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ServerSession.javaAPI DocGlassfish v2 API35665Thu Jul 26 13:43:34 BST 2007oracle.toplink.essentials.threetier

ServerSession

public class ServerSession extends DatabaseSessionImpl implements Server
Implementation of Server INTERNAL: The public interface should be used.

Purpose: A single session that supports multiple user/clients connection at the same time.

Description: This session supports a shared session that can be used by multiple users or clients in a three-tiered application. It brokers client sessions to allow read and write access through a unified object cache. The server session provides a shared read only database connection that is used by all of its client for reads. All changes to objects and the database must be done through a unit of work acquired from the client session, this allows the changes to occur in a transactional object space and under a exclusive database connection.

Responsibilities:

  • Connecting/disconnecting the default reading login.
  • Reading objects and maintaining the object cache.
  • Brokering client sessions.
  • Disabling database modification through the shared connection.
see
ClientSession
see
UnitOfWork

Fields Summary
protected ConnectionPool
readConnectionPool
protected Map
connectionPools
protected ConnectionPolicy
defaultConnectionPolicy
protected int
maxNumberOfNonPooledConnections
protected int
numberOfNonPooledConnectionsUsed
public static final int
MAX_WRITE_CONNECTIONS
public static final int
MIN_WRITE_CONNECTIONS
Constructors Summary
public ServerSession()
INTERNAL: Create and return a new default server session. Used for EJB SessionManager to instantiate a server session

	
    
                           
      
        super();
        this.connectionPools = new HashMap(10);
    
public ServerSession(oracle.toplink.essentials.sessions.Project project, ConnectionPolicy defaultConnectionPolicy, oracle.toplink.essentials.sessions.Login readLogin)
PUBLIC: Create and return a new server session. Configure the default connection policy to be used. This policy is used on the "acquireClientSession()" protocol. Use the readLogin, if specified, for logging into the read connection pool.

        super(project);
        this.connectionPools = new HashMap(10);
        this.defaultConnectionPolicy = defaultConnectionPolicy;
        this.maxNumberOfNonPooledConnections = 50;
        this.numberOfNonPooledConnectionsUsed = 0;
        Login login = (readLogin != null) ? readLogin : project.getDatasourceLogin();
        setReadConnectionPool(login);
    
public ServerSession(oracle.toplink.essentials.sessions.Project project, ConnectionPolicy defaultConnectionPolicy, oracle.toplink.essentials.sessions.Login readLogin, oracle.toplink.essentials.sessions.Login sequenceLogin)
PUBLIC: Create and return a new server session. Configure the default connection policy to be used. This policy is used on the "acquireClientSession()" protocol. Use the readLogin, if specified, for logging into the read connection pool. Use the sequenceLogin, if specified, for creating a connection pool to be used by sequencing through SequencingConnectionHandler sequenceLogin *MUST*: 1. specify *NON-JTS* connections (such as NON_JTS driver or read-only datasource); 2. sequenceLogin.shouldUseExternalTransactionController()==false

        this(project, defaultConnectionPolicy, readLogin);

        if (sequenceLogin != null) {
            //** sequencing refactoring
            getSequencingControl().setShouldUseSeparateConnection(true);
            getSequencingControl().setLogin(sequenceLogin);
        }
    
public ServerSession(oracle.toplink.essentials.sessions.Login login)
PUBLIC: Create and return a new server session. By giving the login information on creation this allows the session to initialize itself to the platform given in the login. This constructor does not return a connected session. To connect the session to the database login() must be sent to it. The login(userName, password) method may also be used to connect the session, this allows for the user name and password to be given at login but for the other database information to be provided when the session is created. By default the server session uses a default connection pool with 5 min 10 max number of connections and a max number 50 non-pooled connections allowed.

        this(new oracle.toplink.essentials.sessions.Project(login));
    
public ServerSession(oracle.toplink.essentials.sessions.Login login, int minNumberOfPooledConnection, int maxNumberOfPooledConnection)
PUBLIC: Create and return a new server session. Configure the min and max number of connections for the default pool.

        this(new oracle.toplink.essentials.sessions.Project(login), minNumberOfPooledConnection, maxNumberOfPooledConnection);
    
public ServerSession(oracle.toplink.essentials.sessions.Login login, ConnectionPolicy defaultConnectionPolicy)
PUBLIC: Create and return a new server session. Configure the default connection policy to be used. This policy is used on the "acquireClientSession()" protocol.

