com.goldencode.p2j.convert.db

Class DBHelper

java.lang.Object

com.goldencode.p2j.convert.db.DBHelper

class DBHelper
extends java.lang.Object

Provides APIs to access the conversion database.

Field Summary

Fields

Modifier and Type	Field and Description
private boolean	connected Flag indicating the database is connected.
private java.sql.Connection	connection Database connection
private static java.lang.String	dbPass Default database password.
private java.lang.String	dbURL Database URL
private static java.lang.String	dbUser Default database user.
private boolean	inPersist Flag indicating if we are persisting the collections.
private static ConversionStatus	LOG Logger
private java.util.Map<java.lang.String,java.sql.PreparedStatement>	statements A cache of prepared statements.
private java.util.Map<java.lang.String,StoredCollection>	stores Cache of db-backed collections.

Constructor Summary

Constructors

Constructor and Description
DBHelper()

Method Summary

Modifier and Type	Method and Description
void	connect() Connect to the database.
boolean	connected() Check if the database is connected.
java.lang.String	convertToSql(java.lang.Class<?> clazz) Convert the specified type to SQL.
private java.sql.PreparedStatement	createStatement(java.lang.String sql) Prepare the SQL statement and cache it.
void	disconnect() Disconnect the database.
int	executeCount(java.lang.String sql, java.lang.Object... args) Execute an SQL which selects a single integer result.
void	executeQuery(java.lang.String sql, java.util.function.Consumer<java.sql.ResultSet> c, java.lang.Object... args) Execute a SQL query statement, which will use the specified consumer to process the results.
java.util.List<java.lang.Object[]>	executeQuery(java.lang.String sql, java.lang.Object... args) Execute a SQL query statement.
void	executeSQL(java.lang.String sql, java.lang.Object... args) Execute a generic SQL.
int	executeUpdate(java.lang.String sql, java.lang.Object... args) Execute an update SQL.
StoredCollection	getCollection(java.lang.String name) Get the stored collection with the specified name.
boolean	inPersist() Get the state of the inPersist flag.
void	persistCollection(java.util.Collection c, java.lang.String sql, java.util.function.BiConsumer<java.sql.PreparedStatement,java.lang.Object> ps) Persist this collection, using the specified SQL and consumer to set the query batch arguments.
void	register(java.lang.String name, StoredCollection c) Register a db-backed collection with the given name.

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Field Detail

LOG

private static final ConversionStatus LOG

Logger

dbUser

private static java.lang.String dbUser

Default database user.

dbPass

private static java.lang.String dbPass

Default database password.

connected

private boolean connected

Flag indicating the database is connected.

connection

private java.sql.Connection connection

Database connection

dbURL

private java.lang.String dbURL

Database URL

statements

private java.util.Map<java.lang.String,java.sql.PreparedStatement> statements

A cache of prepared statements.

stores

private java.util.Map<java.lang.String,StoredCollection> stores

Cache of db-backed collections.

inPersist

private boolean inPersist

Flag indicating if we are persisting the collections.

Constructor Detail

DBHelper

DBHelper()

Method Detail

inPersist

public boolean inPersist()

Get the state of the inPersist flag.

Returns:

See above.

connected

public boolean connected()

Check if the database is connected.

Returns:

The connected state.

disconnect

public void disconnect()

Disconnect the database.

This will persist all db-backed collection.

connect

public void connect()

Connect to the database.

convertToSql

public java.lang.String convertToSql(java.lang.Class<?> clazz)

Convert the specified type to SQL.

Parameters:

clazz - The Java type.

Returns:

The SQL type.

executeUpdate

public int executeUpdate(java.lang.String sql,
                         java.lang.Object... args)

Execute an update SQL.

Parameters:

sql - The SQL update statement.

args - The SQL arguments.

Returns:

The number of affected records.

executeSQL

public void executeSQL(java.lang.String sql,
                       java.lang.Object... args)

Execute a generic SQL.

Parameters:

sql - The SQL statement.

args - The SQL arguments.

executeCount

public int executeCount(java.lang.String sql,
                        java.lang.Object... args)

Execute an SQL which selects a single integer result.

Parameters:

sql - The SQL statement.

args - The SQL arguments.

Returns:

The count result.

executeQuery

public java.util.List<java.lang.Object[]> executeQuery(java.lang.String sql,
                                                       java.lang.Object... args)

Execute a SQL query statement.

Parameters:

sql - The SQL statement.

args - The SQL arguments.

Returns:

The SQL result.

executeQuery

public void executeQuery(java.lang.String sql,
                         java.util.function.Consumer<java.sql.ResultSet> c,
                         java.lang.Object... args)

Execute a SQL query statement, which will use the specified consumer to process the results.

Parameters:

sql - The SQL statement.

c - The consumer to process the result set.

args - The SQL arguments.

getCollection

public StoredCollection getCollection(java.lang.String name)

Get the stored collection with the specified name.

Parameters:

name - The stored collection name.

Returns:

The found collection, or null if it was not yet added to stores.

register

public void register(java.lang.String name,
                     StoredCollection c)

Register a db-backed collection with the given name.

Parameters:

name - The collection name.

c - The collection.

Throws:

java.lang.IllegalStateException - If there is already a collection with this name in stores.

persistCollection

public void persistCollection(java.util.Collection c,
                              java.lang.String sql,
                              java.util.function.BiConsumer<java.sql.PreparedStatement,java.lang.Object> ps)

Persist this collection, using the specified SQL and consumer to set the query batch arguments.

Parameters:

c - The collection to persist.

sql - The insert SQL.

ps - The consumer to add the records as a batch insert.

createStatement

private java.sql.PreparedStatement createStatement(java.lang.String sql)
                                            throws java.sql.SQLException

Prepare the SQL statement and cache it.

Parameters:

sql - The SQL statement to prepare.

Returns:

The prepared statement (a new instance or an instance from the statements cache).

Throws:

java.sql.SQLException - If the SQL statement can't be created.