Package net.jextra.fauxjo

Class StatementCache

java.lang.Object

net.jextra.fauxjo.StatementCache

public class StatementCache
extends Object

Caches PreparedStatements and CallableStatements per Connection, local to the Thread.

If using a modern jdbc driver that caches Statements (PG, Oracle, or MySQL), consider disabling this via its Home object, drivers cache Statements better. Bottom-up, the containment hierarchy is as follows:

• A StmtCache (StatementCache.PerConnectionCache) is an LRU cache storing PreparedStatement or CallableStatements by their sql.
• A StmtCacheMap is created if not exists from calls to prepareStatement or prepareCall and holds StmtCaches by their Connection key.
• StmtCacheMap is a type of the static ThreadLocal created at startup so each thread gets its own StmtCacheMap.

StmtCache guards against ever-changing PreparedStatement sql (not using params) by evicting the LRU entry per call if StmtCache is full or entry has expired.

See Also:

Let drivers cache PreparedStatements, StatementCacheListener, getConnKey(Connection)

Nested Class Summary

Nested Classes

Modifier and Type	Class	Description
class	StatementCache.Config
static interface	StatementCache.ProxyCloser
static class	StatementCache.WrappedPreparedStatement	Block from actually doing close.
static class	StatementCache.WrappedResultSet	Override getStatement to return proxied Statement vs real Statement.

Constructor Summary

Constructors

Constructor	Description
StatementCache()

Method Summary

Modifier and Type	Method	Description
void	addListener(StatementCacheListener listener)
boolean	clear()	Closes and removes all Listeners, PreparedStatements and PreparedCalls for the active Thread.
boolean	clear(Connection conn)
StatementCache.Config	getConfig()
static Long	getConnKey(Connection conn)	Return the Long key to be used for caching the Stmt.
void	getDiagnosticCsv(Connection conn, StringBuilder sb)	If connection is cached, append its contents to the string builder as csv rows.
StatementCacheListener[]	getListeners()
long	getPerConCache_MaxEntries()	Return max Statements (unique sql) allowed in the cache (default is 1000) before evicting the LRU.
long	getPerConCacheMaxTtl()	Return maximum time for a Statement to live in the Connection cache (default is 30 minutes).
void	getStats(StringBuilder strBldrToAppend, DateTimeFormatter optionalDtFormat)	Append stats as json params to strBldrToAppend.
CallableStatement	prepareCall(Connection conn, String sql)
CallableStatement	prepareCall(Connection conn, String sql, int resultSetType, int resultSetConcurrenc)
CallableStatement	prepareCall(Connection conn, String sql, int resultSetType, int resultSetConcurrency, int resultSetHoldability)
PreparedStatement	prepareStatement(Connection conn, String sql, boolean supportsGeneratedKeys)
PreparedStatement	prepareStatement(Connection conn, String sql, int autoGeneratedKeys)
PreparedStatement	prepareStatement(Connection conn, String sql, int[] columnIndexes)
PreparedStatement	prepareStatement(Connection conn, String sql, int resultSetType, int resultSetConcurrency)
PreparedStatement	prepareStatement(Connection conn, String sql, int resultSetType, int resultSetConcurrency, int resultSetHoldability)
PreparedStatement	prepareStatement(Connection conn, String sql, String[] columnNames)
void	removeAllListeners()
boolean	removeListener(StatementCacheListener listener)
void	setPerConCache_Maximums(Integer perConCacheMaxEntries, Long perConCacheMaxTtl)	Set perConCache maximums.
void	setPerConCacheMaxEntries(Long perConCacheMaxEntries)
void	setPerConCacheMaxTtl(Long perConCacheMaxTtl)

Methods inherited from class java.lang.Object

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

Constructor Detail

StatementCache

public StatementCache()

Method Detail

getConfig

public StatementCache.Config getConfig()

getPerConCacheMaxTtl

public long getPerConCacheMaxTtl()

Return maximum time for a Statement to live in the Connection cache (default is 30 minutes). Guard against Statements that concatenate instead of use params.