        this(new oracle.toplink.essentials.sessions.Project(login), defaultConnectionPolicy);
    
public ServerSession(oracle.toplink.essentials.sessions.Project project)
PUBLIC: Create and return a new server session. By giving the project information on creation this allows the session to initialize itself to the platform given in the login. This constructor does not return a connected session. To connect the session to the database login() must be sent to it. The login(userName, password) method may also be used to connect the session, this allows for the user name and password to be given at login but for the other database information to be provided when the session is created. By default the server session uses a default connection pool with 5 min 10 max number of connections and a max number 50 non-pooled connections allowed.

        this(project, MIN_WRITE_CONNECTIONS, MAX_WRITE_CONNECTIONS);
    
public ServerSession(oracle.toplink.essentials.sessions.Project project, int minNumberOfPooledConnection, int maxNumberOfPooledConnection)
PUBLIC: Create and return a new server session. Configure the min and max number of connections for the default pool.

        this(project, new ConnectionPolicy("default"));

        ConnectionPool pool = null;
        if (project.getDatasourceLogin().shouldUseExternalConnectionPooling()) {
            pool = new ExternalConnectionPool("default", project.getDatasourceLogin(), this);
        } else {
            pool = new ConnectionPool("default", project.getDatasourceLogin(), minNumberOfPooledConnection, maxNumberOfPooledConnection, this);
        }
        this.connectionPools.put("default", pool);
    
public ServerSession(oracle.toplink.essentials.sessions.Project project, int minNumberOfPooledConnection, int maxNumberOfPooledConnection, oracle.toplink.essentials.sessions.Login readLogin)
PUBLIC: Create and return a new server session. Configure the min and max number of connections for the default pool. Use the login from the project for the write pool. Use the passed in login for the read pool, if specified, or the project login if not.

param
project the project associated with this session
param
minNumberOfPooledConnection the minimum number of connections in the pool
param
maxNumberOfPooledConnection the maximum number of connections in the pool
param
readLogin the login used to create the read connection pool

        this(project, new ConnectionPolicy("default"), readLogin);

        ConnectionPool pool = null;
        if (project.getDatasourceLogin().shouldUseExternalConnectionPooling()) {
            pool = new ExternalConnectionPool("default", project.getDatasourceLogin(), this);
        } else {
            pool = new ConnectionPool("default", project.getDatasourceLogin(), minNumberOfPooledConnection, maxNumberOfPooledConnection, this);
        }
        this.connectionPools.put("default", pool);
    
public ServerSession(oracle.toplink.essentials.sessions.Project project, int minNumberOfPooledConnection, int maxNumberOfPooledConnection, oracle.toplink.essentials.sessions.Login readLogin, oracle.toplink.essentials.sessions.Login sequenceLogin)
PUBLIC: Create and return a new server session. Configure the min and max number of connections for the default pool. Use the login from the project for the write pool. Use the passed in login for the read pool, if specified, or the project login if not. Use the sequenceLogin, if specified, for creating a connection pool to be used by sequencing through SequencingConnectionHandler sequenceLogin *MUST*: 1. specify *NON-JTS* connections (such as NON_JTS driver or read-only datasource); 2. sequenceLogin.shouldUseExternalTransactionController()==false

param
project the project associated with this session
param
minNumberOfPooledConnection the minimum number of connections in the pool
param
maxNumberOfPooledConnection the maximum number of connections in the pool
param
readLogin the login used to create the read connection pool
param
sequenceLogin the login used to create a connection pool for sequencing

        this(project, new ConnectionPolicy("default"), readLogin, sequenceLogin);

        ConnectionPool pool = null;
        if (project.getDatasourceLogin().shouldUseExternalConnectionPooling()) {
            pool = new ExternalConnectionPool("default", project.getDatasourceLogin(), this);
        } else {
            pool = new ConnectionPool("default", project.getDatasourceLogin(), minNumberOfPooledConnection, maxNumberOfPooledConnection, this);
        }
        this.connectionPools.put("default", pool);
    
public ServerSession(oracle.toplink.essentials.sessions.Project project, ConnectionPolicy defaultConnectionPolicy)
PUBLIC: Create and return a new server session. Configure the default connection policy to be used. This policy is used on the "acquireClientSession()" protocol.

