libQtCassandra: QtCassandra::QCassandraPrivate Class Reference

libQtCassandra 1.0

Private data for the QCassandra class. More...

#include <QCassandraPrivate.h>

Collaboration diagram for QtCassandra::QCassandraPrivate:

List of all members.

Public Member Functions

 QCassandraPrivate (QCassandra *parent)
 Initialize the private QCassandra object.

 ~QCassandraPrivate ()
 Clean up the object.

QString clusterName () const
 Retrieve the name of the cluster.

bool connect (const QString &host, int port)
 Connect to the Cassandra server.

void contexts () const
 Go through the list of contexts and build a list of such.

void createContext (const QCassandraContext &context)
 Create a new context.

void createTable (const QCassandraTable *table)
 Create a table in the Cassandra server.

void disconnect ()
 Disconnect from the Cassandra server.

void dropContext (const QCassandraContext &context)
 Drop an existing context.

void dropTable (const QString &table_name)
 Drop a table from the Cassandra server.

int32_t getCellCount (const QString &table_name, const QByteArray &row_key, const QCassandraColumnPredicate &column_predicate)
 Get a slice of columns from the Cassandra database.

void getColumnSlice (QCassandraTable &table, const QByteArray &row_key, const QCassandraColumnPredicate &column_predicate)
 Get a slice of columns from the Cassandra database.

uint32_t getRowSlices (QCassandraTable &table, const QCassandraRowPredicate &row_predicate)
 This function retrieves a set of rows.

void getValue (const QString &table_name, const QByteArray &row_key, const QByteArray &column_key, QCassandraValue &value)
 Get a value from the Cassandra database.

void insertValue (const QString &table_name, const QByteArray &row_key, const QByteArray &column_key, const QCassandraValue &value)
 Insert a value in the Cassandra database.

bool isConnected () const
 Check whether we're connected.

QString protocolVersion () const
 Retrieve the version of the protocol.

void remove (const QString &table_name, const QByteArray &row_key, const QByteArray &column_key, int64_t timestamp, consistency_level_t consistency_level)
 Remove a cell from the Cassandra database.

void setContext (const QString &context)
 Set the context keyspace name.

void truncateTable (const QCassandraTable *table)
 Truncate a table in the Cassandra server.

void updateContext (const QCassandraContext &context)
 Update an existing context.

void updateTable (const QCassandraTable *table)
 Update a table in the Cassandra server.

Private Member Functions

 QCassandraPrivate (const QCassandraPrivate &)
 Forbid the copy operator.

void mustBeConnected () const throw (std::runtime_error)
 Check that we're connected.

Private Attributes

boost::shared_ptr
< org::apache::cassandra::CassandraClient > 
f_client
 Define a client object.

QCassandraf_parent
 The pointer to the QCassandra object.

boost::shared_ptr
< apache::thrift::protocol::TProtocol > 
f_protocol
 The protocol between us and the Cassandra server.

boost::shared_ptr
< apache::thrift::transport::TTransport > 
f_socket
 The socket used to connect to the Cassandra server.

boost::shared_ptr
< apache::thrift::transport::TTransport > 
f_transport
 The transport handler.


Detailed Description

This class handles such things as the connection to the Cassandra server and hiding all the thrift definitions.

Definition at line 48 of file QCassandraPrivate.h.


Constructor & Destructor Documentation

QtCassandra::QCassandraPrivate::QCassandraPrivate ( QCassandra parent)

This function initialize the QCassandra private object.

Parameters:
[in]parentThe parent pointer (i.e. QCassandra object)

Definition at line 117 of file QCassandraPrivate.cpp.

QtCassandra::QCassandraPrivate::~QCassandraPrivate ( )

This function makes sure we clean up after ourselves.

Definition at line 142 of file QCassandraPrivate.cpp.

References disconnect().

QtCassandra::QCassandraPrivate::QCassandraPrivate ( const QCassandraPrivate ) [inline, private]

By default we forbid the copy operator of the QCassandraPrivate class.

The class includes a network connection and we really do not want to have to clone such a thing.

