context.
* @return whether there is an active HBase table pooled connection
* for this context.
*/
public boolean hasConnection() {
return this.connection != null;
}
/**
* Returns the row reader context for the given data object or null
* if null exists
* @param dataObject the data object
* @return the row reader context for the given data object or null
* if null exists
*/
@Override
public RowReader getRowReader(DataObject dataObject) {
String uuid = ((PlasmaDataObject)dataObject).getUUIDAsString();
return rowReaderMap.get(uuid);
}
/**
* Returns the row reader context for the given row key or null
* if null exists
* @param rowKey the row key bytes
* @return the row reader context for the given row key or null
* if null exists
*/
@Override
public RowReader getRowReader(byte[] rowKey) {
return rowReaderMap.get(Bytes.toString(rowKey));
}
/**
* Returns the row reader context for the given UUID
* @param uuid the UUID
* @return the row reader context for the given UUID
*/
@Override
public RowReader getRowReader(UUID uuid) {
return rowReaderMap.get(uuid.toString());
}
/**
* Adds the given row reader context mapping it to the
* given UUID
* @param uuid the UUID
* @param rowReader the row reader context
* @throws IllegalArgumentException if an existing row reader is already mapped
* for the given data object UUID
*/
@Override
public void addRowReader(UUID uuid, RowReader rowReader) throws IllegalArgumentException {
if (rowReaderMap.get(uuid.toString()) != null)
throw new IllegalArgumentException("given UUID already mapped to a row reader, "
+ uuid);
rowReaderMap.put(uuid.toString(), rowReader);
}
/**
* Returns all row reader context values for this table context.
* @return all row reader context values for this table context.
*/
@Override
public List getAllRowReaders() {
List result = new ArrayList();
result.addAll(rowReaderMap.values());
return result;
}
/**
* Creates and adds a row reader based on the given
* data object and result row mapping it by UUID string
* and row key string.
* @param dataObject the data object
* @return the row reader
* @throws IllegalArgumentException if an existing row reader is already mapped
* for the given data object UUID
*/
@Override
public RowReader createRowReader(DataObject dataObject,
Result resultRow) throws IllegalArgumentException {
byte[] rowKey = resultRow.getRow();
String keyString = Bytes.toString(rowKey);
UUID uuid = ((PlasmaDataObject)dataObject).getUUID();
if (this.rowReaderMap.containsKey(uuid.toString()))
throw new IllegalArgumentException("given UUID already mapped to a row reader, "
+ uuid);
if (this.rowReaderMap.containsKey(keyString))
throw new IllegalArgumentException("existing row reader is already mapped for the given row key, "
+ keyString);
GraphRowReader rowReader = new GraphRowReader(
resultRow.getRow(), resultRow,
dataObject, this);
this.addRowReader(uuid, rowReader);
this.rowReaderMap.put(keyString, rowReader);
// set the row key so we can look it up on
// modify and delete ops
CoreDataObject coreObject = (CoreDataObject)dataObject;
coreObject.getValueObject().put(
CloudGraphConstants.ROW_KEY, rowReader.getRowKey());
return rowReader;
}
/**
* Returns the distributed context associated with this table
* operation context.
* @return the distributed context associated with this table
* operation context.
*/
@Override
public DistributedOperation getFederatedOperation() {
return this.distributedOperation;
}
/**
* Sets the distributed context associated with this table
* operation context.
* @param distributedOperation the operation
*/
@Override
public void setFederatedOperation(DistributedOperation distributedOperation) {
this.distributedOperation = distributedOperation;
}
/**
* Frees resources associated with this reader and any
* component readers.
*/
public void clear() {
this.rowReaderMap.clear();
}
@Override
public void close() throws IOException {
try {
if (this.table != null)
this.table.close();
if (this.connection != null)
this.connection.close();
}
catch (IOException e) {
log.error(e.getMessage(), e);
}
finally {
this.table = null;
this.connection = null;
}
}
}
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