Package org.apache.commons.configuration

Class DatabaseConfiguration

  • All Implemented Interfaces:
    Configuration
    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 is specified in the constructor.

    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');


 Configuration config = new DatabaseConfiguration(datasource, "myconfig", "key", "value");
 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');


 Configuration config1 = new DatabaseConfiguration(datasource, "myconfigs", "name", "key", "value", "config1");
 String value1 = conf.getString("key1");

 Configuration config2 = new DatabaseConfiguration(datasource, "myconfigs", "name", "key", "value", "config2");
 String value2 = conf.getString("key2");
    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
    Version:
    $Id: DatabaseConfiguration.java 1344442 2012-05-30 20:17:35Z oheger $
    Author:
    Emmanuel Bourg

    • Constructor Detail

      • DatabaseConfiguration

        public DatabaseConfiguration​(javax.sql.DataSource datasource,
                             java.lang.String table,
                             java.lang.String nameColumn,
                             java.lang.String keyColumn,
                             java.lang.String valueColumn,
                             java.lang.String name)
        Build a configuration from a table containing multiple configurations. No commits are performed by the new configuration instance.
        Parameters:
        datasource - the datasource to connect to the database
        table - the name of the table containing the configurations
        nameColumn - the column containing the name of the configuration
        keyColumn - the column containing the keys of the configuration
        valueColumn - the column containing the values of the configuration
        name - the name of the configuration

      • DatabaseConfiguration

        public DatabaseConfiguration​(javax.sql.DataSource datasource,
                             java.lang.String table,
                             java.lang.String nameColumn,
                             java.lang.String keyColumn,
                             java.lang.String valueColumn,
                             java.lang.String name,
                             boolean commits)
        Creates a new instance of DatabaseConfiguration that operates on a database table containing multiple configurations.
        Parameters:
        datasource - the DataSource to connect to the database
        table - the name of the table containing the configurations
        nameColumn - the column containing the name of the configuration
        keyColumn - the column containing the keys of the configuration
        valueColumn - the column containing the values of the configuration
        name - the name of the configuration
        commits - a flag whether the configuration should perform a commit after a database update

      • DatabaseConfiguration

        public DatabaseConfiguration​(javax.sql.DataSource datasource,
                             java.lang.String table,
                             java.lang.String keyColumn,
                             java.lang.String valueColumn)
        Build a configuration from a table.
        Parameters:
        datasource - the datasource to connect to the database
        table - the name of the table containing the configurations
        keyColumn - the column containing the keys of the configuration
        valueColumn - the column containing the values of the configuration

      • DatabaseConfiguration

        public DatabaseConfiguration​(javax.sql.DataSource datasource,
                             java.lang.String table,
                             java.lang.String keyColumn,
                             java.lang.String valueColumn,
                             boolean commits)
        Creates a new instance of DatabaseConfiguration that operates on a database table containing a single configuration only.
        Parameters:
        datasource - the DataSource to connect to the database
        table - the name of the table containing the configurations
        keyColumn - the column containing the keys of the configuration
        valueColumn - the column containing the values of the configuration
        commits - a flag whether the configuration should perform a commit after a database update

    • Method Detail

      • isDoCommits

        public boolean isDoCommits()
        Returns a flag whether this configuration performs commits after database updates.
        Returns:
        a flag whether commits are performed

      • getProperty

        public java.lang.Object getProperty​(java.lang.String key)
        Returns the value of the specified property. If this causes a database error, an error event will be generated of type EVENT_READ_PROPERTY with the causing exception. The event's propertyName is set to the passed in property key, the propertyValue is undefined.
        Parameters:
        key - the key of the desired property
        Returns:
        the value of this property

      • addPropertyDirect

        protected void addPropertyDirect​(java.lang.String key,
                                 java.lang.Object obj)
        Adds a property to this configuration. If this causes a database error, an error event will be generated of type EVENT_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

      • addProperty

        public void addProperty​(java.lang.String key,
                        java.lang.Object value)
        Adds a property to this configuration. This implementation will temporarily disable list delimiter parsing, so that even if the value contains the list delimiter, only a single record will be written into the managed table. The implementation of getProperty() will take care about delimiters. So list delimiters are fully supported by DatabaseConfiguration, but internally treated a bit differently.
        Specified by:
        addProperty in interface Configuration
        Overrides:
        addProperty in class AbstractConfiguration
        Parameters:
        key - the key of the new property
        value - the value to be added

      • isEmpty

        public boolean isEmpty()
        Checks if this configuration is empty. If this causes a database error, an error event will be generated of type EVENT_READ_PROPERTY with the causing exception. Both the event's propertyName and propertyValue will be undefined.
        Returns:
        a flag whether this configuration is empty.

      • containsKey

        public boolean containsKey​(java.lang.String key)
        Checks whether this configuration contains the specified key. If this causes a database error, an error event will be generated of type EVENT_READ_PROPERTY with the causing exception. The event's propertyName will be set to the passed in key, the propertyValue will be undefined.
        Parameters:
        key - the key to be checked
        Returns:
        a flag whether this key is defined

      • clearPropertyDirect

        protected void clearPropertyDirect​(java.lang.String key)
        Removes the specified value from this configuration. If this causes a database error, an error event will be generated of type EVENT_CLEAR_PROPERTY with the causing exception. The event's propertyName will be set to the passed in key, the propertyValue will be undefined.
        Overrides:
        clearPropertyDirect in class AbstractConfiguration
        Parameters:
        key - the key of the property to be removed

      • clear

        public void clear()
        Removes all entries from this configuration. If this causes a database error, an error event will be generated of type EVENT_CLEAR with the causing exception. Both the event's propertyName and the propertyValue will be undefined.
        Specified by:
        clear in interface Configuration
        Overrides:
        clear in class AbstractConfiguration

      • getKeys

        public java.util.Iterator<java.lang.String> getKeys()
        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 EVENT_READ_PROPERTY with the causing exception. Both the event's propertyName and the propertyValue will be undefined.
        Returns:
        an iterator with the contained keys (an empty iterator in case of an error)

      • getDatasource

        public javax.sql.DataSource getDatasource()
        Returns the used DataSource object.
        Returns:
        the data source
        Since:
        1.4

      • getConnection

        @Deprecated
protected java.sql.Connection getConnection()
                                     throws java.sql.SQLException
        Deprecated.
        Use a custom data source to change the connection used by the class. To be removed in Commons Configuration 2.0
        Returns a Connection object. This method is called when ever the database is to be accessed. This implementation returns a connection from the current DataSource.
        Returns:
        the Connection object to be used
        Throws:
        java.sql.SQLException - if an error occurs
        Since:
        1.4