Note that most of the objects do not define the copy operator since they are QObject's and these are already not copyable.

Definition at line 81 of file QCassandraPrivate.h.


Member Function Documentation

QString QtCassandra::QCassandraPrivate::clusterName ( ) const

This function sends a message to the Cassandra server to determine the name of the cluster.

Returns:
The name of the cluster.

Definition at line 262 of file QCassandraPrivate.cpp.

References f_client, and mustBeConnected().

bool QtCassandra::QCassandraPrivate::connect ( const QString &  host,
int  port 
)

This function needs to be called before most of the others.

It is not mentioned on each other function that if the connection is not up then an exception is generated. It will be noted, however, that a connection is required for the function to work.

Note that the main QCassandra object is responsible to test whether the connection valid (isConnected()) and to capture exceptions that should be replaced by a boolean return values and similar approaches.

In the early days expect to see exceptions coming up until we take care of them all.

Note that this function first turns off the existing connection if there is one.

Parameters:
[in]hostThe host of the Cassandra server.
[in]portThe port of the Cassandra server.
Returns:
true when the server connected, false otherwise
See also:
isConnected()
disconnect()

Definition at line 173 of file QCassandraPrivate.cpp.

References disconnect(), f_client, f_protocol, f_socket, and f_transport.

void QtCassandra::QCassandraPrivate::contexts ( ) const

This function creates a list of QCassandraContexts and returns the result.

The function retrieves all the keyspaces from Cassandra, transforms them in QCassandraContext objects, and save the result in a QCassandraContexts map indexed by name and returns that object.

The QCassandra object is responsible for caching the result. The result should not change until we create a new table although if another process on another machine changes the Cassandra cluster structure, it will not be seen until the cache is cleared.

Todo:
If ks->name is binary (not valid UTF-8,) then this function fails.

Definition at line 316 of file QCassandraPrivate.cpp.

References QtCassandra::QCassandra::context(), f_client, f_parent, and mustBeConnected().

void QtCassandra::QCassandraPrivate::createContext ( const QCassandraContext context)

This function creates a new context. Trying to create a context with the name of an existing context will fail. Use the update function instead.

The new context identifier is not returned. I'm not too sure what you could do with it anyway since no function make use of it.

At this time, it looks like you cannot include an array of tables in the context or the create function fails.

Parameters:
[in]contextThe context definition used to create the new context.
See also:
updateContext()

Definition at line 348 of file QCassandraPrivate.cpp.

References f_client, mustBeConnected(), and QtCassandra::QCassandraContext::prepareContextDefinition().

Referenced by QtCassandra::QCassandraContext::create().

void QtCassandra::QCassandraPrivate::createTable ( const QCassandraTable table)

This function creates a table in the cassandra server transforming a QCassandraTable in a table definition (CfDef) and then calling the system_add_column_family() function.

Parameters:
[in]tableThe table to be created.

Definition at line 403 of file QCassandraPrivate.cpp.

References f_client, mustBeConnected(), and QtCassandra::QCassandraTable::prepareTableDefinition().

Referenced by QtCassandra::QCassandraContext::createTable().

void QtCassandra::QCassandraPrivate::disconnect ( )

This function destroys the connection of the Cassandra server.

After calling this function, any other function that require a connection will fail.

Definition at line 211 of file QCassandraPrivate.cpp.

References f_client, f_protocol, f_socket, and f_transport.

Referenced by connect(), and ~QCassandraPrivate().

void QtCassandra::QCassandraPrivate::dropContext ( const QCassandraContext context)

This function drops an existing context. After this call, do not try to access the context again until you re-create it.

Parameters:
[in]contextThe context to drop from the attached Cassandra cluster.
See also:
createContext()

Definition at line 387 of file QCassandraPrivate.cpp.

References QtCassandra::QCassandra::clearCurrentContextIf(), QtCassandra::QCassandraContext::contextName(), f_client, f_parent, and mustBeConnected().

Referenced by QtCassandra::QCassandraContext::drop().

void QtCassandra::QCassandraPrivate::dropTable ( const QString &  table_name)

This function drops the named table from the cassandra server.

