org.hyperic.hq.product
Class JDBCQueryCache
java.lang.Object
org.hyperic.hq.product.JDBCQueryCache
public class JDBCQueryCache
- extends java.lang.Object
JDBCQueryCache is a simple caching mechanism to be used with
JDBCMeasurementPlugins.
example:
mysql> select Value, Default from sys_table;
+-----------------------------------+----------+---------+
| Variable_name | Value | Default |
+-----------------------------------+----------+---------+
| DB_Max_Memory | 8192 | 1024 |
| DB_Max_Connections | 400 | 10 |
...
...
String query = "select Value, Default from sys_table";
JDBCQueryCache cache = new JDBCQueryCache(query, "Variable_name", 5000);
Double val = Double.valueOf(cache.get("DB_Max_Memory", "Value").toString());
val = Double.valueOf(cache.get("DB_Max_Connections", "Default").toString());
Constructor Summary |
JDBCQueryCache(java.lang.String query,
java.lang.String queryKey,
long cacheTimeout)
|
Method Summary |
void |
clearCache()
Explicitly clears any cached value |
java.lang.Object |
get(java.sql.Connection conn,
java.lang.String key,
java.lang.String column)
|
java.lang.Object |
getOnlyRow(java.sql.Connection conn,
java.lang.String column)
|
void |
setExpireTime(long expireTime)
Explicitly sets the expire time of the cache to expireTime. |
Methods inherited from class java.lang.Object |
clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait |
JDBCQueryCache
public JDBCQueryCache(java.lang.String query,
java.lang.String queryKey,
long cacheTimeout)
clearCache
public void clearCache()
- Explicitly clears any cached value
setExpireTime
public void setExpireTime(long expireTime)
- Explicitly sets the expire time of the cache to expireTime. Cache will
not repopulate until System.currentTimeMillis() <= expireTime.
getOnlyRow
public java.lang.Object getOnlyRow(java.sql.Connection conn,
java.lang.String column)
throws java.sql.SQLException,
JDBCQueryCacheException
- Returns:
- Object representation of the *only* row and column value
or null if it does not exist
- Throws:
JDBCQueryCacheException
- if there are 0 or > 1 rows in the cache.
java.sql.SQLException
get
public java.lang.Object get(java.sql.Connection conn,
java.lang.String key,
java.lang.String column)
throws JDBCQueryCacheException,
java.sql.SQLException
- Returns:
- Object representation of the row key/column value or null if it
does not exist
- Throws:
JDBCQueryCacheException
java.sql.SQLException
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