This class manages the reuse of Statement objects for prepared statements for a Session instance.

A compiled statement is registered by a session to be managed.

The sql statement text distinguishes different compiled statements and acts as lookup key when a session initially looks for an existing instance of the compiled sql statement.

The unique compiled statement id for the sql statement is used to access the statement.

Changes to database structure via DDL statements, will result in all registered Statement objects to become invalidated. This is done by comparing the schema change and compile timestamps. When a session subsequently attempts to use an invalidated Statement via its id, it will recompiles the Statement using its sql statement still held by this class. failure to recompile invalidates and removes the Statement.

This class keeps count of the number of time each registered compiled statement is linked to a session. It unregisters a compiled statement when it is not in use.

Modified by fredt@users from the original by campbell-burnet@users to simplify, support multiple identical prepared statements per session, and avoid memory leaks. Changed implementation to a session object for optimised access.

Nested and Inner Type Summary

Modifier and Type	Class and Description
private static class	StatementManager.StatementComparator
private static class	StatementManager.StatementWrapper

Field Summary

Modifier and Type	Field and Description
private LongKeyHashMap<StatementManager.StatementWrapper>	csidMap Map: Statement id (int) maps to: wrapper for Statement object.
private Database	database The Database for which this is managing Statement objects.
private long	next_cs_id Monotonically increasing counter used to assign unique ids to Statement objects.
private Session	session The Session for which this is managing Statement objects
private HashSet<StatementManager.StatementWrapper>	statementSet Set of wrappers for Statement object.

Constructor Summary

Access	Constructor and Description
pack-priv	StatementManager(Session the session instance for which this object is to manage Statement objects. session) Constructs a new instance of `StatementManager`.

Method Summary

Modifier and Type	Method and Description
pack-priv Statement	Returns: Statement compile(Result the Result holding the SQL cmd) Compiles an SQL statement and returns a Statement Object
pack-priv void	freeStatement(long the Statement identifier csid) Removes a link between a PreparedStatement and a Statement.
public Statement	Returns: the requested Statement object getStatement(long the identifier of the requested Statement object csid) Used by JDBC for a previously prepared statement.
private Statement	getStatement(StatementManager.StatementWrapper sw)
public Statement	Returns: the requested Statement object getStatement(Statement the old expired statement statement) Recompiles an existing statement.
private long	Returns: the next Statement identifier in the sequence. nextID() Retrieves the next Statement identifier in the sequence.
private Statement	Returns: the new Statement object recompileStatement(Statement the old expired statement cs) Returns an up-to-date Statement using the SQL and settings of the original.
private long	Returns: The statement id assigned to the Statement object registerStatement(StatementManager.StatementWrapper the wrapper for the Statement to add wrapper) Registers a Statement to be managed.
private void	removeStatement(long the Statement identifier csid) Removes an invalidated Statement.
pack-priv void	reset() Clears all internal data structures, removing any references to Statements.

Inherited from java.lang.Object:: clone equals finalize getClass hashCode notify notifyAll toString wait wait wait

Field Detail

csidMap	back to summary
private LongKeyHashMap<StatementManager.StatementWrapper> csidMap Map: Statement id (int) maps to: wrapper for Statement object.

database	back to summary
private Database database The Database for which this is managing Statement objects.

next_cs_id	back to summary
private long next_cs_id Monotonically increasing counter used to assign unique ids to Statement objects.

session	back to summary
private Session session The Session for which this is managing Statement objects

statementSet	back to summary
private HashSet<StatementManager.StatementWrapper> statementSet Set of wrappers for Statement object.

Constructor Detail

StatementManager back to summary

StatementManager	back to summary
pack-priv StatementManager(Session session) Constructs a new instance of `StatementManager`. Parameters session:Session the session instance for which this object is to manage Statement objects.

pack-priv StatementManager(Session session)

Constructs a new instance of StatementManager.

Parameters

session:Session: the session instance for which this object is to manage Statement objects.

Method Detail

compile	back to summary
pack-priv Statement compile(Result cmd) Compiles an SQL statement and returns a Statement Object Parameters cmd:Result the Result holding the SQL Returns:Statement Statement

compile

back to summary

pack-priv Statement compile(Result cmd)

Compiles an SQL statement and returns a Statement Object

Parameters

cmd:Result: the Result holding the SQL

Returns:Statement

Statement

freeStatement	back to summary
pack-priv void freeStatement(long csid) Removes a link between a PreparedStatement and a Statement. If the statement is not linked with any other PreparedStatement, it is removed from management. Parameters csid:long the Statement identifier

freeStatement

back to summary

pack-priv void freeStatement(long csid)

Removes a link between a PreparedStatement and a Statement. If the statement is not linked with any other PreparedStatement, it is removed from management.

Parameters

csid:long: the Statement identifier

getStatement	back to summary
public Statement getStatement(long csid) Used by JDBC for a previously prepared statement. Returns an existing Statement object with the given statement identifier. Returns null if the Statement object has expired and cannot be recompiled Parameters csid:long the identifier of the requested Statement object Returns:Statement the requested Statement object

getStatement

back to summary

public Statement getStatement(long csid)

Used by JDBC for a previously prepared statement. Returns an existing Statement object with the given statement identifier. Returns null if the Statement object has expired and cannot be recompiled

Parameters

csid:long: the identifier of the requested Statement object

Returns:Statement

the requested Statement object

getStatement	back to summary
private Statement getStatement(StatementManager.StatementWrapper sw)

getStatement	back to summary
public Statement getStatement(Statement statement) Recompiles an existing statement. Used by transaction manager for all statements, prepared or not prepred. Parameters statement:Statement the old expired statement Returns:Statement the requested Statement object

getStatement

back to summary

public Statement getStatement(Statement statement)

Recompiles an existing statement. Used by transaction manager for all statements, prepared or not prepred.