Parameters:
[in]table_nameThe name of the table to be dropped.

Definition at line 433 of file QCassandraPrivate.cpp.

References f_client, and mustBeConnected().

Referenced by QtCassandra::QCassandraContext::dropTable().

int32_t QtCassandra::QCassandraPrivate::getCellCount ( const QString &  table_name,
const QByteArray &  row_key,
const QCassandraColumnPredicate column_predicate 
)

This function retrieves a slice from the Cassandra database. A slice is an array of column from a specific row.

The result is passed to a QCassndraTable which is expected to save it as a set of rows, cells, and values.

Parameters:
[in]table_nameName of the table where the cell counting is processed.
[in]row_keyThe key used to identify the row.
[in]column_predicateThe predicate defining the name of the columns to return.
Returns:
The number of cells (Columns) found using the specified predicate.

Definition at line 581 of file QCassandraPrivate.cpp.

References QtCassandra::CONSISTENCY_LEVEL_DEFAULT, QtCassandra::QCassandraColumnPredicate::consistencyLevel(), QtCassandra::QCassandra::defaultConsistencyLevel(), f_client, f_parent, mustBeConnected(), and QtCassandra::QCassandraColumnPredicate::toPredicate().

Referenced by QtCassandra::QCassandraContext::getCellCount().

void QtCassandra::QCassandraPrivate::getColumnSlice ( QCassandraTable table,
const QByteArray &  row_key,
const QCassandraColumnPredicate column_predicate 
)

This function retrieves a slice from the Cassandra database. A slice is an array of column from a specific row.

The result is passed to a QCassndraTable which is expected to save it as a set of rows, cells, and values.

Parameters:
[in,out]tableThe table where values found get inserted.
[in]row_keyThe key used to identify the row.
[in]column_predicateThe predicate defining the name of the columns to return.

Definition at line 618 of file QCassandraPrivate.cpp.

References QtCassandra::QCassandraTable::assignRow(), QtCassandra::QCassandraValue::assignTimestamp(), QtCassandra::CONSISTENCY_LEVEL_DEFAULT, QtCassandra::QCassandraColumnPredicate::consistencyLevel(), QtCassandra::QCassandra::defaultConsistencyLevel(), f_client, f_parent, mustBeConnected(), QtCassandra::QCassandraValue::setBinaryValue(), QtCassandra::QCassandraValue::setTtl(), QtCassandra::QCassandraTable::tableName(), and QtCassandra::QCassandraColumnPredicate::toPredicate().

Referenced by QtCassandra::QCassandraContext::getColumnSlice().

uint32_t QtCassandra::QCassandraPrivate::getRowSlices ( QCassandraTable table,
const QCassandraRowPredicate row_predicate 
)

This function retrieves a set of rows filtered by the specified predicate and return the result in the corresponding table.

Parameters:
[in,out]tableThe table requesting the row slices.
[in]row_predicateThe predicate to select rows and columns.
Returns:
The number of rows read from the Cassandra server.

Definition at line 707 of file QCassandraPrivate.cpp.

References QtCassandra::QCassandraTable::assignRow(), QtCassandra::QCassandraValue::assignTimestamp(), QtCassandra::QCassandraRowPredicate::columnPredicate(), QtCassandra::CONSISTENCY_LEVEL_DEFAULT, QtCassandra::QCassandra::defaultConsistencyLevel(), f_client, f_parent, mustBeConnected(), QtCassandra::QCassandraValue::setBinaryValue(), QtCassandra::QCassandraValue::setTtl(), QtCassandra::QCassandraTable::tableName(), and QtCassandra::QCassandraRowPredicate::toPredicate().

Referenced by QtCassandra::QCassandraContext::getRowSlices().

void QtCassandra::QCassandraPrivate::getValue ( const QString &  table_name,
const QByteArray &  row_key,
const QByteArray &  column_key,
QCassandraValue value 
)

This function retrieves a value from the Cassandra database.

It is retrieve from the current context, table_name, row_key, and column_key.

Parameters:
[in]table_nameName of the table where the value is inserted.
[in]row_keyThe key used to identify the row.
[in]column_keyThe key used to identify the column.
[out]valueThe new value of the cell.

