mdb
790d0dd35f
that we can route read-only queries to one or more read-only mirrors of a database (the MySQL database drivers supports round-robin load balancing of queries to read-only slaves). git-svn-id: https://samskivert.googlecode.com/svn/trunk@1822 6335cc39-0255-0410-8fd6-9bcaacd3b74c
94 lines
4.0 KiB
Java
94 lines
4.0 KiB
Java
//
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// $Id: ConnectionProvider.java,v 1.2 2001/09/21 03:01:46 mdb Exp $
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//
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// samskivert library - useful routines for java programs
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// Copyright (C) 2001 Michael Bayne
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//
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// This library is free software; you can redistribute it and/or modify it
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// under the terms of the GNU Lesser General Public License as published
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// by the Free Software Foundation; either version 2.1 of the License, or
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// (at your option) any later version.
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//
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// This library is distributed in the hope that it will be useful,
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// but WITHOUT ANY WARRANTY; without even the implied warranty of
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// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
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// Lesser General Public License for more details.
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//
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// You should have received a copy of the GNU Lesser General Public
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// License along with this library; if not, write to the Free Software
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// Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
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package com.samskivert.jdbc;
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import java.sql.*;
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import com.samskivert.io.PersistenceException;
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/**
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* As the repository aims to interface with whatever database pooling
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* services a project cares to use, it obtains all of its database
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* connections through a connection provider. The connection provider
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* provides connections based on a database identifier (a string) which
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* identifies a particular connection to a particular database. A user of
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* these services would then coordinate the database identifier (or
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* identifiers) used to invoke a database operation with the database
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* connections that are returned by the connection provider that they
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* provided to the repository at construct time.
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*/
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public interface ConnectionProvider
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{
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/**
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* Obtains a database connection based on the supplied database
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* identifier. The repository expects to have exclusive use of this
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* connection instance until it releases it. This connection will be
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* released subsequently with a call to {@link #releaseConnection} or
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* {@link #connectionFailed} depending on the circumstances of the
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* release. <code>close()</code> <em>will not</em> be called on the
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* connection. It is up to the connection provider to close the
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* connection when it is released if appropriate.
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*
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* @param ident the database connection identifier.
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* @param readOnly whether or not the connection may be to a read-only
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* mirror of the repository.
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*
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* @return an active JDBC connection (which may have come from a
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* connection pool).
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*
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* @exception PersistenceException thrown if a problem occurs trying
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* to open the requested connection.
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*/
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public Connection getConnection (String ident, boolean readOnly)
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throws PersistenceException;
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/**
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* Releases a database connection when it is no longer needed by the
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* repository.
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*
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* @param ident the database identifier used when obtaining this
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* connection.
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* @param readOnly the same value that was passed to {@link #getConnection}
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* to obtain this connection.
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* @param conn the connection to release (back into the pool or to be
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* closed if pooling is not going on).
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*/
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public void releaseConnection (String ident, boolean readOnly,
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Connection conn);
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/**
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* Called by the repository if a failure occurred on the connection.
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* It is expected that the connection will be disposed of and
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* subsequent calls to <code>getConnection</code> will return a
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* freshly established connection to the database.
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*
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* @param ident the database identifier used when obtaining this
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* connection.
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* @param readOnly the same value that was passed to {@link #getConnection}
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* to obtain this connection.
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* @param conn the connection that failed.
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* @param error the error thrown by the connection (which may be used
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* to determine if the connection should be closed or can be reused).
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*/
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public void connectionFailed (String ident, boolean readOnly,
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Connection conn, SQLException error);
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}
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