- All Implemented Interfaces:
public class MetadataWriter extends MetadataSourceA connection to a metadata database with write capabilities. The database must have a schema of the given name, which can be initially empty. Tables and columns are created as needed when the
add(Object)method is invoked.
No more than one instance of
MetadataWritershould be used for the same database. However multiple instances of
MetadataSourcecan be used concurrently with a single
MetadataWriterinstance on the same database.PropertiesThe constructor expects three Java arguments (the metadata standard, the data source and the database schema) completed by an arbitrary amount of optional arguments given as a map of properties. The following keys are recognized by
MetadataSourceand all other entries are ignored:
Optional properties at construction time Key Value type Description
The database catalog where the metadata schema is stored.
The class loader to use for creating
Maximal number of
PreparedStatements that can be kept simultaneously open.
The maximal number of characters allowed for primary keys. This is the value given to the
VARCHARtype when creating new
Maximal number of characters allowed in text columns. This is the parameter given to the
VARCHARtype when creating new columns. Attempts to insert a text longer than this limit will typically throws a
SQLException, but the exact behavior is database-dependent.
Whether columns should be created only for non-empty attributes (
NON_EMPTY, the default) or for all attributes (
Defined in the
All Methods Instance Methods Concrete Methods Modifier and Type Method Description
add(Object metadata)Adds the given metadata object to the database, if it does not already exists.
suggestIdentifier(Object metadata, Map<String,Object> asValueMap)Suggests an identifier (primary key) to be used for the given metadata.
Methods inherited from class MetadataSource
addWarningListener, close, getProvided, lookup, removeWarningListener, search
public MetadataWriter(MetadataStandard standard, DataSource dataSource, String schema, Map<String,?> properties)Creates a new metadata writer.
standard- the metadata standard to implement.
dataSource- the source for getting a connection to the database.
schema- the database schema were metadata tables are stored, or
properties- additional options, or
nullif none. See class javadoc for a description.
public String add(Object metadata) throws MetadataStoreExceptionAdds the given metadata object to the database, if it does not already exists. If the database already contains a metadata equals to the given one, then the database is left unchanged and the identifier of the existing metadata is returned.
metadata- the metadata object to add.
- the identifier (primary key) of the metadata just added, or the identifier of the existing metadata is one exists.
MetadataStoreException- if the metadata object does not implement a metadata interface of the expected package, if an exception occurred while reading or writing the database. In such case, the database content is left unchanged (i.e. this method is a all or nothing operation).
protected String suggestIdentifier(Object metadata, Map<String,Object> asValueMap) throws SQLExceptionSuggests an identifier (primary key) to be used for the given metadata. This method is invoked automatically when a new metadata is about to be inserted in the database. The default implementation uses heuristic rules for a few "well known" metadata like
Citation. Subclasses can override this method for implementing their own heuristic.
This method does not need to care about key collision. The caller will adds some suffix if this is necessary for differentiating otherwise identical identifiers.
metadata- the metadata instance for which to suggests an identifier.
asValueMap- a view of all metadata properties as a map. Keys are UML identifiers.
- the proposed identifier, or
nullif this method does not have any suggestion.
SQLException- if an access to the database was desired but failed.