Class JDBCStatementCache
The entries in the cache contains objects implementing the
java.sql.PreparedStatement
interface, and they are inserted with
a key object implementing the interface StatementKey
. The cached
objects can be either java.sql.PreparedStatement
or
java.sql.CallableStatement
. These two should be separated by
using different types of keys.
The cache only contains free statement objects, and on a successful request
for a cached statement the statement is removed from the cache. The cache is
not intended to hold duplicate statements. The physical prepared statement
should be (re-)inserted into the cache when close
is called on
the logical prepared statement using it.
There is a maximum number of cached statements associated with the cache. If this number is exceeded, the oldest entry will be thrown out. One can always throw out an entry, because the fact that it is in the cache means it is free and not in use.
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Nested Class Summary
Nested ClassesModifier and TypeClassDescriptionprivate static class
ALinkedHashMap
with an upper bound on the number of entries. -
Field Summary
FieldsModifier and TypeFieldDescriptionprivate final LinkedHashMap
<StatementKey, PreparedStatement> Structure holding the cached prepared statement objects. -
Constructor Summary
Constructors -
Method Summary
Modifier and TypeMethodDescriptionboolean
cacheStatement
(StatementKey statementKey, PreparedStatement ps) Cache the prepared statement if it does not already exist.getCached
(StatementKey statementKey) Retrieves a cached prepared statement if one exists.
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Field Details
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statements
Structure holding the cached prepared statement objects.
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Constructor Details
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JDBCStatementCache
public JDBCStatementCache(int maxSize) Creates a new, empty JDBC statement cache.- Parameters:
maxSize
- maximum number of statements in the cache- Throws:
IllegalArgumentException
- ifmaxSize
is less than one
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Method Details
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getCached
Retrieves a cached prepared statement if one exists.- Parameters:
statementKey
- key for the prepared statement to look up- Returns:
- A cached statement if one exists,
null
otherwise.
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cacheStatement
Cache the prepared statement if it does not already exist.- Parameters:
statementKey
- key to insert prepared statement withps
- prepared statement to cache- Returns:
true
if added to the cache,false
if not.
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