        super(project);
        this.connectionPools = new HashMap(10);
        this.defaultConnectionPolicy = defaultConnectionPolicy;
        this.maxNumberOfNonPooledConnections = 50;
        this.numberOfNonPooledConnectionsUsed = 0;
        setReadConnectionPool(project.getDatasourceLogin());
    
Methods Summary
public voidacquireClientConnection(ClientSession clientSession)
INTERNAL: Allocate the client's connection resource.

        if (clientSession.getConnectionPolicy().isPooled()) {
            ConnectionPool pool = (ConnectionPool)getConnectionPools().get(clientSession.getConnectionPolicy().getPoolName());
            Accessor connection = pool.acquireConnection();
            clientSession.setWriteConnection(connection);
            getEventManager().postAcquireConnection(connection);
        } else {
            // This method is synchronized, so while is not required, only if.
            synchronized (this) {
                while (getNumberOfNonPooledConnectionsUsed() >= getMaxNumberOfNonPooledConnections()) {
                    try {
                        wait();// Notify is called when connections are released.
                    } catch (InterruptedException exception) {
                        throw ConcurrencyException.waitFailureOnServerSession(exception);
                    }
                }

                setNumberOfNonPooledConnectionsUsed(getNumberOfNonPooledConnectionsUsed() + 1);
                clientSession.setWriteConnection(clientSession.getLogin().buildAccessor());
                clientSession.connect();
            }
        }
    
public ClientSessionacquireClientSession()
PUBLIC: Return a client session for this server session. Each user/client connected to this server session must acquire there own client session to communicate to the server through. This method allows for a client session to be acquired sharing the same login as the server session.

        return acquireClientSession((ConnectionPolicy)getDefaultConnectionPolicy().clone());
    
public ClientSessionacquireClientSession(java.lang.String poolName)
PUBLIC: Return a client session for this server session. Each user/client connected to this server session must acquire there own client session to communicate to the server through. This method allows for a client session to be acquired sharing its connection from a pool of connection allocated on the server session. By default this uses a lazy connection policy.

        return acquireClientSession(new ConnectionPolicy(poolName));
    
public ClientSessionacquireClientSession(oracle.toplink.essentials.sessions.Login login)
PUBLIC: Return a client session for this server session. Each user/client connected to this server session must acquire there own client session to communicate to the server through. The client must provide its own login to use, and the client session returned will have its own exclusive database connection. This connection will be used to perform all database modification for all units of work acquired from the client session. By default this does not use a lazy connection policy.

        return acquireClientSession(new ConnectionPolicy(login));
    
public ClientSessionacquireClientSession(ConnectionPolicy connectionPolicy)
PUBLIC: Return a client session for this server session. The connection policy specifies how the client session's connection will be acquired.

        if (!isConnected()) {
            throw ValidationException.loginBeforeAllocatingClientSessions();
        }

        log(SessionLog.FINER, SessionLog.CONNECTION, "client_acquired");
        if (!connectionPolicy.isPooled() && (connectionPolicy.getLogin() == null)) {
            //the user has passed in a connection policy with no login info. Use the 
            //default info from the default connection policy
            connectionPolicy.setPoolName(getDefaultConnectionPolicy().getPoolName());
            connectionPolicy.setLogin(getDefaultConnectionPolicy().getLogin());
        }
        if (connectionPolicy.isPooled()) {
            ConnectionPool pool = (ConnectionPool)getConnectionPools().get(connectionPolicy.getPoolName());
            if (pool == null) {
                throw ValidationException.poolNameDoesNotExist(connectionPolicy.getPoolName());
            }
            connectionPolicy.setLogin((Login)pool.getLogin().clone());
        }
        ClientSession client = null;
        if (getProject().hasIsolatedClasses()) {
            client = new IsolatedClientSession(this, connectionPolicy);
        } else {
            client = new ClientSession(this, connectionPolicy);
        }
        if (!connectionPolicy.isLazy()) {
            acquireClientConnection(client);
        }

        return client;
    
public oracle.toplink.essentials.sessions.UnitOfWorkacquireUnitOfWork()
PUBLIC: Return a unit of work for this session. The unit of work is an object level transaction that allows a group of changes to be applied as a unit. First acquire a client session as server session does not allow direct units of work.

see
UnitOfWork

        return acquireClientSession().acquireUnitOfWork();
    
public voidaddConnectionPool(java.lang.String poolName, oracle.toplink.essentials.sessions.Login login, int minNumberOfConnections, int maxNumberOfConnections)
PUBLIC: Add the connection pool. Connections are pooled to share and restrict the number of database connections.