Parameters

statement:Statement: the old expired statement

Returns:Statement

the requested Statement object

nextID	back to summary
private long nextID() Retrieves the next Statement identifier in the sequence. Returns:long the next Statement identifier in the sequence.

nextID

back to summary

private long nextID()

Retrieves the next Statement identifier in the sequence.

Returns:long: the next Statement identifier in the sequence.

recompileStatement	back to summary
private Statement recompileStatement(Statement cs) Returns an up-to-date Statement using the SQL and settings of the original. Returns null if the SQL cannot be compiled. Parameters cs:Statement the old expired statement Returns:Statement the new Statement object

recompileStatement

back to summary

private Statement recompileStatement(Statement cs)

Returns an up-to-date Statement using the SQL and settings of the original. Returns null if the SQL cannot be compiled.

Parameters

cs:Statement: the old expired statement

Returns:Statement

the new Statement object

registerStatement	back to summary
private long registerStatement(StatementManager.StatementWrapper wrapper) Registers a Statement to be managed. Parameters wrapper:StatementManager.StatementWrapper the wrapper for the Statement to add Returns:long The statement id assigned to the Statement object

registerStatement

back to summary

private long registerStatement(StatementManager.StatementWrapper wrapper)

Registers a Statement to be managed.

Parameters

wrapper:StatementManager.StatementWrapper: the wrapper for the Statement to add

Returns:long

The statement id assigned to the Statement object

removeStatement	back to summary
private void removeStatement(long csid) Removes an invalidated Statement. Parameters csid:long the Statement identifier

removeStatement

back to summary

private void removeStatement(long csid)

Removes an invalidated Statement.

Parameters

csid:long: the Statement identifier

reset	back to summary
pack-priv void reset() Clears all internal data structures, removing any references to Statements.

org.hsqldb back to summary

private Class StatementManager.StatementComparator

Class Inheritance

extends Object
implements ObjectComparator<StatementManager.StatementWrapper>

java.lang.Object
org.hsqldb.StatementManager.StatementComparator

All Implemented Interfaces

org.hsqldb.lib.ObjectComparator

Constructor Summary

Access	Constructor and Description
private	StatementComparator()

Method Summary

Modifier and Type	Method and Description
public boolean	equals(StatementManager.StatementWrapper s1, StatementManager.StatementWrapper s2) Implements org.hsqldb.lib.ObjectComparator.equals.
public int	hashCode(StatementManager.StatementWrapper a) Implements org.hsqldb.lib.ObjectComparator.hashCode.
public long	longKey(StatementManager.StatementWrapper a) Implements org.hsqldb.lib.ObjectComparator.longKey.

Inherited from java.lang.Object:: clone equals finalize getClass hashCode notify notifyAll toString wait wait wait

Constructor Detail

StatementComparator	back to summary
private StatementComparator()

Method Detail

equals	back to summary
public boolean equals(StatementManager.StatementWrapper s1, StatementManager.StatementWrapper s2) Implements org.hsqldb.lib.ObjectComparator.equals.

hashCode	back to summary
public int hashCode(StatementManager.StatementWrapper a) Implements org.hsqldb.lib.ObjectComparator.hashCode.

longKey	back to summary
public long longKey(StatementManager.StatementWrapper a) Implements org.hsqldb.lib.ObjectComparator.longKey.

org.hsqldb back to summary

private Class StatementManager.StatementWrapper

Class Inheritance

extends Object

java.lang.Object
org.hsqldb.StatementManager.StatementWrapper

Field Summary

Modifier and Type	Field and Description
pack-priv int	cursorProps
pack-priv ResultMetaData	generatedMetaData
pack-priv int	generatedType
pack-priv HsqlNameManager.HsqlName	schemaName
pack-priv String	sql
pack-priv Statement	statement
pack-priv long	usageCount

Constructor Summary

Access	Constructor and Description
private	StatementWrapper()

Method Summary

Inherited from java.lang.Object:: clone equals finalize getClass hashCode notify notifyAll toString wait wait wait

Field Detail

cursorProps	back to summary
pack-priv int cursorProps

generatedMetaData	back to summary
pack-priv ResultMetaData generatedMetaData

generatedType	back to summary
pack-priv int generatedType

schemaName	back to summary
pack-priv HsqlNameManager.HsqlName schemaName

sql	back to summary
pack-priv String sql

statement	back to summary
pack-priv Statement statement

usageCount	back to summary
pack-priv long usageCount

Constructor Detail

StatementWrapper	back to summary
private StatementWrapper()

public final Class StatementManager

Nested and Inner Type Summary

Field Summary

Constructor Summary

Method Summary

Field Detail

Constructor Detail

Method Detail

private Class StatementManager.StatementComparator

Constructor Summary

Method Summary

Constructor Detail

Method Detail

private Class StatementManager.StatementWrapper

Field Summary

Constructor Summary

Method Summary

Field Detail

Constructor Detail