Definition at line 523 of file QCassandraPrivate.cpp.

References QtCassandra::QCassandraValue::assignTimestamp(), QtCassandra::CONSISTENCY_LEVEL_DEFAULT, QtCassandra::QCassandraValue::consistencyLevel(), QtCassandra::QCassandra::defaultConsistencyLevel(), f_client, f_parent, mustBeConnected(), QtCassandra::QCassandraValue::setBinaryValue(), QtCassandra::QCassandraValue::setNullValue(), and QtCassandra::QCassandraValue::setTtl().

Referenced by QtCassandra::QCassandraContext::getValue().

void QtCassandra::QCassandraPrivate::insertValue ( const QString &  table_name,
const QByteArray &  row_key,
const QByteArray &  column_key,
const QCassandraValue value 
)

This function insert the specified value in the Cassandra database.

It is saved in the current context, table_name, row_key, and column_key.

Parameters:
[in]table_nameName of the table where the value is inserted.
[in]row_keyThe key used to identify the row.
[in]column_keyThe key used to identify the column.
[in]valueThe new value of the cell.

Definition at line 465 of file QCassandraPrivate.cpp.

References QtCassandra::QCassandraValue::binaryValue(), QtCassandra::CONSISTENCY_LEVEL_DEFAULT, QtCassandra::QCassandraValue::consistencyLevel(), QtCassandra::QCassandra::defaultConsistencyLevel(), f_client, f_parent, mustBeConnected(), QtCassandra::QCassandra::timeofday(), QtCassandra::QCassandraValue::timestamp(), QtCassandra::QCassandraValue::TIMESTAMP_MODE_AUTO, QtCassandra::QCassandraValue::TIMESTAMP_MODE_DEFINED, QtCassandra::QCassandraValue::timestampMode(), QtCassandra::QCassandraValue::ttl(), and QtCassandra::QCassandraValue::TTL_PERMANENT.

Referenced by QtCassandra::QCassandraContext::insertValue().

bool QtCassandra::QCassandraPrivate::isConnected ( ) const

This checks whether an f_client point exists.

Note:
To test whether the actual TCP/IP connection is up we'll want to have some NOOP function (i.e. describe_cluster_name()).
Returns:
true if the server is connected

Definition at line 233 of file QCassandraPrivate.cpp.

References f_client.

Referenced by mustBeConnected().

void QtCassandra::QCassandraPrivate::mustBeConnected ( ) const throw (std::runtime_error) [private]

This function verifies that the cassandra server is connected (as in the connect() function was called ans succeeded. If not connected, then an exception is raised.

Exceptions:
std::runtime_errorThis function raises an exception if the QCassandraPrivate object is not currently connected to a Cassandra server.

Definition at line 248 of file QCassandraPrivate.cpp.

References isConnected().

Referenced by clusterName(), contexts(), createContext(), createTable(), dropContext(), dropTable(), getCellCount(), getColumnSlice(), getRowSlices(), getValue(), insertValue(), protocolVersion(), remove(), setContext(), truncateTable(), updateContext(), and updateTable().

QString QtCassandra::QCassandraPrivate::protocolVersion ( ) const

This function sends a message to the Cassandra server to determine the version of the protocol.

Returns:
The version of the protocol.

Definition at line 277 of file QCassandraPrivate.cpp.

References f_client, and mustBeConnected().

void QtCassandra::QCassandraPrivate::remove ( const QString &  table_name,
const QByteArray &  row_key,
const QByteArray &  column_key,
int64_t  timestamp,
consistency_level_t  consistency_level 
)

This function calls the Cassandra server to remove a cell in the Cassandra database.

Parameters:
[in]table_nameThe name of the column where the row is defined.
[in]row_keyThe row in which the cell is to be removed.
[in]column_keyThe cell to be removed, may be empty to remove all the cells.
[in]timestampThe time when the key to be removed was created.
[in]consistency_levelThe consistency level to use to remove this cell.

Definition at line 675 of file QCassandraPrivate.cpp.