        if (minNumberOfConnections > maxNumberOfConnections) {
            throw ValidationException.maxSizeLessThanMinSize();
        }
        if (isConnected()) {
            throw ValidationException.poolsMustBeConfiguredBeforeLogin();
        }
        ConnectionPool pool = null;
        if (login.shouldUseExternalConnectionPooling()) {
            pool = new ExternalConnectionPool(poolName, login, this);
        } else {
            pool = new ConnectionPool(poolName, login, minNumberOfConnections, maxNumberOfConnections, this);
        }
        addConnectionPool(pool);
    
public voidaddConnectionPool(ConnectionPool pool)
PUBLIC: Connection are pooled to share and restrict the number of database connections.

        pool.setOwner(this);
        getConnectionPools().put(pool.getName(), pool);

    
public voidafterTransaction(boolean committed, boolean isExternalTransaction, Accessor accessor)
INTERNAL: Called after transaction is completed (committed or rolled back)

        SequencingCallback callback = getSequencingHome().getSequencingCallback();
        if (callback != null) {
            callback.afterTransaction(accessor, committed);
        }
    
public AccessorallocateReadConnection()
INTERNAL: Return a read connection from the read pool. Note that depending on the type of pool this may be a shared or exclusive connection. Each query execution is assigned a read connection.

        Accessor connection = getReadConnectionPool().acquireConnection();
        getEventManager().postAcquireConnection(connection);
        return connection;
    
public voidconnect()
INTERNAL: Startup the server session, also startup all of the connection pools.

        // make sure pools correspond to their logins
        updateStandardConnectionPools();
        // Configure the read pool
        getReadConnectionPool().startUp();
        setAccessor(allocateReadConnection());
        releaseReadConnection(getAccessor());

        for (Iterator poolsEnum = getConnectionPools().values().iterator(); poolsEnum.hasNext();) {
            ((ConnectionPool)poolsEnum.next()).startUp();
        }
    
public java.lang.ObjectexecuteCall(Call call, oracle.toplink.essentials.internal.sessions.AbstractRecord translationRow, DatabaseQuery query)
INTERNAL: Override to acquire the connection from the pool at the last minute

        RuntimeException exception = null;
        Object object = null;
        boolean accessorAllocated = false;
        if (query.getAccessor() == null) {
            query.setAccessor(this.allocateReadConnection());
            accessorAllocated = true;
        }
        try {
            object = query.getAccessor().executeCall(call, translationRow, this);
        } catch (RuntimeException caughtException) {
            exception = caughtException;
        } finally {
            if (call.isFinished()) {
                //don't release the cursoredStream connection until Stream is closed
                try {
                    if (accessorAllocated) {
                        releaseReadConnection(query.getAccessor());
                        query.setAccessor(null);
                    }
                } catch (RuntimeException releaseException) {
                    if (exception == null) {
                        throw releaseException;
                    }
                    //else ignore
                }
            }
            if (exception != null) {
                throw exception;
            }
        }
        return object;
    
public ConnectionPoolgetConnectionPool(java.lang.String poolName)
PUBLIC: Return the pool by name.

        return (ConnectionPool)getConnectionPools().get(poolName);
    
public java.util.MapgetConnectionPools()
INTERNAL: Connection are pooled to share and restrict the number of database connections.

        return connectionPools;
    
public ConnectionPolicygetDefaultConnectionPolicy()
PUBLIC: The default connection policy is used by default by the acquireClientConnection() protocol. By default it is a connection pool with min 5 and max 10 lazy pooled connections.

        if (defaultConnectionPolicy == null) {
            this.defaultConnectionPolicy = new ConnectionPolicy("default");
        }
        return defaultConnectionPolicy;
    
public ConnectionPoolgetDefaultConnectionPool()
PUBLIC: Return the default connection pool.

        return getConnectionPool("default");
    
public oracle.toplink.essentials.internal.sessions.AbstractSessiongetExecutionSession(DatabaseQuery query)
INTERNAL: Gets the session which this query will be executed on. Generally will be called immediately before the call is translated, which is immediately before session.executeCall.

Since the execution session also knows the correct datasource platform to execute on, it is often used in the mappings where the platform is needed for type conversion, or where calls are translated.

