Package net.sourceforge.jtds.jdbc.cache
Interface StatementCache
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- All Known Implementing Classes:
ProcedureCache
public interface StatementCache
Interface for a statement cache. Abstraction of the caching mechanism by use of this interface will allow developers to create custom caching schemes that are optimal for their specific applications. Any synchronization required by an implementation should utilize the implementing object for the lock.There are two types of attributes that the cache is concerned with:
- statement key
String
generated from the SQL query for which the prepared statement was created, the database name and the parameter types; this key uniquely identifies a server-side preparation of the statement and is used to retrieve the handle of the statement when it needs to be executed- temporary procedure name or
sp_prepare
orsp_cursorprepare
handle on the server - One
PreparedStatement
can map to multiple handles, depending on the types of the parameters it is called with (hence the need to be able to map both keys and SQL strings to handles)
The caching types provided by jTDS should be:
- Arbitrary first un-latched (initial default until other caches are implemented)
- Fast caching (never latches and never releases handles)
- FIFO
- LRU
- No caching
- Touch Count / Most Frequently Used
- Version:
- $Id: StatementCache.java,v 1.6 2007-07-11 19:57:06 bheineman Exp $
- Author:
- Brian Heineman
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Method Summary
All Methods Instance Methods Abstract Methods Modifier and Type Method Description java.lang.Object
get(java.lang.String key)
Returns a statement handle associated with the specified key ornull
if the key specified does not have an associated statement handle.java.util.Collection
getObsoleteHandles(java.util.Collection handles)
Returns aCollection
of obsolete statement handles that may be released, ornull
if no statement handles are obsolete.void
put(java.lang.String key, java.lang.Object handle)
Places the specified statement handle in the cache for the given key.void
remove(java.lang.String key)
Removes a statement key and handle from the cache for the specified key.
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Method Detail
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get
java.lang.Object get(java.lang.String key)
Returns a statement handle associated with the specified key ornull
if the key specified does not have an associated statement handle.- Parameters:
key
- the statement key whose associated handle is to be returned- Returns:
- statement handle
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put
void put(java.lang.String key, java.lang.Object handle)
Places the specified statement handle in the cache for the given key. If a key already exists in the cache, the handle will be overwritten.- Parameters:
key
- the statement key to associated with the handlehandle
- the statement handle
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remove
void remove(java.lang.String key)
Removes a statement key and handle from the cache for the specified key.- Parameters:
key
- the statement key whose associated handle is to be removed from the cache
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getObsoleteHandles
java.util.Collection getObsoleteHandles(java.util.Collection handles)
Returns aCollection
of obsolete statement handles that may be released, ornull
if no statement handles are obsolete.- Parameters:
handles
- the statement handles that are no longer being used- Returns:
Collection
of obsolete statement handles to be removed
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