Package org.jetbrains.mps.openapi.persistence

Interface DataSource

All Known Subinterfaces:

MultiStreamDataSource, StreamDataSource

All Known Implementing Classes:

NullDataSource

public interface DataSource

Represents a location abstraction + some means to work with data at the location. Usually DataSource points to the model data sources. For example it can be based on files, internet content, database content, etc. NB: Must not contain any information on the storage format specifics -- all that belongs to the ModelFactory. For implementation consider extending jetbrains.mps.extapi.persistence.DataSourceBase, MultiStreamSourceBase, StreamSourceBase fixme rather we need to separate the location part of the accessing the data at the location right now we have both here, but no abstract means to read/write because on this level there is no common access mechanism that we could offer

Method Summary

Modifier and Type	Method	Description
void	addListener(DataSourceListener listener)	Registers listeners who need to be notified about changes in the underlying data source.
String	getLocation()	Yields a string representation for the location of the data source (if applicable)
long	getTimestamp()	Retrieves the last modification timestamp.
default DataSourceType	getType()	Defines a data source type for this kind of data sources.
boolean	isReadOnly()	Sometimes there is a possibility to edit DataSource, though it is not available on this level.
void	removeListener(DataSourceListener listener)

Method Detail

getLocation

@NotNull
String getLocation()

Yields a string representation for the location of the data source (if applicable)

addListener

void addListener(@NotNull
                 DataSourceListener listener)

Registers listeners who need to be notified about changes in the underlying data source. It is the responsibility of the DataSource to detect such updates and notify the listeners.

removeListener

void removeListener(@NotNull
                    DataSourceListener listener)

getTimestamp

long getTimestamp()

Retrieves the last modification timestamp. The timestamp should reliably reflect all external changes to the data source.

Returns:

0 if timestamp is not supported for the source, or -1 if the source is dead (like when file is deleted)

isReadOnly

boolean isReadOnly()

Sometimes there is a possibility to edit DataSource, though it is not available on this level. For examples please see StreamDataSource, MultiStreamDataSource.

Returns:

whether this data source can be changed.

getType

@Nullable
default DataSourceType getType()

Defines a data source type for this kind of data sources. The data source type notion is strongly associated with the possibility to provide DataSourceFactory and ModelFactory custom mappings. See DataSourceFactoryRuleService and ModelFactoryService for the implementation details.

Returns:

the unique data source type for this instance of data source if the developer wants others to be able to change the default behavior of this data source (register with the same key) or if he desires to associate this data source with some specific model factory.