Is also the session with the accessor. Will return a ClientSession if it is in transaction and has a write connection.

return
a session with a live accessor
param
query may store session name or reference class for brokers case

        if (query.isObjectLevelModifyQuery()) {
            throw QueryException.invalidQueryOnServerSession(query);
        }
        return this;
    
public intgetMaxNumberOfNonPooledConnections()
PUBLIC: Return the number of non-pooled database connections allowed. This can be enforced to make up for the resource limitation of most JDBC drivers and database clients. By default this is 50.

        return maxNumberOfNonPooledConnections;
    
public intgetNumberOfNonPooledConnectionsUsed()
INTERNAL: Return the current number of non-pooled connections in use.

        return numberOfNonPooledConnectionsUsed;
    
public ConnectionPoolgetReadConnectionPool()
PUBLIC: Return the read connection pool. The read connection pool handles allocating connection for read queries. By default a ReadConnnectionPool with a single connection. This is normally sufficient as a JDBC connection can support concurrent reading. Multiple connections can also be specified and may improve concurrency on some JDBC drivers/databases. If external connection pooling is used, an external connection pool will be used by default. If your JDBC driver does not support concurrency corrently a normal ConnectionPool can be used to ensure exclusive access to the read connection, note that this will give less concurrency.

        return readConnectionPool;
    
protected oracle.toplink.essentials.sessions.LogingetReadLogin()
INTERNAL: Return the login for the read connection. Used by the platform autodetect feature

        return getReadConnectionPool().getLogin();
    
public oracle.toplink.essentials.internal.sequencing.SequencingServergetSequencingServer()
INTERNAL: Return SequencingServer object owned by the session.

        return getSequencingHome().getSequencingServer();
    
public booleanisConnected()
PUBLIC: Return if this session has been connected to the database.

        if (getReadConnectionPool() == null) {
            return false;
        }

        return getReadConnectionPool().isConnected();
    
public booleanisServerSession()
INTERNAL: Return if this session is a server session.

        return true;
    
public voidlogout()
PUBLIC: Shutdown the server session, also shutdown all of the connection pools.

        super.logout();

        getReadConnectionPool().shutDown();

        for (Iterator poolsEnum = getConnectionPools().values().iterator(); poolsEnum.hasNext();) {
            ((ConnectionPool)poolsEnum.next()).shutDown();
        }
    
public voidreleaseClientSession(ClientSession clientSession)
INTERNAL: Release the clients connection resource.

        if (clientSession.getConnectionPolicy().isPooled()) {
            ConnectionPool pool = (ConnectionPool)getConnectionPools().get(clientSession.getConnectionPolicy().getPoolName());
            getEventManager().preReleaseConnection(clientSession.getWriteConnection());
            pool.releaseConnection(clientSession.getWriteConnection());
            clientSession.setWriteConnection(null);
        } else {
            synchronized (this) {
                clientSession.disconnect();
                clientSession.setWriteConnection(null);
                setNumberOfNonPooledConnectionsUsed(getNumberOfNonPooledConnectionsUsed() - 1);
                notify();
            }
        }
    
public voidreleaseReadConnection(Accessor connection)
INTERNAL: Release the read connection back into the read pool.

        getEventManager().preReleaseConnection(connection);
        getReadConnectionPool().releaseConnection(connection);
    
public voidsetConnectionPools(java.util.Map connectionPools)
INTERNAL: Connection are pooled to share and restrict the number of database connections.

        this.connectionPools = connectionPools;
    
public voidsetDefaultConnectionPolicy(ConnectionPolicy defaultConnectionPolicy)
PUBLIC: The default connection policy is used by default by the acquireClientConnection() protocol. By default it is a connection pool with min 5 and max 10 lazy pooled connections.

        this.defaultConnectionPolicy = defaultConnectionPolicy;
    
public voidsetDefaultConnectionPool()
PUBLIC: Creates and adds "default" connection pool using default parameter values

        addConnectionPool("default", getDatasourceLogin(), 5, 10);
    
public voidsetMaxNumberOfNonPooledConnections(int maxNumberOfNonPooledConnections)
PUBLIC: Set the number of non-pooled database connections allowed. This can be enforced to make up for the resource limitation of most JDBC drivers and database clients. By default this is 50.

        this.maxNumberOfNonPooledConnections = maxNumberOfNonPooledConnections;
    
public voidsetNumberOfNonPooledConnectionsUsed(int numberOfNonPooledConnectionsUsed)
Set the current number of connections being used that are not from a connection pool.

