/*
 * Copyright 2004-2019 H2 Group. Multiple-Licensed under the MPL 2.0,
 * and the EPL 1.0 (http://h2database.com/html/license.html).
 * Initial Developer: H2 Group
 */
package org.h2.api;

import java.sql.SQLException;
import java.util.EventListener;

A class that implements this interface can get notified about exceptions
and other events. A database event listener can be registered when
connecting to a database. Example database URL:
jdbc:h2:test;DATABASE_EVENT_LISTENER='com.acme.DbListener'
/**
 * A class that implements this interface can get notified about exceptions
 * and other events. A database event listener can be registered when
 * connecting to a database. Example database URL:
 * jdbc:h2:test;DATABASE_EVENT_LISTENER='com.acme.DbListener'
 */
public interface DatabaseEventListener extends EventListener {

    
This state is used when scanning the database file.
/**
     * This state is used when scanning the database file.
     */
    int STATE_SCAN_FILE = 0;

    
This state is used when re-creating an index.
/**
     * This state is used when re-creating an index.
     */
    int STATE_CREATE_INDEX = 1;

    
This state is used when re-applying the transaction log or rolling back
uncommitted transactions.
/**
     * This state is used when re-applying the transaction log or rolling back
     * uncommitted transactions.
     */
    int STATE_RECOVER = 2;

    
This state is used during the BACKUP command.
/**
     * This state is used during the BACKUP command.
     */
    int STATE_BACKUP_FILE = 3;

    
This state is used after re-connecting to a database (if auto-reconnect
is enabled).
/**
     * This state is used after re-connecting to a database (if auto-reconnect
     * is enabled).
     */
    int STATE_RECONNECTED = 4;

    
This state is used when a query starts.
/**
     * This state is used when a query starts.
     */
    int STATE_STATEMENT_START = 5;

    
This state is used when a query ends.
/**
     * This state is used when a query ends.
     */
    int STATE_STATEMENT_END = 6;

    
This state is used for periodic notification during long-running queries.
/**
     * This state is used for periodic notification during long-running queries.
     */
    int STATE_STATEMENT_PROGRESS = 7;

    
This method is called just after creating the object.
This is done when opening the database if the listener is specified
in the database URL, but may be later if the listener is set at
runtime with the SET SQL statement.
Params:
url – - the database URL/**
     * This method is called just after creating the object.
     * This is done when opening the database if the listener is specified
     * in the database URL, but may be later if the listener is set at
     * runtime with the SET SQL statement.
     *
     * @param url - the database URL
     */
    void init(String url);

    
This method is called after the database has been opened. It is save to
connect to the database and execute statements at this point.
/**
     * This method is called after the database has been opened. It is save to
     * connect to the database and execute statements at this point.
     */
    void opened();

    
This method is called if an exception occurred.
Params:
e – the exception
sql – the SQL statement/**
     * This method is called if an exception occurred.
     *
     * @param e the exception
     * @param sql the SQL statement
     */
    void exceptionThrown(SQLException e, String sql);

    
This method is called for long running events, such as recovering,
scanning a file or building an index.

More states might be added in future versions, therefore implementations
should silently ignore states that they don't understand.

Params:
state – the state
name – the object name
x – the current position
max – the highest possible value (might be 0)/**
     * This method is called for long running events, such as recovering,
     * scanning a file or building an index.
     * <p>
     * More states might be added in future versions, therefore implementations
     * should silently ignore states that they don't understand.
     * </p>
     *
     * @param state the state
     * @param name the object name
     * @param x the current position
     * @param max the highest possible value (might be 0)
     */
    void setProgress(int state, String name, int x, int max);

    
This method is called before the database is closed normally. It is save
to connect to the database and execute statements at this point, however
the connection must be closed before the method returns.
/**
     * This method is called before the database is closed normally. It is save
     * to connect to the database and execute statements at this point, however
     * the connection must be closed before the method returns.
     */
    void closingDatabase();

}