org.apache.commons.dbutils

Class QueryLoader

java.lang.Object

org.apache.commons.dbutils.QueryLoader

public class QueryLoader
extends Object

QueryLoader is a registry for sets of queries so that multiple copies of the same queries aren't loaded into memory. This implementation loads properties files filled with query name to SQL mappings. This class is thread safe.

Constructor Summary

Constructors

Modifier	Constructor and Description
protected	QueryLoader() QueryLoader constructor.

Method Summary

Modifier and Type	Method and Description
static QueryLoader	instance() Return an INSTANCE of this class.
Map<String,String>	load(String path) Loads a Map of query names to SQL values.
protected Map<String,String>	loadQueries(String path) Loads a set of named queries into a Map object.
void	unload(String path) Removes the queries for the given path from the cache.

Methods inherited from class java.lang.Object

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

Constructor Detail

QueryLoader

protected QueryLoader()

QueryLoader constructor.

Method Detail

instance

public static QueryLoader instance()

Return an INSTANCE of this class.

Returns:

The Singleton INSTANCE.

load

public Map<String,String> load(String path)
                        throws IOException

Loads a Map of query names to SQL values. The Maps are cached so a subsequent request to load queries from the same path will return the cached Map. The properties file to load can be in either line-oriented or XML format. XML formatted properties files must use a .xml file extension.

Parameters:

path - The path that the ClassLoader will use to find the file. This is not a file system path. If you had a jarred Queries.properties file in the com.yourcorp.app.jdbc package you would pass "/com/yourcorp/app/jdbc/Queries.properties" to this method.

Returns:

Map of query names to SQL values

Throws:

IOException - if a file access error occurs

IllegalArgumentException - if the ClassLoader can't find a file at the given path.

InvalidPropertiesFormatException - if the XML properties file is invalid

See Also:

Properties

loadQueries

protected Map<String,String> loadQueries(String path)
                                  throws IOException

Loads a set of named queries into a Map object. This implementation reads a properties file at the given path. The properties file can be in either line-oriented or XML format. XML formatted properties files must use a .xml file extension.

Parameters:

path - The path that the ClassLoader will use to find the file.

Returns:

Map of query names to SQL values

Throws:

IOException - if a file access error occurs

IllegalArgumentException - if the ClassLoader can't find a file at the given path.

InvalidPropertiesFormatException - if the XML properties file is invalid

Since:

1.1

See Also:

Properties

unload

public void unload(String path)

Removes the queries for the given path from the cache.

Parameters:

path - The path that the queries were loaded from.