param
int

        this.numberOfNonPooledConnectionsUsed = numberOfNonPooledConnectionsUsed;
    
public voidsetReadConnectionPool(ConnectionPool readConnectionPool)
PUBLIC: Set the read connection pool. The read connection pool handles allocating connection for read queries. By default a ReadConnnectionPool with a single connection. This is normally sufficient as a JDBC connection can support concurrent reading. Multiple connections can also be specified and may improve concurrency on some JDBC drivers/databases. If external connection pooling is used, an external connection pool will be used by default. If your JDBC driver does not support concurrency corrently a normal ConnectionPool can be used to ensure exclusive access to the read connection, note that this will give less concurrency.

        if (isConnected()) {
            throw ValidationException.cannotSetReadPoolSizeAfterLogin();
        }
        this.readConnectionPool = readConnectionPool;
        this.readConnectionPool.setOwner(this);
    
public voidsetReadConnectionPool(oracle.toplink.essentials.sessions.Login readLogin)
PUBLIC: Creates and sets the new read connection pool.

        if (isConnected()) {
            throw ValidationException.poolsMustBeConfiguredBeforeLogin();
        }
        ConnectionPool pool = null;
        if (readLogin.shouldUseExternalConnectionPooling()) {
            pool = new ExternalConnectionPool("read", readLogin, this);
        } else {
            pool = new ConnectionPool("read", readLogin, 2, 2, this);
        }
        this.readConnectionPool = pool;
    
protected voidupdateStandardConnectionPools()
INTERNAL: Updates standard connection pools. Should not be called after session is connected. This is needed in case of pools' logins been altered after the pool has been created (SessionManager does that) All pools should be re-created in case their type doesn't match their login. In addition, sequenceConnectionPool should be removed in case its login has shouldUseExternaltransactionController()==true (see setSequenceConnectionPool)

        if (getDefaultConnectionPool() != null) {
            if (getDefaultConnectionPool().isThereConflictBetweenLoginAndType()) {
                setDefaultConnectionPool();
            }
        }

        if (getReadConnectionPool() != null) {
            if (getReadConnectionPool().isThereConflictBetweenLoginAndType()) {
                setReadConnectionPool(getReadConnectionPool().getLogin());
            }
        }
    
public voiduseExclusiveReadConnectionPool(int minNumerOfConnections, int maxNumerOfConnections)
PUBLIC: Configure the read connection pool. The read connection pool handles allocating connection for read queries. By default a ReadConnnectionPool with a single connection. This is normally sufficient as a JDBC connection can support concurrent reading. Multiple connections can also be specified and may improve concurrency on some JDBC drivers/databases. If external connection pooling is used, an external connection pool will be used by default. If your JDBC driver does not support concurrency corrently a normal ConnectionPool can be used to ensure exclusive access to the read connection, note that this will give less concurrency.

        setReadConnectionPool(new ConnectionPool("read", getDatasourceLogin(), minNumerOfConnections, maxNumerOfConnections, this));
    
public voiduseExternalReadConnectionPool()
PUBLIC: Configure the read connection pool. The read connection pool handles allocating connection for read queries. By default a ReadConnnectionPool with a single connection. This is normally sufficient as a JDBC connection can support concurrent reading. Multiple connections can also be specified and may improve concurrency on some JDBC drivers/databases. If external connection pooling is used, an external connection pool will be used by default. If your JDBC driver does not support concurrency corrently a normal ConnectionPool can be used to ensure exclusive access to the read connection, note that this will give less concurrency.

        setReadConnectionPool(new ExternalConnectionPool("read", getDatasourceLogin(), this));
    
public voiduseReadConnectionPool(int minNumerOfConnections, int maxNumerOfConnections)
PUBLIC: Configure the read connection pool. The read connection pool handles allocating connection for read queries. By default a ReadConnnectionPool with a single connection. This is normally sufficient as a JDBC connection can support concurrent reading. Multiple connections can also be specified and may improve concurrency on some JDBC drivers/databases. If external connection pooling is used, an external connection pool will be used by default. If your JDBC driver does not support concurrency corrently a normal ConnectionPool can be used to ensure exclusive access to the read connection, note that this will give less concurrency.

        setReadConnectionPool(new ReadConnectionPool("read", getDatasourceLogin(), minNumerOfConnections, maxNumerOfConnections, this));