org.apache.commons.configuration2

Class DatabaseConfiguration

java.lang.Object

org.apache.commons.configuration2.event.BaseEventSource

org.apache.commons.configuration2.AbstractConfiguration

org.apache.commons.configuration2.DatabaseConfiguration

All Implemented Interfaces:

Configuration, EventSource, ImmutableConfiguration, SynchronizerSupport

public class DatabaseConfiguration
extends AbstractConfiguration

Configuration stored in a database. The properties are retrieved from a table containing at least one column for the keys, and one column for the values. It's possible to store several configurations in the same table by adding a column containing the name of the configuration. The name of the table and the columns have to be specified using the corresponding properties.

The recommended way to create an instance of DatabaseConfiguration is to use a configuration builder. The builder is configured with a special parameters object defining the database structures used by the configuration. Such an object can be created using the database() method of the Parameters class. See the examples below for more details.

Example 1 - One configuration per table

 CREATE TABLE myconfig (
     `key`   VARCHAR NOT NULL PRIMARY KEY,
     `value` VARCHAR
 );

 INSERT INTO myconfig (key, value) VALUES ('foo', 'bar');

 BasicConfigurationBuilder<DatabaseConfiguration> builder =
     new BasicConfigurationBuilder<DatabaseConfiguration>(DatabaseConfiguration.class);
 builder.configure(
     Parameters.database()
         .setDataSource(dataSource)
         .setTable("myconfig")
         .setKeyColumn("key")
         .setValueColumn("value")
 );
 Configuration config = builder.getConfiguration();
 String value = config.getString("foo");
 

Example 2 - Multiple configurations per table

 CREATE TABLE myconfigs (
     `name`  VARCHAR NOT NULL,
     `key`   VARCHAR NOT NULL,
     `value` VARCHAR,
     CONSTRAINT sys_pk_myconfigs PRIMARY KEY (`name`, `key`)
 );

 INSERT INTO myconfigs (name, key, value) VALUES ('config1', 'key1', 'value1');
 INSERT INTO myconfigs (name, key, value) VALUES ('config2', 'key2', 'value2');

 BasicConfigurationBuilder<DatabaseConfiguration> builder =
     new BasicConfigurationBuilder<DatabaseConfiguration>(DatabaseConfiguration.class);
 builder.configure(
     Parameters.database()
         .setDataSource(dataSource)
         .setTable("myconfigs")
         .setKeyColumn("key")
         .setValueColumn("value")
         .setConfigurationNameColumn("name")
         .setConfigurationName("config1")
 );
 Configuration config1 = new DatabaseConfiguration(dataSource, "myconfigs", "name", "key", "value", "config1");
 String value1 = conf.getString("key1");
 

The configuration can be instructed to perform commits after database updates. This is achieved by setting the commits parameter of the constructors to true. If commits should not be performed (which is the default behavior), it should be ensured that the connections returned by the DataSource are in auto-commit mode.

Note: Like JDBC itself, protection against SQL injection is left to the user.

Since:

1.0

Constructor Summary

Constructors

Constructor and Description
DatabaseConfiguration() Creates a new instance of DatabaseConfiguration.

Method Summary

Modifier and Type	Method and Description
protected void	addPropertyDirect(String key, Object obj) Adds a property to this configuration.
protected void	addPropertyInternal(String key, Object value) Adds a property to this configuration.
protected void	clearInternal() Removes all entries from this configuration.
protected void	clearPropertyDirect(String key) Removes the specified value from this configuration.
protected void	close(Connection conn, Statement stmt, ResultSet rs) Close the specified database objects.
protected boolean	containsKeyInternal(String key) Checks whether this configuration contains the specified key.
protected Object	extractPropertyValue(ResultSet rs) Extracts the value of a property from the given result set.
String	getConfigurationName() Returns the name of this configuration instance.
String	getConfigurationNameColumn() Returns the name of the table column with the configuration name.
DataSource	getDatasource() Returns the used DataSource object.
DataSource	getDataSource() Returns the DataSource for obtaining database connections.
String	getKeyColumn() Returns the name of the column containing the configuration keys.
protected Iterator<String>	getKeysInternal() Returns an iterator with the names of all properties contained in this configuration.
protected Object	getPropertyInternal(String key) Returns the value of the specified property.
String	getTable() Returns the name of the table containing configuration data.
String	getValueColumn() Returns the name of the column containing the configuration values.
boolean	isAutoCommit() Returns a flag whether this configuration performs commits after database updates.
protected boolean	isEmptyInternal() Checks if this configuration is empty.
void	setAutoCommit(boolean autoCommit) Sets the auto commit flag.
void	setConfigurationName(String configurationName) Sets the name of this configuration instance.
void	setConfigurationNameColumn(String configurationNameColumn) Sets the name of the table column with the configuration name.
void	setDataSource(DataSource dataSource) Sets the DataSource for obtaining database connections.
void	setKeyColumn(String keyColumn) Sets the name of the column containing the configuration keys.
void	setTable(String table) Sets the name of the table containing configuration data.
void	setValueColumn(String valueColumn) Sets the name of the column containing the configuration values.

