org.opennms.netmgt.config

Class DatabaseSchemaConfigFactory

java.lang.Object

org.opennms.netmgt.config.DatabaseSchemaConfigFactory

All Implemented Interfaces:

DatabaseSchemaConfig

public final class DatabaseSchemaConfigFactory
extends Object
implements DatabaseSchemaConfig

This is the singleton class used to load the configuration for the OpenNMS database schema for the filters from the database-schema XML file. Note: Users of this class should make sure the init() is called before calling any other method to ensure the config is loaded before accessing other convenience methods.

Author:

Sowmya Nataraj

Constructor Summary

Constructors

Constructor and Description
DatabaseSchemaConfigFactory(InputStream is) Constructor for DatabaseSchemaConfigFactory.

Method Summary

Modifier and Type	Method and Description
String	addColumn(List<Table> tables, String column) Validate that a column is in the schema, add it's table to a list of tables, and return the full table.column name of the column.
String	constructJoinExprForTables(List<Table> tables) Construct a SQL FROM clause joining the given tables to the primary table.
Table	findTableByVisibleColumn(String colName) Find the table which has a visible column named 'colName'
DatabaseSchema	getDatabaseSchema() Return the database schema.
static DatabaseSchemaConfigFactory	getInstance() Return the singleton instance of this factory.
List<String>	getJoinTables(List<Table> tables) Return the sequence of tables necessary to join the primary table to the given tables.
Table	getPrimaryTable() This method is used to find the table that should drive the construction of the join clauses between all table in the from clause.
Lock	getReadLock()
Table	getTableByName(String name) Find a table using its name as the search key.
int	getTableCount() Return a count of the number of tables defined.
Lock	getWriteLock()
static void	init() Load the config from the default config file and create the singleton instance of this factory.
static void	reload() Reload the config from the default config file
static void	setInstance(DatabaseSchemaConfigFactory instance) setInstance

Methods inherited from class java.lang.Object

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

Constructor Detail

DatabaseSchemaConfigFactory

public DatabaseSchemaConfigFactory(InputStream is)
                            throws IOException

Constructor for DatabaseSchemaConfigFactory.

Parameters:

is - a InputStream object.

Throws:

IOException

Method Detail

getReadLock

public Lock getReadLock()

getWriteLock

public Lock getWriteLock()

init

public static void init()
                 throws IOException

Load the config from the default config file and create the singleton instance of this factory.

Throws:

IOException - Thrown if the specified config file cannot be read

IOException - if any.

reload

public static void reload()
                   throws IOException

Reload the config from the default config file

Throws:

IOException - Thrown if the specified config file cannot be read/loaded

IOException - if any.

getInstance

public static DatabaseSchemaConfigFactory getInstance()

Return the singleton instance of this factory.

Returns:

The current factory instance.

Throws:

IllegalStateException - Thrown if the factory has not yet been initialized.

setInstance

public static void setInstance(DatabaseSchemaConfigFactory instance)

setInstance

Parameters:

instance - a DatabaseSchemaConfigFactory object.

getDatabaseSchema

public DatabaseSchema getDatabaseSchema()

Return the database schema.

Specified by:

getDatabaseSchema in interface DatabaseSchemaConfig

Returns:

the database schema

getPrimaryTable

public Table getPrimaryTable()

This method is used to find the table that should drive the construction of the join clauses between all table in the from clause. At least one table has to be designated as the driver table.

Specified by:

getPrimaryTable in interface DatabaseSchemaConfig

Returns:

The name of the driver table

getTableByName

public Table getTableByName(String name)

Find a table using its name as the search key.

Specified by:

getTableByName in interface DatabaseSchemaConfig

Parameters:

name - the name of the table to find

Returns:

the table if it is found, null otherwise.

findTableByVisibleColumn

public Table findTableByVisibleColumn(String colName)

Find the table which has a visible column named 'colName'

Specified by:

findTableByVisibleColumn in interface DatabaseSchemaConfig

Parameters:

colName - a String object.

Returns:

the table containing column 'colName', null if colName is not a valid column or if is not visible.

getTableCount

public int getTableCount()

Return a count of the number of tables defined.

Specified by:

getTableCount in interface DatabaseSchemaConfig

Returns:

the number of tables in the schema

getJoinTables

public List<String> getJoinTables(List<Table> tables)

Return the sequence of tables necessary to join the primary table to the given tables.

Specified by:

getJoinTables in interface DatabaseSchemaConfig

Parameters:

tables - list of Tables to join

Returns:

a list of table names, starting with the primary table, going to each of the given tables, or a zero-length array if no join exists or only the primary table was specified

constructJoinExprForTables

public String constructJoinExprForTables(List<Table> tables)

Construct a SQL FROM clause joining the given tables to the primary table.

Specified by:

constructJoinExprForTables in interface DatabaseSchemaConfig

Parameters:

tables - list of Tables to join

Returns:

an SQL FROM clause or "" if no expression is found

addColumn

public String addColumn(List<Table> tables,
                        String column)
                 throws FilterParseException

Validate that a column is in the schema, add it's table to a list of tables, and return the full table.column name of the column.

Specified by:

addColumn in interface DatabaseSchemaConfig

Parameters:

tables - a list of tables to add the column's table to

column - the column to add

Returns:

table.column string

Throws:

FilterParseException - if the column is not found in the schema