References QtCassandra::CONSISTENCY_LEVEL_DEFAULT, QtCassandra::QCassandra::defaultConsistencyLevel(), f_client, f_parent, and mustBeConnected().

Referenced by QtCassandra::QCassandraContext::remove().

void QtCassandra::QCassandraPrivate::setContext ( const QString &  context_name)

The Cassandra database system reacts to commands in a specific keyspace which is managed like a context. This context must be specified before other functions are called or those other functions will fail.

Parameters:
[in]context_nameThe name of the context to use as the current context.

Definition at line 293 of file QCassandraPrivate.cpp.

References f_client, and mustBeConnected().

void QtCassandra::QCassandraPrivate::truncateTable ( const QCassandraTable table)

This function truncates (i.e. removes all the rows and their data) a table from the cassandra server.

Parameters:
[in]tableThe table to be created.

Definition at line 447 of file QCassandraPrivate.cpp.

References f_client, mustBeConnected(), and QtCassandra::QCassandraTable::tableName().

Referenced by QtCassandra::QCassandraContext::truncateTable().

void QtCassandra::QCassandraPrivate::updateContext ( const QCassandraContext context)

This function updates an existing context. Some options may not be updateable.

The context should be one that you loaded from the cluster to be sure that you start with the right data.

Parameters:
[in]contextThe context to update in the attached Cassandra cluster.
See also:
createContext()

Definition at line 369 of file QCassandraPrivate.cpp.

References f_client, mustBeConnected(), and QtCassandra::QCassandraContext::prepareContextDefinition().

Referenced by QtCassandra::QCassandraContext::update().

void QtCassandra::QCassandraPrivate::updateTable ( const QCassandraTable table)

This function updates a table int the cassandra server.

Parameters:
[in]tableThe table to be updated.

Definition at line 418 of file QCassandraPrivate.cpp.

References f_client, mustBeConnected(), and QtCassandra::QCassandraTable::prepareTableDefinition().

Referenced by QtCassandra::QCassandraContext::updateTable().


Member Data Documentation

The client object is what we use everywhere to communicate with the Cassandra server. It is a Cassandra Client object that knows how to convert the Cassandra specific messages and send them over the transport object.

To create a client, we need to create a socket, a transport and a protocol. If any one of those steps fails, then you cannot communicate with the Cassandra server.

The main raison for failure is an invalid IP/port combinaison or your Cassandra server isn't running.

Definition at line 90 of file QCassandraPrivate.h.

Referenced by clusterName(), connect(), contexts(), createContext(), createTable(), disconnect(), dropContext(), dropTable(), getCellCount(), getColumnSlice(), getRowSlices(), getValue(), insertValue(), isConnected(), protocolVersion(), remove(), setContext(), truncateTable(), updateContext(), and updateTable().

This variable member holds the QCassandra object pointer. This QCassandra object owns the QCassandraPrivate object (it's a 1 to 1.) This is why this pointer is a bare pointer. When the QCassandra goes, so does the QCassandraPriavet. And if the QCassandraPrivate goes, that's because the QCassandra is going.

Definition at line 86 of file QCassandraPrivate.h.

Referenced by contexts(), dropContext(), getCellCount(), getColumnSlice(), getRowSlices(), getValue(), insertValue(), and remove().

This object defines the protocol. In other words, it knows how to send and receive messages (i.e. header, footer, etc.)

Definition at line 89 of file QCassandraPrivate.h.

Referenced by connect(), and disconnect().

This pointer holds a Thrift socket used to communicate with the Cassandra server.

At our level we just provide the socket to the framed transport. How it is being used is Thrift responsibility.

It is setup with the IP address and port that one can use to access the Cassandra server.

Definition at line 87 of file QCassandraPrivate.h.

Referenced by connect(), and disconnect().

The transport object of the Thrift system to manage the data being send and received from the Cassandra server.

The socket is attached to the transport system.

Definition at line 88 of file QCassandraPrivate.h.

Referenced by connect(), and disconnect().


The documentation for this class was generated from the following files:

This document is part of the libQtCassandra Project.

Copyright by Made to Order Software Corp.

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