Methods inherited from class org.apache.commons.configuration2.AbstractConfiguration

addErrorLogListener, addProperty, append, beginRead, beginWrite, clear, clearProperty, cloneInterpolator, containsKey, copy, endRead, endWrite, get, get, getArray, getArray, getBigDecimal, getBigDecimal, getBigInteger, getBigInteger, getBoolean, getBoolean, getBoolean, getByte, getByte, getByte, getCollection, getCollection, getConfigurationDecoder, getConversionHandler, getDouble, getDouble, getDouble, getEncodedString, getEncodedString, getFloat, getFloat, getFloat, getInt, getInt, getInteger, getInterpolator, getKeys, getKeys, getKeysInternal, getList, getList, getList, getList, getListDelimiterHandler, getLogger, getLong, getLong, getLong, getProperties, getProperties, getProperty, getShort, getShort, getShort, getString, getString, getStringArray, getSynchronizer, immutableSubset, initLogger, installInterpolator, interpolate, interpolate, interpolatedConfiguration, isEmpty, isScalarValue, isThrowExceptionOnMissing, lock, setConfigurationDecoder, setConversionHandler, setDefaultLookups, setInterpolator, setListDelimiterHandler, setLogger, setParentInterpolator, setPrefixLookups, setProperty, setPropertyInternal, setSynchronizer, setThrowExceptionOnMissing, size, sizeInternal, subset, unlock

Methods inherited from class org.apache.commons.configuration2.event.BaseEventSource

addEventListener, clearErrorListeners, clearEventListeners, clone, copyEventListeners, createErrorEvent, createEvent, fireError, fireEvent, getEventListenerRegistrations, getEventListeners, isDetailEvents, removeEventListener, setDetailEvents

Methods inherited from class java.lang.Object

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

Constructor Detail

DatabaseConfiguration

public DatabaseConfiguration()

Creates a new instance of DatabaseConfiguration.

Method Detail

getDataSource

public DataSource getDataSource()

Returns the DataSource for obtaining database connections.

Returns:

the DataSource

setDataSource

public void setDataSource(DataSource dataSource)

Sets the DataSource for obtaining database connections.

Parameters:

dataSource - the DataSource

getTable

public String getTable()

Returns the name of the table containing configuration data.

Returns:

the name of the table to be queried

setTable

public void setTable(String table)

Sets the name of the table containing configuration data.

Parameters:

table - the table name

getConfigurationNameColumn

public String getConfigurationNameColumn()

Returns the name of the table column with the configuration name.

Returns:

the name of the configuration name column

setConfigurationNameColumn

public void setConfigurationNameColumn(String configurationNameColumn)

Sets the name of the table column with the configuration name.

Parameters:

configurationNameColumn - the name of the column with the configuration name

getKeyColumn

public String getKeyColumn()

Returns the name of the column containing the configuration keys.

Returns:

the name of the key column

setKeyColumn

public void setKeyColumn(String keyColumn)

Sets the name of the column containing the configuration keys.

Parameters:

keyColumn - the name of the key column

getValueColumn

public String getValueColumn()

Returns the name of the column containing the configuration values.

Returns:

the name of the value column

setValueColumn

public void setValueColumn(String valueColumn)

Sets the name of the column containing the configuration values.

Parameters:

valueColumn - the name of the value column

getConfigurationName

public String getConfigurationName()

Returns the name of this configuration instance.

Returns:

the name of this configuration

setConfigurationName

public void setConfigurationName(String configurationName)

Sets the name of this configuration instance.