setPerConCacheMaxTtl

public void setPerConCacheMaxTtl(Long perConCacheMaxTtl)

getPerConCache_MaxEntries

public long getPerConCache_MaxEntries()

Return max Statements (unique sql) allowed in the cache (default is 1000) before evicting the LRU. Guards against Statements concatenating instead of using params.

setPerConCacheMaxEntries

public void setPerConCacheMaxEntries(Long perConCacheMaxEntries)

setPerConCache_Maximums

public void setPerConCache_Maximums(Integer perConCacheMaxEntries,
                                    Long perConCacheMaxTtl)

Set perConCache maximums.

Parameters:

perConCacheMaxEntries - stmt max Statements before evict LRU (default is 1000)

perConCacheMaxTtl - stmt max time to live before evict LRU (default is 30 minutes)

prepareStatement

public PreparedStatement prepareStatement(Connection conn,
                                          String sql,
                                          boolean supportsGeneratedKeys)
                                   throws SQLException

Throws:

SQLException

prepareStatement

public PreparedStatement prepareStatement(Connection conn,
                                          String sql,
                                          int resultSetType,
                                          int resultSetConcurrency)
                                   throws SQLException

Throws:

SQLException

prepareStatement

public PreparedStatement prepareStatement(Connection conn,
                                          String sql,
                                          int resultSetType,
                                          int resultSetConcurrency,
                                          int resultSetHoldability)
                                   throws SQLException

Throws:

SQLException

prepareStatement

public PreparedStatement prepareStatement(Connection conn,
                                          String sql,
                                          int autoGeneratedKeys)
                                   throws SQLException

Throws:

SQLException

prepareStatement

public PreparedStatement prepareStatement(Connection conn,
                                          String sql,
                                          int[] columnIndexes)
                                   throws SQLException

Throws:

SQLException

prepareStatement

public PreparedStatement prepareStatement(Connection conn,
                                          String sql,
                                          String[] columnNames)
                                   throws SQLException

Throws:

SQLException

prepareCall

public CallableStatement prepareCall(Connection conn,
                                     String sql)
                              throws SQLException

Throws:

SQLException

prepareCall

public CallableStatement prepareCall(Connection conn,
                                     String sql,
                                     int resultSetType,
                                     int resultSetConcurrenc)
                              throws SQLException

Throws:

SQLException

prepareCall

public CallableStatement prepareCall(Connection conn,
                                     String sql,
                                     int resultSetType,
                                     int resultSetConcurrency,
                                     int resultSetHoldability)
                              throws SQLException

Throws:

SQLException

clear

public boolean clear(Connection conn)
              throws SQLException

Throws:

SQLException

clear

public boolean clear()
              throws SQLException

Closes and removes all Listeners, PreparedStatements and PreparedCalls for the active Thread.

Returns:

true if any actual work was done and false if there was nothing to remove (most likely already closed).

Throws:

SQLException

addListener

public void addListener(StatementCacheListener listener)

removeListener

public boolean removeListener(StatementCacheListener listener)

removeAllListeners

public void removeAllListeners()

getListeners

public StatementCacheListener[] getListeners()

getStats

public void getStats(StringBuilder strBldrToAppend,
                     DateTimeFormatter optionalDtFormat)
              throws SQLException

Append stats as json params to strBldrToAppend.

Throws:

SQLException

getDiagnosticCsv

public void getDiagnosticCsv(Connection conn,
                             StringBuilder sb)
                      throws Exception

If connection is cached, append its contents to the string builder as csv rows.

Parameters:

conn - represented by the cache

sb - will have cache entries appended

Throws:

Exception

getConnKey

public static Long getConnKey(Connection conn)
                       throws SQLException

Return the Long key to be used for caching the Stmt.

conn.getMetaData().getConnection().hashCode() is used in case conn is a new pooled wrapper connection. Using an always-new wrapped connection from a pool like Hikari as a cache key will leak memory.

Parameters:

conn - used to create its cache key

Throws:

SQLException