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The FoundationDB SQL Layer Driver for JDBC4
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/*-------------------------------------------------------------------------
*
* Copyright (c) 2004-2011, PostgreSQL Global Development Group
* Copyright (c) 2004, Open Cloud Limited.
*
*
*-------------------------------------------------------------------------
*/
package org.postgresql.core;

import org.postgresql.PGNotification;
import org.postgresql.util.HostSpec;

import java.sql.*;
import java.util.Set;

/**
 * Provides access to protocol-level connection operations.
 *
 * @author Oliver Jowett ([email protected])
 */
public interface ProtocolConnection {
    /**
     * Constant returned by {@link #getTransactionState} indicating that no
     * transaction is currently open.
     */
    static final int TRANSACTION_IDLE = 0;

    /**
     * Constant returned by {@link #getTransactionState} indicating that a
     * transaction is currently open.
     */
    static final int TRANSACTION_OPEN = 1;

    /**
     * Constant returned by {@link #getTransactionState} indicating that a
     * transaction is currently open, but it has seen errors and will
     * refuse subsequent queries until a ROLLBACK.
     */
    static final int TRANSACTION_FAILED = 2;

    /**
     * @return the host and port this connection is connected to.
     */
    HostSpec getHostSpec();

    /**
     * @return the user this connection authenticated as.
     */
    String getUser();

    /**
     * @return the database this connection is connected to.
     */
    String getDatabase();

    /**
     * @return the server version of the connected server, formatted as X.Y.Z.
     */
    String getServerVersion();

    /**
     * @return the current encoding in use by this connection
     */
    Encoding getEncoding();
    
    /**
     * Returns whether the server treats string-literals according to the SQL
     * standard or if it uses traditional PostgreSQL escaping rules. Versions
     * up to 8.1 always treated backslashes as escape characters in
     * string-literals. Since 8.2, this depends on the value of the
     * standard_conforming_strings server variable.
     * 
     * @return true if the server treats string literals according to the SQL
     *   standard
     */
    boolean getStandardConformingStrings();

    /**
     * Get the current transaction state of this connection.
     * 
     * @return a ProtocolConnection.TRANSACTION_* constant.
     */
    int getTransactionState();

    /**
     * Retrieve and clear the set of asynchronous notifications pending on this
     * connection.
     *
     * @return an array of notifications; if there are no notifications, an empty
     *   array is returned.
     */
    PGNotification[] getNotifications() throws SQLException;

    /**
     * Retrieve and clear the chain of warnings accumulated on this connection.
     *
     * @return the first SQLWarning in the chain; subsequent warnings can be
     *   found via SQLWarning.getNextWarning().
     */
    SQLWarning getWarnings();

    /**
     * @return the QueryExecutor instance for this connection.
     */
    QueryExecutor getQueryExecutor();

    /**
     * Sends a query cancellation for this connection.
     * @throws SQLException if something goes wrong.
     */
    void sendQueryCancel() throws SQLException;

    /**
     * Close this connection cleanly.
     */
    void close();

    /**
     * Check if this connection is closed.
     *
     * @return true iff the connection is closed.
     */
    boolean isClosed();
    
    /**
     * 
     * @return the version of the implementation
     */
    public int getProtocolVersion();

    /**
     * Sets the oids that should be received using binary encoding.
     *
     * @param useBinaryForOids The oids to request with binary encoding.
     */
    public void setBinaryReceiveOids(Set useBinaryForOids);

    /**
     * Returns true if server uses integer instead of double for binary
     * date and time encodings.
     * 
     * @return the server integer_datetime setting.
     */
    public boolean getIntegerDateTimes();

    /**
     * Return the process ID (PID) of the backend server process handling this connection.
     */
    public int getBackendPID();
    
    /**
     * Return true if the connection is to the FoundationDB SQL layer, 
     * Return false otherwise. 
     */
    boolean isFoundationDBServer();

    /**
     * Return the real FoundationDB SQL Layer version number,
     * Return null otherwise.
     */
    String getFoundationDBServerVersion();
}