Parameters:

configurationName - the name of this configuration

isAutoCommit

public boolean isAutoCommit()

Returns a flag whether this configuration performs commits after database updates.

Returns:

a flag whether commits are performed

setAutoCommit

public void setAutoCommit(boolean autoCommit)

Sets the auto commit flag. If set to true, this configuration performs a commit after each database update.

Parameters:

autoCommit - the auto commit flag

getPropertyInternal

protected Object getPropertyInternal(String key)

Returns the value of the specified property. If this causes a database error, an error event will be generated of type READ with the causing exception. The event's propertyName is set to the passed in property key, the propertyValue is undefined.

Specified by:

getPropertyInternal in class AbstractConfiguration

Parameters:

key - the key of the desired property

Returns:

the value of this property

addPropertyDirect

protected void addPropertyDirect(String key,
                                 Object obj)

Adds a property to this configuration. If this causes a database error, an error event will be generated of type ADD_PROPERTY with the causing exception. The event's propertyName is set to the passed in property key, the propertyValue points to the passed in value.

Specified by:

addPropertyDirect in class AbstractConfiguration

Parameters:

key - the property key

obj - the value of the property to add

addPropertyInternal

protected void addPropertyInternal(String key,
                                   Object value)

Adds a property to this configuration. This implementation temporarily disables list delimiter parsing, so that even if the value contains the list delimiter, only a single record is written into the managed table. The implementation of getProperty() takes care about delimiters. So list delimiters are fully supported by DatabaseConfiguration, but internally treated a bit differently.

Overrides:

addPropertyInternal in class AbstractConfiguration

Parameters:

key - the key of the new property

value - the value to be added

isEmptyInternal

protected boolean isEmptyInternal()

Checks if this configuration is empty. If this causes a database error, an error event will be generated of type READ with the causing exception. Both the event's propertyName and propertyValue will be undefined.

Specified by:

isEmptyInternal in class AbstractConfiguration

Returns:

a flag whether this configuration is empty.

containsKeyInternal

protected boolean containsKeyInternal(String key)

Checks whether this configuration contains the specified key. If this causes a database error, an error event will be generated of type READ with the causing exception. The event's propertyName will be set to the passed in key, the propertyValue will be undefined.

Specified by:

containsKeyInternal in class AbstractConfiguration

Parameters:

key - the key to be checked

Returns:

a flag whether this key is defined

clearPropertyDirect

protected void clearPropertyDirect(String key)

Removes the specified value from this configuration. If this causes a database error, an error event will be generated of type CLEAR_PROPERTY with the causing exception. The event's propertyName will be set to the passed in key, the propertyValue will be undefined.

Specified by:

clearPropertyDirect in class AbstractConfiguration

Parameters:

key - the key of the property to be removed

clearInternal

protected void clearInternal()

Removes all entries from this configuration. If this causes a database error, an error event will be generated of type CLEAR with the causing exception. Both the event's propertyName and the propertyValue will be undefined.

Overrides:

clearInternal in class AbstractConfiguration

getKeysInternal

protected Iterator<String> getKeysInternal()

Returns an iterator with the names of all properties contained in this configuration. If this causes a database error, an error event will be generated of type READ with the causing exception. Both the event's propertyName and the propertyValue will be undefined.

Specified by:

getKeysInternal in class AbstractConfiguration

Returns:

an iterator with the contained keys (an empty iterator in case of an error)

getDatasource

public DataSource getDatasource()

Returns the used DataSource object.

Returns:

the data source

Since:

1.4

close

protected void close(Connection conn,
                     Statement stmt,
                     ResultSet rs)

Close the specified database objects. Avoid closing if null and hide any SQLExceptions that occur.

Parameters:

conn - The database connection to close

stmt - The statement to close

rs - the result set to close

extractPropertyValue

protected Object extractPropertyValue(ResultSet rs)
                               throws SQLException

Extracts the value of a property from the given result set. The passed in ResultSet was created by a SELECT statement on the underlying database table. This implementation reads the value of the column determined by the valueColumn property. Normally the contained value is directly returned. However, if it is of type CLOB, text is extracted as string.

Parameters:

rs - the current ResultSet

Returns:

the value of the property column

Throws:

SQLException - if an error occurs